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Measuring Social Value Orientation - Judgment and Decision Making

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<strong>Measuring</strong> <strong>Social</strong> <strong>Value</strong> <strong>Orientation</strong><br />

Ryan O. Murphy 1<br />

Kurt A. Ackermann 1<br />

Michel J. J. H<strong>and</strong>graaf 2<br />

Tuesday 21 st September, 2010<br />

1 ETH Zürich<br />

Chair of <strong>Decision</strong> Theory <strong>and</strong> Behavioral Game Theory<br />

Clausiusstrasse 50, 8092 Zürich<br />

Switzerl<strong>and</strong><br />

2 University of Amsterdam<br />

Faculty of <strong>Social</strong> <strong>and</strong> Behavioural Sciences<br />

Roetersstraat 15, 1018 WB Amsterdam<br />

The Netherl<strong>and</strong>s<br />

rmurphy@ethz.ch<br />

kurt.ackermann@gess.ethz.ch<br />

h<strong>and</strong>graaf@uva.nl<br />

This is version 1.00. This draft is currently under review.<br />

Please do not quote or cite this draft without an author’s permission.<br />

This research has been supported by United States<br />

National Science Foundation grant SES-0637151.<br />

Additional thanks to Mike Kuhlman, Jeff Joireman, Michael Schulte-Mecklenbeck, <strong>and</strong> Miguel Fonseca for<br />

their constructive feedback on early versions of this paper.


Contents<br />

1 Introduction 1<br />

2 <strong>Social</strong> <strong>Value</strong> <strong>Orientation</strong> Framework 3<br />

3 Existing Measurements of SVO 6<br />

3.1 The Altruism Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6<br />

3.1.1 The Altruism Scale described . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6<br />

3.1.2 Discussion of the Altruism Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7<br />

3.2 The 9-item Triple-Dominance Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9<br />

3.2.1 The 9-item Triple-Dominance Scale described . . . . . . . . . . . . . . . . . . . . . 10<br />

3.2.2 Discussion of the 9-item Triple-Dominance Scale . . . . . . . . . . . . . . . . . . . 11<br />

3.2.3 Rank correlation technique: Another application of decomposed games . . . . . 14<br />

3.3 Utility measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14<br />

3.3.1 Utility measurement described . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15<br />

3.3.2 Discussion of utility measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . 17<br />

3.3.3 Indifference curves: A graphical approach to measuring SVO . . . . . . . . . . . . 18<br />

3.4 The <strong>Social</strong> Behavior Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20<br />

3.4.1 The <strong>Social</strong> Behavior Scale described . . . . . . . . . . . . . . . . . . . . . . . . . . . 20<br />

3.4.2 Discussion of the <strong>Social</strong> Behavior Scale . . . . . . . . . . . . . . . . . . . . . . . . . 21<br />

3.5 The Ring Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21<br />

3.5.1 The Ring Measure described . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22<br />

3.5.2 Discussion of the Ring Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23<br />

3.5.3 Circle-test: A one-item version of the Ring Measure . . . . . . . . . . . . . . . . . . 24<br />

3.6 Regression <strong>and</strong> clustering approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25<br />

3.6.1 Regression <strong>and</strong> clustering approach described . . . . . . . . . . . . . . . . . . . . . 25<br />

3.6.2 Discussion of regression <strong>and</strong> clustering approaches . . . . . . . . . . . . . . . . . 26<br />

3.7 Schulz <strong>and</strong> May’s Sphere Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26<br />

3.7.1 The Sphere Measure described . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26<br />

3.7.2 Discussion of the Sphere Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27<br />

4 The SVO Slider Measure 28<br />

4.1 Primary SVO Slider items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28<br />

4.2 Secondary SVO Slider items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31<br />

4.3 Web-based SVO Slider Measure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31<br />

5 Psychometric properties of SVO measures 33<br />

5.1 Slider Measure validation procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33<br />

5.2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34<br />

5.3 Reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35<br />

5.3.1 Triple-Dominance Measure test-retest reliability . . . . . . . . . . . . . . . . . . . 35<br />

5.3.2 Ring Measure test-retest reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35<br />

5.3.3 Slider Measure test-retest reliability . . . . . . . . . . . . . . . . . . . . . . . . . . . 36<br />

5.4 Convergent validity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36<br />

5.4.1 Categorical agreement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36<br />

5.4.2 Correlational agreement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37<br />

5.5 Additional results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37


5.6 Separating joint maximization <strong>and</strong> inequality aversion . . . . . . . . . . . . . . . . . . . . 39<br />

6 Discussion 40<br />

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No man is an isl<strong>and</strong>, entire of itself; every man is a piece of the continent, a part of the<br />

main. If a clod be washed away by the sea, Europe is the less, as well as if a promontory<br />

were, as well as if a manor of thy friend’s or of thine own were.<br />

1 Introduction<br />

–John Donne<br />

Devotions Upon Emergent Occasions, Meditation XVII<br />

The assumption of narrow self-interest is fundamental to rational choice theory. The assump-<br />

tion postulates that decision makers (DMs) are concerned about maximizing their own material gain,<br />

indifferent to the payoffs of other DMs around them. This is a simplifying assumption that yields a<br />

powerful apparatus to predict <strong>and</strong> explain human behavior across a wide variety of domains. How-<br />

ever there are reliable counterexamples demonstrating that DMs’ elicited preferences <strong>and</strong> choices are<br />

influenced in part by the payoffs of other DMs thus challenging what some have termed the selfish-<br />

ness axiom (Henrich et al. 2005). Furthermore, evidence for prosociality, helping behavior, <strong>and</strong> results<br />

from the endeavor of uncovering its underlying motivational bases is well documented (e.g. Batson<br />

1995, Sell et al. 2009). In addition to behavioral evidence, specific neurological correlates related to<br />

concern for other’s outcomes have been identified (e.g. Haruno & Frith 2009, van den Bos, van Dijk,<br />

Westenberg, Rombouts, & Crone 2009, Tricomi, Rangel, Camerer, & O’Doherty 2010). Other regard-<br />

ing preferences have even been demonstrated in non-human primates (e.g. de Waal, Leimgruber, &<br />

Greenberg 2008).<br />

To illustrate the notion of interdependent interests, consider the following choice between two<br />

options. In each case the DM is choosing between certain distributions of money, one portion to<br />

herself, <strong>and</strong> some portion to be given to another person, who is unknown to her. The DM <strong>and</strong> the<br />

other person will remain mutually anonymous while <strong>and</strong> after the decision is made. Hence this is<br />

not a strategic decision (i.e., not within the purview of Game Theory as only one DM influences the<br />

payoffs of both people, hence there are not strategic concerns) but rather is a one-shot individual<br />

decision. Anonymity removes the potential influence of fear of reprisal, reciprocity, reputation, etc.<br />

so that the utility of outcomes defined by the DM (see Kelley & Thibaut 1978) solely reflects the DM’s<br />

social value (Dehue, McClintock, & Liebr<strong>and</strong> 1993, p.274)<br />

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Table 1: A simple binary choice<br />

Option 1 Option 2<br />

$85 to the DM $100 to the DM<br />

$85 to another person $50 to another person<br />

The “rational” solution to this choice is trivial; a rational DM (Homo Economicus) would select<br />

option 2 as it results in a larger individual payoff. That, by choosing option 2 over option 1, an extra<br />

$15 is gained at a “cost” of $35 from another person is immaterial from the normative vantage point:<br />

the only pertinent consideration is the DM’s individual payoff, irrespective of the payoffs to others. In<br />

this instance, the normative account diverges from actual behavior. We find that incentivized DMs,<br />

in an anonymous one-shot decision context, choose option 1 about 40% of the time, a finding that<br />

is consistent with other research results (Van Lange, Otten, De Bruin, & Joireman 1997, Au & Kwong<br />

2004, Bogaert, Boone, & Declerck 2008, Balliet, Parks, & Joireman 2009). 1<br />

Studies on the motivations that underlie interdependent decision behavior have a long history <strong>and</strong><br />

these motivations have been referred to by a variety of names, including: social preferences, social<br />

motives, other regarding preferences, welfare tradeoff ratios, <strong>and</strong> social value orientation (SVO). For<br />

consistency, we refer to this construct as SVO for the remainder of this paper. It is worth noting that<br />

the assumption of narrow self interest is a special case of SVO, <strong>and</strong> that SVO is not a challenge to<br />

rational choice theory per se, but rather the extension of a postulate in an effort to increase the theory’s<br />

psychological realism <strong>and</strong> descriptive accuracy.<br />

In the present paper, we provide an overview of existing methods that measure variations in SVOs<br />

across individuals <strong>and</strong> highlight some limitations with these existent measures. We then introduce a<br />

new measure of SVO that has several advantages over other methods. The new measure is referred<br />

to as the SVO Slider measure <strong>and</strong> can be administered online or as a one-page paper based choice<br />

task (see the Appendix, Section §6). A detailed discussion of the new measure is provided, along with<br />

norming data <strong>and</strong> evidence of the new measure’s convergent validity with existing methods. We con-<br />

clude with a discussion of the research streams that would benefit from a more sensitive <strong>and</strong> higher<br />

1 Au & Kwong (2004, p.74) report 49.7% cooperators over several studies <strong>and</strong> Van Lange et al. (1997) report about 60%<br />

cooperators across different western countries. Van Lange et al. (2007) summarized the latter results by stating that the<br />

ratio between cooperators, individualists <strong>and</strong> competitors in Western countries is roughly 4:2:1.<br />

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resolution measure of SVO <strong>and</strong> extend an invitation to others to use this new measure.<br />

2 <strong>Social</strong> <strong>Value</strong> <strong>Orientation</strong> Framework<br />

SVO provides a framework for characterizing how decision makers (DMs) value joint outcomes<br />

(Messick & McClintock 1968, Griesinger & Livingston 1973, Liebr<strong>and</strong> 1984). A graphical representation<br />

of the full framework, highly similar to the one provided by (Liebr<strong>and</strong> 1984, p. 246) is provided in<br />

Figure 1 <strong>and</strong> shows different motivations associated with different joint outcomes.<br />

Payoff to other<br />

Figure 1: A graphical representation of the SVO framework<br />

100<br />

75<br />

50<br />

25<br />

0<br />

50<br />

Martyr<br />

15<br />

85<br />

Masochistic<br />

15<br />

15<br />

Sadomasochistic<br />

Sadistic<br />

Altruistic<br />

50<br />

100<br />

50<br />

0<br />

Payoff to self<br />

Prosocial<br />

85<br />

85<br />

Individualistic<br />

Competitive<br />

0 25<br />

50 75 100<br />

A point in the Cartesian plane corresponds to a specific joint outcome. The x-axis corresponds<br />

to the value of the DM’s individual payoff. The y-axis corresponds to the other person’s payoff. Al-<br />

though there are an infinite number of possible joint outcomes, those along the ring, intersecting one<br />

of the eight cardinal directions, provide clear exemplars of different joint outcomes that correspond<br />

to particular preferences. For example, the point on the ring that maximizes individual earnings is at<br />

3<br />

85<br />

15<br />

100<br />

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x = 100 <strong>and</strong> y = 50 (i.e. Individualistic); the point on the ring that maximizes joint earnings is at x = 85<br />

<strong>and</strong> y = 85 (i.e. Prosocial). These points <strong>and</strong> their respective archetypical motivations are listed in<br />

Table 2, along with other respective motivations. The values presented in Table 2 are consistent with<br />

Figure 1 <strong>and</strong> correspond to different motivations. 2<br />

Table 2: Archetypal SVO outcomes<br />

Self Other <strong>Orientation</strong> Inferred Motivation<br />

85 85 Prosocial Maximize joint payoff or minimize difference between payoffs<br />

100 50 Individualistic Maximize payoff to self<br />

85 15 Competitive Maximize positive difference between self <strong>and</strong> other’s payoff<br />

50 0 Sadistic Minimize other’s payoff<br />

15 15 Sadomasochistic Minimize joint payoff or minimize difference between payoffs<br />

0 50 Masochistic Minimize payoff to self<br />

15 85 Martyr Maximize negative difference between other’s <strong>and</strong> self payoff<br />

50 100 Altruistic Maximize other’s payoff<br />

One way to determine an individual’s preferences across different joint distributions is to present a<br />

DM with a series of allocation decisions <strong>and</strong> ask her to select her most preferred apportionments (e.g.<br />

the choice presented in Table 1). These resource allocation decisions are sometimes referred to as<br />

decomposed games (Pruitt 1967, Messick & McClintock 1968). The term decomposed games emerged<br />

from seminal work that used simple two-player binary option games (e.g. the Prisoner’s Dilemma) to<br />

study choice behavior. One problem with using a game to study intrinsic preferences is that a game<br />

is by definition a strategic interaction. Games require DMs to choose not only according to their pref-<br />

erences, but with those preferences conditioned on their beliefs of what they think other players will<br />

choose, knowing that the other players are likely thinking the same thing, <strong>and</strong> so on. These decisions<br />

are complex in that they draw upon both preferences <strong>and</strong> beliefs about others’ preferences, <strong>and</strong> beliefs<br />

about others’ beliefs, etc. As a method to measure preferences alone, it is muddled <strong>and</strong> confounded<br />

by the strategic nature of the interaction. A solution to this measurement problem is to decouple<br />

preference considerations from strategic considerations. This simplified choice task is called a de-<br />

composed game. Although it is technically not a game, it does give an unconfounded measure of an<br />

2 One thing that is worth noting is that in the economics literature, the term altruistic encompasses any positive other<br />

regarding preference, whereas in the psychology literature there is a distinction made between prosocial <strong>and</strong> altruistic<br />

orientations. For this paper we too will maintain the distinction between these two motivations, using altruistic to refer to<br />

the particular motivation of maximizing another’s payoff, indifferent to one’s own.<br />

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individual’s preferences for joint outcomes. For example, if a DM chooses Option 2 from the alloca-<br />

tion choice presented in Table 1, we would infer that her motivation to maximize her own earnings is<br />

stronger than her motivation to maximize joint earnings; we would say she has a revealed preference<br />

consistent with an individualistic social value orientation.<br />

Any individual choice task where a DM makes a selection from among different allocations of<br />

resources to himself <strong>and</strong> others is a decomposed game. Decomposed games have been used exten-<br />

sively to study SVO (e.g. Messick & McClintock 1968, McClintock, Messick, Kuhlman, & Campos 1973,<br />

Kuhlman & Marshello 1975a,b, Van Lange, Otten, De Bruin, & Joireman 1997). The dictator game 3<br />

happens to be a decomposed game too. For clarity, we refer to non-game contexts as allocation deci-<br />

sions in order to emphasize the non-strategic nature of the relevant choice tasks.<br />

The framework presented in Figure 1 <strong>and</strong> Table 2 provides a taxonomy (Liebr<strong>and</strong> 1984) of revealed<br />

social preferences but has several unusual categories that are rarely consistent with real DMs’ choices.<br />

Thus researchers have focused their attention on a subset of items in a particular region of the ring.<br />

According to McClintock & Messick (1965), a person can fulfill one of three different orientations. A<br />

person may be motivated to secure maximal resources for himself, indifferent to how much the other<br />

receives (i.e. maximizing own gain). Or a person may prefer to maximize the sum of the outcomes for<br />

both self <strong>and</strong> other (i.e. maximizing joint gain). Or a person may prefer to maximize the difference be-<br />

tween his own outcome <strong>and</strong> the other’s outcome (maximizing relative gain). These three motivational<br />

orientations have longst<strong>and</strong>ing labels in the psychology literature as individualistic, cooperative (i.e.<br />

prosocial), <strong>and</strong> competitive, respectively Deutsch (1960). The most common current measure of SVO,<br />

a 9-item triple dominance scale (see Van Lange et al. 1997), uses the same three categories. There<br />

are a variety of other approaches to the measure of SVO which range from distinguishing simply be-<br />

tween two categories (individualistic <strong>and</strong> prosocial) to differentiating among up to ten categories as<br />

proposed by MacCrimmon & Messick (1976).<br />

3 This is an unfortunate name as it is technically not a game either, as only one DM can influence the joint payoffs.<br />

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3 Existing Measurements of SVO<br />

In this section, existing approaches to the measurement of SVO are described <strong>and</strong> discussed in ap-<br />

proximate chronological order of publication. This provides a general overview of the history of SVO<br />

measurements <strong>and</strong> offers insight into how methods have changed <strong>and</strong> developed over time. Figure<br />

14 shows a diagram of the measurement techniques over time. In discussing different approaches to<br />

SVO measurement, the current paper focuses on methods that assess people’s preferences for certain<br />

allocations of resources. These preferences are revealed by eliciting people’s judgments or choice be-<br />

havior when they are presented with options containing different distributions of outcomes for the<br />

self <strong>and</strong> for some other person. Questionnaire methods regarding altruistic or prosocial attitudes (e.g.<br />

Rushton et al. 1981, Cr<strong>and</strong>all 1975) are excluded from the present paper.<br />

3.1 The Altruism Scale<br />

Sawyer (1966) devised a method for assessing the degree of concern a DM has for the outcomes<br />

for himself <strong>and</strong> others. He called this method the Altruism Scale. However it should be noted that<br />

Sawyer’s method can assess a range of different orientations including prosocial, individualistic, <strong>and</strong><br />

competitive motivations, <strong>and</strong> it would be more accurate to call it the <strong>Social</strong> Preference Scale. Within<br />

Sawyer’s theoretical framework, the subjective attractiveness of a joint outcome was conceptualized<br />

as the linear combination P + (w · O) where P is the payoff for the self <strong>and</strong> O is the payoff for another<br />

person. The coefficient w represents how much weight a DM gives to the outcome for another, relative<br />

to his own outcome. If a person is individualistic <strong>and</strong> therefore only interested in only his own welfare,<br />

the coefficient w would be zero. If a person is cooperative <strong>and</strong> cares about both his own, <strong>and</strong> the<br />

other person’s welfare, w would be greater than zero. Conversely, if a person is competitive <strong>and</strong> tries<br />

to maximize the difference between the own <strong>and</strong> the other’s payoff, w will be less than zero.<br />

3.1.1 The Altruism Scale described<br />

Sawyer’s method uses a conjoint measurement technique to estimate an individual’s weighting<br />

of outcomes for others (w). An index of altruism is computed based on the desirability rankings of<br />

own/other outcome combinations. Specifically, subjects (college students in this case) were asked to<br />

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imagine that they would take a seminar with only one other fellow student <strong>and</strong> that each would re-<br />

ceive a grade of A, B or C at the end of the seminar. Subjects were then asked to rank their preferences<br />

for the allocations of these grade combinations. After all 9 of the rankings are made by a DM, the<br />

altruism index a can be calculated as follows:<br />

a =<br />

(sum of ranks in row C) − (sum of ranks in row A)<br />

(sum of ranks in column C) − (sum of ranks in column A)<br />

The index a is a manifest variable <strong>and</strong> serves as a proxy for the latent variable w. The numerator in<br />

computing a corresponds to how much a person cares about the outcome for the other person. If, for<br />

example, a person cares about the other’s welfare, the DM will assign high ranks to the options where<br />

the other person receives A grades <strong>and</strong> low ranks to the outcomes where the other person receives<br />

C grades. In this case, the numerator is positive, indicating positive altruism. Conversely, a negative<br />

result indicates negative altruism (i.e. competitiveness). If the result is zero, it implies that the person<br />

is indifferent to the other student’s grade. 4<br />

According to Sawyer, w ranges continuously from −1 to +1, i.e. from perfectly competitive (w =<br />

−1) to perfectly cooperative (w = +1), with narrow self interest (w = 0) at the midpoint. It is worth<br />

noting that a can take on values outside of this range given atypical motivations (e.g. masochistic). It<br />

is also worth noting that for Sawyer’s Altruism scale, a is undefined if a DM provides purely altruistic<br />

ranking (ranks that are consistent with maximizing the grade of the other student <strong>and</strong> indifferent to<br />

the DM’s own grade).<br />

3.1.2 Discussion of the Altruism Scale<br />

The Altruism scale was an early innovation but as a means to measure social preferences it has<br />

limitations. First, the metric space of academic grades is not straightforward <strong>and</strong> is obviously not<br />

amendable to incentive compatible research. This particular choice context may force DMs to take<br />

4 Sawyer used a second method to directly assess a by asking the DM to choose 1 out of 21 scale values, which corresponded<br />

to values of a ranging from −1 to +1 in increments of 0.1. The scale is anchored by statements at the values −1,<br />

−0.5, 0, +0.5 <strong>and</strong> +1. For example, the statement reflecting an a value of +1 indicates agreement with the following statement:<br />

“I am equally interested in how good his grade is <strong>and</strong> in how good my grade is,” whereas the statement reflecting an<br />

a value of 0 indicates agreement with: “I am only interested in how good my grade is; how good or poor his grade is makes<br />

no difference to me.”<br />

7<br />

(1)


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Sawyer’s altruism index (a )<br />

Other<br />

1<br />

0.8<br />

0.6<br />

0.4<br />

0.2<br />

0<br />

-0.2<br />

-0.4<br />

-0.6<br />

-0.8<br />

-1<br />

Competitive<br />

A 5 4 3<br />

B 4 3 2<br />

C 3 2 1<br />

C B<br />

Self<br />

A<br />

Figure 2: Sawyer’s Altruism Scale - Preference rankings <strong>and</strong> the a index<br />

Other<br />

A 9 7 4<br />

B 8 5 2<br />

C 6 3 1<br />

C B<br />

Self<br />

A<br />

Other<br />

A 7 5 3<br />

B 6 4 2<br />

C 5 3 1<br />

C B<br />

Self<br />

A<br />

Other<br />

A 9 6 3<br />

B 8 5 2<br />

C 7 4 1<br />

C B<br />

Self<br />

A<br />

Other<br />

Individualistic<br />

A 3 2 1<br />

B 3 2 1<br />

C 3 2 1<br />

C B<br />

Self<br />

A<br />

-1 -0.8 -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1<br />

Coeficient (w): The weight for another’s outcome<br />

Other<br />

A 7 4 1<br />

B 8 5 2<br />

C 9 6 3<br />

C B<br />

Self<br />

A<br />

Other<br />

A 5 3 1<br />

B 6 4 2<br />

C 7 5 3<br />

C B<br />

Self<br />

A<br />

A 6 3 1<br />

B 8 5 2<br />

C 9 7 4<br />

C B<br />

Self<br />

A<br />

Other<br />

Prosocial<br />

A 3 2 1<br />

B 4 3 2<br />

C 5 4 3<br />

C B<br />

Self<br />

A<br />

Figure 3: Examples of different preference rankings (the 3 × 3 matrixes at the top of the figure) are<br />

displayed here. Further, the relationship of these rankings to the underlying utility weight (w, shown<br />

on the x-axis) for another’s outcome, <strong>and</strong> Sawyer’s altruism index a are shown. The ranking of 1<br />

indicates that this allocation of grades is the DMs most preferred joint outcome. As can be seen, ties<br />

in ranking outcomes are allowed. Particular rankings are consistent with underlying utility weights,<br />

<strong>and</strong> further each ranking matrix corresponds to an a index. Although w is continuous, the resulting<br />

altruism index a is a step function that can take on only one of nine values given w between -1 <strong>and</strong><br />

1 inclusive. Some rankings correspond to a single point of w, whereas other rankings are consistent<br />

with a range of w values.<br />

a zero-sum mentality if they are accustomed to curved grading systems or are concerned with their<br />

overall class ranking.<br />

Second, a procedure for rank ordering preferences that presents subjects with all stimuli at the<br />

same time runs the risk of yielding unreliable data because people usually are not very skilled at re-<br />

liably ranking multiple items simultaneously (Saaty 1980). Hence, as proposed by Sawyer himself, it<br />

would probably be beneficial to let subjects make sequential pairwise comparisons in order to reduce<br />

complexity of the judgment task <strong>and</strong> therefore yield more accurate rank orders. How one would elicit<br />

global rankings based on sequential pairwise rankings is not an issue Sawyer addresses nor does it<br />

8<br />

Other<br />

1.000<br />

0.625<br />

0.500<br />

0.333<br />

0.000<br />

-0.333<br />

-0.500<br />

-0.625<br />

-1.000


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have an obvious solution.<br />

Third, the altruism scale cannot differentiate between prosocial motivations <strong>and</strong> inequality aver-<br />

sion. It also yields an undefined a index for a DM with an altruistic motivational orientation.<br />

Fourth, the process of reducing a set of rank orderings into a single index may be problematic.<br />

Each a value at one of the three anchors (-1, 0, +1) has a clear interpretation, whereas values in be-<br />

tween are not readily interpretable. Further, the index a is an ordinal variable at best (Stevens 1946,<br />

1950) <strong>and</strong> is limited to 9 particular values. Moreover, the mapping from underling utility w to the<br />

index a has a “many-to-one” structure which necessarily results in the loss of information.<br />

With respect to psychometric properties of his measure, Sawyer reported only moderate validity<br />

<strong>and</strong> reliability. For example, the correlation between values obtained by the direct scale estimation<br />

measure <strong>and</strong> the values obtained by the ranking method was only r = 0.32, hence challenging the<br />

measure’s convergent validity. Sawyer reasoned that the discrepancy between the two measures was<br />

probably due to differences in task complexity <strong>and</strong> to multidimensionality in the rankings (i.e., the di-<br />

rect estimation measure promotes unidimensional judgments whereas the conjoint method allowes<br />

for more complex preferences to manifest themselves).<br />

3.2 The 9-item Triple-Dominance Scale<br />

Decomposed games have their roots in two-option two-player games (e.g. the Prisoner’s dilemma)<br />

that have been the “fruit flies” of social decision research. Messick & McClintock (1968) <strong>and</strong> Pruitt<br />

(1967) independently devised what have been termed decomposed games by deconstructing binary<br />

social dilemmas into individual decision problems. The reason for this simplification is to disentangle<br />

intrinsic motivations from strategic concerns. Allocation choices can be constructed that differenti-<br />

ate between archetypal motivations; Messick & McClintock (1968) concerned themselves with three<br />

common SVOs, namely prosocial, individualistic, <strong>and</strong> competitive, ignoring other less common mo-<br />

tivations.<br />

For example, the allocation decision presented in Table 1 is designed to differentiate between<br />

prosocial <strong>and</strong> individualistic motivations. A prosocial person would choose Option A <strong>and</strong> an indi-<br />

vidualist would choose Option B. This type of item is referred to as a double-dominance item as it can<br />

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discriminate between two of the three most common SVOs. However, a competitive type would also<br />

select option B, as it has a greater relative difference between the payoffs. So with this particular allo-<br />

cation decision it is not possible to differentiate between individualists <strong>and</strong> competitors as both types<br />

would make the same choice.<br />

There are two methods which solve this problem <strong>and</strong> distinguish between the three most common<br />

SVOs. First, a researcher can examine the complete set of choices made in a series of two-option,<br />

double dominance allocation decisions. The set of choices that pits each of the common SVOs against<br />

each of the other common SVO types is necessarily exhaustive <strong>and</strong> can isolate a DM’s primary social<br />

motivation. This method would also identify an individual’s least preferred social outcome. A second<br />

method to differentiate between the three most common SVOs uses a single allocation decision that<br />

has three options (as proposed by McClintock, Messick, Kuhlman, & Campos 1973) such that each<br />

option dominates both the other two options with respect to a particular motivational orientation.<br />

These types of items have the property of triple dominance, as they can differentiate between three<br />

social orientations. These types of items were adopted by Kuhlman & Marshello (1975a) who also<br />

used other decomposed game classes (double-dominance <strong>and</strong> single-dominance) for assessing SVO.<br />

Building on this work, the 9-item triple-dominance measure of SVO (see Van Lange et al. 1997) has<br />

evolved <strong>and</strong> has become a widely-used measurement method (e.g. applied by Joireman, Van Lange, &<br />

Van Vugt 2004, Utz 2004, Utz, Ouwerkerk, & Van Lange 2004, van Dijk, De Cremer, & H<strong>and</strong>graaf 2004,<br />

Stouten, De Cremer, & Van Dijk 2005, de Kwaadsteniet, van Dijk, Wit, & de Cremer 2006, Van Lange,<br />

Bekkers, Schuyt, & Van Vugt 2007, Declerck & Bogaert 2008, van Prooijen, De Cremer, van Beest, Ståhl,<br />

van Dijke, & Van Lange 2008, van den Bos, van Dijk, Westenberg, Rombouts, & Crone 2009, Haruno &<br />

Frith 2009), in part due to its straight forward structure <strong>and</strong> ease of use (Van Lange, De Cremer, van<br />

Dijk, & Van Vugt 2007).<br />

3.2.1 The 9-item Triple-Dominance Scale described<br />

The triple dominance SVO items can be seen in Table 3. For each item there is one allocation<br />

option that is prosocial, individualistic, <strong>and</strong> competitive. The scoring rule for this scale is to count<br />

the number of selfish, prosocial, <strong>and</strong> competitive options a DM selects. If a DM chooses six or more<br />

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Prosocial Individualistic Competitive<br />

Item Self Other Self Other Self Other<br />

1 80 80 92 40 80 0<br />

2 84 84 96 44 84 4<br />

3 88 88 100 48 88 4<br />

4 82 82 96 44 84 4<br />

5 84 84 96 44 82 2<br />

6 84 84 98 44 84 4<br />

7 86 86 96 44 86 6<br />

8 84 84 94 44 84 4<br />

9 82 82 92 44 80 4<br />

Table 3: Simple trichotomous choices of distributions. Note: These values have been st<strong>and</strong>ardized<br />

to range between 0 <strong>and</strong> 100 in order to facilitate comparison with the other measures presented in<br />

this paper. The original items ranged between 80 <strong>and</strong> 580 <strong>and</strong> were presented in the units of points<br />

(examples of the original form are shown in Van Lange et al. 1997, 2007).<br />

options from a particular category, then the DM is categorized as being that type. If a DM does not<br />

choose at least six options from one category, then she is not categorized (e.g. McClintock & Allison<br />

1989, Platow, McClintock, & Liebr<strong>and</strong> 1990, Van Lange & Kuhlman 1994). In other variants of the<br />

Triple-Dominance scale, only six items are used <strong>and</strong> subjects are classified when at least five of the six<br />

choices are consistent with one of the three social value orientations (e.g. Van Lange 1999). However,<br />

the method of counting choices made in several decomposed games <strong>and</strong> classifying subjects into<br />

respective SVO categories according to their choice pattern with respect to a particular consistency<br />

criterion is exemplary for the general evaluation procedure used in decomposed game measures. This<br />

holds for the 9-item Triple-Dominance SVO scale as well as for other variants using mixed dominance<br />

classes (e.g. Kuhlman & Marshello 1975a,b).<br />

3.2.2 Discussion of the 9-item Triple-Dominance Scale<br />

Although the 9-item Triple-Dominance SVO scale is the most commonly used measure of SVO<br />

to date, it has some shortcomings. First, it can classify individuals to only one of three categories:<br />

prosocial, individualistic, or competitive, <strong>and</strong> provides no information beyond this categorization.<br />

This result is only at the nominal level (Stevens 1946, 1950), the lowest level of measurement. However<br />

social motivations are a continuous construct <strong>and</strong> one practical result of forced categorization is low<br />

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Figure 4: The 9-item Triple-Dominance scale. Each item is represented in the self/other allocation<br />

plane as three points connected by two lines. Notice the high degree of similarity among the items. It<br />

may be more accurate to say this is a scale with one item repeated nine times.<br />

statistical power.<br />

Payoff to other<br />

100<br />

80<br />

60<br />

40<br />

20<br />

0<br />

0 20 40 60 80 100<br />

Payoff to self<br />

Second, it cannot discriminate between joint payoff maximization <strong>and</strong> inequality aversion. Al-<br />

though these preferences may be related, they are not the same. For example, there is evidence that<br />

persons classified as prosocial are concerned with both the maximization of joint gain <strong>and</strong> equality in<br />

outcomes (Van Lange 1999). Further there are choice contexts where these motivations would lead to<br />

substantially different behavior.<br />

Third, the 9-item Triple-Dominance measure can only establish a DM’s first preference, not her<br />

lesser preferences. Take for example an individual who has a rank order of preferences as individ-<br />

ualistic, prosocial, <strong>and</strong> competitive. Contrast this individual to someone who ranked preferences<br />

of individualistic, competitive, <strong>and</strong> then prosocial. These individuals may approach the world very<br />

differently than each other. Furthermore, knowing what an individual’s least preferred allocation is<br />

would be informative, as an avoidant personality or prevention focus (Higgins 1997) can serve as a<br />

motivational foundation. People who are strongly motivated to avoid their least preferred option,<br />

rather than focusing on their most favored option, would make different choices depending on the<br />

full ranking of their preferences. It is thus important to know not just a DM’s most preferred outcome,<br />

but also the entire rank ordering of her social preferences.<br />

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Fourth, three-option choice sets are more complicated than binary choices. The simplest choice<br />

is between two options <strong>and</strong> only requires the DM to make one comparison in the process of making<br />

a decision. Increasing to three options requires the DM to make three comparisons. The inclusion<br />

of one particularly unattractive option has been shown to have an effect on revealed preferences (Si-<br />

monson 1989) in unanticipated ways.<br />

Fifth, it seems to have become quite common practice that the two categories of individualistic<br />

<strong>and</strong> competitive orientations are being merged to form one group which is then compared to indi-<br />

viduals in the prosocial category (see for example Joireman et al. 2004, Utz 2004, Stouten et al. 2005,<br />

de Kwaadsteniet et al. 2006, Cornelissen et al. 2007, van Prooijen et al. 2008, van den Bos et al. 2009).<br />

Obviously such procrusteanism sacrifices information. This collapsing across categories is not an<br />

intrinsic limitation of the Triple-Dominance SVO measure, but rather a regrettable convention that<br />

has evolved with it when the number of subjects per category is considered to be too low (see e.g.<br />

Van Lange & Liebr<strong>and</strong> 1991).<br />

Sixth, offering the nearly identical choice nine times may induce subjects to vary their responses<br />

in unexpected ways. In some cases, this variation may be reflective of their honest preferences. For<br />

example we had one subject in pretesting explain that he answered about half of the items selfishly<br />

<strong>and</strong> the other half cooperatively. His goal he explained was to be nice, but not too nice. This subject<br />

treated the scale holistically <strong>and</strong> made a set of answers that, when considered in total were sensible,<br />

but would have resulted in an uncategorizable result using the st<strong>and</strong>ard scoring rule. In other cases,<br />

subjects may become bored or suspicious of answering the same item repeatedly <strong>and</strong> thus vary their<br />

answers. Ironically, this high degree of redundancy in triple dominance scales may undermine its<br />

ability to classify subjects. For example, in the study conducted by Kuhlman & Marshello (1975a), the<br />

percentage of unclassifiable subjects was 25% (42 out of 167), Kuhlman et al. (1992) report 29.3% (41<br />

out of 140) unclassifiable subjects, <strong>and</strong> Sheldon (1999), who made use of the Kuhlman <strong>and</strong> Teta mea-<br />

sure, even applied an alternative scoring method after having lost 27% (25 out of 90) of the subjects<br />

for analysis because they were not classifiable.<br />

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3.2.3 Rank correlation technique: Another application of decomposed games<br />

Another measurement technique that makes use of decomposed games for assessing SVO was<br />

introduced by Iedema & Poppe (1994a,b, 1995). Iedema & Poppe presented subjects with pairwise<br />

comparisons of eight different own/other payoff allocations, resulting in a total of 28 allocation de-<br />

cisions. Then, ranks were assigned to the eight payoff allocations for each subject according to how<br />

often each of these eight alternatives had been selected. Prior to this assessment, Iedema & Poppe<br />

had compiled ideal rank orders of the eight alternatives with respect to six different social orienta-<br />

tions (individualism, altruism, equality, cooperation, competition <strong>and</strong> maximin). The assessed rank<br />

orders were then correlated (Spearman’s rank order correlation) with each of the six ideal rank orders<br />

for each subject, yielding six correlation coefficients per subject, each of which was indicative of the<br />

relation between the subject’s rank order <strong>and</strong> the corresponding ideal rank orders of the six social ori-<br />

entations. These coefficients were then transformed into Fisher Z -scores ranging from −3 to +3 <strong>and</strong><br />

subjects were classified to a particular SVO category matching their highest Z -score, provided that<br />

this score was greater than a predetermined threshold. In one instance a threshold of .55 (which cor-<br />

responds to a correlation coefficient of .5) (Iedema & Poppe 1994a,b) was used. In another instance,<br />

a threshold of .881 (corresponding to a correlation of .707, reflecting the threshold of 50% explained<br />

variance) (Iedema & Poppe 1995) was required.<br />

3.3 Utility measurement<br />

Utility measurement in general refers to the systematic estimation <strong>and</strong> mapping of how subjec-<br />

tively valuable goods or outcomes are to a DM. Utility is an abstract construct that is inferred from<br />

the revealed preferences of DMs as they make choices among available alternatives. These alterna-<br />

tives can include “bundled outcomes,” sets of discrete goods that are considered <strong>and</strong> evaluated as a<br />

whole set. Obviously, the utility of these bundled outcomes results from the constituent parts therein.<br />

However, the way a DM integrates information about the items <strong>and</strong> makes tradeoffs between them<br />

may not be so obvious. Early studies of these kinds of choices by Thurstone (1931) involved subjects<br />

making paired comparisons between sets of goods (2 hats, 4 pairs of shoes) vs. (4 hats, X pairs of<br />

shoes) where X was varied systematically by the experimenter. This approach yielded an estimated<br />

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value of X where a DM was indifferent between the sets. Given this indifference point, the relative<br />

contribution of the discrete items to the bundle’s overall utility could be inferred.<br />

With respect to SVO, joint allocations are viewed as “bundled outcomes” that have at least two dis-<br />

tinct potential sources of utility for a DM– the payoff for the self <strong>and</strong> the payoff for another. Individual<br />

differences emerge because different people place different subjective values upon these sources of<br />

utility <strong>and</strong> make different subjective tradeoffs when evaluating the bundle as a whole. Although the<br />

notion of utility is most closely associated with economics, this framework is consistent with func-<br />

tional measurement (Anderson 1970), specifically in the context of information integration theory<br />

(Anderson 1968).<br />

3.3.1 Utility measurement described<br />

The approach of using utility measurement in the context of own-other-outcome is not a new<br />

idea. Edgeworth (1881) assumed that between pure selfishness <strong>and</strong> pure prosociality (or in h is words<br />

- Pure Universalistic) there are a wide range of middle orientations. He wrote:<br />

For between the two extremes Pure Egoistic <strong>and</strong> Pure Universalistic there may be an indefinite<br />

number of impure methods; wherein the happiness of others as compared by the<br />

agent (in a calm moment) with his own, neither counts for nothing, nor yet “counts for<br />

one,” but counts for a fraction. (Edgeworth 1881, p.16)<br />

From this, one can readily see that the idea of utility in social contexts as being affected not only by<br />

one’s own welfare, but also by the welfare of others, is not new. Edgeworth assumed that the welfare<br />

of others does not have the same impact on one’s happiness as one’s own welfare, but instead has<br />

a fraction of that impact. Hence the magnitude of such a fraction can be considered an index of<br />

prosociality. The coefficients or weights attached to the outcomes of others as specified in utility<br />

functions is what Edgeworth meant when using the term fraction in this context.<br />

The framework of using joint utility evaluations was chosen by Wyer (1969) who used it to suc-<br />

cessfully predict choice behavior in particular classes of strategic games. His approach transformed<br />

preferences for outcome allocations into utilities. Wyer, as well as Griesinger & Livingston (1973),<br />

modeled the utility of joint allocations as a linear combination of the weighted outcomes for the self<br />

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<strong>and</strong> for another. Wyer used a utility function with the form<br />

U = (w1RS) + ((1 − ) w2RS) + (w3RO) (2)<br />

where RS represents the outcome for self, RO represents the outcome for other, w1,2,3 represent weights<br />

reflecting the values attached to the respective outcomes <strong>and</strong> is an indicator function which yields<br />

the value of 1 if RS > 0 <strong>and</strong> 0 if RS ≤ 0. In his experiment, Wyer used a 21-point rating scale to assess<br />

the desirability of allocation outcomes. Subjects were asked how much they would like, for example, a<br />

distribution of 2 points for themselves <strong>and</strong> −3 points for another. The scale ranged from between −10<br />

<strong>and</strong> +10 in interval steps. These desirability ratings were then inserted into the above formula as an<br />

estimated utility value, conditional on that particular allocation (in this example RS = 2 <strong>and</strong> RO = −3).<br />

After a series of ratings were obtained from a research subject, the weights w1,2,3 were estimated by<br />

ordinary least-squares fitting.<br />

Different sets of weights indicate different social orientations. Considering instances of positive<br />

outcomes, a person with an individualistic orientation would have a high positive w1 weighting <strong>and</strong><br />

a w3 weighting close to zero. Prosocial individuals would have positive values for both w1 <strong>and</strong> w3<br />

that are similar in magnitude. Wyer showed that the competitive orientation would be reflected by a<br />

positive w1 <strong>and</strong> a negative w3.<br />

More complex utility models have been posited. For example, second order polynomials have<br />

been used to account for joint utilities. Radzicki (1976), used a conjoint measurement technique to<br />

identify a best fitting utility function. Subjects were asked to make rankings of 25 outcome alloca-<br />

tions from the most preferred to the least preferred distributions. These rankings were then analyzed<br />

<strong>and</strong> linear programming methods were used to determine the form of the utility function that fit the<br />

particular rankings best. This method yielded a particular utility function, along with weighting co-<br />

efficients, for each of the subjects. Radzicki found that linear functions fit 41% of the participants’<br />

rankings best, whereas for 8% of the participants’ rankings, none of the considered functions fit the<br />

data sufficiently. In many cases though, non-linear functions exhibited a significantly better fit to<br />

the data than simple linear models. For example, for people who were concerned with equality in<br />

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outcomes, the function which best fit the particular rankings was of the form<br />

u(x, y) = ax + by + cx 2 + d y 2 + e(| x − y | q ) (3)<br />

where q < 1. Although the simplicity of linear models is convenient <strong>and</strong> in many cases sufficient to<br />

describe choice behavior with respect to joint allocations, non-linear models allow for more sophis-<br />

ticated descriptions of choice behavior <strong>and</strong> are able to account for more complex patterns in data.<br />

Non-linear approaches are suggested by MacCrimmon & Messick (1976) <strong>and</strong>, Wyer (1969) himself<br />

noted that non-linear relations between given outcomes <strong>and</strong> their utilities could well be possible, if<br />

not probable, when payoff amounts exceed a certain range of values under consideration. For exam-<br />

ple, the increase of a payoff amount from one dollar to two dollars is probably not equally valued as<br />

an increase from 500 dollars to 501 dollars with respect to utility. From this point of view, non-linear<br />

models are justifiable when the values of outcomes presented to decision makers vary widely in the<br />

amounts under consideration.<br />

3.3.2 Discussion of utility measurements<br />

As McClintock & Van Avermaet (1982) noted, the approach of using utility functions for the evalu-<br />

ation of social value orientations as performed by Wyer (1969, 1971) or Radzicki (1976) is focused on<br />

revealing a mode of measurement that adequately describes the combinatory rules underlying prefer-<br />

ence choices within the framework of own-other-outcome allocations <strong>and</strong> theoretically allows for an<br />

infinite number of possible social value orientation. Therefore, these models do not state particular<br />

SVOs a priori, but rather let SVOs be inferred from or interpreted by specific combinatory rules <strong>and</strong><br />

weight values provided by the respective utility functions. By contrast, methods following the line of<br />

Messick & McClintock (1968) –such as the trichotomous measure or decomposed games in general as<br />

well as the ring measure– are more concerned with the “substantive nature” (McClintock & Van Aver-<br />

maet 1982, p.59) of SVO. That is, the existence of a number of predefined SVOs is assumed a priori <strong>and</strong><br />

the emphasis is placed upon measuring them directly by letting people decide between two or more<br />

outcome allocations that are indicative of particular archetypical social orientations.<br />

Nevertheless, there are certain problems with the use of utility measurement for assessing SVO.<br />

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First, when SVOs for different persons are expressed using different functional forms, each represen-<br />

tation potentially containing a different number of parameters, it is difficult to compare or aggregate<br />

results. For example Radzicki’s method is likely too flexible to be useful <strong>and</strong> certainly over-fits ratings<br />

data that are at least in some part measurement error.<br />

Second, DMs are not making choices in these utility estimation methods, but rather judging the at-<br />

tractiveness of different hypothetical allocations. This rating procedure makes strong linear assump-<br />

tions of the response scale which are likely not met, especially given the scale’s structure (a 21-point<br />

rating scale!). Eliciting judgments rather than choices introduces a level of abstraction that does not<br />

offer clear benefits. Moreover, inducing participants to honestly report their preferences by incentive<br />

compatible methods is not easily accommodated with judgment tasks like the ones suggested above.<br />

3.3.3 Indifference curves: A graphical approach to measuring SVO<br />

In addition to utility functions as representations of different SVOs, indifference curves too can be<br />

used as a representation of preferences for different joint outcomes. Consider a set of curves plotted<br />

on a two-dimensional plane defined by the payoff to self on the x-axis <strong>and</strong> payoff to another on the<br />

y-axis. Radzicki (1976) depicted indifference curves resulting from a utility function corresponding to<br />

the best fit of subjects’ rating data.<br />

Another approach along these lines was developed by Harrison (1998) who conducted what he<br />

termed an “indifference curve experiment” based on a procedure described by MacCrimmon & Toda<br />

(1969) <strong>and</strong> similar to the approach by Thurstone (1931). Harrison requested subjects make several<br />

pairwise choices between various joint allocations of money. For example, subjects chose between<br />

an allocation of $10 to themselves <strong>and</strong> $8 to another, or say $17 for themselves <strong>and</strong> $15 to another.<br />

The first optional distribution was referred to as the “reference allocation” <strong>and</strong> for a set of choices<br />

was always the same. After multiple choices are made, one can infer an indifference curve running<br />

through the reference point <strong>and</strong> the boundary between those allocations that were preferred over the<br />

reference allocation <strong>and</strong> those allocations which were not preferred over the reference allocation (see<br />

Figure 5).<br />

By repeating this procedure <strong>and</strong> using a different reference allocation point, an arbitrary number<br />

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Figure 5: An example of the indifference curve method. The left panel shows 18 pairs of potential allocation<br />

choices that a subject would consider. Each of them has in common the Reference Allocation.<br />

Each of the Optional Allocations is either chosen over the Reference Allocation or not. The resulting<br />

pattern of preferred options can be used to identify an indifference curve which necessarily intersects<br />

the Reference Allocation point.<br />

payoff to<br />

other<br />

30<br />

20<br />

10<br />

10, 8<br />

Reference allocation<br />

Optional allocation<br />

17, 15<br />

10 20 30<br />

payoff to<br />

self<br />

payoff to<br />

other<br />

30<br />

20<br />

10<br />

10 20 30<br />

Reference allocation<br />

Selected allocation<br />

Non-selected allocation<br />

of indifference curves can be discerned, resulting in a contour map consistent with a DM’s SVO. This<br />

measurement procedure can be done to an arbitrary level of precision depending on the number of<br />

choice sets presented to a DM. The example shown in Figure 5 shows how one indifference curve can<br />

be inferred from 18 distinct pairwise choices; these are actual stimuli from Harrison (1998).<br />

It is worth noting that such a procedure has some advantages. First, subjects are presented with<br />

pairwise comparisons rather than multiple comparisons or abstract rating scales. Furthermore, no a<br />

priori assumption about the existence of a number of predefined social value orientations is needed,<br />

while the indifference curve patterns resulting from the procedure allow for interpretations regarding<br />

the extent to which they are consistent of respective SVOs. This method can also quickly identify<br />

intransitive choice sets or r<strong>and</strong>om responding from particular subjects, as no indifference curve can<br />

be inferred from their allocation decisions. It can also readily accommodate incentive compatible<br />

choices.<br />

This approach however has some limitations. First the resulting indifference curves are identified<br />

heuristically <strong>and</strong> not analytically. This means that a curve is “eye-balled” into place in order to di-<br />

vide the chosen points from the non-chosen points. An infinite number of bivariate functions could<br />

yield a curve that separates the chosen options from the non-chosen options while intersecting the<br />

reference allocation. Identifying the “best” fitting curve is impossible given the low resolution of the<br />

19<br />

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choice data <strong>and</strong> the heuristic method of curve fitting does not lend itself to parameterization. In order<br />

to address this issue, a researcher could specify a number of forms for the joint utility function (similar<br />

to Radzicki (1976)), <strong>and</strong> then roughly estimate an underlying utility function with general parameters<br />

that are consistent with the choices. Although this would quantify the heuristic indifference curve to<br />

some degree, the resulting joint utility function <strong>and</strong> parameters are not easily comparable between<br />

subjects given the variety of functional forms that may emerge as being consistent with the under-<br />

lying set of binary choices. Another shortcoming with this approach, is the relatively large number<br />

of choices a DM is required to make in order to infer one indifference curve. In the example shown,<br />

which is based on stimuli from Harrison (1998), 18 binary choices were used to approximate just one<br />

indifference curve.<br />

3.4 The <strong>Social</strong> Behavior Scale<br />

The <strong>Social</strong> Behavior Scale was devised as a measure that controls for individualism by keeping<br />

the outcome distributable to self constant <strong>and</strong> letting only the outcome distributable to the other<br />

vary over the choice alternatives. Consequently, decision makers are not given the opportunity to<br />

maximize their own gain by choosing a particular alternative, but only have control over the outcome<br />

for another.<br />

3.4.1 The <strong>Social</strong> Behavior Scale described<br />

The social behavior scale is a choice task with four alternatives as shown in Figure 6. The alterna-<br />

tives are: Rivalry & superiority; superiority; equality; <strong>and</strong> altruism & group enhancement. Outcomes<br />

for self <strong>and</strong> other are depicted as small squares <strong>and</strong> labeled as “chips.” This measure was devised by<br />

Knight & Kagan (1977) in effort to study the social behavior of young children from different ethnic<br />

groups. In their experimental study, children were told that the more chips they acquired, the more<br />

toys they would receive. This “currency” is easily comprehensible <strong>and</strong> can be presented without nu-<br />

merical abstraction, ideal for use with children, especially when there may be differences with respect<br />

to their formal educational experience. Subjects were asked to choose one out of the four alternatives<br />

according to their preferences.<br />

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Other<br />

outcome<br />

Self<br />

outcome<br />

Figure 6: <strong>Social</strong> behavior scale<br />

Rivalry Altruism<br />

Rivalry &<br />

superiority<br />

3.4.2 Discussion of the <strong>Social</strong> Behavior Scale<br />

Superiority Equality<br />

Altruism & group<br />

enhancement<br />

As a result of its properties, especially with regard to assessing individualistic orientations, the<br />

social behavior scale is too restricted to be an appropriate measure for SVO in general. Of course, one<br />

can readily imagine an alternative form of the <strong>Social</strong> Behavior Scale, where individualism is not strictly<br />

controlled. Such an alternative form would present allocation decisions across a range of different<br />

outcomes with simplified stimuli. Such a method could be advantageous when conducting studies<br />

with children or populations not accustomed to quantified information.<br />

3.5 The Ring Measure<br />

The ring measure is a method for assessing SVO that uses a series of dichotomous allocation de-<br />

cisions <strong>and</strong> derives an SVO score from the combined results of the choices made by a subject. The<br />

method is based on the notion that joint payoffs can be represented on a Cartesian coordinate system<br />

where payoffs to the DM are represented on the x-axis <strong>and</strong> payoffs to another person are represented<br />

on the y-axis (see Figure 1). This idea is consistent with the geometrical model which was devised<br />

by Griesinger & Livingston (1973) <strong>and</strong> Wyer (1969, 1971). Griesinger & Livingston stated that a per-<br />

son’s SVO can be conceptualized as a vector with a certain direction <strong>and</strong> magnitude in the joint payoff<br />

plane. The utility of a particular payoff allocation can then be expressed as the scalar product of<br />

the motivational vector with the vector of the given choice, or in other words, the projection of the<br />

given choice vector on the motivational vector. Consequently, a person will always choose the pay-<br />

off allocation with the greatest projection on his or her motivational vector. Further, the angle of the<br />

motivational vector is indicative of a respective SVO. For example, a motivational vector at the angle<br />

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of θM = 45 ◦ represents a prosocial orentation, whereas an individualistic motivation is represented by<br />

a vector at θM = 0 ◦ (see Figure 1). Following this conceptualization, Liebr<strong>and</strong> (1984) developed <strong>and</strong><br />

established the Ring Measure as a novel method for assessing SVO.<br />

3.5.1 The Ring Measure described<br />

The ring measure presents subjects with a set of N dichotomous allocation decisions that are de-<br />

fined by N points on a circle centered at the Cartesian origin (x = 0, y = 0). Each pair of adjacent points<br />

(defining a chord on the circle) serve as the two distribution options, <strong>and</strong> the subject makes a series<br />

of choices over these different allocations. Researchers have set the value of N at both 24 (Liebr<strong>and</strong> &<br />

McClintock 1988) <strong>and</strong> 16 (Liebr<strong>and</strong> 1984). 5<br />

After a research participant has made her N allocation choices, a vector is computed by adding<br />

her chosen options together, thus yielding two numbers (the sum of money the subject allocated to<br />

herself, <strong>and</strong> the sum of money the subject allocated to the other person). The resulting point can be<br />

interpreted as a vector (using the center point of the ring as its origin). The angle of this vector cor-<br />

responds to a person’s SVO <strong>and</strong> can be computed by θ = arctan( y<br />

x ), where y is the sum of allocations<br />

to the other <strong>and</strong> x is the sum of allocations to the self. The length of the vector indicates the internal<br />

consistency of the subject’s allocation decisions. If a person makes inconsistent choices, the result is<br />

necessarly a shorter vector. Perfectly consistent choice sets have the property of having one option<br />

being chosen twice (the most preferred distribution in the whole set), one option never being chosen<br />

(the least preferred allocation), <strong>and</strong> the remaining allocations being chosen exactly once. The vector<br />

resulting from a perfectly consistent set of choices will have a length equal to twice the radius of the<br />

circle used to generate the items, given that the center of the circle is fixed at the Cartesian origin. Be-<br />

cause of the structure of items in a Ring Measure, the more rigorous property of preference transitivity<br />

cannot be evaluated for a subject’s set of choices, only the weaker condition of consistency with an<br />

underlying vector.<br />

To date, the ring measure has been implemented with a defining center point at (0,0), yielding<br />

both positive <strong>and</strong> negative allocation values. However, to facilitate comparison with other measure-<br />

5 Liebr<strong>and</strong> (1984) employed 16 equally spaced pairs of outcomes on each of two circles (A <strong>and</strong> B) with radii of $7.00<br />

(circle A) <strong>and</strong> $8.50 (circle B), resulting in a total of 32 outcome pairs as choice allocations.<br />

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ment methods presented in this paper, the values in Table 10 have been st<strong>and</strong>ardized to range be-<br />

tween 0 <strong>and</strong> 100. This is equivalent to defining a ring with a center at (50,50) <strong>and</strong> a radius of 50 units.<br />

In order to prevent invalid classifications, DMs were typically only classified if the consistency of<br />

their choices was at least 60%. However, there is some variety regarding the st<strong>and</strong>ards for establish-<br />

ing a classification. For example, some classifications are made with a 50% consistency level (e.g.<br />

Van Lange 1999) or, in other cases, only if a vector is not shorter than a quarter (e.g. McClintock &<br />

Liebr<strong>and</strong> 1988) or even a fifth (e.g. Dehue et al. 1993) of the maximum possible vector length.<br />

3.5.2 Discussion of the Ring Measure<br />

At first blush the Ring Measure’s agnostic method of defining items evenly over the complete circle<br />

may appear to be a sensible approach. However there is overwhelming evidence demonstrating that<br />

SVOs are not uniformly distributed among people <strong>and</strong> that the vast majority of DMs have motivations<br />

consistent with one of three categories. Therefore using items from the whole space of possible SVOs<br />

is necessarily inefficient. The structure of the Ring Measure assigns equal value to the following two<br />

items: (1) Is a person more prosocial or more individualistic? (2) Is a person more a martyr or more<br />

masochistic? Clearly the first question is more useful in trying to underst<strong>and</strong> the motivations of typ-<br />

ical DMs. But, because of its blanket approach, the majority of items contained in the Ring Measure<br />

provide no useful information about the motivations of the person answering them. The only items<br />

that offer any useful diagnostic information are those with slopes that are nearly perpendicular to<br />

the underlying motivational vector of the decision maker. This agnostic approach results in a highly<br />

inefficient research tool.<br />

Second, the ring measure fails to classify a significant number of subjects due to inconsistent<br />

choice behavior. In their analysis of several studies that applied the Ring Measure, Au & Kwong<br />

(2004) reported percentages of up to 20% unclassifiable subjects <strong>and</strong> in two experiments performed<br />

by Liebr<strong>and</strong> (1984) himself, the percentage of unclassifiable subjects across the two experiments was<br />

15%. In analyzing these percentages, one has to take into consideration, that Liebr<strong>and</strong> (1984) used<br />

a 60% consistency criterion, whereas in at least some studies analyzed by Au & Kwong, a 50% con-<br />

sistency criterion was chosen (e.g. Van Lange 1999). Part of this inconsistency could be the result of<br />

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asking for people’s preferences across such a wide range of distributions, some of which they may have<br />

only weak preferences about. Moreover, inequality aversion would manifest itself as inconsistency in<br />

the Ring Measure. There are two different distribution options that minimize the difference between<br />

joint payoffs <strong>and</strong> if a subject were to choose both of these distributions when given the chance, the<br />

result would be an inconsistent choice set, as well as a shorter vector. And a further complication is<br />

that the Ring Measure has both positive <strong>and</strong> negative options. Given the evidence of how losses loom<br />

larger than gains (Kahneman & Tversky 1979), it is possible that DMs make different tradeoffs when<br />

considering positive outcomes versus negative (or mixed) outcomes. Lastly, the presence of losses<br />

makes it a challenge to implement the Ring Measure in an incentive compatible way as taking money<br />

from research subjects is generally verboten.<br />

Third, the Ring Measure would diagnose inequality aversion as inconsistency. The 45 ◦ diagonal<br />

line from the origin intersects the ring in two places; the point in quadrant 1 corresponds to both<br />

minimizing inequality as well as maximizing joint gain, whereas the point in quadrant 3 corresponds<br />

to minimizing inequality but minimizing joint gain. If a DM were sufficiently motivated by inequality<br />

aversion, he would produce an inconsistent set of allocations by selecting allocations on the diagonal<br />

whenever possiable. The Ring Measure does not address this limitation.<br />

3.5.3 Circle-test: A one-item version of the Ring Measure<br />

Sonnemans, van Dijk, & Winden (2006) conducted a study which required that subjects complete<br />

an SVO measure four times within the context of an ongoing public goods game. To these ends, the<br />

researchers modified the Ring Measure so that subjects had to make only one allocation decision to<br />

yield an SVO score. They termed this modified Ring Measure the “Circle Test.” In the Circle Test, sub-<br />

jects were provided with a graphical representation of the SVO Ring on a computer screen (similar to<br />

Figure 1). Subjects were then requested to make their joint allocation decision by clicking on a posi-<br />

tion somewhere on the arc of the circle. Once a position was tentatively chosen, the corresponding<br />

vector appeared on the screen as an arrow. Subjects then could, if they wanted to, change the angle<br />

of the vector while seeing how these changes affected the payoff allocations for themselves <strong>and</strong> the<br />

other person. Once a subject found her most preferred joint allocation, she confirmed her decision<br />

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<strong>and</strong> this completed the measurement session.<br />

The Circle Measure is a highly efficient measure of SVO, requiring only one allocation choice be<br />

made in order to yield a continuos score for a person. But one disadvantage of this brevity is that no<br />

information about measurement reliability can be gained. As the circle measure has only one item,<br />

it is not possible to check whether the choice is transitive or consistent with respect to other choices.<br />

The the measure does not provide any possibility to assess the magnitude of measurement error, <strong>and</strong><br />

at the extremes cannot asses if a participant responded veridically or r<strong>and</strong>omly. Another limitation<br />

is that the changes in payoffs that correspond to movements on the arc are non-linear. The visual<br />

representation is straight forward but the underlying tradeoffs that occur as a DM moves between<br />

different points on the arc are non-intuitive. The arc defining the joint payoffs is necessarily curved<br />

(its second derivative is non-zero), thus not only are the joint payoffs changing as a DM adjusts the<br />

allocation vector, but the rate of change for each of the payoffs is also changing. DMs may mitigate this<br />

complexity by selecting cardinal points on the circle rather than points consistent with their actual<br />

preferences. Lastly, secondary preferences about different allocation options remain unknown when<br />

using the circle measure.<br />

3.6 Regression <strong>and</strong> clustering approach<br />

Consistent with judgment (e.g. Wyer 1969, 1971) <strong>and</strong> conjoint measurement (e.g. Luce & Tukey<br />

1964, Sawyer 1966, Radzicki 1976), Knight & Dubro (1984) developed another method for assessing<br />

SVO that applies regression <strong>and</strong> cluster analysis to well structured preference judgments.<br />

3.6.1 Regression <strong>and</strong> clustering approach described<br />

To obtaining preference data, Knight & Dubro had subjects rate the desirability of joint alloca-<br />

tions on a 7-point scale, where the possible allocations were composed of all combinations of payoffs<br />

ranging from 0¢ to 6¢ in increments of 1¢, resulting in a total of 49 possible allocations <strong>and</strong> the same<br />

number of ratings. Then, for each person’s ratings, a multiple regression equation was used to model<br />

the desirability ratings, while three predictors were used in the analyses: own gain (number of cents<br />

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for self), other’s gain (number of cents for the other) <strong>and</strong> equal gains (difference between the own gain<br />

<strong>and</strong> the other’s gain). The resulting regression coefficients were then used in a cluster analysis which<br />

yielded six general clusters. These clusters were interpreted as different categories of SVO: equality;<br />

group enhancement; superiority; individualism; equality & individualism; <strong>and</strong> individualism & supe-<br />

riority.<br />

3.6.2 Discussion of regression <strong>and</strong> clustering approaches<br />

The similarities between the utility measurement approach, as proposed by Wyer (1969) (see sec-<br />

tion 3.3), <strong>and</strong> this regression analysis method are clear. In both methods, preference data are elicited<br />

<strong>and</strong> used to compute parameter values by a least squares estimation technique. The weights attached<br />

to outcome values in the utility functions are conceptually equivalent to the regression coefficients.<br />

The novelty of Knight & Dubro’s approach is the use of regression coefficients in a cluster analysis in<br />

order to classify people into SVO categories. Given the relatively high median squared multiple cor-<br />

relation coefficients for each of the six clusters, ranging from 0.609 to 0.858, it is clear that subjects<br />

exhibited substantial consistency in their judgments of the attractiveness of joint distributions.<br />

One minor drawback with respect to the feasibility of the measure is that Knight & Dubro’s proce-<br />

dure, like the utility measure approaches, makes use of more sophisticated statistical tools that may<br />

be a barrier to adoption for some researchers. Additionally, the amounts of money used as payoffs in<br />

their study were exceptionally small.<br />

3.7 Schulz <strong>and</strong> May’s Sphere Measure<br />

3.7.1 The Sphere Measure described<br />

On the basis of previous work on techniques of assessing SVO such as utility measurement (e.g.<br />

Wyer 1969, 1971, Griesinger & Livingston 1973, Radzicki 1976), the Ring Measure procedure (Liebr<strong>and</strong><br />

1984), <strong>and</strong> the regression <strong>and</strong> clustering approach (Knight & Dubro 1984), an additional way of de-<br />

termining people’s social motivations was devised by Schulz & May (1989). They differentiate be-<br />

tween simple linear SVOs (individualism, sacrifice, altruism, aggression, cooperation, competition),<br />

nonsimple linear SVOs (all possible mixtures of simple linear SVOs), simple conditional linear SVOs<br />

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(maximin <strong>and</strong> egalitarianism) as proposed by MacCrimmon & Messick (1976), <strong>and</strong> nonsimple nonlin-<br />

ear SVOs (all possible mixtures of simple conditional <strong>and</strong> nonconditional linear SVOs). For assessing<br />

these different SVO types, Schulz & May applied two measurement methods with the goal of compar-<br />

ing results from each of them. First they used a ranking procedure <strong>and</strong> second they used a pairwise<br />

comparison procedure. Concretely, subjects first made pair-wise comparisons between all possible<br />

combinations of 15 own-other-payoff distributions, resulting in a total of 105 comparisons per sub-<br />

ject. After completing the pair-wise comparison task, subjects were asked to rank order the same 15<br />

payoff allocations without ties using a graphic presentation of the allocation options. The data from<br />

both methods were then analyzed by using a utility model with the general form<br />

u x, y = ax + by + c x − y (4)<br />

which is flexible enough to contain all of the archetypical SVO types as special cases. Roughly speak-<br />

ing, while the Ring Measure uses the parameters a <strong>and</strong> b for calculating the SVO angle on a two-<br />

dimensional plane, Schulz & May extend the model with parameter c, thus yielding a three-dimensional<br />

model. The third dimension is useful in accounting for conditional SVOs (e.g. egalitarian or maximin).<br />

In order to restrict the model, the authors set the condition such that a 2 +b 2 +c 2 = 1, giving the model<br />

a spherical representation. Similar to the Ring Measure procedure, subjects are then categorized ac-<br />

cording to their vector direction. In contrast to the Ring Measure, the Sphere Measure vector extends<br />

into space <strong>and</strong> results as a point on the unit sphere rather than a point on a two dimensional circle.<br />

3.7.2 Discussion of the Sphere Measure<br />

Although Schulz & May make use of sophisticated mathematical tools, <strong>and</strong> uses a more complex<br />

geometric representation than previous methods, the measure still yields results at the nominal level.<br />

Richer results could be extracted from the data of Schulz & May (e.g. transitivity of individual’s choice<br />

sets; the angle of the projection of the inferred motivational vector on the self/other plane) but are<br />

unfortunately not. Further, this measurement method places substantial dem<strong>and</strong>s upon subjects,<br />

requiring them to make 105 pair-wise decisions about joint payoff allocations, as well as rank order<br />

15 different self/other allocations. Considering the resolution of the results, these dem<strong>and</strong>s are hard<br />

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to justify.<br />

4 The SVO Slider Measure<br />

We introduce here a new measure of SVO that has several advantages over existing measurement<br />

methods. The new method is referred to as the SVO Slider Measure <strong>and</strong> it can be administered as a<br />

paper based survey or as an online measure. The measure has six primary items with nine optional<br />

follow-up items. All of the items have the same general form. Each item is an allocation choice over a<br />

well defined continuum of joint payoffs. For example, consider a DM choosing a value x between 50<br />

<strong>and</strong> 100 inclusive. Her payoff would be x, whereas the other’s payoff would be 100− x. The DM would<br />

indicate her allocation choice by marking a line at the point that defines her most preferred joint<br />

distribution (see Item 1 in Figure 7, see also Table 11). After the DM has marked her most preferred<br />

allocation point, she would write the corresponding payoffs resulting from her choice to the right<br />

of the item. Although this step of writing the values is redundant, it serves to verify that the DM<br />

underst<strong>and</strong>s the choice task <strong>and</strong> the resulting allocations.<br />

4.1 Primary SVO Slider items<br />

There are six primary slider items. They are defined to cover the four most common social orien-<br />

tations, namely altruistic, prosocial, individualistic, <strong>and</strong> competitive. The items are shown in Figure<br />

7.<br />

These six items were derived from the six lines that fully interconnect the four points correspond-<br />

ing to the most common social orientations reported in the literature (altruistic, prosocial, individ-<br />

ualistic, <strong>and</strong> competitive; see Figure 8). A DM evaluates each of the items sequentially <strong>and</strong> for each<br />

one indicates her most preferred joint distribution. The set of responses can then be scored to yield<br />

an SVO single score for the DM, as well as the rank order of her social preferences, <strong>and</strong> a check for her<br />

preference transitivity.<br />

There are several advantages with the SVO Slider Measure. First, the responses can be evaluated<br />

for comprehension (e.g. checking the correspondence between the mark on the distribution line <strong>and</strong><br />

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Figure 7: Primary SVO Slider items. The first item is completed, indicating a DM chose to allocate<br />

herslf 81 <strong>and</strong> the other person 69.<br />

1<br />

2<br />

3<br />

4<br />

5<br />

6<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

100<br />

85<br />

50<br />

100<br />

50<br />

100<br />

100<br />

94<br />

87<br />

54 59 63 68 72 76 81 85<br />

98<br />

96 94 93 91 89 87 85<br />

54 59 63 68 72 76 81 85<br />

89<br />

98<br />

88<br />

89<br />

79 68 58 47 36 26 15<br />

96<br />

81<br />

50 56 63 69 75 81 88 94<br />

91<br />

15 19 24 28 33 37 41 46<br />

85<br />

85<br />

x<br />

94<br />

50 54 59 63 68 72 76 81<br />

75<br />

93<br />

85 85 85 85 85 85 85 85<br />

76<br />

93<br />

69<br />

94<br />

91<br />

63<br />

96<br />

89<br />

56<br />

98<br />

87<br />

50<br />

100<br />

100<br />

68 59 50 41 33 24 15<br />

the written distribution values). Second, the responses can be evaluated for transitivity. Although SVO<br />

is a matter of subjective preferences, these preferences should conform to the elemental requirement<br />

of transitivity. R<strong>and</strong>om responding on behalf of a subject would likely result in an intransitive set of<br />

responses. Third, the responses yield a full ranking of preferences over motivations. Fourth, the scale<br />

can be scored in a straight-forward manor as follows. The mean allocation for self is computed as is<br />

the mean allocation for the other. Then 50 is subtracted from each of these means (to account for the<br />

midpoint of the ring being at 50, 50). Then the inverse tangent of the ratio between these means is<br />

computed. The reason for the subtraction of 50 from each of the means is to “shift” the base of the<br />

resulting angle to the center of the circle rather than having its base start at the Cartesian origin. The<br />

resulting angle is interpretable just as the resulting angle vector that comes from the Ring Measure.<br />

SVO ◦ <br />

(Āo) − 50)<br />

= arctan<br />

(Ās) − 50)<br />

This response format is highly sensitive to individual differences <strong>and</strong> yields an index at the ratio level<br />

of measurement. Assessing SVO in this way also facilitates parameterization <strong>and</strong> model assessment<br />

(see section 5.6) that is not possible with other existent measures. Nonetheless, reducing the high res-<br />

29<br />

50<br />

85<br />

85<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other<br />

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olution score to a nominal category may be desirable in some cases, <strong>and</strong> Slider angles can be trans-<br />

formed into corresponding categories with ease.<br />

It can be shown that the resulting angle for a perfect altruist would be 61.39 ◦ . A prosocial DM<br />

with inequality aversion would yield an angle of 37.48 ◦ . A prosocial DM who endeavored to maximize<br />

joint gain (<strong>and</strong> is inequality tolerant) would yield an angle between 37.09 ◦ <strong>and</strong> 52.91 ◦ . The reason<br />

for this range is that this DM would be wholly indifferent across the entire SVO Slider item that has<br />

a slope of -1 (e.g. the item with endpoints 100,50 <strong>and</strong> 50,100) as it has a constant sum. A perfectly<br />

consistent individualist yields an angle between -7.82 ◦ <strong>and</strong> 7.82 ◦ . The reason for this range is that this<br />

particular DM would be wholly indifferent across the entire SVO Slider item that has an undefined<br />

slope (endpoints 85, 85 <strong>and</strong> 85, 15). A perfectly consistent competitor yields an angle of -16.26 ◦ . Given<br />

Figure 8: This figure shows where in the self/other allocation plane the six primary items are from the<br />

Slider Measure.<br />

Payoff to other<br />

100<br />

75<br />

50<br />

25<br />

50<br />

100<br />

0 25<br />

50 75 100<br />

Payoff to Self<br />

the angles that result from idealized SVO types, proper boundaries between categories can be derived.<br />

Altruists would have an angle greater than 57.15 ◦ ; prosocials would have scores between 22.45 ◦ <strong>and</strong><br />

57.15 ◦ ; individualists would have scores between -12.04 ◦ <strong>and</strong> 22.45 ◦ ; <strong>and</strong> competitive types would<br />

have an angle less than -12.04 ◦ . As it can be seen, these boundaries are not at intuitive locations. The<br />

reason for this is that the Slider Measure only uses a subset of possible items from the allocation plane<br />

<strong>and</strong> these items are not symmetrically distributed around the whole of the ring. Because only an<br />

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asymmetric set of items is used here, the resulting convex hull of possible scores is “squished” to the<br />

upper-right, relative to the midpoint of the ring. This feature does not adversely affect the validity<br />

of the measure. 6 We recognize that computing results from the SVO slider (checking for transitivity,<br />

establishing the ranking of preferences, finding a subject’s SVO angle) may be arduous <strong>and</strong> thus we<br />

have developed several analysis scripts that automate <strong>and</strong> simplify the process. These scripts are<br />

available on our SVO website at http://vlab.ethz.ch/svo/SVO_Slider/.<br />

4.2 Secondary SVO Slider items<br />

There are nine secondary Slider Measure items. This set of items is designed to disentangle the<br />

motivation of joint maximization from the motivation of inequality aversion. The items are defined<br />

in the prosocial area of the self/other allocation plane <strong>and</strong> have approximately the same magnitude<br />

(ranging between 50 <strong>and</strong> 100) as the six primary Slider items. One noteworthy feature is that all of<br />

the distribution ranges intersect the diagonal line. This is an important feature of the set as the diag-<br />

onal line corresponds to perfectly equal allocations, i.e., those distributions that minimize inequality<br />

between the DM <strong>and</strong> the other person. A participant motivated to minimize inequality would make<br />

allocations on or very near the 45 ◦ line. Conversely a participant motivated to maximize joint gains<br />

would make allocations near the endpoints, as far from the diagonal as possible, as these allocations<br />

maximize collective earnings. Previous measures of SVO have not been able to make a differentiation<br />

between these two motivations. The nine items are shown in Figure 9. An example of results from<br />

these items is discussed in Section §5.6.<br />

4.3 Web-based SVO Slider Measure<br />

In addition to being administrable as a paper-based measure, the Slider Measure has been pro-<br />

grammed as an online research tool (http://vlab.ethz.ch/svo/slider/). Once a researcher has<br />

an account, he or she can create a new study. This requires two things. First the researcher must<br />

6 It would be possible to extend the Slider Measure in such a way that it would have a symmetric set of items <strong>and</strong> thus<br />

have a rotationally symmetric convex hull of possible scores. This extended measure certainly would be more aesthetically<br />

pleasing <strong>and</strong> would have intuitive angles as boundaries between the categories. However, this extended measure would<br />

require about five times as many items <strong>and</strong> would likely yield no better estimation of a person’s SVO as the additional items<br />

would be targeting the sparsely populated categories (e.g. martyr, sadomasochistic). In developing the Slider Measure we<br />

strove for efficiency over aesthetics.<br />

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Figure 9: This figure shows the location of the nine secondary items for the Slider Measure in the<br />

self/other allocation plane.<br />

Payoff to other<br />

100<br />

75<br />

50<br />

25<br />

50<br />

100<br />

70<br />

100<br />

90<br />

100<br />

0 25<br />

50<br />

Payoff to Self<br />

75 100<br />

select which SVO measures to use (Slider primary items <strong>and</strong>/or Slider secondary items); second the<br />

researcher must input a list of subjects’ emails. These subjects then receive an email invitation to par-<br />

ticipate in online research. Each email invitation has a unique tokened link that when clicked upon<br />

takes the subject directly to the SVO website. Once there, the subject is presented with instructions<br />

<strong>and</strong> then a series of allocation choices. For each subject, the items are presented in a r<strong>and</strong>om order.<br />

Subjects record their choices by moving a slider back <strong>and</strong> forth, changing the joint allocations until<br />

they find their most preferred outcome (see Figure 10 for a screen shot). Once they are satisfied with<br />

the distribution, they finalize it by clicking the “Submit” button. Then the program takes them to<br />

the next item or if they have answered all of the items, to a conclusion <strong>and</strong> “thanks for participating”<br />

page. After all the subjects on the invitation list have participated (or a predetermined end date/time,<br />

whichever happens first) the researcher is sent via email a datafile with the subjects’ identifying infor-<br />

mation, item order, all of their choices, summary scores, <strong>and</strong> transitivity verification.<br />

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Figure 10: Online Slider Measure.<br />

5 Psychometric properties of SVO measures<br />

Considering the relatively large number of measurement methods that have been developed, rel-<br />

atively little effort has been made to validate them. However, some data are available. For example,<br />

Liebr<strong>and</strong> & van Run (1985) reported 73% agreement between the ring measure <strong>and</strong> the decomposed<br />

game procedure proposed by Kuhlman & Marshello (1975a), but only under the terms that altru-<br />

ists <strong>and</strong> cooperators were combined into a single category. Otherwise, the agreement between the<br />

two measures can at best be deemed only moderate, at least with respect to the altruistic <strong>and</strong> co-<br />

operative categories. Another test of the convergent validity of two SVO measures was performed<br />

by Parks (1994), who compared data from a classical decomposed game technique (Kuhlman et al.<br />

1986) to data from the regression <strong>and</strong> clustering approach (Knight & Dubro 1984). In coding data<br />

from both measures so that higher scores indicate greater cooperation, he reported a very small <strong>and</strong><br />

non-significant correlation (r = 0.08) between the two SVO measures, hence challenging the basic as-<br />

sumption that the same construct was assessed. Although there are other studies in which different<br />

measures of SVO were applied (e.g. Sheldon 1999, Van Lange 1999), results from which convergent<br />

validity could be inferred are often neither reported nor sufficiently elucidated.<br />

5.1 Slider Measure validation procedure<br />

In order to assess the psychometric properties of the new SVO Slider Measure it was tested in tan-<br />

dem with the established <strong>and</strong> commonly used measures of SVO; namely the Triple-Dominance Mea-<br />

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sure <strong>and</strong> the Ring Measure. Fifty-six individuals were recruited to participate in a multi-part “decision<br />

making study” at a European university. Participation was voluntary <strong>and</strong> no deception was used in<br />

this research. Participants were guaranteed strict confidentiality for all of their answers. The stimuli in<br />

the experiment were made incentive compatible by means of a lottery: for each experimental session<br />

four participants were r<strong>and</strong>omly selected after making their choices <strong>and</strong> for each selected person one<br />

of their allocation decisions was implemented (i.e. their allocation choice was carried out such that<br />

they received some chosen payoff, as well as did some other r<strong>and</strong>omly selected person, according to<br />

their actual choice). For all research sessions, participants were reminded that their decisions were<br />

private <strong>and</strong> that there was a real chance that their choices would have a pecuniary effect upon them-<br />

selves <strong>and</strong> some other person if they happened to be selected by lottery. DMs selected by lottery were<br />

paid privately in cash within a week of their participation. The average earnings were about 70 Swiss<br />

francs (US$68) each.<br />

Three research sessions were run, with one week separating the sessions. Each research session<br />

required fewer than 15 minutes to conduct <strong>and</strong> used paper based methods. In the first session, partic-<br />

ipants completed the 9-item Triple-Dominance Measure <strong>and</strong> the 24 item Ring Measure. In the second<br />

session, participants completed the Slider Measure (the 6 primary items) <strong>and</strong> the Triple-Dominance<br />

Measure. In the third session, participants completed the Ring Measure <strong>and</strong> the Slider Measure. All<br />

of the measures used st<strong>and</strong>ardized values between 0 <strong>and</strong> 100. This design allowed us to assess the<br />

test-retest reliability of the Triple-Dominance Measure, the Ring Measure, <strong>and</strong> the Slider Measure. It<br />

also allowed us to compute the associations between the different measures <strong>and</strong> establish norming<br />

data <strong>and</strong> convergent validity for the new SVO Slider Measure.<br />

5.2 Results<br />

Table 4 shows the percentage of individuals that were assigned to each of the different SVO cat-<br />

egories by the different measurement methods, ordered by experimental session. Across all mea-<br />

surement methods there is a clear majority type, namely prosocial, occurring about 59% of the time.<br />

Individualist is less common, but found about 34% of the time. Competitive <strong>and</strong> unclassifiable types<br />

complete the remainder of the sample representing about 3-4% each.<br />

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Table 4: The percentage of individuals that were assigned to each of the different SVO categories by<br />

the different measurement methods, ordered by experimental session.<br />

5.3 Reliability<br />

SVO<br />

Session 1 Session 2 Session 3 Gr<strong>and</strong><br />

TD RM TD SM RM SM mean<br />

Prosocial 60 53 61 58 57 64 59<br />

Individualistic 21 45 32 39 36 34 34<br />

Competitive 2 2 4 4 4 2 3<br />

Unclassifiable 17 0 4 0 2 0 4<br />

5.3.1 Triple-Dominance Measure test-retest reliability<br />

Table 5: A cross tabulation showing the frequency of categorization from test-retest for the Triple-<br />

Dominance Measure.<br />

Session 1<br />

Session 2<br />

Prosocial Individualistic Competitive Unclassifiable<br />

Prosocial 23 1 0 1<br />

Individualistic 2 8 0 0<br />

Competitive 0 1 0 0<br />

Unclassifiable 3 5 1 1<br />

Forty-six participants completed both sessions 1 <strong>and</strong> 2. Of those, 32 (23+8+0+1) were categorized<br />

in the same SVO category each time by the Triple-Dominance Measure, yielding a consistency of 70%<br />

(Goodman <strong>and</strong> Kruskal’s gamma 7 = 0.391).<br />

5.3.2 Ring Measure test-retest reliability<br />

Forty-four participants completed both sessions 1 <strong>and</strong> 3. Of those, 30 (18 + 12 + 0 + 0) were cate-<br />

gorized into the same SVO category each time by the Ring Measure, yielding a consistency of 68%.<br />

Further the correlation between the resulting angles from the test-retest of the ring measure was<br />

r = 0.599.<br />

7 As the Triple-Dominance Measure yields a nominal level variable with more than two categories, a Pearson product<br />

moment correlation coefficient is not an appropriate statistic for assessing its reliability, hence the non-parametric<br />

Gamma statistic is used as an index of test-retest association.<br />

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Table 6: A cross tabulation showing the frequency of categorization from test-retest for the Ring Measure.<br />

9<br />

Session 1<br />

Session 3<br />

Prosocial Individualistic Competitive Unclassifiable<br />

Prosocial 18 3 0 0<br />

Individualistic 8 12 1 0<br />

Competitive 0 1 0 0<br />

Unclassifiable 0 0 0 0<br />

5.3.3 Slider Measure test-retest reliability<br />

Table 7: A cross tabulation showing the frequency of categorization by test-retest for the Primary SVO<br />

Slider items.<br />

Session 2<br />

Session 3<br />

Prosocial Individualistic Competitive Unclassifiable<br />

Prosocial 25 1 0 0<br />

Individualistic 3 15 0 0<br />

Competitive 0 1 1 0<br />

Unclassifiable 0 0 0 0<br />

Forty-six participants completed both sessions 2 <strong>and</strong> 3. Of those, 41 were categorized in the same<br />

SVO category each time by the Slider Measure, yielding a consistency of 89%. Further the correlation<br />

between the resulting angles from the test-retest SVO Slider Measure was r = 0.915.<br />

5.4 Convergent validity<br />

5.4.1 Categorical agreement<br />

Across research sessions, the Triple-Dominance Measure <strong>and</strong> the Ring Measure categorized the<br />

same subjects into the same SVO category 62% of the time. The Triple-Dominance Measure <strong>and</strong> the<br />

Slider Measure categorized the same subjects in the same SVO category 70% of the time. And the Ring<br />

Measure <strong>and</strong> the Slider Measure categorized the same subjects in the same SVO category 75% of the<br />

time.<br />

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5.4.2 Correlational agreement<br />

The Ring Measure <strong>and</strong> Slider Measure both produce continuous results (in the form of angles<br />

within the self/other allocation plane), <strong>and</strong> these results are amenable to computing correlation co-<br />

efficients across different measures. Table 8 displays these correlation coefficients, showing both the<br />

test-retest reliability of the Ring Measure (r = 0.599) <strong>and</strong> Slider Measure (r = 0.915), as well as the<br />

correlations between SVO angles across the different measurement methods.<br />

Table 8: The correlation coefficients between the different sessions <strong>and</strong> methods. These values show<br />

both the test-retest reliabilities, as well as the cross method correlations (in grayed boxes) which address<br />

convergent validity.<br />

RM-1 RM-3 SM-2 SM-3<br />

RM-1 1 - - -<br />

RM-3 0.599 1 - -<br />

SM-2 0.724 0.536 1 -<br />

SM-3 0.680 0.641 0.915 1<br />

The results show that the Slider Measure correlates as well with the Ring Measure as the Ring<br />

Measure does with itself across retests. This is strong evidence that the methods are measuring the<br />

same thing <strong>and</strong> further it demonstrates that the Slider Measure is more reliable than the Ring Measure<br />

(the mean correlation between the different methods is r = 0.649 whereas the test-retest correlation<br />

for the Ring Measure is only r = .599).<br />

5.5 Additional results<br />

As noted before, one advantage of the Slider Measure is its resolution as it yields a ratio level mea-<br />

surement. Previous measures of SVO often reduced output to categorical levels, which can be a limita-<br />

tion. Retaining the ratio level variable, the distribution of SVO angles can be plotted <strong>and</strong> the density of<br />

different orientations can be estimated. Figure 11 shows this distribution. A lowess (Clevel<strong>and</strong> & De-<br />

vlin 1988) smoothed kernel density estimation was made of the distribution of SVO scores to provide<br />

some general idea of its shape. We find a multimodal distribution of SVO types in our sample. The<br />

largest clustering is in the prosocial region shifted slightly to the left (toward individualistic). The sec-<br />

ond clustering is in the individualistic region <strong>and</strong> is shifted to the right (toward prosocial). Within this<br />

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Figure 11: The distribution of SVO scores from the Slider Measure as represented by angles. The dark<br />

line is a smoothed kernel density estimation.<br />

region is the most common SVO score of 7.82 ◦ which corresponds to perfectly individualistic choices.<br />

The density function trails off to the left, denoting only a few competitive types.<br />

The transitivity of responses can also be assessed with the Slider Measure. We found that 97% of<br />

our subjects produced completely transitive sets of social preferences. This finding st<strong>and</strong>s in stark<br />

contrast to the consistency results from the Ring Measure where only 53% of the same subjects pro-<br />

duced internally consistent results. The cause of this difference is likely the result of the Ring Mea-<br />

sure’s blanket approach to measuring social preferences which introduces a substantial amount of<br />

noise.<br />

The full ranking of people’s social preferences can be obtained from evaluating the primary items<br />

of the Slider Measure. Across sessions the majority of people’s first preference was consistent with a<br />

prosocial orientation (see Table 9 for the full rankings). Considering these people who most preferred<br />

to be prosocial, about 66% of them had individualistic as their next preference, whereas the remaining<br />

34% preferred altruism. The least preferred SVO from the Slider Measure was competitive, with 52%<br />

of subjects revealing this as their least favorite orientation. Altruism was also commonly the least<br />

preferred option, being ranked last by 42% of the participants.<br />

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Table 9: Full rank orderings of social preferences from the SVO Slider Measure across sessions<br />

First preference Second preference Third preference Least prefered Percent<br />

Prosocial Individualistic Altruistic Competitive 28%<br />

Prosocial Altruistic Individualistic Competitive 25%<br />

Prosocial Individualistic Competitive Altruistic 13%<br />

Individualistic Prosocial Competitive Altruistic 24%<br />

Individualistic Competitive Prosocial Altruistic 5%<br />

Individualistic Prosocial Altruistic Competitive 2%<br />

Competitive Individualistic Prosocial Altruistic 3%<br />

5.6 Separating joint maximization <strong>and</strong> inequality aversion<br />

The Secondary items from the Slider Measure are designed to differentiate between two different<br />

prosocial motivations: joint maximization <strong>and</strong> inequality aversion. As prosocial behavior can arise<br />

from both of these underlying motivations, we demonstrate here how to disentangle these motiva-<br />

tions using the Secondary Slider items.<br />

In order to identify prosocial DM’s underlying motivations, two mean difference scores were com-<br />

puted for each subject. The first difference score was defined as the average distance each of the<br />

subject’s allocations was from the allocation that minimized the difference between the payoff for the<br />

self <strong>and</strong> the other. Distance here was defined geometrically in the self/other plane. If a DM always<br />

chose allocations that were on the diagonal line (see Figure 9), her mean difference score would be 0,<br />

indicating perfect consistency with inequality aversion. A second difference score was computed for<br />

each participant that was defined as the mean distance between her selected allocation on an item<br />

<strong>and</strong> the particular allocation that maximized joint payoff for that item. If the mean difference for this<br />

second index was zero, it indicates that a DM’s allocation choices are perfectly consistent with joint<br />

maximization. These indexes are by definition negatively correlated given our set of nine items, as the<br />

more inequality averse a DM was, the less joint maximizing she was, <strong>and</strong> vice versa. Based on these<br />

goodness-of-fit scores, DMs could be categorized as inequality averse or joint gain maximizing.<br />

Results from session 2 show that for the 34 people who were prosocial (according to the primary<br />

slider items from session 2), 21 (62%) were joint maximizing whereas 12 (35%) were inequality averse;<br />

one participant left some items blank <strong>and</strong> was excluded from this analysis. The results were similar for<br />

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session 3 in which of the 36 people who were categorized as prosocial (again according to the primary<br />

slider items from that session), 20 (56%) were joint maximizing <strong>and</strong> 16 (44%) were inequality averse.<br />

Between sessions, we find that 76% of subjects had the same categorization.<br />

Although it is beyond the scope of this paper, the data from the SVO Slider Measure (both primary<br />

<strong>and</strong> secondary items) are amendable to sophisticated modeling. Several models of other regarding<br />

preferences have been developed in behavioral economics (see, for instance Fehr & Schmidt 1999,<br />

Bolton & Ockenfels 2000, Andreoni & Miller 2002, Charness & Rabin 2002, Engelmann & Strobel 2004)<br />

that address issues of equity, inequality aversion, fairness, <strong>and</strong> reciprocity. The psychological litera-<br />

ture related to the same issues has developed in parallel but largely done so independently. Perhaps<br />

one reason for this schism is the lack of a common measurement methods between the two fields.<br />

The SVO Slider Measure could act as a bridge to connect these two related but estranged research<br />

streams.<br />

6 Discussion<br />

The arc of scientific knowledge is bounded by our ability to measure things. This paper is about<br />

measuring SVO, a fundamental concept in social decision making. We have provided an overview<br />

of different ways social preferences have been measured to date across a variety of disciplines, high-<br />

lighted limitations with existent measures, <strong>and</strong> reported on the development of a new measure of<br />

individuals’ social preferences. This new measure is efficient, easy to implement, has very good psy-<br />

chometric properties (established convergent validity <strong>and</strong> high test-retest reliability), yields a score at<br />

the ratio level, <strong>and</strong> facilitates comparison to previous findings. The advent of a high resolution mea-<br />

sure of SVO opens opportunities for different research streams to use social preferences as a depen-<br />

dent variable. These types of studies could address questions regarding how context, information,<br />

experience, <strong>and</strong> framing affect peoples’ propensities to make tradeoffs in resources between them-<br />

selves <strong>and</strong> others. These lines of research could also answer larger questions like: when is Homo<br />

Economics a generally good approximation of human behavior <strong>and</strong> when is it insufficient or even<br />

grossly inaccurate.<br />

<strong>Social</strong> preferences are of utmost importance in underst<strong>and</strong>ing how interrelated DMs allocate scarce<br />

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resources among themselves <strong>and</strong> others. The postulate of narrow self interest is a point conjecture,<br />

namely that DMs have exactly zero interest in the outcomes of other people. Although this is a useful<br />

baseline assumption in that it facilitates tractable models with precise predictions, <strong>and</strong> in many cases<br />

works well as an “as if” model, there are numerous examples where it fails to account for DMs’ be-<br />

havior. Real people’s preferences are often much richer, more nuanced, <strong>and</strong> complex than narrow self<br />

interest. Moreover it is worth recognizing that the point conjecture is inadequate not only to account<br />

for different people having different social preferences, but the malleability of these preferences in<br />

different situations.<br />

The notion that a DM’s utility is not exclusively a function of his own material well being, but<br />

is also affected by the well being of others (No man is an isl<strong>and</strong>. . . ) is not a new idea. Edgeworth<br />

(1881) explicitly postulated this idea <strong>and</strong> anticipated a wide range of social orientations. The modern<br />

challenge is quantifying Edgeworth’s fraction by building reliable <strong>and</strong> efficient methods to measure<br />

this degree of entanglement in DM’s utilities <strong>and</strong> thus exp<strong>and</strong>ing theories of social decision making<br />

that can accommodate the richness <strong>and</strong> dynamics of social preferences.<br />

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References<br />

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Murphy, Ackermann & H<strong>and</strong>graaf (2010) DRAFT v0.6 <strong>Measuring</strong> SVO<br />

Appendix<br />

a<br />

1<br />

2<br />

3<br />

4<br />

5<br />

6<br />

Figure 12: Paper based SVO Slider Measure, primary items<br />

In the following decision task, you are given the opportunity to distribute money between yourself <strong>and</strong> some other<br />

person whom you will remain anonymous. For each of the following 6 questions, please indicate the distribution you<br />

prefer most by marking the respective position along the midline. You can only make one mark for each question.<br />

There are no right or wrong answers, just place your mark at the position of your most preferred distribution. After<br />

you have made your decision, write the resulting distribution of money on the spaces on the right.<br />

In the example below, a person has chosen to distribute money so that he/she receives 50 dollars, while the<br />

anonymous other person receives 40 dollars.<br />

You receive<br />

30<br />

50<br />

100<br />

50<br />

100<br />

50<br />

100<br />

85<br />

85<br />

85<br />

85<br />

100<br />

50<br />

54 59 63 68 72 76 81 85<br />

98<br />

56 63 69 75 81 88 94 100<br />

94<br />

54 59 63 68 72 76 81 85<br />

89<br />

88 81 75 69 63 56 50<br />

79 68 58 47 36 26 15<br />

87 89 91 93 94 96 98 100<br />

81<br />

76 72 68 63 59 54 50<br />

85 85 85 85 85 85 85 85<br />

76<br />

68 59 50 41 33 24 15<br />

98 96 94 93 91 89 87 85<br />

46<br />

Instructions<br />

Example:<br />

35 40 45 50 55 60 65 70<br />

Other receives 80 70 60 50 40 30 20 10 0<br />

Other 40<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

96 94 93 91 89 87 85<br />

41 37 33 28 24 19 15<br />

48<br />

You<br />

50<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other


Murphy, Ackermann & H<strong>and</strong>graaf (2010) DRAFT v0.6 <strong>Measuring</strong> SVO<br />

Figure 13: Paper based SVO Slider Measure, secondary items<br />

7<br />

8<br />

9<br />

10<br />

11<br />

12<br />

13<br />

14<br />

15<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

You receive<br />

Other receives<br />

100<br />

100<br />

50<br />

100<br />

94<br />

56 63 69 75 81 88 94 100<br />

99<br />

88<br />

81<br />

70 74 78 81 85 89 93 96<br />

70<br />

100<br />

50<br />

100<br />

100<br />

96<br />

75<br />

69<br />

98 96 95 94 93 91 90<br />

63<br />

56<br />

50<br />

100<br />

74 78 81 85 89 93 96 100<br />

96<br />

56 63 69 75 81 88 94 100<br />

94<br />

96<br />

93<br />

93 89 85 81 78 74 70<br />

88 81 75 69 63 56 50<br />

93<br />

89<br />

50 56 63 69 75 81 88 94<br />

90<br />

100<br />

100<br />

89<br />

90 91 93 94 95 96 98 99<br />

85<br />

85<br />

81<br />

81<br />

78<br />

78<br />

74<br />

74<br />

70<br />

100<br />

91 93 94 95 96 98 99 100<br />

99<br />

99<br />

98 96 95 94 93 91 90<br />

98<br />

96<br />

70 74 78 81 85 89 93 96<br />

90<br />

100<br />

95<br />

94<br />

93<br />

91<br />

90<br />

100<br />

70<br />

100<br />

91 93 94 95 96 98 99 100<br />

94<br />

88 81 75 69 63 56 50<br />

49<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other<br />

You<br />

Other


Murphy, Ackermann & H<strong>and</strong>graaf (2010) DRAFT v0.6 <strong>Measuring</strong> SVO<br />

Table 10: The st<strong>and</strong>ardized items from the 24-item Ring Measure. Notice how the values have been<br />

transformed to be positive <strong>and</strong> range between 0 <strong>and</strong> 100.<br />

Option 1 Option 2<br />

Item Self Other Self Other<br />

1 50 100 37 98<br />

2 37 98 25 93<br />

3 25 93 15 85<br />

4 15 85 7 75<br />

5 7 75 2 63<br />

6 2 63 0 50<br />

7 0 50 2 37<br />

8 2 37 7 25<br />

9 7 25 15 15<br />

10 15 15 25 7<br />

11 25 7 37 2<br />

12 37 2 50 0<br />

13 50 0 63 2<br />

14 63 2 75 7<br />

15 75 7 85 15<br />

16 85 15 93 25<br />

17 93 25 98 37<br />

18 98 37 100 50<br />

19 100 50 98 63<br />

20 98 63 93 75<br />

21 93 75 85 85<br />

22 85 85 75 93<br />

23 75 93 63 98<br />

24 63 98 50 100<br />

50


Murphy, Ackermann & H<strong>and</strong>graaf (2010) DRAFT v0.6 <strong>Measuring</strong> SVO<br />

Figure 14: SVO measurement overview. The diagram reflects a subjective estimation of influences<br />

certain measurement techniques had on the development of subsequent ones. Arrows in the diagram<br />

mean that there are respective citations. When two papers are not connected to each other in this<br />

figure, it does not necessarily mean that there is no relation between them, it simply means that there<br />

is no citation.<br />

1965<br />

1970<br />

1980<br />

1990<br />

1995<br />

Utility & Conjoint Tradition Decomposed Games Tradition<br />

Sawyer<br />

(1966)<br />

Altruism Scale<br />

Griesinger & Livingston<br />

(1973)<br />

Geometric Model<br />

Radzicki<br />

(1976)<br />

Conjoint Measurement<br />

Wyer<br />

(1969)<br />

Utility Measurement<br />

Knight & Dubro<br />

(1984)<br />

Regression & Clustering<br />

Schulz & May<br />

(1989)<br />

Sphere Measure<br />

Iedema & Poppe<br />

(1994)<br />

Rank Correlation Procedure<br />

51<br />

Messick & McClintock<br />

(1968)<br />

Decomposed Games<br />

Liebr<strong>and</strong><br />

(1984)<br />

Ring Measure<br />

Kuhlman & Marshello<br />

(1975)<br />

DG Procedure<br />

VanLange & Kuhlman<br />

(1994)<br />

9 Item Triple Dominance Scale<br />

Pruitt<br />

(1967)<br />

Decomposed Games<br />

McClintock et al.<br />

(1973)<br />

Three option DG<br />

Knight & Kagan<br />

(1977)<br />

<strong>Social</strong> Behavior Scale<br />

Kuhlman et al.<br />

(1992)<br />

DG Procedure


Murphy, Ackermann & H<strong>and</strong>graaf (2010) DRAFT v0.6 <strong>Measuring</strong> SVO<br />

Table 11: SVO Item endpoints <strong>and</strong> subsequent slopes that define each of the Slider Measure items.<br />

Option 1 Option 2 Descriptive information<br />

Item Self Other Self Other Slope Equation<br />

1 50 100 85 85 -0.43 y = − 3 850<br />

7 · x + 7<br />

2 50 100 100 50 -1.00 y = −1 · x + 150<br />

3 50 100 85 15 -2.43 y = − 17<br />

4 85 85 100 50 -2.33<br />

1550<br />

7 · x + 7<br />

y = − 7 850<br />

3 · x + 3<br />

5 85 85 85 15 Undefined y ∈ [15,85], x = 85<br />

6 100 50 85 15 2.33 y = 7 550<br />

3 · x + 3<br />

7 100 50 70 100 -1.67 y = − 5 650<br />

3 · x + 3<br />

8 90 100 100 90 -1.00 y = −1 · x + 190<br />

9 100 70 50 100 -0.60 y = − 3<br />

5 · x + 130<br />

10 100 70 90 100 -3.00 y = −3 · x + 370<br />

11 70 100 100 70 -1.00 y = −1 · x + 170<br />

12 50 100 100 50 -1.00 y = −1 · x + 150<br />

13 100 90 70 100 -0.33<br />

3<br />

y = − 1<br />

14 100 90 70 100 -0.33<br />

370<br />

3 · x + 3<br />

y = − 1 370<br />

3 · x + 3<br />

15 90 100 100 50 -5.00 y = −5 · x + 550<br />

52

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