S1 (FriAM 1-65) - The Psychonomic Society

Posters 2055–2061 Friday Noon
problem, we present a range of reinforcement learning models that explore
how slight shifts in attended dimensions and reinforced units of
behavior can result in different allocation strategies. Beyond mimicking
aggregate human data, our models explain how sequential
decision making can be understood as a combination of feedback- and
strategy-driven processes, effectively reconceptualizing probability
matching as representational learning.
(2055)
Exploring the Supraliminal Mere Exposure Effect. MARC G.
BERMAN, RICHARD GONZALEZ, & MICHAEL S. FRANKLIN,
University of Michigan—The mere exposure effect is a phenomenon
where participants prefer stimuli that have been repeatedly presented
as opposed to stimuli that have not been presented. The stimuli in most
mere exposure studies are neutral and novel to the participant, therefore
eliminating preexisting valence. Here, we explored how the
supraliminal mere exposure effect was affected by differently valenced
stimuli (as determined by independent raters). In addition, we
explored potential factors accounting for the observed heterogeneity
whereby some participants show the mere exposure effect and others
do not. Furthermore, we present a statistical method for analyzing
mere exposure data using ordinal regression that is more sensitive
than previously utilized techniques and permits modeling the heterogeneity.
Preliminary findings suggest that subjects who do show the
effect are not influenced by stimulus valence and utilize recognition
to determine stimulus preference. Therefore, it appears that recognition
overrides initial stimulus valence in supraliminal mere exposure
preference judgments.
(2056)
A Comparison of Reaction-Time Models of Multiple-Choice Decisions.
FABIO LEITE & ROGER RATCLIFF, Ohio State University
(sponsored by Roger Ratcliff)—Several sequential sampling models
for multiple-choice decisions were evaluated. These models used various
racing diffusion processes (e.g., Usher & McClelland’s, 2001,
leaky competing accumulator model). The structures of the models
differed on a number of dimensions, including starting point of competing
accumulators, lateral inhibition, and constraints on accumulation
rates (e.g., accumulators only allowed to take nonnegative values).
Data were collected from a letter-discrimination experiment in
which stimulus difficulty or probability of the response alternatives
was varied along with number of response alternatives. Performance
of the models was addressed by testing them against empirical data,
including issues of psychological plausibility of parameter estimates
and mimicry among models.
(2057)
Effects of Caffeine on Deck Selection in Two Gambling Tasks.
PATRICK A. RAMIREZ & DANIEL S. LEVINE, University of Texas,
Arlington—Participants were given two different gambling tasks: the
Iowa Gambling Task (IGT) due to Bechara et al., and a variant of the
modified IGT due to Peters and Slovic, in either order, with 100 trials
in each. On the second task, the participants were given either a caffeinated
drink (treatment), a decaffeinated drink (placebo), or water
(control). It was found that caffeine significantly increased the tendency
to choose advantageous decks, but only on the Bechara task and
not on the Peters task. The advantage of caffeine on the Bechara task
was manifest even on the first 20 deck selections. This led us to conjecture
that the effect of caffeine could be primarily an enhancement
of attention, with the Bechara task being the more subject to inattention
because the Peters task has more variability in its outcomes.
(2058)
Human and Optimal Valuation in a Sequential Decision-Making
Task With Uncertainty. KYLER M. EASTMAN, BRIAN J. STANKIE-
WICZ, & ALEX C. HUK, University of Texas, Austin—Many sequential
sampling models suggest that decisions rely on the accumulation
of evidence over time until reaching a particular threshold.
77
These models can often account for variations of speed and accuracy
in perceptual tasks by manipulation of this threshold. But how does
this threshold get determined in real-world decisions? It has been hypothesized
that the threshold maximizes some reward function, possibly
incorporating measurements of both speed and accuracy (Gold
& Shadlen, 2003). This approach has produced a family of models that
accurately describes behavior for two-alternative forced choice
(2AFC) tasks. (Bogacz et al., 2006) However, it has been unclear what
the optimal threshold becomes when additional perceptual information
can be obtained at a cost. We present a model of optimal sequential
decision making in a task that extends the traditional 2AFC
by adding the option of additional information. In the task, the observer
receives a sample from two overlapping distributions.
• JUDGMENT •
(2059)
Associations Between Absent Events in Contingency Judgment.
LEYRE CASTRO, FABIÁN A. SOTO, & EDWARD A. WASSERMAN,
University of Iowa—Studies of contingency judgment have shown that
cue–outcome associations can be strengthened or weakened even
when the cues are absent (e.g., retrospective revaluation effects). But,
there is no evidence in the mainstream contingency judgment literature
for the formation of new associations between an absent cue and
an absent outcome. Interestingly, research with human infants
(Cuevas, Rovee-Collier, & Learmonth, 2006) and nonhuman animals
(Dwyer, Mackintosh, & Boakes, 1998) has disclosed that new associations
between cues and outcomes can be formed when neither of
them is presented. In our own contingency judgment experiments, we
have found evidence for the formation of new associations between
cues and outcomes that are absent, but that are associatively activated.
Our results raise difficult problems for cognitive or inferential accounts
(e.g., De Houwer, Beckers, & Vandorpe, 2005), but they can
be readily explained by associative learning models (e.g., Dickinson
& Burke, 1996; Van Hamme & Wasserman, 1994).
(2060)
The Effect of Race on Guilty Verdicts: Order Matters. LESLIE N.
KNUYCKY, HEATHER M. KLEIDER, & ASHLEY MYERS, Georgia
State University (sponsored by Stephen D. Goldinger)—Factors
other than case evidence (i.e., available cognitive capacity, judgment
instructions) influence juror verdicts (Goldinger et al., 2003). Racial
bias, one factor shown to affect jury judgments (Jones & Kaplan,
2003), is posited as an automatic response often difficult to intentionally
control. We examined whether attempts to inhibit bias may
“backfire” when race is made especially salient. In two experiments,
case presentation order (varying position of black or white defendants)
and instructions to ignore race impacted jury decisions. The results
showed that with no instruction, black defendants received
harsher judgments when presenting white- before black-defendant
cases. This order effect was negated in Experiment 2 with instruction
to disregard race, as guilty verdicts increased overall for black defendants.
This suggests that when race is “noticeable” via presentation
order or instruction, racially biased decisions result. Such decisions
lead to more severe verdicts for black defendants than when race goes
“undetected.”
(2061)
Judgments of Randomness: Is There a Bias Toward High Alternation?
FIONA E. J. MCDONALD & BEN R. NEWELL, University of
New South Wales (sponsored by Ben R. Newell)—Extensive research
has documented that people are poor generators of random sequences.
A key feature of human generated sequences is a tendency for excessive
alternation of outcomes. The research on judgments of randomness
is not as extensive but it has been found that when judging sequences,
there is also a tendency to judge those with excessive
alternation as most random. We challenge this notion, finding through
a series of experiments only minimal bias in judgments of random-