Affective startle modulation in anticipation and perception

Psychophysiology, 38 ~2001!, 719–722. Cambridge University Press. Printed in the USA.
Copyright © 2001 Society for Psychophysiological Research
BRIEF REPORT
Affective startle modulation in anticipation and perception
DEAN SABATINELLI, MARGARET M. BRADLEY, and PETER J. LANG
National Institute of Mental Health Center for the Study of Emotion and Attention, University of Florida, Gainesville, USA
Abstract
Startle modulation was investigated as participants first anticipated and then viewed affective pictures in order to
determine whether affective modulation of the startle reflex is similar in these different task contexts. During a 6-s
anticipation period, a neutral light cue signaled whether the upcoming picture would portray snakes, erotica, or
household objects; at the end of the anticipatory period, a picture in the signaled category was viewed for 6 s. Male
participants highly fearful of snakes were recruited to maximize emotional arousal during anticipation and perception.
Results indicated that the startle reflex was potentiated when anticipating either unpleasant ~phobic! or pleasant ~erotic!
pictures, compared to neutral stimuli, whereas during perception, reflexes were potentiated when viewing unpleasant
stimuli, and reduced when viewing pleasant pictures. The startle reflex is modulated by hedonic valence in picture
perception, and by emotional arousal in a task context involving picture anticipation.
Descriptors: Emotion, Anticipation, Startle reflex, Affective pictures
The magnitude of the startle reflex covaries with hedonic valence
during stimulus perception. Affective modulation of the startle
reflex is found when people view pictures or films, listen to
sounds, or smell odors ~for an overview, see Bradley, Cuthbert, &
Lang, 1999!. In each case, larger reflexes are elicited when processing
unpleasant stimuli, compared to pleasant stimuli. Furthermore,
these modulatory differences are greatest for unpleasant and
pleasant stimuli that are rated as highly arousing ~Cuthbert, Bradley,
& Lang, 1996!. We have suggested that reflex modulation
during perception reflects motivational priming, in which activation
of the defensive motivational system by an unpleasant stimulus
primes related reflexes, such as the startle reflex ~Lang,
Bradley, & Cuthbert, 1997!.
Potentiation of the blink reflex has also been found when
participants simply anticipate the occurrence of an unpleasant
event, such as intense noise ~Patrick & Berthot, 1995! or shock
~Grillon, Ameli, Woods, Merikangas, & Davis, 1991!. Determining
whether potentiation during aversive anticipation is related to stimulus
unpleasantness or to stimulus arousal relies on assessing
reflex magnitude during the anticipation of a similarly arousing
pleasant stimulus. Studies of startle modulation during anticipation
have not typically included pleasant stimuli, due at least in
This work was supported in part by National Institute of Mental Health
grants MH37757 and MH43975 and P50-MH52384, a NIMH Behavioral
Science grant to the Center for the Study of Emotion and Attention
~CSEA!, University of Florida, Gainesville, Florida.
Address reprints requests to: Margaret M. Bradley, Box 100165 HSC,
University of Florida, Gainesville, FL 32610-0165, USA. E-mail: bradley@
ufl.edu.
719
part to difficulties in identifying an arousing appetitive stimulus
that is also in the same sensory modality as an electric shock or a
noise blast. Here, we measured the magnitude of the startle reflex
while participants anticipated the presentation of highly arousing
unpleasant or pleasant pictures. Pictures were used as stimuli
because numerous studies have confirmed that perception of these
stimuli elicits emotional reactions in self-report, physiological, and
behavioral systems ~e.g., Lang, Greenwald, Bradley, & Hamm,
1993!.
Compared to the anticipation of an intense unconditioned stimulus
such as electric shock ~Grillon et al., 1991!, pictures may be
less likely to engage strong anticipatory responses. Thus, in the
present study, we selected picture stimuli that were maximally
arousing. Previous research ~e.g., Hamm, Cuthbert, Globisch, &
Vaitl, 1997! has found that aversive responding is heightened when
fearful participants view fear-related pictures; therefore the present
study presented pictures of snakes to participants reporting high
snake fear. For pictures rated as pleasant, erotic materials elicit the
strongest affective reactions, particularly for men ~Bradley, Codispoti,
Sabatinelli, Cuthbert, & Lang, 2000!, who were recruited as
participants in the current study.
Each trial consisted of an anticipation and a perception period.
During each 6-s anticipatory period, one of three cue lights signaled
that the upcoming picture would depict either snakes, erotica,
or household objects. Following anticipation, the picture was
presented for 6 s. An acoustic startle probe was presented in the
latter half of the anticipation or perception period, and the reflexive
eyeblink response measured. If the startle reflex is modulated by
picture content similarly in anticipation and perception, reflexes
elicited when anticipating unpleasant ~snake! pictures will be larger

720 D. Sabatinelli, M.M. Bradley, and P.J. Lang
than those elicited when anticipating pleasant ~erotic! pictures.
Conversely, if reflex modulation during anticipation is primarily
sensitive to emotional arousal, reflexes will be potentiated when
anticipating emotionally arousing ~pleasant or unpleasant!, compared
to neutral, stimuli. As larger electrodermal responses have
been found when anticipating ~Simons, Öhman, & Lang, 1979! or
perceiving ~e.g., Bradley et al., 1999; Lang et al., 1993! affectively
arousing stimuli, this measure was included here to assess the
specificity of the startle reflex as an index of affective processing.
Method
Participants
Thirty-two male University of Florida students were recruited
after being identified as meeting a preliminary criterion of elevated
snake fear. Participation was voluntary and compensated
with course credit or a payment of $10. After completing the
procedure, all participants filled out a snake fear questionnaire
~SNAQ; Klorman, Weerts, Hastings, Melamed, & Lang, 1974!.
Twenty-four participants falling above the 85th percentile of snake
fear for men were accepted into the final group ~final SNAQ
mean 13.5, SD 5!.
Materials and Design
Forty-eight color pictures were selected from the International
Affective Picture System 1 ~Center for the Study of Emotion and
Attention, 1999!, including equal numbers of erotic, household
object, and snake scenes. In addition to three practice pictures, five
blocks of nine pictures were arranged such that three pictures from
each category were presented randomly in a block. Three presentation
orders were developed such that, across participants, each
picture was seen equally often in the first, second, or third portion
of each block. Pictures were presented using a Kodak Ektagraphic
III AM slide projector situated adjacent to the experimental room.
A slide screen hung approximately 2minfront of the participant,
with three clear lights arranged horizontally above the screen,
20 cm apart from each other. Each of the three lights was used to
cue the presentation of a specific category of pictures ~snakes,
erotica, or household objects!, counterbalanced across participants.
Each trial consisted of a 6-s anticipatory interval, during which one
of the three lights was continuously lit, followed by a6sperception
period, in which a picture in the cued category was presented.
Intertrial intervals ranged from 10 to 20 s.
The acoustic startle probe consisted of a 99 dB, 50-ms presentation
of white noise, with instantaneous rise time, produced by a
Coulbourn S81-02 noise generator, gated through a Coulbourn
S82-24 amplifier, and presented over matched Telephonics TDH-49
headphones. Of the 43 startle stimuli presented, 24 occurred during
the 6-s anticipation interval ~4,000 or 5,500 ms after cue onset!,
8 for each of the three picture categories. Twelve probes were
presented during the 6-s perception interval ~3,500 or 4,000 ms
1 The International Affective Picture System ~IAPS! is available on
CD-ROM and as photographic slides. The stimulus sets and technical
manual ~CSEA, 1999! can be obtained on request from Margaret M.
Bradley or Peter J. Lang, NIMH Center for the Study of Emotion and
Attention, Box 100165 HSC, University of Florida, Gainesville, FL 32610-
0165, USA.
IAPS numbers used in this study were: Erotica: 4210, 4220, 4232,
4290, 4300, 4310, 4607, 4608, 4651, 4652, 4655, 4664, 4680, 4800, 4810;
Household objects: 7002, 7006, 7009, 7025, 7030, 7034, 7040, 7140, 7190,
7217, 7224, 7234, 7235, 7490, 7900; Snakes: 1000, 1010, 1020, 1030,
1040, 1050, 1070, 1080, 1090, 1100, 1110, 1111, 1112, 1113, 1120.
after picture onset!, four for each picture category. Three probes
were presented during practice trials, and four probes were presented
during intertrial intervals. Nine non-probed trials were also
included.
Physiological Recording and Data Reduction
Stimulus control and physiological data acquisition were accomplished
using an IBM-compatible computer running VPM software
~Cook, 1994!.
The eyeblink component of the startle reflex was recorded
electromyographically from the orbicularis oculi muscle beneath
the left eye, using miniature SensorMedics Ag0AgCl electrodes
placed 1.5 cm apart. The raw signal was amplified by 30,000 and
band-pass filtered at 90–250 Hz using a Coulbourn S75-01 amplifier.
The amplified signal was then rectified and integrated using
a Coulbourn S76-01 contour-following integrator set at an actual
time constant of 123 ms, and sampled at 20 Hz beginning 3 s
before each trial. Sampling increased to 1000 Hz 50 ms prior to the
onset of the startle probe and continued for 250 ms. Sampling then
continued at 20 Hz until 3 s after picture offset. Startle blinks were
scored off-line with an interactive computer program that scored
onset latency and peak.
Skin conductance was transduced with SensorMedics standard
electrodes filled with a 0.05 molar NaCl0Unibase cream electrolyte
affixed to the hypothenar eminence of the left palm. A Coulbourn
S71-22 skin conductance coupler provided a constant 0.5 V
across the two electrodes. After log transformation, change scores
were calculated for skin conductance by subtracting the mean
activity in the 1 s preceding cue-light onset from the average
response during each of the 6-s anticipation and 6-s perception
intervals.
Procedure
The physiological sensors were attached while the participant
reclined in a comfortable chair. The participant was then told
which of the three cue lights ~left, middle, right! would signal
whether the upcoming picture would involve snakes, household
objects, or erotica. Picture onset coincided with cue-light offset,
and participants were instructed to look at the picture the entire
time it was on the screen, and to ignore occasional noises presented
over the headphones. Following the session, participants filled out
the SNAQ and three other questionnaires, and were debriefed.
Data Analysis
A23 repeated-measures analysis of variance was conducted for
blink magnitude and skin conductance change individually, with
Processing Period ~anticipation, perception!, and Picture Content
~erotica, household object, snake! as within-subjects factors. For
repeated-measures analyses, a Greenhouse–Geisser correction was
used when appropriate.
Results
Startle Reflex
Modulation of the startle reflex by picture content differed in
anticipation and perception, as indicated by a significant Period
~anticipation, perception! Content ~erotic, household object, or
snake pictures! interaction, F~2,46! 5.13, p .05, E .96 ~see
Figure 1!.
During anticipation, the startle reflex was modulated by picture
content, F~2,46! 5.03, p .05, E .89, with larger blinks
elicited when anticipating either pictures of erotica or snakes,

Reflex modulation in anticipation and perception 721
Figure 1. Top panel: Startle blink magnitude when anticipating the presentation
of pictures of erotica, household objects, or snakes ~left!, and
during perception of these pictures ~right!. Bottom panel: Skin conductance
change when anticipating the presentation of pictures of erotica, household
objects, or snakes ~left! and during perception of these pictures ~right!.
compared to neutral pictures, quadratic F~1,23! 6.77, p .05. 2
Compared to anticipating neutral pictures, blinks were clearly
potentiated when anticipating erotica, F~1,23! 7.86, p .05,
marginally potentiated when anticipating snakes, F~1,23! 4.01,
p .06, and, importantly, blinks elicited when anticipating erotic
and snake pictures did not differ.
During picture viewing, blink magnitude was again related to
picture valence, F~2,46! 3.75, p .05, E .87, but, as expected,
this relationship was linear rather than quadratic, in that larger
blinks were elicited when viewing pictures of snakes, compared to
when viewing erotica, F~1,23! 5.73, p .05. Compared to
2 Including probe delay ~4 s or 5.5 s following cue onset! in the analysis
of startle magnitude during picture anticipation yielded a marginal interaction
of picture content and probe delay, F~2,46! 2.96, p .08.
However, because startle modulation during anticipation has been shown to
be highly sensitive to the timing of stimulus onset ~e.g., Anthony &
Putnam, 1985!, follow-up tests were conducted. Picture content affected
blink magnitude at each delay, F~2,46! 3.77, p .05 for 4-s probes;
F~2,46! 4.12, p .05 for 5.5-s probes. At the earlier probe time, larger
blinks were elicited during anticipation of erotic, compared to snake,
pictures, F~1,23! 10.69, p .01. At the later probe position, blinks were
potentiated when anticipating erotic and snake pictures, compared to household
object picture anticipation, quadratic F~2,46! 7.20, p .05. Blink
magnitude did not significantly change as a function of probe delay when
anticipating either erotica or snakes.
household object pictures, blinks were significantly inhibited when
viewing erotica, F~1,23! 5.16, p .05. Blinks elicited when
viewing snake pictures were not potentiated, compared to neutral
pictures, for the group as a whole. However, for highly fearful
participants ~e.g., scores above the 95th percentile of snake fear;
n 8!, reliable startle potentiation was obtained for snake, compared
to neutral, pictures, F~2,14! 7.33, p .01.
Skin Conductance
As expected, skin conductance change varied with picture content,
F~2,46! 16.60, p .001, E .78. Larger electrodermal changes
occurred when anticipating or viewing emotional ~erotic or snake!
compared to neutral, pictures, quadratic F~1,23! 18.30, p
.001, an effect that was significant in both anticipation, F~1,23!
9.37, p .01, and perception, F~1,23! 18.96, p .001. A
significant interaction of period and content, F~2,46! 3.56, p
.05, E .99, indicated that although responses to erotica were
elevated compared to household objects in anticipation, F~1,23!
16.36, p .001, and perception, F~1,23! 20.01, p .001,
responses to snakes were elevated in perception only, F~1,23!
9.39, p .01.
Discussion
Startle reflex magnitude during anticipation reflected the emotional
arousal of the expected stimulus, rather than its hedonic
valence. Anticipating an emotionally arousing picture, compared
to a neutral picture, augmented startle magnitude, regardless of
whether the upcoming picture was pleasant or unpleasant. Reflex
potentiation during aversive anticipation replicates prior studies
that have used shock as the predicted stimulus ~e.g., Grillon et al.,
1991!, indicating that fearful pictures prompt similar anticipatory
modulation. The current data suggest, however, that the startle
reflex is also potentiated during anticipation of highly arousing
pleasant stimuli, specifically as men anticipated the presentation of
pictures of erotica. This pattern of startle modulation differs from
the widely replicated effect found during picture perception, in
which smaller blinks occur when viewing pleasant, compared to
unpleasant pictures. Indeed, once the anticipated erotic picture was
presented, startle magnitude became inhibited relative to neutral
and unpleasant pictures. Electrodermal activity, on the other hand,
showed consistently greater responses when anticipating or perceiving
erotic, relative to neutral, pictures.
There was no evidence that anticipation of engaging stimuli in
the visual modality ~i.e., erotic pictures! accentuated reflex inhibition
to an acoustic startle probe, as a modality-directed attention
account might predict ~Anthony & Graham, 1985!. Rather, as
noted above, reflexes were significantly larger when anticipating
erotic, compared to neutral, pictures, and furthermore, were equivalent
when anticipating either snake or erotic stimuli. It is possible,
of course, that this anticipatory pattern is unique to men who are
fearful of snakes. However, the fact that electrodermal and startle
responses during picture perception were completely consistent
with previous data from unselected participants ~e.g., Bradley
et al., 1999! argues against this hypothesis.
Although previous studies have found startle modulation by
hedonic valence in the absence of a picture stimulus, these effects
have been obtained following the presentation of a specific picture
stimulus. For example, startle continues to be modulated by hedonic
valence if the participant is instructed to maintain a mental
image of a just-presented picture ~Schupp, Cuthbert, Bradley,
Birbaumer, & Lang, 1997!, or if a picture is briefly presented

722 D. Sabatinelli, M.M. Bradley, and P.J. Lang
~500 ms! and startle reflexes are elicited shortly after picture offset
~Codispoti, Bradley, & Lang, 2000!. The data suggest that hedonic
startle modulation is a phenomenon of perception, when participants
actively encode specific, motivationally relevant sensory
stimuli.
The current data demonstrate that a signal predicting an emotional
stimulus, in the absence of specific stimulus information,
Anthony, B. J., & Graham, F. K. ~1985!. Blink reflex modification by
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~Received July 25, 2000; Accepted January 4, 2001!