Social Presence Enhances Selective Spatial

Social Presence Enhances Selective Spatial Attention Without Reducing Adaptation to Distractor Utility
Juliane Albert1, Henrik Singmann1, Julia Merkt1, Laura Schweikert1, Andreas Kappes1, Denis Köhler2, Caterina Gawrilow1, & Mike Wendt1
1 University of Hamburg 2 University of Applied Sciences Heidelberg
Quasi-experimental design: Control conditions of two
experiments sharing the same paradigm, only differing in
presence of experimenter.
38 students: 18 alone, 20 with presence of experimenter.
2 Outlier were excluded from the presence conditions:
1 participant with extreme high error rate, z > 3, p < .003,
1 participant with extreme high reaction time, z > 4, p < .001.
In condition of social presence the experimenter sat sideways
to the participant. The experimenter was not able to observe
the monitor.
Flanker task
Stimuli: Digits from 2 to 9, flankers were single digits
(e.g., 686), target and flanker always differed.
Task: Participants had to judge the parity of the central digit
Quantity: 8 blocks à 100 Trials: 4 blocks with mostly
incompatible trials (80% incompatible), 4 blocks with mostly
compatible trials (20% incompatible)
On errors: aversive sound & signal on the screen
Example Trial
400 ms
100 ms
600 ms
Attentional Focus
Presence of others
restricted the attentional
focus: Participants showed
a smaller flanker
compatibility effect for
the error rate when
the experimenter was
Significant interaction
of flanker compatibility 0.5
with condition for the
error rate, F(1,34) = 4.75,
p = .04, but not for the
reaction times,
F(1,34) = 1.13, p = .3.
p = .3
p = .04
Effect size (d)
• The presence of others can facilitate or impede performance
in cognitive tasks: Social facilitation.
Theoretical Introduction
Two theories provide different explanations for the
• The theory provided by Zajonc (1965) explains social
facilitation effects with classical drive reduction theory:
The presence of others leads to increased arousal. This should
lead to an advantage for simple tasks (i.e., a increased
tendency for dominant response) and a disadvantage for
complex tasks (i.e., a decreased tendency for the nondominant response).
• Baron (1986) suggests an explanation of attentional focusing:
The presence of others leads to increased cognitive load. This
narrows the attentional focus on task-relevant stimuli
Empirical Evidence
• Huguet et al. (1999) supported the attentional view with a
reduced Stroop compatibility effect when a confederate was
present compared to task execution in isolation.
• However, the effect of narrowed attentional focus on Stroop
compatibility effects is controversial. Chen (2003) found an
increased Stroop compatibility effect with narrowed focus.
The present study
We extended these findings in two ways.
• First, to examine whether interference reduction also occurs
when target and distractor stimuli are presented at different
locations, we used an Eriksen flanker task.
• Second, we manipulated the utility of flanker stimuli by
varying the frequency of compatible (i.e. target and flanker
stimuli are associated with the same response) and
incompatible (i.e. target and flanker stimuli are associated
with different responses) trials to investigate whether strategic
adaptation (Botvinick et al., 2001) of the attentional focus is
influenced by social presence.
• To investigate the effects on strategic adaption we also
compared the flanker compatibility effect following
compatible and incompatible trials (e.g., Gratton et al. 1992).
error rate (E)
reaction time (RT)
Effect size (d) of flanker compatibility
effect between conditions
Strategic Adaption
• The flanker compatibility effect was reduced in blocks with high
percentage of incompatible trials compared to blocks with a low
percentage of incompatible trials (E: p = .02, RT: p =.13).
• The flanker compatibility effect was smaller after incompatible
trials than after compatible trials (E: p = .02, RT: p =.01).
• This strategic adaption of processing selectivity to the utility of
flanker information did not differ whether the experimenter was
present or not (ps > .3).
160 ms
Baron, R. S. (1986). Distraction-conflict theory: Progress and problems. In: L. Berkowitz (Ed.), Advances
in experimental social psychology (pp. 1-40). New York: Academic Press.
Botvinivck, M. M. , Braver, T. S., Barch, D. M., Carter, C. S., & Cohen, J. D. (2001). Conflict Monitoring
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Chen, Z. (2003). Attentional focus, processing load, and Stroop interference. Perception &
Psychophysics, 65(6), 888-900.
Gratton, G., Coles, M. G., Donchin, E. (1992). Optimizing the use of information: Strategic control of
activation of responses. Journal of Experimental Psychology: General, 121(4), 480-506.
Huguet, P., Galvaing, M.P., Montail, J. M., & Dumas, F. (1999). Social Presence Effects in the Stroop Task:
Further Evidence for an Attentional View of Social Facilitation. Journal of Personality and Social
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Zajonc, R. B. (1965). Social facilitation. Science, 149, 269-274.
• We found an effect of social presence on the general flanker
compatibility effect. This results adds evidence to the attentional
account of social facilitation.
• We found no evidence for social presence effects on strategic
adaption to flanker utility, hence no evidence for the notion of
heightened arousal.
• However the experiments lacks (a) power and (b) a more direct
test of the Zajonc hypotheses. Furthermore (c) the presence of
the experimenter instead of a confederate plus the aversive
sound leaves space for alternative explanations.
Poster presented at the 21th Annual Convention of the Association for Psychological Science in San Francisco, CA, May 2009