Psychology
2013. Vol.4, No.8, 619-621
Published Online August 2013 in SciRes (http://www.scirp.org/journal/psych) http://dx.doi.org/10.4236/psych.2013.48088
Social Inhibition of Vection*
Takeharu Seno1,2,3
1Faculty of Design, Kyushu Unive rsity, Fukuoka, Japan
2Institute for Advanced Study, Kyushu University, F u kuoka, Japan
3Research Center for Appli ed Perceptual Science, Kyushu University, Fukuoka, Jap a n
Received May 31st, 2013; revised Ju ne 29th, 2013; accepted July 15th, 2013
Copyright © 2013 Takeharu Seno. This is an open access article distributed under the Creative Commons Attri-
bution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the
original work is properly cited.
The purpose of this study was to examine whether the social interaction can affect vection strength. We
compared the strength of self-motion perception (vection) with and without an audience (two people in
addition to the participant) present during stimulus presentation. We presented the optical flow (dots’ ex-
pansion) for 40 seconds and obtained vection duration and latency and we also obtained the subjective
strength of vection via magnitude estimation. We found that vection was inhibited by the presence of an
audience. We speculate that audience presence might distract the attention of participants from the vection,
depriving them of the attentional resources inhibited vection.
Keywords: Vection; Social Inhibition; Audience
Introduction
Self-motion perception as determined solely by visual cues is
called “vection” (e.g. Fischer & Kornmüller, 1930). Stimulus
attributes for the effective induction of vection have been ex-
tensively studied (Seno et al., 2009). Relationships between
vection and attention (Seno et al., 2011a), time perception
(Seno et al., 20011b), memory (Seno et al., 2013), the effect of
alcohol consumption (Seno & Nakamura, in press), cognitive
bias (Palmisano & Chan, 2004) and quantity perception (Seno
et al., 2011c) have also been reported, as well as relationships
between vection and multiple modalities (e.g. Riecke et al.,
2009), personality attributes of observers (Seno et al., 2011d),
and aging and development (Haibach et al., 2009; Shirai et al,
2012). Furthermore vection enhanced a type of visual illusion
(Fukuda & Seno, 2012) and the semantic meaning could affect
vection strength (Seno & Fukuda, 2012). Multiple aspects of
the human mind are involved in vection. One important issue
that has not been addressed is the impact of social psychologi-
cal factors on vection. We focused on social facilitation and
inhibition of vection.
An “audience effect” has been established in the field of so-
cial psychology (Travis, 1925), in which the existence of an
audience can facilitate or inhibit the performance of a partici-
pant. Even when the presence of an audience is not logically
related to the execution of a task, audience presence can modu-
late the performance of a participant. In most cases, the domi-
nant task outcome is facilitated by the presence of an audience,
and the non-dominant task outcome is inhibited (review in Za-
jonc, 1965). It has been also reported that arousal levels are
increased by audience presence (Mason & Brady, 1964). Con-
sidering previous studies, we predicted that vection could be
modulated by audience presence. In our previous vection stud-
ies, vection was reported in 70% of all stimulus presentation
period (Seno et al., 2011a, 2011b, 2011c, 2011d), and was thus
the dominant task outcome. We predicted that perception of
vection would be facilitated and that the duration of vection
would be elongated by audience presence. In this case, our
study would be the first to report that the perception of vection
can be altered by social context.
Method
Participants
Eleven adult volunteers participated in the experiment. The
volunteers were either graduate or undergraduate students (7
females and 4 males; aged 20 to 25 years) with no reported
visual or vestibular abnormalities. They previously attended
some vection experiments. Thus the task of reporting vection
was easy and accustomed task for them.
Apparatus
Stimuli were generated and controlled by a computer
(MB543J/A, Apple) and presented on a plasma display (3D
Viera, 50-inch, Panasonic, with 1024 × 768 pixel resolution at a
60 Hz refresh rate). The experiment was conducted in a dark
chamber.
Stimuli
We used an expanding optical flow pattern, which was cre-
ated by positioning 16,000 dots at random inside a simulated
cube and moving the observer’s viewpoint to simulate a for-
ward self-motion of 16 m/s. The stimuli were identical to those
used by Seno et al. (2010), and the duration of the stimulus was
*The author was supported by Funds for the Development of Human Re-
sources in Science and Technology (Japan Science and Technology Agency)
This work is supported by Program to Disseminate Tenure Tracking System,
MEXT, Japan.

T. SENO
fixed at 40 seconds. The stimuli were displayed on a 50-inch
plasma display with a viewing distance of 57 cm.
Participants
Eleven adult volunteers participated in the experiment. The
volunteers were either graduate or undergraduate students (7
females and 4 males; aged 20 to 25 years) with no reported
visual or vestibular abnormalities. They previously attended
some vection experiments. Thus the task of reporting vection
was easy and accustomed task for them.
Audiences
Two adult male graduate students. They were 22 and 23
years old and did not know the purpose of this experiment.
They kept watching the participant during the stimulus presen-
tation. They stood on the right and left sides of the participants
with 60 cm distances. They did not speak anything.
Procedure
The participants completed the task either alone or in the
presence of an audience, which consisted of two third persons.
The audience stood beside the observer and watched their per-
formance througho ut the experiment (Figure 1).
Eight trials were conducted for each condition, and partici-
pants were asked to press a button when they perceived self-
motion. At the end of each trial, the participants were instructed
to rate the subjective strength of vection using a scale from 0
(no vection) to 100 (very strong vection). The participants re-
ported these values using a keyboard. The with- and without-
audience conditions were counterbalanced over the eleven par-
ticipants. The participants were given complete instructions
before the experiment began.
Result
The results were shown in Figure 2. Substantial vection was
reported in both the with- and without-audience conditions.
Latency and duration of vection was shorter and longer, respec-
tively, in the without-audience condition. The reported values
were larger in the without-audience condition than in the with-
audience condition. T-tests revealed significant differences be-
tween the with- and without-audiences conditions for all three
measures (latency, t(10) = 3.47, p < .01; duration, t(10) = 2.29,
p < .05; magnitude, t(10 ) = 2.18, p = .05).
Discussion
We concluded that the strength of vection was larger in the
without-audience condition, and thus, contrary to our prediction,
found evidence for the social inhibition of vection by an audi-
ence. Even though perception of vection was the dominant task
outcome it was inhibited by audience presence. In subjective
reports, some participants said that their attention had been
distracted from the vection stimulus by the presence of an au-
dience. Vection indication requires attentional resources (Seno
et al., 2011a). Thus, the presence of an audience during the task
may be distract in g.
Additionally, we conducted an informal observation with
three naïve participants in which we placed two cardboard
boxes instead of audiences beside the participants. Then vection
Figure 1.
A schematic illust ration of the enviro nment of experiment (with-
audience condition).
Figure 2.
The latency, duration, and magnitude of vection in
the with- and without-audience c o n ditions.
620

T. SENO
strength was not changed in that condition. Thus the effect of
being things was not obtained. The audience of human was the
critical factor for inhibition of vection.
We also should consider the gender effect of the audience. In
this study, we employed two male audiences. In the future
study, all variations of male and female audiences should be
examined. We examined only the case of two male audiences.
This was the limitation of our study, we should note. In future,
further examination of various types of audiences should be
examined.
We conclude that, social context (presence of an audience)
can affect vection strength. This could be an important demon-
stration of an instance in which social context can alter percep-
tion, although further research is necessary to clarify this rela-
tionship.
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