Vection Is Not Determined by the Retinal Coordinate

doi:10.4236/psych.2014.51003

Paper Menu >>

Journal Menu >>

Psychology

2014. Vol.5, No.1, 12-14

Published Online January 2014 in SciRes (http://www.scirp.org/journal/psych) http://dx.doi.org/10.4236/psych.2014.51003

Vection Is Not Determined by the Retinal Coordinate

Takeharu Seno1,2,3

1Faculty of Design, Kyushu University, Fukuoka, Japan

2Institute for Advanced Study, Kyushu University, Fukuoka, Japan

3Research Center for Applied Perceptual Science, Kyushu University, Fukuoka, Japan

Email: [email protected]-u.ac.jp

Received November 6th, 2013; revised December 5th, 2013; accepted January 3rd, 2014

bution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the

original work is properly cited. In accordance of the Creative Commons Attribution License all Copyrights ©

are guarded by law and by SCIRP as a guardian.

We examined whether vection was determined by the retinal coordinate. The participants sat on a chair

with their body rotated 0, 45, 90 and 135 degrees and with their head facing directly at the stimulus screen.

Vection strength was changed by rotation of the body. Thus vection was affected by the body coordinate

and it was not determined by the retinal coordinate alone.

Keywords: Retinal Coordinate; Head Coordinate; Body Coordinate; Body Rotation

Introduction

When stationary observers are exposed to a large-field visual

motion, simulating the retinal flow generated by self-translation

or self-rotation, they often experience an illusory perception of

self-motion, known as vection (Fischer & Kornmuller, 1930).

In the history of vection research, various stimulus attributes

which are effective or ineffective for vection induction have

been examined (e.g. Seno et al., 2009).

One important attribute is in which coordinate vection is de-

termined, whether in the retinal, body, head and/or world coor-

dinates. Morse & Rieser (2003) reported that vection is strongly

determined by the retinal coordinate. Kano (1991) also reported

that vection is affected both by retinal and world coordinates.

These results suggest that vection is affected by the retinal co-

ordinate.

Other studies reported that vection is affected by vestibular

inputs. Young & Shelhamer (1990) and Mueller & Kornilova

(1994) reported that vection in microgravity condition became

unstable and sometimes could be induced in the opposite direc-

tion to the normal vection. Lepecq et al. (2006) reported that by

adding a vestibular input during vection, the vection direction

could be biased intentionally. These results implied that vection

was not determined by the retinal coordinate alone.

Nakamura & Shimojo (1998) reported that the vertical vec-

tion was modulated by the body posture whereas the horizontal

vection was not modulated by the posture. This result implied

that vection is mediated by both retinal and body coordinates.

In this study, we set four different body postures with the

same retinal optic flow. The body was rotated horizontally 0, 45,

90 or 135 degrees with the head always directly facing the

screen. The participants twisted their head to face the screen. If

the vection is determined by the retinal coordinate, the vection

strength would be constant for each of the different body pos-

tures.

Method

Appara tus

Stimuli were generated and controlled by a computer (MB-

543J/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.

Parti cipa nts

Sixteen naïve volunteers participated in this experiment. Par-

ticipants were graduate or undergraduate students. All partici-

pants reported normal vision and no history of vestibular sys-

tem diseases. None of them was aware of the purpose of the

experiment.

Stimuli

Optic flow displays (101˚ × 80˚; presented for 30 s) consisted

of about 1000 randomly positioned dots per frame and the

global dot motion simulated forwards self-motion (16 m/s). The

screen size was bigger than that in our previous studies (Seno et

al., 2009, 2013). The stimuli were the same as those in Seno

(2013a & 2013b). There was no fixation point in the stimuli.

However, the participants were instructed to fixate on the focus

of the expansion (FOE). We think that the FOE would be the

role of the fixation point.

Procedure

Participants were asked to press a button when they per-

ceived forward self-motion, and keep the button depressed for

the duration of self-mot ion. After each trial, the participants

rated subjective vection strength using a 101-point rating

scale ranging from 0 (no vection) to 100 (very strong vec-

tion).

OPEN ACCESS

T. SENO

There were four conditions in participants’ body posture. The

head was always fixed facing straight at the screen but the body

was rotated 0, 45, 90 and 135 degrees by rotating the subject’s

chair (Figure 1). We believe that even with maxi mum rotati on of

the body, the participants still could gaze the stimuli as correctly

as the experimenter intended. The experimenter observed,

checked and confirmed that the participants could do that during

the experiment (Please check the Figure 1).

Result and Discussion

The results were shown in Figure 2. The latency was the

shortest in the 0 degree condition and it became longer as the

degree of rotation was increased. The duration and magnitude

were the longest and largest in the 0 degree condition and it

became shorter and smaller as the rotation was increased.

One-way ANOVA revealed a significant main effect of the

body rotation in all three measures (latency, F (3,45) = 3.64, p

< 0.05; duration, F (3,45) = 7.72 p < 0.01; magnitude, F(3,45) =

4.32, p < 0.01). Multiple comparisons revealed significant dif-

ferences between the 0 degree condition and the other three

rotated conditions (Holm, p < 0.05). The obtained vection in the

0 degree condition was stronger than the vection obtained by

the same stimuli in our previous studies (e.g. Seno, et al., 2011).

This is related the fact that in this study we used lager stimulus

(101˚ × 80˚) than that in the previous study (72˚ × 57˚). The

vection was the strongest when the body and the head direc-

tions were the same. When the discrepancy between the head

and the body positions was increased, vection strength was

weakened. Thus vection was determined less by the retinal

coordinate but is significantly more affected by the body coor-

dinate. We speculate that vection is determined by the output

from the integration of multiple coordinates.

We should do the same experiment using visual rotation

along with yaw axis in the future. We obtained the subjective

direction of vection in this experiment by oral report after fin-

ishing the whole experimental procedure. The participants

mainly reported the forward self-motion to the stimuli, i.e.

moving into the display. Thus the direction of the head deter-

mined and dominated the direction of the self-motion. However,

further examination for this problem should be needed. This

will be a very important topic of this field.

In fact, there was the possibility that in the condition of ex-

treme rotation (e.g. 135 degree), the observers might have con-

tinuous efforts to maintain such an unnatural posture, and then,

their attention would be deprived from the vection task. Vection

induction requires attentional resources (Seno et al., 2011).

When the attention was deprived, vection should be weaker. In

this study we could not deny this possibility. In future examina-

tions, we should control the deprived attentional resources by

the different postures.

Figure 1.

The postures of the participants who viewed the optical flows.

Figure 2.

Results of vection strength (latency, duration and magnitude). Error bars indicate SEs.

OPEN ACCESS 13

T. SENO

Acknowledgemen ts

This work is supported by Program to Disseminate Tenure-

Tracking System, MEXT, Japan.

REFERENCES

Fischer, M. H., & Kornmüller, A. E. (1930). Optokinetischausgelöste-

bewegungswahrnehmungen und optokinetischernystagmus. Journal

fürPsychologie und Neurologie (Leipzig), 41, 273-308

Kano, C. (1991). The perception of self-motion induced by peripheral

visual information in sitting and supine postures. Ecological Psy-

chology, 3, 241-252. http://dx.doi.org/10.1207/s15326969eco0303_3

Lepecq, J. C., De Waele, C., Mertz-Josse, S., Teyssèdre, C., Tram

BaHuy, P., Baudonnière, P. M., & Vidal, P. P. (2006). Galv anic ves-

tibular stimulation modifies vectio n path in healthy subjects. Journal

of Neurophysiology, 95, 3199-3207.

http://dx.doi.org/10.1152/jn.00478.2005

Morse, D. L., & Rieser, J. J. (2003). Linear vection shows a retinal

frame of reference. Journal of Vision, 3, 493.

http://dx.doi.org/10.1167/3.9.493

Mueller, C. H., Kornilova, L., Wiest, G., & Steinhoff, N. (1994). Psy-

chophysical studies of visuo-vestibular interaction in microgravity.

Acta Astronautica, 33, 9-13.

http://dx.doi.org/10.1016/0094-5765(94)90102-3

Nakamura, S., & Shimojo, S. (1998). Orientation of selective effects of

body tilt on visually induced perception of self-motion. Perceptual

and Motor Skills, 87, 667-672.

http://dx.doi.org/10.2466/pms.1998.87.2.667

Seno, T., Ito, H., & Sunaga, S. (2009). The object and background

hypothesis for vection. Vision Research, 49, 2973-2982.

http://dx.doi.org/10.1016/j.visres.2009.09.017

Seno, T., Kawabe, T., Ito., H. & Sun aga, S. (2013). Vection modulates

emotional valence of au tobiographical episodic me mories. Cognition,

126, 115-120. http://dx.doi.org/10.1016/j.cognition.2012.08.009

Seno, T., Ito, H ., & Sunaga, S. (2011). Inconsistent locomotion inhib its

vection. Perception, 40, 747-750. http://dx.doi.org/10.1068/p7018

Seno, T., Ito, H., & Sunaga, S. (2011). Attentional load inhib its vection.

Attention, Perception & Psychophysics, 73, 1467-1476.

http://dx.doi.org/10.3758/s13414-011-0129-3

Seno, T. (2013). Social inhibition of vection. Psychology, Scientific

Research, 4, 619-621.

Seno, T. (2013). Music enhances vection. Psychology, Scientific Re-

search, 7, 566-568.

Young, L. R., & Shelhamer, M. (1990). Microgravity enhances the

relative contribution of visually-induced motion sensation. Aviation,

Space, and Environmental Medicine, 61, 525-530.

OPEN ACCESS