what is salient in binocular rivalry fumihiko taya* and ken mogi**, *department of physiology1,...

What is salient in binocular rivalry

Fumihiko Taya* and Ken Mogi**,

*Department of Physiology1, Osaka University Medical School

**Sony Computer Science Laboratory

Abstract

• We studied what stimulus features count as salient in binocular rivalry.

• We found that motion is very salient and is a determining factor in the ocular dominance pattern in binocular rivalry.

• We arrive at a model of binocular rivalry involving three layers.

Neural correlates with the ocular dominance pattern in binocular rivalry

• Logothetis et al., 1989

• Leopold et al., 1996

• Kovacs et al., 1996

• Sheinberg et al., 1997

• Tononi et al., 1997

• Fries et al., 1997

• Lumer et al., 1998

Studies on binocular rivalry

• Studies on binocular rivalry has been conducted in an “all-or-none” paradigm, neglecting the spatial heterogeneity of the dominance pattern.

• Here, we investigate the spatio-temporal structure of ocular dominance pattern in binocular rivalry.

Method(1/2)

Phase difference

Left eye Right eye

Visual awareness

Fixation pointIndicator

Methods (2/2)• Stimulus we used were:

– Circles moving at a speed of 2.2 degrees/s

– Stationary circles

• We presented rivalrous images to each eyes (visual angle 11 degrees) with Crystal Eyes (StereoGraphics Corporation, Washington D.C., US).

• Monitor: FlexScan E67T (Eizo) at 150 frames/s.

Visual awareness in binocular rivalry• Both of the moving circles were always

present in visual awareness– Down to 0.3 degrees per second– Up to 20 degrees per second

• Sometimes one or both of the stationary circles disappeared from visual awareness

Change of visual awareness:moving circles

Time

Change of visual awareness:stationary circles

Average number of circles seen in the moving and stationary conditions

0

0.5

1

1.5

2

2.5

Subject FT Subject KM Moving ConditionAverage number of circles seen at any given

instant

Quantitative Analysis

• Subjects were requested to report the perceived color at the position of an indicator which flashed in several position on the screen.

Results: 180 degrees

Results: 72 degrees

Results: 0 degrees

Results: left eye

Results: right eye

Summary of results

• The spatio-temporal dominance pattern was strongly influenced by the presence of moving circles.

• The visual system behaves as dynamical adaptive system to represent the salient features at any given psychological moment.

MethodLeft eye Right eye

Visual awareness

Fixation pointIndicator

Results: the effective range of moving circles

Results

• The effective range of moving circle was about 2.2 degrees, namely the effect of salient features remained for about 1 second.

• The salient feature only had effect on the subsequent visual awareness.

• The prediction had no effect on determining the ocular dominance pattern.

Change of visual awareness:Interactive operation

Time

Result: move circles voluntarily

Three phenomenological layers

Attention

Salient features

Visual qualia

Visual Awareness

Conclusion