1. What is salient in binocular rivalry Fumihiko Taya* and Ken Mogi**, *Department of Physiology1, Osaka University Medical School **Sony Computer Science Laboratory

2. 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.

3. 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

4. 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.

5. Method(1/2) Phase difference Left eye Right eye Visual awareness Fixation point Indicator

6. 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.

7. 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

8. Change of visual awareness: moving circles Time

9. Change of visual awareness: stationary circles

10. Average number of circles seen in the moving and stationary conditions

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

12. Results: 180 degrees

13. Results: 72 degrees

14. Results: 0 degrees

15. Results: left eye

16. Results: right eye

17. 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.

18. Method Left eye Right eye Visual awareness Fixation point Indicator

19. Results: the effective range of moving circles

20. 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.

21. Change of visual awareness: Interactive operation Time

22. Result: move circles voluntarily

23. Three phenomenological layers Attention Salient features Visual qualia Visual Awareness

24. Conclusion