Shigehito TANAHASHI^1*, Kaori SEGAWA¹, Meihong ZHENG^1,2, Junko KUZE^1,3, and Kazuhiko UKAI¹

¹Department of Applied Physics, School of Advanced Science and Engineering, Waseda University, Shinjuku, Tokyo 169-8555, Japan
²Center for Psychology and Cognitive Science, Tsinghua University, Haidian District, Beijing, China 100084
³Faculty of Health Science, Nihon Fukushi University, Handa, Aichi 475-0012, Japan

(Received April 4, 2012; Revised June 16, 2012; Accepted July 5, 2012)

The authors examined whether the perceptual reversal rate changes under monocular versus binocular viewing conditions. Our results suggest that the perceptual reversal interval increases during monocular viewing. The ratio of the reversal rate (1/interval) for the two viewing conditions (binocular/monocular) was 1.28 over a wide range of pattern luminance levels. The quoted ratio was 1.40 when the luminance was high. Such a ratio parallels the value of a well-known binocular summation index (√2), which was derived from the signal detection theory. The binocular summation index shows that the strength of an input signal is enhanced by binocular viewing. However, how the binocular summation shortens the perceptual reversal interval is unclear. This issue can be resolved if the perceptual reversal is derived by integrating the strength of an unconscious image signal. Thus, we discussed the mechanism of perceptual switch by associating two classical, well-studied phenomena, binocular summation and perceptual switch.

Key words: perceptual rivalry, perceptual reversal interval, binocular summation, luminance dependence

^*E-mail address: kg21mj23@toki.waseda.jp