Stochastic Properties of Segmentation-Rivalry Alternations.

K. F. Arrington

Perception, 1996; 25, Suppl. p. 62.
European Conference on Visual Perception (ECVP),
Strasbourg, France, 9-13th September 1996.

Abstract.

Segmentation rivalry is the alternation of perceived depth that occurs when depth information from, e.g. occlusion and stereo disparity cues, are inconsistent (Arrington & Held, 1995, Arvo Abstracts). It was conjectured that the rivalry is based on reciprocal inhibition between end-stopped cell populations that code the same spatial location but opposite direction of surface segmentation in depth. Here the stochastic properties of these depth alternations are analyzed and compared to prior analysis (Blake, Fox, McIntyre, 1971, J. Exp. Psych. 88:3) of binocular rivalry alternations, which have suggested that successive phase durations are approximated by a theoretical gamma distribution: f(x)=b^a/Exp[LogGamma(a)]*x^(a-1)*Exp[-b*x]. Phenomenally in-front (F) vs. phenomenally behind (B) phase durations during segmentation rivalry were collected at 2' stereo disparity that produces a maximal alternation rate and approx. 50% duty cycle. Least square error fit to the two duration data sets was very good (F: a=3.69, b=0.514; B: a=6.54, b=0.780) and the chi-square goodness-of-fit showed insignificant (p .LE. 0.01) departures from the theoretical gamma distribution when the histogram was smoothed and in some cases when not smoothed.


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