Abstract
We present a novel face adaptation paradigm that follows from Li and Atick’s (1994) theory of
efficient binocular encoding. In this theory, the inputs to the two eyes are combined using
separately adaptable binocular summation and differencing channels. We designed a dichoptic
test stimulus for which the summation channel sees one face image, and the differencing channel
sees a different face image. The pairs of faces seen by the two channels were male/female, happy/sad, or turned slightly to the left/right. The face perceived by the observer depended on
the relative sensitivities of the two channels. We manipulated channel sensitivity by selective
adaptation with images that were low-pass filtered white noise. In correlated adaptation, each
eye received the same adaptation image, which selectively adapted the summation channel; in
anticorrelated adaptation, the adaptor contrast was reversed between the eyes, selectively
adapting the differencing channel. After adaptation, we presented the dichoptic test stimulus,
and found that the observer perceived the summation channel’s face image most often after
anticorrelated adaptation, and perceived the differencing channel’s face image most often after
correlated adaptation. For male/female and left/right judgements, perception was generally
biased towards the summation channel; for happy/sad judgements, there was little or no bias.
