Abstract
Adaptation to a visual pattern could alter the sensitivities of neuronal populations encoding the pattern, which usually results in a visual aftereffect. However, the function role of visual adaptation is still equivocal and its relation to visual aftereffect is largely unknown. In this study, we took advantage of face view adaptation to investigate these issues. In the first experiment, we measured the magnitude of the face viewpoint aftereffect (Fang and He, 2005) as a function of the angular difference between adapting and test face views. Test face views were always near the front view. The magnitude of the aftereffect increased as the angular difference increased from 0 deg to 20 deg, then decreased until 90 deg. Unlike the tilt aftereffect, substantial face viewpoint aftereffect could be observed even at 90 deg. In the second experiment, we measured the effect of adaptation to different face views on face view discrimination at the front view. Compared to the pre-adaptation discrimination threshold, adaptation to the front view (0 deg) decreased the threshold, but adaptation to 15, 30, 60 and 90 deg side views increased the threshold, which was highest in the 30 deg side view adaptation condition. These results suggest that the functional role of face view adaptation not only adjusted the boundary of our perceptual categories, but also changed the performance of our face view discrimination. We propose a computational model to account for these two phenomena and their relation in terms of the adjustments of tuning functions of face view selective neurons after adaptation.
Supported by the National Natural Science Foundation of China (Project 30870762).