Transfer of perceptual learning to completely untrained locations after double training

Abstract

Visual perceptual learning can transfer completely to a new location if the new location is trained with an irrelevant task (Xiao et al., Current Biology, 2008). This feature-plus-location double training result suggests that perceptual learning may occur in non-retinotopic brain areas, and learning transfers as spatial attention to the new location is improved through location training. What unknown is how double training will affect performance in other completely untrained locations. We found that (1) Vernier learning was normally location and orientation specific. However, if Vernier was trained at the V and H orientations, one orientation at the upper left visual field (ori1_loc1) and the other at the lower left visual field (ori2_loc2), each serving as location training for the other orientation, learning transferred not only completely to trained locations (ori1_loc2 & ori2_loc1), but also equally to the completely untrained visual quadrants in the right visual field (ori1_loc3/ori2_loc3). (2) Similar results were found when Vernier was trained at one quadrant and motion direction was trained at a diagonal quadrant as location training, in which Vernier learning transferred to the diagonal quadrant, as well as to other completely untrained quadrants at the same (5^o) and different (10^o) eccentricities. (3) However, in a texture discrimination task (Karni & Sagi, 1991), although the usually location specific learning could transfer to a diagonal quadrant when the transfer location was trained with detecting an array of ovals among circles, learning transferred less significantly to a third completely untrained quadrant. The first two experiments suggest that the observers may have learned the strategy to attend to a peripheral target in a clear field after double training. However, the third experiment indicates that training for precise spatial attention is still required for learning to transfer to a completely untrained location in a cluttered area.

Footnotes

 Natural Science Foundation of China grants 30725018.