Abstract
Visual perceptual learning (VPL) is defined as long-term improvement on a visual task as a result of visual experience (Sasaki et al., 2012). The improvement is usually highly specific to the location where the trained feature is presented, which refers to location specificity. Location specificity is regarded as manifestation of changes in early visual areas in association with VPL. Recently, Xiao et al. (2008) have demonstrated that location specificity of VPL is abolished by double training. For example, location-specific contrast discrimination learning can be rendered completely transferrable from the upper left to a new location in the lower-right quadrant if the new location is trained with an additional orientation discrimination task. This evidence challenges traditional views towards location specificity. However, the mechanism underlying double training remains unclear. In the current study, we applied a double training paradigm to investigate why it occurs. Subjects performed orientation discrimination training at the upper left quadrant for 6 days and then performed contrast discrimination training at the lower right quadrant for another 6 days. We found that, after the initial orientation discrimination training, the threshold significantly decreased at the trained location. In addition, the performance enhancement partially transferred to the lower right quadrant. However, hardly any transfer occurred at the upper right quadrant. The additional training led to some amount of improvement in orientation discrimination at the newly trained location, but not in the upper right quadrant. The result suggests that it is easier to trigger the transfer of orientation discrimination to the diagonal quadrant compared with the parallel quadrant. The effect of double training could be at least partially confounded by the fact that VPL is more likely to be transferred in diagonal direction than in parallel direction.
Meeting abstract presented at VSS 2014