Asymmetrical Transfer of Learning Effects between Signal-Based and Criterion-Based Task Uncertainties in Perceptual Decision

People frequently encounter diverse uncertainties stemmed from environmental noise or insufficient personal knowledge. It remains unknown whether there is a general neural mechanism dealing with various uncertainties. Investigating the transfer of learning effects between tasks with different uncertainties paves the way to the fully understanding of this issue. Nevertheless, previous literatures have shown controversial evidences due to the contextual difference between tasks. In the present study we adapted Glass Pattern to manipulate a 2-dimensional stimulus space incorporating two uncertainties (Signal-Based uncertainty due to noisy stimulus signal and Criterion-Based uncertainty due to unknown category boundary) in one categorization task that was to discriminate radial from concentric patterns. We trained two groups of participants along the Criterion-Based and the Signal-Based dimensions, respectively, and tested on both dimensions before and after the training. After 4 to 5 successive days of training, learning effect significantly transferred from Criterion-Based task to Signal-Based task (p<0.01), but not vice versa (p = 0.18). More interestingly, however, a brief adaptive QUEST test with feedback on Criterion-Based task after Signal-Based training leaded to a rapid transfer of learning effect. Altogether, the current results suggested that two separate but overlapping mechanisms are engaged in processing the two sources of task uncertainty.