Unconscious orientation exposure in TPE training enables transfer of foveal orientation learning to orthogonal orientations
55.11, Tuesday, May 14, 5:15 - 7:15 pm, Royal Ballroom 1-3
Ying-Zi Xiong1, Jun-Yun Zhang1, Cong Yu1; 1Department of Psychology and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
Foveal orientation discrimination learning can transfer completely to an orthogonal orientation with training-plus-exposure (TPE) training, in which the observers practice one orientation while being exposed to an orthogonal transfer orientation in an irrelevant task (Zhang et al., JN2010). We propose that perceptual learning is high level, but multi-session training and focused attention at the trained orientation may suppress untrained orientation, which blocks learning transfer. It is the exposure that reactivates the suppressed orientation inputs, so that high-level learning can connect to these inputs to allow learning transfer. Here we show that the exposure is equally effective without awareness. Specifically, an observer either practiced Gabor orientation discrimination (126o/36o, 1.5cpd/6 cpd, 0.47 contrast) or was exposed to the orthogonal Gabor (36o/126o) in one same eye in alternating blocks of trials. In the exposure condition the observers judged whether the stimulus was a Gabor or a letter C while the fellow eye was presented with flashing white noise to suppress the awareness of the Gabor/C stimulus, which led to chance-level performance. However, learning still transferred completely to the orthogonal orientation, suggesting that the exposure enabled learning transfer without stimulus awareness. Learning did not transfer in a control condition in which no Gabor/C stimulus was present, although the observers were unaware of the stimulus absence due to flashing noise suppression, so the transfer could not result from the presence of the flashing noise. These results suggest that the exposure part of TPE training requires no conscious monitoring and attentional modulation. The unconscious orientation exposure may reactivate V1 inputs representing the transfer orientation that are likely suppressed by training-related focused feature attention on a different orientation, which establishes functional connections between high-level learning and the untrained orientation to allow learning transfer.