Abstract
Can predictive yet subliminal cues play a role in human decision-making? To address this question, we combine the paradigms of perceptual learning on Gabor stimuli with perceptual decision making on degraded face/place images. Specifically, our design is an implicitly primed categorization task. Orientations of subthreshold Gabor cues (2 cycles/degree with white noise added) are predictive of the categories of 1800 face/place stimuli whose Fourier phases are scrambled at various levels. In each trial, category-paired, subliminal Gabor stimuli were presented for 300msec as preparatory cues, and were then followed immediately by a degraded face/place stimulus for a categorical judgment that lasted until a participant made a key response, within the time window of 1500msec. We examine if perceptual learning occurs for repeated Gabor stimuli, and further induces associative learning between Gabor orientations and face-place categories. After 3 days of training with auditory trial feedback, participants (N=4) showed learning effects for the face-place discrimination task in terms of increased accuracy and decreased reaction time. The observed result of better decisions for the main task can occur due to the priming from subliminal Gabor cues, and/or the improved face-place judgment. Control experiments are underway to clarify the contribution of Gabor stimuli to the observed learning effects and to examine the potential influence of subliminal cues on decision-making under different uncertainty levels.
This work is supported by NIH-NEI R21 EY018925, R01 EY015980-04A2, and R01 EY019466.