Implicit Measures of One-Shot Perceptual Learning

Perception is an active process shaped by the interplay of bottom-up information arriving at the sensory systems and top-down priors based on previous experience. While knowledge about the world is usually acquired via repeated encounters, the Mooney disambiguation effect is a commonly known example of one-shot perceptual learning. Mooney images are ambiguous two-tone images which are, without additional information, devoid of meaning for the perceiver. However, after a single exposure to the corresponding unambiguous original image, the content of the Mooney images becomes readily available. Usually, this effect is assessed by asking participants before and after disambiguation whether they subjectively recognized the figure of the Mooney image, but this subjective measure has several limitations. The present experiments aimed at identifying indirect measures of this special case of one-shot-learning by adapting a task in which participants had to identify whether red dots appeared on or off the main figures of different Mooney images. We found that, following disambiguation, error rates (ER) decreased while as discrimination rates (d’) increased. These objective measures of gradual nature, which do neither require conscious insight nor explicit subjective examination, could potentially allow follow-up studies to manipulate perceptual learning and assess its neural basis through neuroimaging methods.