Configuration perceptual learning and its relationship with element perceptual learning.

Visual perceptual learning has been studied extensively and reported to enhance the perception of almost all types of training stimuli, from low- to high-level visual stimuli. Notably, high-level stimuli are often composed of multiple low-level features. Therefore, it is natural to ask whether training of high-level stimuli affects the perception of low-level stimuli and vice versa. In the present study, we trained subjects with either a high-level configuration stimulus or a low-level element stimulus. The high-level configuration stimulus consisted of two Gabors in the left and right visual fields, respectively, and the low-level element stimulus was the Gabor in the right visual field of the configuration stimulus. We measured the perceptual learning effects using the configuration stimulus and the element stimuli in both left and right visual fields. We found that the configuration perceptual learning equally improved the perception of the configuration stimulus and both element stimuli. In contrast, the element perceptual learning was confined to the trained element stimulus. These findings demonstrate an asymmetric relationship between perceptual learning of the configuration and the element stimuli and suggest a hybrid mechanism of the configuration perceptual learning. Our findings also offer a promising paradigm to promote the efficiency of perceptual learning-that is, gaining more learning effect with less training time.