Abstract
A fundamental function of biological vision is to detect and recognize potential food items and predators from naturally cluttered backgrounds when form and coloration of target objects are similar to the background. Brady and Kersten (2003) previously showed that subjects can do this via bootstrapped learning. Sleep, specifically rapid eye movement (REM), has been shown to enhance perceptual learning. Here, we examined the role of REM sleep in object learning in ambiguous backgrounds. At 9AM and 5PM, 82 subjects were tested on an object learning task. At 1PM, subjects fitted with EEG electrodes and randomized to a quiet wake condition (QW) or nap condition with or without REM. Stimuli used are artificial, morphogenic objects that appear to be organic forms but do not resemble a familiar class of organism and are camouflaged by similar shapes. During AM training, subjects were shown three objects in cluttered backgrounds and asked to trace each object in the foreground (Trace condition). Next, subjects passively view these camouflaged objects appearing with a characteristic sound. At PM test, subjects were asked to recognize objects in the Test condition and re-trace objects in the Trace condition. REM group was significantly better than NREM and QW in recognition (Test), both QW and NREM performed just above chance. Both nap groups were significantly better than QW in the Trace condition. We found an essential role for REM sleep in learning to detect and recognize novel objects from camouflage. Rapid eye movement sleep occupies a large proportion of sleep during early development, and has been hypothesized to be related to cortical plasticity. The following results suggest that learning to recognize and segment objects that share the same form and coloration as their background requires REM sleep in adulthood and has implications for infant object learning.