Daytime sleep following observational practice does not enhance a visual-spatial and a motor representation

The present study examined if a daytime nap of 90 min can further improve skill memory afforded by observation and physical practice. Moreover, we determined if a 'nap' benefit was restricted to a particular representational form (spatial or motor) that can be used to govern performance. Participants were assigned to one of four experimental conditions: physical practice with no nap, physical practice with a nap, observation with no nap, and observation with a nap. Specifically, after either physical or observational practice of a 1300-ms sequence of flexion and extensions at the right elbow, a participant experienced a 90-min nap or an equivalent period of wake-filled rest. Each participant then completed a retention test and a set of inter-manual transfer tests that probed the efficacy of spatial and motor representations that developed because of the practice modality and if a nap was experienced. As expected, retention and transfer performance were superior following physical practice compared to observation. However, observation offered benefits to skill revealed by lower RMSE for observers at retention compared to that displayed during the initial trials for the individuals' privy to physical practice. A nap only supported a reduction in error when administered after physical practice. This was true not only for retention but also during tests that relied on available visual-spatial and motor representations. Counter to recent reports, observers did not benefit from a nap. A nap following observation harmed individuals to instantiate the visual-spatial and the motor representation for movement sequence production.