1. A system for improving memory having a training mode and a sleep consolidation mode, the system comprising: a user interface comprising a control allowing a user to switch the device to the training mode to indicate a training session; a sensory stimulator configured to provide a plurality of distinct sensory stimuli; a sleep monitor configured to monitor a user's sleep state without contacting the user's head; a controller comprising control logic receiving input from the user interface and configured to select a contextual sensory stimulus for a specific training session and to control the application of the contextual sensory stimulus, wherein the controller receives information on the user's sleep state from the sleep monitor, and controls the sensory stimulator to apply the contextual sensory stimulus from the specific training session according to a training schedule when the user is experiencing slow wave sleep during a sleep consolidation mode; and a learning database configured to be populated with training content and contextual sensory stimuli co-presented with the training content, wherein the controller is configured to use information from the database to determine the training schedule by selecting which contextual sensory stimuli to repeat and when to repeat each sensory stimuli associated with particular training content over multiple nights of sleep.