Sleeping not only protects memories from being forgotten, it also makes them easier to access, according to new research which suggest that after sleep we are more likely to recall facts which we could not remember while still awake.
In two situations where subjects forgot information over the course of 12 hours of wakefulness, a night's sleep was shown to promote access to memory traces that had initially been too weak to be retrieved.
The research tracked memories for novel, made-up words learned either prior to a night's sleep, or an equivalent period of wakefulness. Subjects were asked to recall words immediately after exposure, and then again after the period of sleep or wakefulness.