We all have had the experience of improved memory if we know others expect us to remember.
I guess such improvement occurs because we work harder at it, using more intensive rehearsal and perhaps using deliberate association strategies.
The others were exposed to the same material late, just before the night's sleep.
When subjects were told they would be tested later, they were more likely to remember if they had slept immediately after the learning.
Also, recall of biological memory launches a recon-structive process whereby the memory can be reinforced or drastically altered.
Forty minutes later, the volunteers were asked to learn a second, slightly different set of card pairs.When both groups were tested for recall of the first set of cards, the sleep group remembered much better (85% correct versus 60% for the awake group).The explana-tion begins with the knowledge that when temporary memories (as for the first card set) are recalled, they are vulnerable to being destroyed by new mental activity (as with the second card set).At least two processes seem to be at work: 1) sleep protects new memories from disruption by the interfering experiences that are inevitable during wakefulness, and 2) sleep consolidates memories according to their relative importance and the learner's expectations for remembering.A good illustration of reducing interference comes from a study of napping at the University of Lübeck in Germany.