If you want to remember anything, then go to sleep
The first reports of enhanced memory consolidation during sleep came from studies investigating declarative memory for verbal material. Jenkins and Dallenbach in 1924 published in American Journal of Psychology, found less forgetting of nonsense syllables after sleep periods than after wakefulness. Fowler et al. in 1973 published in Science, found higher retention of paired-associate words when subjects slept during the first half of the night than when they were awake during daytime. A more recent study confirmed this finding, controlling for circadian rhythm by testing subjects that slept or stayed awake during the first or second half of the night (Plihal and Born 1997, Journal of Cognitive Neuroscience)
Experiments done in Dr. Jan Born’s lab at the Department of Endocrinology, University of Lubeck, Germany to investigate the effect of sleep within few hours of learning or after some intervening time on enhancement of memory. They have chosen 12 American students with no prior knowledge to German language and divided them into four experimental conditions, learn morning-test morning, learn evening-test evening, learn morning-test evening and learn evening-test morning. Subjects were given 24 pair English German vocabulary list to learn and tested by recalling the German words correspond to the English words given in a written format and then calculate the correct answers. These students have regular sleep pattern throughout the experiments. It shows that people learn in evening tend to remember more than those learn in the morning. This is because they go to sleep after three hours of their learning task while those that learned in the morning they go to sleep after 15 hours of the experiment. This may suggest that sleeping may help in recall.
In a second experiment to confirm that, it is the sleep after learning and not the time of learning which result in enhancement of memory. Two groups of students were given task to learn. The first group went to sleep after the learning experiment while the second group where kept awake. The test done after 48 hors of the experiment with a normal schedule in the second day. They have found that the group, which slept after learning, remembers better than those who kept awake. This may indicate that sleep after learning may prove beneficial on memory in human.
Tags: Learning , Memory , Sleep , Wakefulness
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