a sleep trend wherein sleep takes place in fairly brief naps throughout a 24-hour timeframe. A human infant might begin life with a rhythm which comprises six sleep periods. The rhythm comes to be monophasic, with one long sleep period each day, by around the time the child is of school age. Biphasic sleep trends, that consist of one daytime nap as well as the long, commonly nocturnal, period of sleep, are observed in a multitude of societies and in older adults.