PSYC 2800 : Why Do We Sleep and Dream.docx
Document Summary
Origins of biological rhythms: biorhythm: inherent timing mechanism that controls or initiates various biological processes. Biological clock: behaviour is not simply driven by external cues from the environment, rhythms are endogenous (control comes from within, biological clock (endogenous clock) Allows animals to anticipate events before they happen. Example: birds migrate before it gets cold. Biological rhythms: period, time required to complete a cycle of activity, circannual rhythm, yearly (e. g. migratory cycles of birds) Around a year : infradian rhythm, less than a year (e. g. human menstruation cycle, circadian rhythm, daily (e. g. human sleep cycle) Around a day : ultradian rhythm, less than a day (e. g. eating cycle) We measure this by measuring activity level when they are awake (nocturnal), measure the activity of rat on the running wheel. Free-running rhythms: rhythm of the body"s own devising in the absence of all external cues.
