exogenous zeitgebers AO3

Question 1

evaluation of exogenous zeitgebers - environmental observations (limitation)

Answer 1

• exogenous zeitgebers do not have the same effect in all environments
• the experience of people who live in places where there is very little darkness in summer and very little light in winter tell a different story from the usual narrative.
• for instance, people who live within the artic circle (e.g the inuits of greenland) have similar sleep patterns all year round, depite spending around 6 months in almost total darkness.
• this suggests the sleep/wake cycle is primarily controlled by endogenous pacemakers that can override environmental changes in light

Question 2

evaluation of exogenous zeitgebers - case study evidence (limitation)

Answer 2

• evidence challenges the role of exogenous zeitgebers
• miles et al recount the study of a young man, blind from birth, who had an abnormal circadian rhythm of 24.9 hours.
• despite exposure to social cues, such as regular mealtimes, his sleep/wake cycle could not adjusted.
• this suggests that social cues are not effective in resetting the biological rhythm