Biopsychology Flashcards
(3 cards)
Exogenus Zeitgebers
Environmental events responsible for entraining the SCN.
Light is the most important zeitgeber in humans. Helps to maintain the sleep/wake cycle by resetting the SCN. Receptors in the SCN are sensitive to changes in light levels during the day and use this info to synchronise the activity of the body’s organs and glands. Light rested the internal biological clock each day, keeping it on a 24-hour cycle.
Social cues such as mealtimes, bedtime and social events also act as a zeitgeber. Research also suggests adapting to local times for eating and sleeping is an effective way on entraining circadian Rhythms and beating jet lag.
Supporting evidence for the role exogenous zeitgebers in circadian rhythms control?
Campbell and Murphy (1998) found that shining a light on the back of participants knees shifted the circadian rhythm, this implies natural light plays a role in entraining our biological clocks, to keep the sleep/wake cycle in synchrony with the outside world.
Practical application - led to treatments for jet lag, burgess et al (2003) found the exposure to bright light prior to an east-west flight reduced jet lag. Participants exposed to bright light felt sleepier 2 hours earlier in the evening and woke up 2 hours earlier in the morning, ie closer to local times conditions they would find after a west-east flight, huge economic benefits
Contradictory evidence for exogenus zeitgebers
Miles (1977) studied a young man who was blind from birth, despite exposure to social cues, such as regular mealtimes, his sleep/wake cycle remained abnormal, this suggests social cues alone aren’t effective In resetting the biological rhythm.
