AO3 rhythms Flashcards
(16 cards)
RTS the effect of endogenous pacemakers on the sleep wake cycle (circadian rhythm) was conducted by…
DeCoursey et al who destroyed the SCN connections in the brains of 30 chipmunks who were then returned to their natural habitat and observed for 80 days
What did DeCoursey et al find?
They found that the sleep/wake cycle of the chipmunks had dissapered by the end of the study and a significant proportion of them had been killed by predators. They were vulnerable to attack as they should’ve been asleep
Why does DeCoursey et al’s research support endogenous facotrs influencing circadian rhythms?
Because exogenous zeitgebers alone were not able to maintain the sleep wake cycle of the chipmunks
How can Decoursey et als research be criticised?
Criticised by ani al bias as humans may have a more complex interaction between endogenous pacemakers and exogenous zeitgebers as there are a greater number of zeitgebers such as social interaction and clocks
RTS the role of endogenous pacemakers on the sleep wake cycle was conducted by…
Siffre who lived in a cave isolated from all exogenous zeitgebers e.g clocks and the light dark cycle for 6 months
What was found in Siffre’s research?
Within a few days he had developed a consistent 25 hour cycle and continued to fall asleep and wake up on a regular schedule
Siffre’s research suggests that…
The sleep wake cycle is controlled by an endogenous pacemaker due to Siffre developing a consistent rhythm, when seperated from external cues, showing its generally governed by endogenous pacemakers
RTC that infradian rhythms such as the mensutral cycle are mainly governed by an endogenous system was concucted by…
Russel who asked a sample of women to wear a cotton pad under their arm. The pads were then rubbed on the upper lip of 5 sexually inactive women. This process was repeated for 5 months
What did russel find?
Russel found that 4 out of the 5 women developed menstural cycles that synchronised to within one day of the donor cycle. This shows that the infradian rhythm can be affected by exogenous zeitgebers as well as controlled by endogenous factors
What is a limitation of Russels research into infradian rhythm?
The research was a field experiment so has low control over extreneous variables. The research took part in the ppts natural environment where other exogenous factors such as light, stress and changes in diet could also have affected the infradian rhythm
The role of exogenous zeitgebers in infradian rhythms such as pheromones can also be explained by…
evolutionary psychologists
What do evelutionary psychologists state?
That it would have been advantageous in our evolutuionary past for a social group to synchronise pregnancies so many women could be breast feeding at the same time so one mother can take on caring for an orphaned child
What is a strength into research invstigating ultradian rhythm?
It has practical applications in understanding age related changes in sleep. The knowledge that the growth hormone is produced in stage 4 sleep has been associated with sleep defecit in old age as research has found older people experience less stage 4 sleep
What has been developed due to research into ultradian rhythms?
Medication and relaxation techniques have been developed to increase stage 4 sleep in lder individuals and therefore, prevent some issues associated with old age such as reduced alertness
What is a further strength of research into ultradian rhythms?
It uses scientific methods as it is basd on objective and empirical techniques such as EEG to measure brain activity and controlled lab settings. These scientifically measure the activity of the brain throughout the 5 stages of sleep to identify the length of the rhythm and how many times the rhythm occurs throughout the duration of sleep whilst excluding extreneous variables such as noise and temperature.
However, research into endogenous and exogenous factors in ultradian rhythms is conducted in an artificial setting and so the sleep experiences of participants in these studies may not reflect their genuine sleep patterns, governed by…
exogenous pacemakers due to the unfamiliar surroundings and because they are attatched to electrodes which may alter the length of the ultradian rhythm making it difficult to generalise findings
