EP

Question 1

Summary

Answer 1

Biological rhythms are regular patterns of psychological or biological activity over a given period of time

Circadian rhythm - once in 24th e.g. sleep wake cycle
Regulated by both internal and external factors. Internal are endogenous pacemakers and are body’s internal clock

External factors are exogenous zeitgebers and are external cues which interact with EP thaat affect rhythm e.g. light

Suprachiasmatic nucleus (SCN) is an EP which affects sleep wake cycle. Found in hypothalamus in both hemispheres and is group of neurons which regulate pineal gland actions.

Pineal gland responsive to light (EZ). During darkness, it converts serotonin to melatonin.

Explains why we get tired at night

In absence of EZ, SCN works independently on 25 hr or longer cycle. Sleep wake cycle is longer than 24 hrs when we have no external cues to regulate.

Question 2

Strength 1

Answer 2

Strength of research into effect of endogenous pacemakers have on our circadian rhythms is that it has practical application

Bc research suggests that disrupting our circadian rhythms on a regular basis has negative effects, such as reduced conc at 6am.

Therefore, preventative measures (scheduled breaks) have been implemented to reduce accidents.

Question 3

Supp

Answer 3

Supporting research evidence from Siffre (1975). Spent 61 days in underground cave deprived of natural light,

Found biological rhythm remained regular but rhythm extended to just over 25hours

Suggests sleep-wake cycle is mainly controlled by EP, in absence of EZ

Question 4

I

Answer 4

Individual differences

Variability between groups of participants which most research doesnt account for

Research suggested that cycle length can vary between 13 to 65 hours.

This challenges concept that circadian rhythms are the same in all of us, and therefore reduces validity of research that doesnt account for these differences