Biopsychology - infradian and ultradian rhythms

Question 1

examples of infradian rhythms

Answer 1

menstrual cycle and seasonal affective disorder (SAD)

Question 2

menstrual cycle

Answer 2

lasts around 28 days, endogenous system - hormones (oestrogen and progesterone), some evidence suggests exogenous zeitgebers (stress, diet, exercise, syncing)

Question 3

SAD

Answer 3

low mood when number of daylight hours shorten, longer period of melatonin secretion from the pineal gland, and so less serotonin secretion.

Question 4

evaluation of infradian rhythms

Answer 4

+ real life application of light therapy treating SAD, reduces affect for 80% of people
+ menstrual synchrony can be explained by natural selection
+ evidence of synced menstruation - McKintock (1971) - 135 women at uni, cycles synced with friendship groups
+ evidence of synced menstruation - Stern and McKintock (1998), 29 women with irregular cycles, breathe in pheromone from other women and cycles moved closer to theirs
- confounding variables may be affecting rather than synced cycles

Question 5

example of ultradian rhythm

Answer 5

sleep cycle

Question 6

the sleep cycle

Answer 6

5 distinct stages over 90 mins that repeat every night. each stage has different levels of brainwave activity, meaning it can be monitored by EEGs

Question 7

evaluation of ultradian rhythms

Answer 7

+ practical applications of understanding age related changes in sleep/wake cycle. age shortens cycle and so there is less growth hormones, causing impairments. relaxation and medication can be developed and used to treat
- individual differences. Tucker et al - large difference in sleep stages 3 and 4. are the differences biologically determined? makes it difficult to describe ‘normal’ sleep cycle.

Question 8

what is the use of sleep labs

Answer 8

can be used to monitor sleep

Question 9

evaluation of sleep labs

Answer 9

+ high internal validity
+ more objective way of measuring data
- lacks ecological validity