biopsychology- infradian and ultradian rhythms Flashcards
what is an infradian rhythm?
a rhythm that lasts longer than 24 hours
what is an example of an infradian rhythm?
-menstrual cycle- lasts about 28 days
-rising oestrogen levels cause ovaries to release an egg (ovulation). progesterone helps womb lining to thicken, readying for pregnancy. if not pregnant, egg is absorbed and womb lining comes away (menstrual flow)
what study explored infradian rhythms?
McClintock and Stern (1998)
-studied 29 women w/irregular periods
-pheromones taken from s/o at a different stage of their cycle, via a cotton pad to the armpit
-then cleaned with alcohol and rubbed on the upper lips of other p’s
-68% experienced changes to their cycle which brought them closer to the cycle of their ‘odour donor’
what psychological disorder has an infradian rhythm?
-seasonal affective disorder (SAD), depressive disorder that has a seasonal pattern of onset
-follows a circannual rhythm as it’s subject to a yearly cycle
what is the potential mechanism for SAD?
-melatonin
-during night, pineal gland secretes melatonin until dawn when there’s an increase in light
-in winter less light means secretion continues for longer
-has a knock-on effect for production of serotonin in brain- neurotransmitter linked to depression
ao3 of infradian rhythms: research on menstrual cycle shows it’s biological basis
p- may be an evolutionary advantage to menstrual synchrony. women fall pregnant same time the babies can be collectively cared for in a group
e- would allow babies who had lost their mothers to have access to breastmilk improving changes of survival
e- validity questioned- Schank (2004) argued women syncing increases competition for best males and as competition too high some will miss out
l- uncertain whether synchronous menstrual cycles has the evolutionary value that’s been claimed
ao3 of infradian: methodology used in synchronised studies
-many factors that may change a women’s menstrual cycle and act as a confounding variable (e.g. stress, changes in diet, etc)
-supposed pattern of synchronisation in McClintock and others’ studies may occur by chance
-could be argued such studies lack IV as and are not measuring what their supposed to be due to lack of control
UR- how many stages of sleep are there?
five
over what time frequency to the stages of sleep repeat?
span approximately 90 minutes
what are the features of stage 1 and 2 sleep?
-light sleep, may be easily woken
-in stage 1, brain waves are high frequency and have short amplitude (alpha waves)
-stage 2, these continue but there are occasional random changes in pattern called sleep spindles
what are the features of stage 3 and 4 sleep?
-deep sleep/ slow wave sleep (SWS)
-delta waves which have lower frequency, higher amplitude
-hard to wake up s/o atp
what are the features of stage 5 sleep?
-REM sleep
-body paralysed yet brain activity speeds up significantly in a manner that resembles the awake brain
-brain produce theta waves
-dreams most often experienced during REM sleep
who investigated ultradian rhythms?
Dement & Kleitman (1957)
Describe the study and findings of Dement & Kleitman (1957)
-investigated relationship between eye movements in REM and non-REM sleep
-monitored sleep patterns of nine adult p’s for 6-17 nights in sleep lab. brain activity recorded on EEG. no caffeine or alcohol as a control.
-IV- whether woken from REM or N-REM
-DV- whether could recall dream and detail of it
-found dream recall during REM was 152 compared to 11 NREM
ao3 ultradian rhythms: individual differences
-Tucker et al. found large differences between p’s in terms of the duration of each sleep stage- especially 3 and 4
-likely to be biologically determined
-makes it hard to study as a nomothetic approach
