infradian rhythms Flashcards
1
Q
explain the menstrual cycle for infradian rhythms?
A
- governed by monthly changes in hormone levels that regulate ovulation
- typical cycle= 28 days to complete
- rising levels of oestrogen cause the ovary to develop an egg and release it
- progesterone helps womb lining get thicker, if pregnancy doesn’t occur the egg is absorbed into body and lining sheds=period
2
Q
explain the research study for the menstrual cycle for infradian rhythms?
A
- menstrual cycle is endogenous
- however ev shows it can be influenced by exogenous factors eg. cycles of other women
- mcClintock study into 29 women with history of irregular periods
- used cotton pads worn by other women’s armpits and swabbed on other women top lips
- 68% of women experienced changes to their cycle which brought them closer
3
Q
explain seasonal affective disorder (SAD) for infradian rhythms
A
- depression that has a seasonal pattern of onset
- symptoms normally triggered during winter months when number of daylight hours decrease
- during the night the pineal gland secretes melatonin until dawn when there is an increase in light
- in winter due to lack of light, secretion process happens for longer = knock on effect on production of serotonin (a chemical linked to the onset of depressive symptoms
4
Q
name types of infradian rhythms?
A
- seasonal affective disroder
- menstrual cycle
5
Q
name types of circadian rhythms?
A
-sleep/wake cycle
6
Q
explain Ultradian rhythms?
A
- stages of sleep cycle
- psychologists have identified 5 stages of sleep= approx. 90 mins
- monitored using EEG
- stage1and2: light sleep, easily woken brain, wave patterns begin rhythmic alpha waves to theta waves (slower)
- stage3and4: slower delta waves, higher amplitude than earlier patterns, difficult to wake someone
- stage5, REM (rapid eye movement) sleep: body paralysed but brain activity speeds up, correlated with dreaming.
7
Q
evaluate the evolutionary basis of the menstruation cycle?
A
WEAKNESS
- McClintock study has evolutionary value as it would’ve been advantageous for women to menstruate together and fall pregnant around the same time= collective caring
- questioned by Jeffery Schkank, if too many women are cycling together= competition for highest quality males
- seems like avoidance of synchrony would be the most adaptive strategy
8
Q
evaluate methodological limitations of synchronisation studies?
A
WEAKNESS
- many confounding variables may affect a woman’s menstrual cycle eg. stress
- this means any observed patterns of could have occurred by chance
- research normally uses small samples of women, relying on self-reporting techniques
9
Q
evaluate evidence for distinct stages in sleep (ultradianR)?
A
- study monitored sleep patterns of 9 adults in a sleep lab
- EEG used to record brain waves, researchers controlled effects of caffine and alcohol
- REM activity was correlated with dreaming
- replications noted similar findings
- but small sample size= weakness
