ultradian + infradian rhythms

Question 1

ultradian rhythms

Answer 1

• span a period less than 24 hours
• e.g. 5 sleep stages
• we follow a pattern alternating between:
• stage 5, rapid eye movement (REM) + stages 1-4, non-rapid eye movement (NREM)
• cycle repeats every 90 mins = basic rest activity cycle (BRAC)
  = continues when we’re awake
  = go from state of alertness to physiological fatigue
• each stage shows a distinct EEG pattern
• e.g. enter deep sleep, brainwaves slow + BR, HR decrease
• e.g. during stage 5, pattern resembles an awake person = DREAMING OCCURS

Question 2

infradian rhythms

Answer 2

• span a period longer than 24 hours e.g. weeks, months or even a year
• e.g. menstrual cycle = lasts about a month
  = average is 28 days
• hormones regulate the menstrual cycle
• ovulation occurs roughly halfway through the menstrual cycle
  = oestrogen levels at peak (16-32 hours)
• after ovulation, progesterone levels increase in prep for possible implantation of an embryo in uterus

Question 3

evaluation of ultradian rhythms

Answer 3

• violinists
• individual differences

Question 4

evaluation of infradian rhythms

Answer 4

• masculine vs feminine
• pheromones

Question 5

ad of ultradian rhythms

Answer 5

• psych found support for ultradian rhythms
• studied a group of elite violinists
• found that practice sessions were limited to 90 mins at a time
• violinists frequently napped to recover from practise, best violinists napped more
• same found among, athletics, chess players etc..
  = supports BRAC

Question 6

disad of ultradian rhythms

Answer 6

• psych suggests that there are individual differences in ultradian rhythms
  = biologically determined
  = may even be genetic in origin
• parts were studied in a lab, over 11 consecutive days + nights
• researchers assessed:
• sleep duration
• time taken to fall asleep
• amount of time in each sleep stage
  = found differences in all of these characteristics

Question 7

ad of infradian rhythms

Answer 7

• infradian rhythms can affect behaviour
• psych found that women express a preference for feminised male faces
• when choosing a partner for a LT relationships
• HOWEVER, showed a preference for masculinised faces during ovulation

Question 8

disad of infradian rhythms

Answer 8

• the menstrual cycle is not only governed by infradian rhythms
• when several women of childbearing age live together (+ don’t take contraceptives)
  = their menstrual cycles synchronise
• in one study, samples of sweat were collected from one group of women
• then rubbed onto the upper lip of another group of women
  = their menstrual cycles became synchronised
  = suggests that synchronisation is affected by pheromones