Biopsychology: Biological rhythms

Question 1

define the term biological rhythms

Answer 1

• periodic activity governed by endogenous pacemakers (internal biological clocks) and exogenous zeitgebers (external changes in the env)

Question 2

state and describe are the types of rhythms (3)

Answer 2

1. circadian rhythm - rhythm with a 24hr cycle
2. ultradian - rhytm shorter than a day
3. infradian - rhythm longer than a day

Question 3

name 1 process which we have a circadian rhythm for and describe how this rhythm is governed by internal and external mechanisms (4)

Answer 3

• the sleep wake cycle
• exogenous zeitgebers: the fact we feel drowsy at night and alert during the day shows the effect of light (an external factor) on our internal body clock
• endogenous pacemakers: SCN receives information about light even when our eyes are closed = internal body clock
• pinneal gland: produces and releases diff amounts of melatonin in response to light levels which make us more or less alert

Question 4

name a case study which supports circadian rhythms (1)

Answer 4

Michel Siffre

Question 5

describe the procedure, findings and conclusion of Michel Siffre’s case study (6)

Answer 5

procedure:
- 2 months living in total isolation in alps
- no acces to clock, calendar or sunlight
- slept and ate only when his body told him to
findings
- his biological rhythm settles to just outside 25 hours
- natural fell asleep and woke up on a regule schedule
conclusion
- we have a circadian rhythm for sleep/wake cycle

Question 6

who conduscted research which compared the effects of exogenous zeitgebers and endogenous pacemakers on the circadian rhythm ? (1)

Answer 6

Folkard

Question 7

describe the procedure, findings and conclusion of Folkard’s research (5)

Answer 7

skprocedure:
- studied 12 ppl that lived in dark cave for 3 weeks
- went to bed when clock said 11:45pm and woke up when clock said 7:45am
- researchers gradually sped up the clock to a 22 hour day

findings
- only 1 ppnt adjusted to new regime

conclusion:
-sleepwake cycle is an example of a circadian rhythm

Question 8

what are the 3 evaluation pointa for circadian rhythms ? (3)

Answer 8

✅ research support - Siffre

❌ cave case studies - very small sample size - small group of ppnts or just 1 individual + not easily replicated hard to determine reliability

❌ individual diffs not taken into account in research into circadian rhythm - research found that ‘morning people’ prefer to get up and go to bed early but ‘evening people’ prefer to wake and go to bed later- innate individual differences in circadian rhythms

Question 9

give an example of an infradian rhythm (1)

Answer 9

the menstrual cycle

Question 10

describe the menstrual cycle (5)

Answer 10

• lasts for approx 28 days
• during each cycle oestrogen lvls rise causing ovaries to develop and release an egg = ovulation
• after ovulation progesterone thickens lining of uterus preparing body for pregnancy
• if egg isnt fertilised and pregnancy doesnt happen the egg is absorbed into the body and the womb lining comes away = menstruation
• cycle repeats

Question 11

what are pheromones (2)

Answer 11

• external factors that regulate the menstrual cycle
• chemicals which act like hormones outside body of the secreting idividual affecting behavior of recieving individual

Question 12

who conducted research into infradian rhythms ? (1)

Answer 12

McClintock

Question 13

describe the procedure and findings of McClintock’s research

Answer 13

procedure:
- 29 ppnts

• 9 of women had sample of pheromones taken from their armpit at diff stages in their cycle = odor donors
• 20 had pheromones rubbed on their top lip = odor reciever

findings:
68% of odor recievers reported changes to their cycle that brought them closer to cycle of their odor donor

conclusion:
exogenous zeitgebers may synchronise menstrual cycles

Question 14

what are the 2 evaluation points for infradian rhythms (2)

Answer 14

✅ research shows evolutionary basis for pheromones synchronised menstrual cycles beneficial as all children would be born at same time so could be reared collectively

❌ McClintock issues with validity - factors such as diet, lifestyle + stress werent controlled + small sample size, other research failed to replicate this study

Question 15

give an example of a ultradian rhythm (1)

Answer 15

stages of sleep

Question 16

describe the stages of sleep (4)

Answer 16

• 90 minute cycle “the sleep escalator”
• 5 mins of light sleep - transition from wakefulnesss to sleep
• 65 mins of normal or non- REM sleep
• 20 mins of REM sleep (where we dream)

Question 17

describe the light sleep stage of sleep (stage 1 + 2) (4)

Answer 17

• last around 5 mins
• can be easily woken
• in stage 1 brain waves are in high frequency + short amplitude = alpha waves
• in stage 2 alpha waves continue but there are occasional random changes in pattern = sleep spindles

Question 18

describe the non-REM sleep stage - stage 3 and 4 (4)

Answer 18

• lasts around 65 mins
• cant be easily woken
• known slow wake sleep
• brain waves have lower frequency and higher amplitude

Question 19

descirbe the REM (rapid eye movement) sleep stage - stage 5 (5)

Answer 19

• lasts around 20 mins
• body is paralysed but brain is most alert
• this is when we dream
• brain produces theta waves
• eyes occasionaly move around

Question 20

who conducted research supporting ultradian rhythms ? (1)

Answer 20

Demend and Kleitman

Question 21

describe the procedure and findings of Dement + Kleitman’s research (3)

Answer 21

procedure:
- measures brain activity using EEG

findings:
- REM sleep highly correlated with dreaming

• when ppl were woken up during REM stage ppl could recall v clearly what they dreamed compared to other stages of sleep

Question 22

what are the evaluation points for ultradian rhythms

Answer 22

✅ dement and klietmans research high validity + scietific replicated on multiple occasions + use EEG’s scientific credibility

✅ knowledge on ultradian rhythms has practical value
slow sleep stage reduces with age and growth hormones are produced during slow sleep stage - this can explain impairments in older ppl, so relaxation medication can be developed to improve slow sleep stage which will prevent these impairements

❌/✅ lab study - ppnts attached to machinery - doesnt resemble ordinary sleep however ✅ control extraneous variables which may affect sleep eg temp + noise