Biopsychology: Biological Rhythms

Question 1

What is a circadian rhythm?

Answer 1

Biological rhythms, subject to a 24 hour cycle, that regulate internal processes e.g sleep/wake cycle.

Question 2

Give two examples of a circadian rhythm:

Answer 2

Sleep/wake cycle
Changes in core body temperature

Question 3

What are endogenous pacemakers

Answer 3

The body’s internal biological ‘clocks’

Question 4

What are exogenous zeitgebers?

Answer 4

External changes in the environment

Question 5

Who conducted research into the sleep/wake cycle?

Answer 5

Siffre

Question 6

What did Siffre do to investigate the impact of the sleep/wake cycle and what did he find?

Answer 6

• Spent extended periods of time underground in a cave, where changes in natural light and sound did not occur.
• His biological rhythm was around 25 hours, with him waking up and sleeping in a regular schedule

Question 7

What are the three evaluation points for Siffre’s research into the sleep/wake cycle:

Answer 7

1) Shift work (S)
2) Medical treatment (S)
3) Individual differences (L)

Question 8

Explain shift work (S) as an evaluation point for Siffre’s research into the sleep/wake cycle

Answer 8

• Provide an understanding of the impacts of disrupting circardian cycles
• Boivin found that night shift workers were more likely to make mistakes than day shift workers (due to decreased concentration) , and were x3 more likely to develop heart disease

Question 9

Explain medical treatment(S) as an evaluation point for functional recovery:

Answer 9

-Research into circadian rhythms has improved medical treatments.
- Advanced the field of chronotheraputics, where medical treatment is given according to a person’s biological rhythms.
- Can help increase the effectiveness of a drug e.g. aspirin is more effective when taken at night as most heart attacks occur in the morning.

Question 10

Explain individual differences (L) as an evaluation point for research into the sleep/wake cycle:

Answer 10

• Generalisations are difficult to make as individual differences in sleep/wake cycles occur.
• Difficult to use the research data to discuss anything more than averages.

Question 11

What is an infradian rhythm?

Answer 11

Type of biological rhythm where less than one cycle occurs in 24 hours e.g. menstrual cycle, SAD.

Question 12

What is an ultradian rhythm?

Answer 12

Type of biological rhythm where more than one cycle occurs in 24 hours e.g. sleep cycle

Question 13

Who investigated the impact of endogenous and exogenous factors on biological rhythms via the menstrual cycle?

Answer 13

Stern and McClintock

Question 14

What did Stern and McClintock do to investigate the impact of endogenous and exogenous factors on biological rhythms via the menstrual cycle and what did they find?

Answer 14

• Gathered 29 women with irregular periods and collected samples of their pheromones at different stages of the menstrual cycle via a cotton pad.
• Pads were rubbed on the upper lip of the other participants according to the day of their MC (e.g. on day one they got a pad from the first day of their MC, on day two they got a pad from second day)
• Found that 68% of women experiences changes in their cycle which brought them closer the cycle of their ‘odour donor’

Question 15

Explain the theory behind the cause of SAD due to disruptions in infradian rhythms:

Answer 15

• During the night, the pinael gland secretes melatonin until dawn where there is an increase in light.
• During winter the lack of light in the morning means this secretion process happens for longer.
  -This is thought to have a knock-on effect on the production of serotonin in the brain- leading to the onset of depressive symptoms.

Question 16

Give two examples of infradian rhythms:

Answer 16

• Menstrual cycle
• SAD

Question 17

Give one example of an ultradian rhythm:

Answer 17

Stages of sleep (sleep cycle)

Question 18

There are __ main stages of sleep in the sleep cycle, with each whole cycle lasting around ___ minutes.

Answer 18

5
90

Question 19

What happens in stage 1 of the sleep cycle?

Answer 19

• Light sleep where the person may be easily woken
• Alpha waves are present (high frequency, short amplitude)

Question 20

What happens in stage 2 of the sleep cycle?

Answer 20

• Alpha waves continue
• Occasional random changes in sleep spindles

Question 21

What happens in stage 3 and 4 of the sleep cycle?

Answer 21

• Deep sleep (slow wave sleep) where it is difficult to wake the person up.
• Delta waves are present (Lower frequency, higher amplitude)

Question 22

What happens in stage 5 of the sleep cycle?

Answer 22

• The body is paralysed yet brain activity closely resembles that of the awake brain.
• Theta waves are present.
• REM occurs- can result in dreams.

Question 23

What are the three evaluation points for infradian rhythms:

Answer 23

1) Evolutionary basis (S)
2) Real world application (S)
3) Methodological limitations (L)

Question 24

Explain evolutionary basis (S) as an evaluation point for infradian rhythms:

Answer 24

• The menstrual synchrony research may be used to explain natural selection
• Menstrual synchrony is thought to have evolutionary value as it may have been advantageous for women who menstruate together to get pregnant at the same time.
• Allow for infants who have lost their mothers to have access to breast milk- improving their chances of survival.

Question 25

Explain real world application (S) as an evaluation point for infradian rhythms:

Answer 25

• One of the most effective treatments for SAD is a light box that simulates very strong light to reset the body’s internal clock.
• Effective in around 80% cases- (yet high relapse rate - 46%)
• Preferred treatment over antidepressants

Question 26

Explain methodological limitations (L) as an evaluation point for infradian rhythms:

Answer 26

• Menstrual synchrony studies were flawed.
• Confounding variables that could have impacted the P’s menstrual cycle were present e.g. stress, exercise, diet.
• Any supposed synchrony could have just been due to chance.

Question 27

What are the three evaluation points for ultradian rhythms:

Answer 27

1) Improved understanding (S)
2) Scientific methods (S)
3) Individual differences (L)

Question 28

Explain improved understanding (S) as an evaluation point for ultradian rhythms:

Answer 28

• Research into ultradian rhythms has improved our understanding of age-related changes in sleep.
• Sleep scientists have observed that deep sleep reduces with age.
• The resulting sleep deficit may explain issues in old age, such as reduced alertness - which can be practically treated through medications

Question 29

Explain scientific methods (S) as an evaluation point for ultradian rhythms:

Answer 29

• Conducting sleep studies in a lab allows for extraneous variables that may affect sleep to be controlled e.g. noise, temperature
• Increases internal validity of the study (not necessarily externally valid though - do second sleep study in Ps home as well to counteract this)

Question 30

Explain individual differences (L) as an evaluation point for ultradian rhythms:

Answer 30

• Research shows that there is are significant variations between peoples sleep cycles, especially in stages 3 and 4.
• Tucker et al suggests these stages are likely to be biologically determined- making it difficult to describe ‘normal sleep’ in a meaningful way.