p2 - biopsychology (rhythms). ✔️

Question 1

What is a biological rhythm?

Answer 1

All living organisms have them. Changes in body processes across a time period.

Question 2

What is a circadian rhythm, and examples?

Answer 2

Last 24 hours.
Sleep/wake cycle - Drowsy at night, alert during day.
Temperature - Lowest 4am, highest 6pm.

Question 3

What are the three research studies into the sleep/wake cycle?

Answer 3

Siffre, 1962 + 1972
Aschoff + Wever, 1976
Folkard et al, 1985

Question 4

What did Aschoff + Wever do, involving the sleep/wake cycle?

Answer 4

Participants spent 4 weeks in a WWII bunker deprived of natural light.
All but one participant displayed a circadian rhythm between 24-25 hours, rather than 24 hours exactly.
In conclusion, endogenous pacemakers are the most influential on the sleep/wake cycle.

Question 4

What research did Siffre do, involving the sleep/wake cycle?

Answer 4

Spent several periods underground to study the effect on rhythms.
1962, spent 2 months in a cave.
1972, spent 6 months in a cave.
In 1962, re-surfaced believing it was mid-August when it was actually mid-September. Always woke and slept on a regular cycle.
In conclusion, endogenous pacemakers are the most influential on the sleep/wake cycle.

Question 5

What do Folkard et al do, involving the sleep/wake cycle?

Answer 5

12 people lived in a dark cave for 3 weeks, where they woke at 7:45am and slept at 11:45am due to a clock.
Researchers sped up the clock so the day only lasted 22 hours.
Only one participant was able to adjust.
In conclusion, endogenous pacemakers are the most influential on the sleep/wake cycle.

Question 6

What are the two research studies into the body temperature cycle?

Answer 6

Folkard, 1977
Gupta, 1977

Question 7

What did Folkard do, involving the temperature cycle?

Answer 7

Was interested in cognitive ability and its association with body temperature.
Read children stories at 3 and 9pm.
Children had high recall and better understanding at 3pm.
In conclusion, higher body temperature improves cognitive function.

Question 8

What did Gupta do, involving the temperature cycle?

Answer 8

Tested IQ of participants at 7, 2 and 9pm.
Improved performance seen at 7pm.
In conclusion, higher body temperature improves cognitive function.

Question 9

Advantages of circadian rhythms?

Answer 9

Research support - Siffre, Aschoff + Wever, Folkard.
Increases validity.

Question 10

Disadvantages of circadian rhythms?

Answer 10

Problems with research support - Limited samples (Siffre = Case study).
Not generalisable.

Question 11

What is an exogenous zeitgeber?

Answer 11

External cues that affect or entrain our biological rhythms.

Question 12

What is an endogenous pacemaker?

Answer 12

Internal body clock that regulates many of our biological rhythms.

Question 13

Who researched exogenous zeitgebers, and what did they do?

Answer 13

Campbell + Murphy, 1998
- Demonstrated light may be detected by skin receptor sites even when not received by eyes.
- 15 participants woken at various times where a light was shone on the back of their knees.
- Deviation of usual sleep/wake cycle by up to 3 hours.

Question 14

What are the two exogenous zeitgebers?

Answer 14

Light
- Resets the body’s main endogenous pacemaker, SCN.
- Indirectly influences key process in the body that control functions like hormone selection and blood circulation.

Social cues
- When you eat and go to sleep.

Question 15

What are the two endogenous pacemakers?

Answer 15

SCN
- In the hypothalamus.
- Controls biological rhythms, links to areas responsible for sleep and arousal.
- Receives information about light levels from the optic nerve.

Pineal gland
- Produces melatonin which makes us drowsy.
- During day, pineal gland is inactive.

Question 16

What are the two research studies into endogenous pacemakers?

Answer 16

DeCoursey et al, 2000
Ralph et al, 1990

Question 17

What did DeCoursey do, involving endogenous pacemakers?

Answer 17

Destroyed SCN connections of 30 chipmunks who were returned to their natural habitat and observed for 30 days.
Found the sleep/wake cycle disappeared a significant portion of the chipmunks were killed by predators.

Question 18

What did Ralph et al do, involving endogenous pacemakers?

Answer 18

Bred ‘mutant’ hamsters with a 20 hour sleep/wake cycle.
When SCN cells from mutants were transplanted into normal hamsters, cycles of the second group were defaulted to 20 hours.

Question 19

Advantages of exogenous zeitgebers?

Answer 19

Research support - Campbell + Murphy, 1998. Supports light as an exogenous zeitgeber as it impacts sleep/wake cycle.

Question 20

Disadvantages of exogenous zeitgebers?

Answer 20

Problems with research support - Yet to be replicated. Critical in the way the study was conducted as light may have been exposed to participant’s eyes.
Reduces reliability.

Problems with research support, interactions - Isolating light doesn’t tell us about interaction between internal and external influences.
Ignores insight into other zeitgebers that may have an influence. Not the whole picture.

Question 21

Advantages of DeCoursey et al’s research into endogenous pacemakers?

Answer 21

Research support - Supports the SCN as an endogenous pacemaker.
Increases validity.

Question 22

Disadvantages of DeCoursey et al’s research into endogenous pacemakers?

Answer 22

Problems with research support - Lacks cross-species validity, chipmunks.
Cannot generalise to humans.

Ethical issues - Cruel procedures + deaths.

Question 23

Advantages of Ralph et al’s research into endogenous pacemakers?

Answer 23

Research support - Supports the SCN as an endogenous pacemaker.
Increases validity.

Question 24

Disadvantages of Ralph et al's research into endogenous pacemakers?

Answer 24

Case study - Only one person. Cannot generalise findings.

Question 25

Why does disruption to biological rhythms have negative consequences?

Answer 25

Goes against an individual's endogenous patterns, so there are physiological and psychological costs of disruption as the body attempts to readjust.

Question 26

When does jet lag occur?

Answer 26

When the individual crosses time zones as it disrupts the natural rhythm of the biological clock, if there is a sufficient difference between internal and external time.

Question 27

Symptoms of jet lag and shift work?

Answer 27

Fatigue, insomnia, anxiety, constipation or diarrhoea, dehydration and increases susceptibility to illness.

Question 28

What is phase delay?

Answer 28

- East to west. - Easier to adjust as it lengthens the day, meaning you just stay awake longer.

Question 29

What is phase advance?

Answer 29

- West to east. - Harder to adjust as you miss a whole night's sleep, unless you force yourself to sleep when not tired.

Question 30

Who researched into jet lag, and what did they find?

Answer 30

Klein, Wegman + Hunt, 1971. Found adjustment of sleep/wake cycle was faster westbound than eastbound. Westbound - 1 day. Eastbound - 6 days.

Question 31

Why does shift work cause disruption to biological rhythms?

Answer 31

Individual is working when the body wants to sleep, and sleeping when the body wants to be awake.

Question 32

Why is shift work worse than jet lag?

Answer 32

Involves prolonged conflict between internal clocks and external stimuli.

Question 33

How can the body cope with shift work?

Answer 33

If given enough time, the body can reprogramme our biological rhythms by reducing disruption.

Question 34

What are the two ways shift work can be worsened?

Answer 34

1. The person reverting to 'normal' sleep/wake cycles at the weekend. 2. Shifts altering from one week to the next. Biorhythms are in a permanent state of desynchronisation.

Question 35

What are the three research studies into shift work?

Answer 35

Czeisley et al, 1982. Dawson + Campbell, 1991 Monk + Folkard, 1983.

Question 36

What did Monk + Folkard do, involving shift work?

Answer 36

Identified 2 types of shift work: - Rapid rotation: Where workers change shift every third shift. - Slow rotation: Where workers changed shift every week or month. - Fast rotation is a constant state of disruption, struggling to adjust to sleep/wake cycles.

Question 37

What did Czeisley et al do, involving shift work?

Answer 37

Tested impact of phase delay shifts Vs advance shifts (early shift to day shift to night shift. - Workers reported feeling better and less tired and managers reported increased productivity and fewer errors. - Found it was better to have slower shift changes: a pattern of 21 days is better than 7 days.

Question 38

What did Campbell + Murphy do, involving shift work?

Answer 38

Found that light acts as a zeitgeber in maintaining the rhythm of the SCN. - Found the bright light could be used as a substitute for sunlight. - Workers exposed to a 4-hour pulse of bright light showed improvements in work performance.

Question 39

What are the economic implications of desynchronisation?

Answer 39

- Reduced productivity at work. - Reduced employee morale.

Question 40

What are real examples of disasters that happened during early morning shifts?

Answer 40

- Chernobyl - High number of fatalities on the roads (most lorry accidents occur between 4-7am).

Question 41

What are the health risks of desynchronisation?

Answer 41

- Increased risk of heart disease. - Digestive disorders. - Regular tiredness (20% of workers fall asleep at work).

Question 42

Advantages of jet lag research?

Answer 42

Supporting evidence - Klein’s research has been supported by Schwartz et al, 1995. Analysed the results of American baseball games in relation to whether the teams travelled east to west, or west to east. Found west coast teams travelling east lost more games. Suggests westbound flights are easier to adjust to. Increases validity. Practical applications - Combating the negative affects of disruption. Melatonin tablets used as cure for jetlag. Social factors can also help, like getting used to the eating times in the new time zone. Suggest research helps improve the quality of people’s lives. Useful.

Question 43

Disadvantages of jet lag research?

Answer 43

Lack of control - Studies not always well controlled. For example, Schwartz’s study, ability of the team was a factor but not accounted for. Suggests factors other than jetlag and disruption to rhythms could have led to poorer performance of teams. Reduces reliability.

Question 44

Advantages of shift work research?

Answer 44

Supporting evidence - Negative affects are well-documented and suggest research is valid in the real world. Accident records and self-reports, e.g. lorry accidents, Chernobyl. Increases validity. Practical applications - Used to improve shift patterns and reduce the likelihood of accidents, e.g. to reset the SCN so shifts follow a phase delay rather advance pattern. Useful.

Question 45

What are infradian rhythms, and examples?

Answer 45

Lasts over 24 hours. The menstrual cycle. Seasonal Affective Disorder (SAD).

Question 46

Explain the menstrual cycle.

Answer 46

- Governed by monthly changes in hormone levels which regulate ovulation. - Typically lasts 28 days, from the first day of a woman’s period until the day before her next period. - Rising levels of oestrogen cause the ovary to develop an egg and realise it (ovulation). - After ovulation, progesterone grows the womb lining thicker, ready for pregnancy. - If pregnancy does not occur, the egg is absorbed into the body and the womb lining leaves the body (menstruation). - The menstrual cycle is an endogenous system, although psychologists argue it may be influenced by exogenous factors such as other women’s cycles.

Question 47

Explain seasonal affective disorder (SAD).

Answer 47

- A depressive disorder which has a seasonal pattern and is diagnosed as a mental disorder. - Main symptoms: persistent low mood, a general lack of activity and interest in life. - Symptoms are triggered when daylight hours become shorter. - Particular kind of rhythm called a circannual rhythm, a yearly cycle. - Melatonin may be related to the onset of SAD. - During the night, pineal gland secretes melatonin until daylight occurs. During winter, there is a lack of light so secretion lasts longer. - Affects the production of serotonin, linked to depression.

Question 48

Advantages of the menstrual cycle as an infradian rhythm?

Answer 48

Research support - Stern + McClintock, found that pheromones of other women can have a significant influence on the menstrual cycle. Suggests exogenous factors are involved in infradian rhythms. Increases validity. Evolution - Argue that for our ancestors, if all females menstruate and fall pregnant together, then new-borns can be cared for collectively as a group. Suggests exogenous factors are involved. Evolutionary advantage.

Question 49

Advantages of SAD as an infradian rhythm?

Answer 49

Practical applications - Most effective treatment for SAD is phototherapy. A lightbox is used to stimulate very strong light in morning and evening. Resets melatonin levels, and relieves symptoms in 60% of sufferers. Useful. Increases validity.

Question 50

Disadvantages of the menstrual cycle as an infradian rhythm?

Answer 50

Problems with research support - Synchronisation studies criticised due to poor control. McClintock’s study, changes in cycle could have been due to other factors such as stress or diet. Findings may have been down to confounding variables, and so we cannot be sure of the role of other women in the menstrual cycle. Decreases validity. Evolution - Argue that if too many females cycled together in a group, there would be more competition for mates and lower the fitness of any potential offspring. Suggests no exogenous factors are involved in the menstrual cycle, as that would be an evolutionary disadvantage.

Question 51

What is an ultradian rhythm?

Answer 51

Lasts less 24 hours.

Question 52

Describe stage 1 of the sleep cycle.

Answer 52

Drowsiness - Transition between awake and asleep. - Physiological functions slow down. - Brainwave patterns become slower and more rhythmic (alpha).

Question 53

Describe stage 2 of the sleep cycle.

Answer 53

Light sleep - Easily woken. - Brainwave patterns become even slower (theta). - Drop in body temperature and relaxed muscles.

Question 54

Describe stage 3 of the sleep cycle.

Answer 54

Deep sleep - Difficult to wake up. - Brainwaves are slower and have great amplitude (delta). - NREM sleep. - Crucial for physical restoration, immune system strengthening and memory consolidation.

Question 55

Describe stage 4 of the sleep cycle.

Answer 55

Deepest NREM sleep - Same as stage 3.

Question 56

Describe the REM stage of the sleep cycle.

Answer 56

- Body is paralysed. - Brain activity speeds up. - Dreaming. - Brain waves similar to wakefulness, indicating high activity (beta).

Question 57

Advantages of research into ultradian rhythms?

Answer 57

Practical applications - Understanding stages of sleep could lead to treatments for sleep disorders, such as insomnia or psychiatric illness, such as dementia. Useful. Increases validity. Research support - EEG scans demonstrating stages of sleep. Replicated multiple times by different researchers. Dement + Kleitman identified clear correlation between REM sleep and dreaming - when participants were woken from REM they could recall dreams accurately. Replicable means highly reliable. Increases validity.