PAPER 2 - Biopsychology - Biological rhythms

Question 1

Define biological rhythms.

Answer 1

Distinct patterns of changes in the body activity that conform to cyclical time periods. All living organisms are subject to them.

Question 2

What are biological rhythms influenced by?

Answer 2

Internal body clocks (endogenous pacemakers) as well as externa. changes to the environment (exogenous zeitgebers)

Question 3

Define circadian rhythms.

Answer 3

A type of biological rhythm, subject to. 24-hour cycle, which regulates a number of body processes such as the sleep/wake cycle and changes in core body temperature.

Question 4

What study researches the sleep/wake cycle / circadian rhythms?

Answer 4

Siffre’s cave study

Question 5

Explain the procedure of Siffre’s case study.

Answer 5

Siffre = self-styled caveman, spent several extended periods underground to study the effects on his own biological rhythms.
He was deprived of exposure to natural light and sound but had access to adequate food and drink for 2 months in 1962 in the Alps.
A decade later he repeated this for 6 months in a Texan cave.

Question 6

Explain Siffre’s findings.

Answer 6

His free-running biological rhythm settled down to one that was just beyond 24 hours (around 25 hours) though he did continue to fall asleep and wake up on a regular schedule.

Question 7

Discuss the procedure of Aschoff and Wevers research on circadian rhythms.

Answer 7

Convinced participants to spend 4 weeks in a WW2 bunker deprived of natural light.

Question 8

Discuss the findings of Aschoff and Wevers research on circadian rhythms.

Answer 8

All but one of the participants displayed a circadian rhythm between 24 and 25 hours.
Paired with Siffre’s study we can be convinced that the ‘natural’ sleep/wake study may be longer but is entrained by exogenous zeitgebers associated with our 24 hour day e.g. daylight hours, typical meal times etc…

Question 9

Whose research counter-argues the effect of the environment on our circadian rhythm?

Answer 9

Folkard et al. 1985

Question 10

Discuss Folkard et al.’s research on circadian rhythms.

Answer 10

Studies 12 people who agreed to live in a dark cave for 3 weeks, retiring to bed when the clock said 11:45 and rising when it said 7:45.
Over the course of study, the researchers gradually speeded up the clock unbeknown to participants so an apparent 24 hour day lasted 22 hours.

Question 11

Discuss Folkards findings and conclusion.

Answer 11

Not on of his participants could comfortably adjust to the new regime suggesting the existence of a strong free-running circadian rhythm that cannot easily be override by changes in the external environment.

Question 12

STRENGTH - Evaluate the practical application of circadian rhythms (shift work)

Answer 12

Can be strongly applied to shift work e.g…
- Night workers engaged in shift work experience a period of reduced concentration at around 6 in the morning so are more likely to make mistakes (Boivin et al. 1996)
- Shift workers are three times more likely to develop heart disease which may in part be due to the stress of adjusting to different sleep/wake patterns and the lack of quality sleep during the day.
= Therefore, research into the sleep/wake cycle may have economic implications in terms of how best to manage worker productivity.

Question 13

STRENGTH - Evaluate the practical application of circadian rhythms (drug treatments)

Answer 13

Circadian rhythms coordinate a number of the body’s basic processes such as heart rate, digestion and hormone levels…effects pharmacokinetics (the action of drugs on the body and how well they are absorbed and distributed)
Research into circadian rhythms has revealed there are peak times during the day or night when drugs are likely to be at their most effective.
This has led to the development of guidelines to do with the timing of drug dosing for a whole range of medications including anti-cancer, cardiovascular, respiratory, anti-ulcer, and anti-epileptic drugs (Baraldo 2008)

Question 14

LIMITATION - Evaluate the use of case studies and small samples in circadian rhythm research.

Answer 14

Studies of the sleep/wake cycle tend to involve small groups of participants, as in the experiment by Aschoff and Wever, or studies of single individuals, as in the case of Siffre.
= limits the meaningful generalisations that could be made as those involved maye not be representative of the wider population!

Question 15

LIMITATIONS - Evaluate the lack of control in circadian rhythm research.

Answer 15

Still had access to artificial light e.g. siffre turned on a lamp when we woke up which remained on until bedtime…Czeisler et al. 1999 should the use of a light may be comparable to participants taking a drug that rests their biological clock.

Question 16

LIMITATIONS - Evaluate the individual difference in circadian rhythm research.

Answer 16

Some individual sleep/wake cycles vary from 13-65 hours!! (Czeisler et al. 1999)
Larks and owls as well - personal preference plays a part too!

Question 17

Define infradian rhythms.

Answer 17

A type of biological rhythm with a frequency of less than one cycle in 24 hours, such as menstruation and seasonal affective order.

Question 18

Discuss the menstrual cycle as an infradian biological rhythm.

Answer 18

It is governed by monthly changes in hormone levels.
Cycle starts on the first day of menstruation and ends on the day before her next period.
Typical cycle lasts 28 days.
Rising levels of oestrogen cause the ovary to develop an egg and release it (ovulation)
Progesterone then helps the womb lining to thicken readying the body for pregnancy.
If pregnancy does not occur the egg is absorbed into the body, and the uterus lining sheds (menstrual flow).

Question 19

Research study on the menstrual cycle as an infradian biological rhythm.

Answer 19

Stern and McClintock:
Although an endogenous system, evidence suggests it may be affected by exogenous factors e.g. cycles of other women.
Samples of pheromones gathered (cotton pad in armpit for 8 hours) from 9 of 29 women with irregular periods at different stages in their cycle. Samples treated with alcohol and frozen and rubbed on the upper lip of other 20 participants. One day one, given a sample for day one, On day two, given a sample for day two. etc….
68% experienced changes to their cycle which brough them closer to their ‘odour donor’.

Question 20

What is SAD?

Answer 20

Seasonal affective disorder - a depressive order which has a seasonal onset and is described and diagnosed as a mental disorder in DSM-5.

Question 21

Symptoms of SAD.

Answer 21

Persistent low mood alongside a general lack of activity and interest in life.
Referred to as winter blues as the symptoms are triggered during the winter months when the number of daylight hours become shorter.

Question 22

SAD as a biological rhythm.

Answer 22

It is an infradian rhythm called a circannual as it is subject to a yearly cycle.
Also classified as a circadian rhythm as the experience of SAD may be due to the disruption of the sleep/wake cycle and this can be attributed to prolonged periods of daily darkness during winter.

Question 23

Hormones and SAD.

Answer 23

Melatonin is implicated in the cause of SAD.
Night: pineal gland secretes melatonin until dawn due to an increase in light!
Winter: lack of light in the morning = secretion process continues…knock-on effect on the production of serotonin in the brain - a chemical that has been linked to the onset of depressive symptoms.

Question 24

Define ultradian rhythm.

Answer 24

A type of biological rhythm with a frequency of more that inbe cycle in 24 hours, such as the stages of sleep.

Question 25

The stages of sleep as ultradian rhythm introduction.

Answer 25

Psychologists have identified 5 distinct stages of sleep that altogether span approximately 90-minutes - a cycle that continues throughout the course of the night. Each is characterised by a different level of brainwave activity (monitored using an EEG)

Question 26

Stage 1 and 2 of sleep cycle.

Answer 26

Light sleep, easily woken up. At beginning - slow rhythmic alpha waves....become theta waves.

Question 27

Stage 3 and 4 of sleep cycle.

Answer 27

Deep, slow wave sleep, difficult to rouse. Delta waves, slower, greater amplitude.

Question 28

Stage 5/REM of sleep

Answer 28

Body is paralysed yet brain activity speeds up significantly that resembles an awake memory. REM stands for rapid eye movement. REM activity during sleep is highly correlated with the experience of dreaming.

Question 29

STRENGTH: Evaluation of the evolutionary basis of the menstrual cycle.

Answer 29

Menstrual synchrony = evolutionary value e.g. advantageous for females to menstruate together and fall pregnant around the same time so that newborns could be cared for collectively = increase chances of offspring's survival. Validity of the evolutionary perspective questioned: Schank 2004 argued if too many women were cycling together this would produce competition for the highest quality males (lowering the fitness of any potential offspring). From this pov, the avoidance of synchrony would appear to be most adaptive evolutionary strategy and therefore naturally selected.

Question 30

LIMITATIONS: Evaluate the methodological limitations in synchronisation studies.

Answer 30

Some argue many factors that may affect change in woman's menstrual cycle, including stress, changes in diet exercise etc., that might act confounding variables. This means that any supposed pattern of synchronisation, as seen in the studies by McClintock and others, is no more than would have been expected to occur by chance. In addition, research typically involves small samples of women and relies on participants self-reporting the onset of their own cycle. Perhaps more critically, other studies failed to find any evidence of menstrual synchrony in all-female samples.

Question 31

STRENGTH: Evaluate evidence supporting the idea of distinct stages in sleep.

Answer 31

Dement and Kleitman 1975 monitored the sleep patterns of 9 adult participants in a sleep lab. Brainwave activity was recorded on an EEG and the researchers controlled for the effects of caffeine and alcohol. REM activity during sleep was highly correlated with the experience of dreaming, brain activity varied according to vivid dreams were, and participants woken during dreaming reported very accurate recall of their dreams. Replications of this investigation have noted similar findings, though the small size of the original sample has been criticised by some. Nevertheless, study suggests that REM (dream) sleep is an important component of the ultradian sleep cycle.

Question 32

Evaluate animal studies.

Answer 32

Much of knowledge of the effects of pheromones on behaviour is derived from animal studies. The role of pheromones in animal sexual selection is well-documented . For instance, the fact that sea urchins release pheromones into the surrounding water so other urchins in the colony will eject their sec cells simultaneously. In contrast, evidence for the effects in human behaviour remains speculative and inconclusive (and this includes the , so far unproven, idea that transmission of pheromones between humans may act as an aphrodisiac!)

Question 33

Evaluate the practical applications of SAD.

Answer 33

One of the most effective treatments for SAD is photography. This is a lightbox that simulates very strong light in the morning and evening. It is thought to reset melatonin levels in people with SAD. This relieves symptoms in up to 60% of sufferers. However, the same study recorded a placebo effect of 30% using a sham negative-ion generator. Casts doubt on the chemical influence of photography.