Biopsychology: Biological Rhythms

Question 1

Circadian Rhythm

Answer 1

A type of biological rhythm, subject to a 24 hour cycle, which regulates the number of body processes such as the sleep/wake cycle

Question 2

Define biological rhythms:

Answer 2

Clear patterns of changes in the body activity that conform to cyclical time periods. Biological rhythms are influenced by endogenous pace makers as well as exogenous zeitgebers in the environment.

Question 3

Siffre Cave Study:

Answer 3

Spent 60 days first time then 205 days the second time in a midnight cave
Deprived of exogenous zeitgebers eg. Clocks and natural light
His free running biological clock ran on a 25 hour sleep wake cycle

Question 4

Aschoff and Wever

Answer 4

A group of participants spent four weeks in a WW2 bunker deprived of natural light.
Participants showed a sleep wake cycle of 25hrs
This suggests that natural sleep-wake cycle is 25hrs but has been entrained by exogenous zeitgebers such as natural light.

Question 5

Practical applications of circadian rhythms to drug treatments

Answer 5

Circadian rhythm is coordinate a number of the bodies basic processes such as heart rate and digestion.
Research into circadian rhythms revealed that there are peak times during the day and night where medicines are most effective
Lead to developments if timings of intake for many drugs

Baraldo: pharmacokinetics

Question 6

Practical application of circadian rhythms to shift work

Answer 6

Research has implications on how we manage productivity
Boivin et al:
Night workers who do night shifts experience reduced concentration at around 6 am meaning mistakes are more likely to happen. This is because of Desynchronisation (adverse consequences of disturbing circadian rhythms)
There is also a relationship between shift work and poor health, could be caused by inability to adjust to different sleep/wake cycle

Question 7

The sleep wake cycle

Answer 7

The fact that we feel drowsy when it’s nighttime and alert during the day demonstrates the effect of daylight (an important exogenous zeitgeber) on our sleep wake cycle.

Question 8

Weakness of studies into sleep/wake cycles

Answer 8

Small groups and case studies are used. These may not be representative of the wider population and this limits meaningful generalisations can be made. Siffre was the age of 60 during his study, make be different depending on age

Question 9

Poor control of study

Answer 9

The use of artificial lights during the studies
Czeisler: adjust participants sleep wake cycles from 22 to 28 using just dim lighting. The use of lighting acts as an uncontrolled confounding variable.

Question 10

Individual difference

Answer 10

Czeisler
Varies from 13-65
Natural preferences makes “larks” and “owls”.
And age differences: Duffy

Makes the use of case studies even more problematic

Question 11

Folkard

Answer 11

12 people left in the dark cave for three weeks in the absence of normal life and external factors. They agreed to wake up at 11:45 -7:45
The clock was spent up to 22 hours and not one of the participants could adapt

Folkard: what do you temperature on cognitive abilities. Bedtime stories and the ability to recall them at 9 am versus 3 pm.