Biopsychology: Circadian rhythms Flashcards

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1
Q

What is meant by biological rhythms?

A

Distinct patterns of changes in body activity that conform to cyclical time periods.

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2
Q

What 2 things are biological rhythms governed by?

A
  1. The body’s internal biological ‘clocks’ (endogenous pacemakers)
  2. External changes in the environment (exogenous zeitgebers)
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3
Q

What cycle does the circadian rhythm operate on?

A

24 hour cycle

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4
Q

What can reset the body clock?

A

Environmental events (exogenous zeitgebers)

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5
Q

What’s an example of a exogenous zeitgeber?

A

Light levels

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6
Q

Give two examples of the circadian rhythm?

A
  • sleep/wake cycle
  • core body temperature
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7
Q

What does the sleep/wake cycle explain?

A

It explains why we are drowsy at night-time and alert during the day

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8
Q

What is the sleep/wake cycle also governed by? and what is it called?

A

An internal (endogenous) pacemaker - a biological clock called the suprachiasmatic nucleus (SCN)

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9
Q

Where does the SCN lie and do? and what can reset it?

A
  • Lies in the hypothalamus
  • Provides information from the eye about light
  • Exogenous zeitgebers (light) can reset the SCN
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10
Q

What are researchers interested in studying?

A

Seeing what would happen if our biological ‘clock’ ran by itself without the influence of external stimuli (e.g. light)

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11
Q

Who conducted a study in a cave? and what was the study called?

A
  • Siffre
  • Siffre’s cave study
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12
Q

What was the AIM, METHOD and RESULTS of Siffre’s cave study?

A

AIM: To study the effects of his own biological rhythms

METHOD:
- Deprived of exposure to natural light & sound
- But with access to adequate food and drink

RESULTS:
- His ‘free running’ biological rhythms settled down to one that was just beyond the usual 24hrs (around 25hrs)
- though he did continue to fall asleep and wake up on a regular schedule

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13
Q

When did Siffre resurface and what did he think?

A

Mid-september 1962 after two months in the caves believing it was mid-august

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14
Q

Who else did research into circadian rhythms? and what was this study called?

A

Aschoff & Wever’s bunker study

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15
Q

What did Aschoff & Wever’s bunker study do?

A

Convinced a group of participants to spend 4 weeks in a World War 2 bunker deprived of natural light

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16
Q

What happened to the circadian rhythms of the participants in Aschoff & Wever’s bunker study?

A

All by 1 participant displayed a circadian rhythm between 24-25 hrs the rest extended to 29 hours

17
Q

What do both study’s suggest?

A

That the ‘natural’ sleep/wake cycle may be slightly longer than 24 hours

  • but that is entrained by exogenous zeitgebers associated with our 24-hour day (such as the number of daylight hours, typical mealtimes, etc)
18
Q

One strength of the research into the circadian rhythm

A

POINT: Provides an understanding of the adverse (unfortunate) consequences that occur when the rhythms are disrupted.

EVIDENCE: Night shift workers will experience reduced concentration at around 6AM.

EXPLAIN: Shift workers are more likely to develop heart disease than people who work typical work patterns.

LINK: Research could have real-world economic applications in terms of how to manage productivity.

19
Q

CA for the strengths of shift work

A
  • Tend to use correlational methods
  • Hard to establish if the desynchronisation of the sleep-wake cycle was the cause
  • May be due to high divorce rates or the strain of missing family events
  • Therefore it may not be biological factors creating adverse consequences
20
Q

Another strength of the research into the circadian rhythms

A

POINT: Has been used to improve medical treatments

EVIDENCE: Aspirin (treatment for heart attacks) is most effective taken last thing at night

EXPLAIN:
- as it reduces blood platelet activity
- which can reduce the risk of heart attacks
- Heart attacks most likely to happen early morning= so timing of Aspirin is important

LINK: Shows how circadian rhythm can help increase effectiveness of drug treatments

21
Q

One limitation of the research into the circadian rhythms

A

POINT: Generalisations are difficult to make due

EVIDENCE:
- very small samples of participants (e.g. 1 in Siffre’s)
- Individual differences (sleep/wake cycle different for everyone, between 13-65 hrs)
- Some like going to bed early & rising early (‘larks’)

EXPLAIN: Difficult to use the research data to discuss anything more than averages

LINK: May be meaningless then