AQA Psychology - Biological Rhythms - Disruption

Flashcards to match the notes I have written with the same title.

Includes key research, implications, significance, reduction and effects of disrupting biological rhythms.


Symptoms of a Disrupted Biological Rhythm

Poor attention

Slow reaction times

Impaired reasoning skills



Weakened immune system

Lack of concentration

Memory loss

Mood swings


Heart Disease

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Health and safety: Chernobyl & most lorry accidents happen in early hours

Work productivity: decreases because of the lack of concentraction and morale

Employee illness: increased stress and lowered immune system leads to more absences

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Endogenous pacemakers become desynchronised with exogenous zeitgebers.

SCN signals to the pineal gland to produce melatonin when there are low levels of light, this causes sleepiness. Shift workers need to be awake at night so are fighting against the production of melanin (hence accidents happen).

Body temperature drops in the early morning - increasing drowsiness.

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Reducing Effects

Jet lag:

  • phase delay (east to west) is easier to adjust to than phase advance. 
  • follow local exogenous zeitgebers
  • melatonin tablets taken before bed

Shift work:

  • forward/clockwise shift rotation (phase delay) easier to adjust to
  • Czeisler (1982) says long shifts are best, Bambra (2008) says short are best.
  • Exposure to pulse of very bright light can reset endogenous pacemakers
  • Other exogenous zeitgebers, such as eating patterns and social interaction, can be used to adjust bodily rhythms.
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Key Studies

Schwartz et al (95) - baseball teams from the east playing in the west (phase delay) won more games than teams from the west playing in the east (phase advance).

Czeisler et al (82) - Utah chemical plant had backward/anticlockwise shifts of 7 days. Changed it to forward/clockwise rotation of 21 days. 9 months later productivity and health had increased.

Bambra (2008) - found fast, forward/clockwise shift rotation to be best for health and work-life balance.

Dawson & Campbell (91) - exposed shift workers to 4hr pulse of bright light. Their body clocks reset.

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i think you mean melatonin not melanin

Rosie Thompson


Oopsie, just corrected it :)

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