Circadian rhythms

Cards (14)

  • What is a biological rhythm?
    cyclical patterns within biological systems that have evolved in response to environmental influences, e.g. day and night.
  • what governs biological rhythms?
    endogenous pacemakers - internal body clock
    exogenous Zeitgebers - environmental factors
  • What are the 3 types of biological rhythms
    Circadian, Infradian, Ultradian
  • What is a circadian rhythm?
    regular bodily rhythms that occur on a 24-hour cycle
  • What is an example of a circadian rhythm?
    sleep/wake cycle
  • What is a study for circadian rhythm?
    The michel siffre study (2972)
  • What did michel siffre do?
    ' Spent 6 months underground in a cave in texas with no cues to the time of day.
  • What was he wired up via? Why?
    Computer and video so that his bday functions could be monitored all of the time
  • What daily cycle did siffre seem to establish?
    25 hours
  • How many days did siffre lose when he emerged room isolation?
    28
  • What is a limitation of circadian rhythms? (Poor control in siffre's study)
    P - There was poor control in Siffre's study.

    E - Siffre still had access to an artificial light (a lamp) which he turned on every time he woke up until he went to sleep. (This is an example of an Exogenous Zeitgeber)

    T - Light in this instance acts as a confounding variable, psychologists have now argued that artificial light has an effect on biological rhythms, meaning Siffre's findings are questionable and so forth lack credibility.
  • What is a strength of circadian rhythms? (Practical applications)
    P - Shift workers experience a period of reduced concentration at around 6am

    E - There are also links between shift work and poor health (e.g. 3x more likely to develop heart disease).

    T - Therefore research into the sleep/wake cycle may have economic implications in terms of how best to manage worker productivity.
  • What is another limitation of circadian rhythms?
    (Small sample)
    P - Studies into the sleep/wake cycle tend to use small samples, or one participant.

    E - The people involved may not be representative of the wider population.

    T - This therefore limits the extent to which these studies provide meaningful generalisations. Furthermore, Siffre observed that his own internal bodily rhythm slowed down by the time he reached 60, meaning age is a factor to be considered when drawing conclusion.
  • What is another limitation of circadian rhythms? (Individual differences)
    P - issues with generalising findings from studies of the sleep/wake cycles as individuals can have different cycles varying from 13-65 hours.

    E -Duffy et al. (2001) found that some people such as 'morning people' prefer to rise and go to bed early (about 6 am and 10 pm) whereas 'evening people' prefer to wake and go to bed later (about 10 am and 1 am).

    T - This demonstrates that there may be innate individual differences in circadian rhythms, which suggests that researchers should focus on these differences during investigations.