Biopsychology - Rhythms Flashcards
(44 cards)
What are biological rhythms?
Biological rhythms are distinct patterns of changes in body activity that conform to cyclical time periods. They are influenced by internal body clocks (endogenous pacemakers) and external changes in the environment (exogenous zeitgebers).
What are circadian rhythms?
Circadian rhythms are a type of biological rhythm that follows a 24-hour cycle, regulating various body processes such as the sleep/wake cycle and changes in core body temperature.
What is the sleep/wake cycle?
The sleep/wake cycle is a circadian rhythm that repeats every 24 hours, influenced by natural light as a primary exogenous zeitgeber.
What did Siffre’s Cave Study demonstrate?
Siffre’s Cave Study showed that even without natural light or time cues, individuals maintained a free-running biological rhythm, averaging around 25 hours.
What were the findings of Aschoff and Wever (1976)?
Aschoff and Wever found that participants in a WW2 bunker maintained a circadian rhythm of 24–25 hours, indicating that natural light is not essential for circadian rhythms.
What did Folkard et al. (1985) discover?
Folkard et al. found that most participants could not adapt to a 22-hour day in a dark cave, suggesting a strong influence of internal biological clocks.
How does research on circadian rhythms apply to shift work?
Research has linked disrupted circadian rhythms from shift work to decreased concentration and increased health risks, highlighting economic implications for productivity and healthcare.
What is the significance of circadian rhythms in drug treatments?
Circadian rhythms influence pharmacokinetics, and timing medication with these rhythms can improve effectiveness, supporting the concept of chronotherapeutics.
What is a limitation of studies like Siffre’s?
Studies like Siffre’s used small, specific samples, which limits generalisability due to individual differences and unrepresentative samples.
What is a concern regarding control in biological rhythm studies?
Poor control in studies, such as the use of artificial light, may influence biological rhythms and affect study outcomes.
What did Czeisler et al. (1999) find about individual differences in circadian rhythms?
Czeisler et al. found that circadian cycles can vary significantly among individuals, indicating that general conclusions may not apply to everyone.
What should you remember about research questions in this context?
Research questions may refer to either specific studies or theoretical understanding of circadian rhythms, and should always be applied to behavior.
What are infradian rhythms?
A type of biological rhythm with a frequency of less than once in 24 hours, such as menstruation or seasonal affective disorder (SAD).
What are ultradian rhythms?
A type of biological rhythm with a frequency of more than one cycle in 24 hours, such as the stages of sleep.
What is the menstrual cycle in relation to infradian rhythms?
The menstrual cycle is an infradian rhythm governed by hormone levels, with a typical cycle lasting 28 days. Rising oestrogen causes egg release (ovulation), then progesterone thickens the womb lining. If no pregnancy, hormone levels drop, womb lining is shed.
What was the aim of McClintock’s study (1998)?
Investigated whether menstrual cycles synchronise due to pheromones.
What was the sample used in McClintock’s study (1998)?
29 women with irregular cycles.
What procedure was used in McClintock’s study (1998)?
Pheromone samples collected from 9 women at different menstrual stages using cotton pads placed in armpits and treated with alcohol. Pads were rubbed on the upper lip of other participants.
What were the findings of McClintock’s study (1998)?
68% of participants experienced changes to their cycle, bringing them closer to the ‘odour donor’.
What was the conclusion of McClintock’s study (1998)?
Suggests menstrual cycles can be influenced by exogenous zeitgebers (pheromones).
What is Seasonal Affective Disorder (SAD)?
SAD is a depressive disorder with a seasonal onset (typically winter). It is an infradian rhythm influenced by light levels. Melatonin secretion is prolonged due to darkness, which may reduce serotonin production, linked to depressive symptoms.
What are the stages of sleep in relation to ultradian rhythms?
Stage 1 & 2: Light sleep. Brainwaves are alpha, then theta. Easily woken. Stage 3 & 4: Deep sleep (slow-wave sleep). Delta waves. Hard to wake. Stage 5 (REM): Body is paralysed. Brain activity resembles awake brain. Dreams occur. EEG shows high activity.
What is the evolutionary basis of the menstrual cycle?
Menstrual synchrony (McClintock) may have evolutionary benefits like shared childcare and social bonding. However, if too many women ovulate together, it could produce competition for the most genetically fit males (Schank, 2004), which would be disadvantageous.
What are the methodological limitations in synchronisation studies?
McClintock’s study lacked control over confounding variables such as diet, stress, and exercise. Small sample size and self-reports reduce reliability. Cycle changes may have occurred due to chance.
