biological rhythms Flashcards
biopsychology
What is a Circadian rhythm?
Rhythms lasting around 24 hours regulated by an internal pacemaker but external factors can reset it.
What’s an example of a Circadian rhythm?
The sleep/wake cycle
Body temperature
What research is there for Circadian rhythms?
Michel Siffre - French cave explorer - spent 179 days in a cave
at first his sleep/wake cycle was erratic but once it settled, it came to a 25 hour cycle.
What’s a strength of Circadian rhythms?
Useful implications- we now know the effect working night shifts or not having a good routine can affect health
What’s a limitation of Circadian rhythms?
Ignores individual differences - early and late risers may have different cycles and we cannot assume peoples circadian rhythms are the same
What’s an Infradian rhythm?
Rhythms longer tan 24 hours lasting months, weeks or years.
What’s an example of an Infradian rhythm?
The female menstrual cycle
Seasonal affective disorder (SAD)
What research is there for Infradian rhythms?
Weller et al 1999 - 51 pairs of women in a small office
menstrual cycles synchronised showing biological rhythms can be influenced by external factors
What are the strengths of Infradian rhythms?
Supported by evolutionary principles (Durante et al 2008) 88 women on low and high fertility days- unconsciously dressed more revealing on high fertility days
Useful applications- treatment for SAD - Lumie alarm clocks
What’s an Ultradian rhythm?
Rhythms lasting less than 24 hours
What’s an example of an Ultradian rhythm?
Sleep stages
What research is there for Ultradian rhythms?
Dement and Kleitman 1957 - measure brain activity during sleep, woken up in different stages of sleep and asked if they dreamt
What are the limitations of Ultradian rhythms?
Too many individual differences to account for - Tucker et al 2007 stages of sleep especially 3/4 differ in each individual
Lacks ecological validity - sleeping in a lab with an EEG cap is uncomfortable and disrupts normal sleep
