6. BIOPSYCHOLOGY (INFRADIAN RHYTHMS) Flashcards
What is an infradian rhythm?
An infradian rhythm is a biological rhythm with a frequency of less than one cycle in 24 hours, such as menstruation or seasonal affective disorder (SAD).
What is Seasonal Affective Disorder (SAD)?
SAD is a type of depression that occurs seasonally, typically in the winter months, when there are fewer daylight hours. Symptoms include low mood, lack of interest, and low energy.
Why is SAD considered an infradian rhythm?
SAD is a type of infradian rhythm known as a “circannual rhythm,” as it follows a yearly cycle, with symptoms often triggered by changes in light exposure during the winter.
What factors influence Seasonal Affective Disorder (SAD)?
SAD is influenced by exogenous zeitgebers, particularly the amount of daylight, which affects sleep/wake cycles and melatonin production.
What is the menstrual cycle and why is it considered an infradian rhythm?
The menstrual cycle is an example of an infradian rhythm because it lasts longer than 24 hours, typically 28 days, and is regulated by hormonal changes.
How long is the typical menstrual cycle?
The menstrual cycle averages 28 days, but can vary between 23 and 36 days.
What regulates the menstrual cycle?
The menstrual cycle is primarily regulated by hormonal changes, with ovulation occurring roughly halfway through the cycle.
How can the menstrual cycle be influenced by external factors?
The menstrual cycle can be influenced by exogenous factors such as pheromones, which may alter the timing of the cycle.
What was the aim of McClintock & Stern’s (1998) study?
McClintock & Stern aimed to investigate whether menstrual cycles could be influenced by exogenous zeitgebers, specifically female pheromones.
How did McClintock & Stern (1998) conduct their research?
The study involved 29 women with irregular periods. Pheromone samples were collected from 9 women at different stages of their menstrual cycles and applied to 20 participants. The researchers observed if the participants’ cycles synchronized with the “odour donor” cycles.
What were the results of McClintock & Stern’s (1998) study?
The study found that 68% of women experienced changes to their menstrual cycles that brought them closer to the cycle of the “odour donor,” suggesting that pheromones can influence menstrual cycles.
What is a limitation of McClintock & Stern’s study on pheromones and menstrual cycles?
A limitation is that only 68% of women experienced cycle changes, suggesting that individual differences may play a significant role, and the sample size was small, reducing generalizability.
What is a major methodological issue with McClintock & Stern’s research?
The research was correlational, meaning it did not establish causation, and other confounding variables such as stress, diet, or exercise may have influenced the results.
What practical applications come from research on infradian rhythms?
One practical application is the treatment of SAD using phototherapy, which uses strong light to reset melatonin levels and has been effective in relieving symptoms in many sufferers
What is phototherapy, and how is it related to infradian rhythms?
Phototherapy involves exposure to bright light to treat SAD, as it is believed to affect melatonin production, aligning with the idea that exogenous zeitgebers like light can influence infradian rhythms.
