Biological Rhythms: Infradian And Ultradian Rhythms

Question 1

What is the menstrual cycle an example of?

Answer 1

Infradian rhythms

Question 2

What does the menstrual cycle refer to?

Answer 2

The time between the first day of a woman’s period to the day before her next period

Question 3

How long does the typical menstrual cycle take to complete?

Answer 3

28 days

Question 4

During each menstrual cycle what causes the ovary to develop an egg and release it?

Answer 4

The hormone Oestrogen

Question 5

What happens after ovulation?

Answer 5

The hormone progesterone helps the womb lining grow thicker, readying the womb for pregnancy

Question 6

What happens if pregnancy doesn’t occur?

Answer 6

The egg is absorbed into the body, the womb lining comes away and leaves the body

Question 7

What type of system is the menstrual cycle?

Answer 7

Endogenous system

Question 8

What does evidence suggest the menstrual cycle may be affected by?

Answer 8

Exogenous factors e.g. other woman’s cycles

Question 9

What did Stern and McClintocks’ study show?

Answer 9

How menstrual cycles may synchronise as a result of the influence of pheromones

Question 10

What did Stern and McClinton study?

Answer 10

29 women with a history of irregular period

Question 11

What was gathered from the 9 women?

Answer 11

Pheromones by a cotton pad placed under there armpit

Question 12

How long were the cotton pads worn?

Answer 12

For at least 8 hours to ensure the pheromones were picked up

Question 13

What were the pads treated with?

Answer 13

Alcohol and frozen to be rubbed on the upper lip of another participant

Question 14

What happened on day 1?

Answer 14

Pads from the start of the menstrual cycle were applied to all 20 women

Question 15

What happened on day 2?

Answer 15

Everyone was given a pad from the second day

Question 16

What did Stern and McClinton find?

Answer 16

68% of women experienced changes to their cycle which brought them closer to the cycle of their ‘odour donor’

Question 17

What is Seasonal Affective Disorder?

Answer 17

A depressive disorder which has a seasonal pattern of onset

Question 18

What are the main symptoms of SAD?

Answer 18

Persistent low mood, lack of activity and interest in life

Question 19

When are the symptoms of SAD triggered?

Answer 19

During the winter months when the number of daylight hours becomes shorter

Question 20

What type of Infradian rhythm is SAD?

Answer 20

Circannual rhythm

Question 21

What other type of rhythm can SAD be classed as?

Answer 21

Circadian rhythm

Question 22

What have psychologists hypothesised?

Answer 22

The hormone melatonin is implicated in the cause of SAD

Question 23

What happens during the night?

Answer 23

The pineal gland secretes melatonin until dawn when there is an increase in light

Question 24

What happens during winter?

Answer 24

The lack of light in the morning means this secretion process continues for longer this is thought to have a knock on effect on the production of serotonin in the brain

Question 25

Menstrual synchrony evaluation: Research has explained it may be by natural selection

Answer 25

• synchronisation of the menstrual cycle is thought to have evolutionary value
• for people in the past it may have been advantageous for women to menstruate together and become pregnant at the same time
• this would allow babies who had lost their mothers during or after childbirth to have access to breast milk thereby improving their survival chances
• suggests synchronisation is an adaptaive strategy

Question 26

Synchronisation evaluation: methodological shortcomings

Answer 26

• many factors effect the menstrual cycle like stress or changes in diet
• these factors may act as confounding variables which means any supposed pattern of synchronisation is no more than would have been expected to occur by chance
• this may explain why other studies have failed to replicate findings - Trevathan et al
• menstrual synchrony is flawed

Question 27

What is an example of an ultradian rhythm?

Answer 27

The sleep cycle

Question 28

How many stages have psychologists identified for sleep?

Answer 28

5 that altogether span 90 minutes

Question 29

What is each stage characterised by?

Answer 29

A different level of brainwave activity which can me monitored using an EEG

Question 30

What is stages 1 and 2?

Answer 30

Light sleep where someone may be easily woken

Question 31

What types of brain waves are stage 1?

Answer 31

High frequency with short amplitude - alpha waves

Question 32

What type of brain waves are stage 2?

Answer 32

Alpha waves but there are occasional random changes in pattern called sleep spindles

Question 33

What is stages 3 and 4?

Answer 33

Deep sleep or slow wave sleep

Question 34

What brain waves are stages 3 and 4?

Answer 34

Delta waves with lower frequency and high amplitude - it’s difficult to wake someone at this point

Question 35

What is stage 5?

Answer 35

REM - the body is paralysed but brain activity closely resembles being awake

Question 36

What brain waves occur in REM sleep?

Answer 36

Theta waves and the eyes occasionally move around, thus rapid eye movement

Question 37

What brain waves occur in REM sleep?

Answer 37

Theta waves and the eyes occasionally move around, thus rapid eye movement

Question 38

What is expected during REM?

Answer 38

Dreams however these can also occur in deep sleep

Question 39

Ultradian rhythm evaluation: improved understanding of age-related changes in sleep

Answer 39

• sleep scientists have observed SWS reduces with age
• growth hormone is mostly produced during SWS therefore this reduced in older people
• according to Eve van Cauter et al the resulting sleep deficit may explain various issues in old age such as reduced alertness
• in order to increase SWS, relaxation and medication may be used
• suggests knowledge of ultradian rhythms has practical value

Question 40

Ultradian rhythms evaluation: significant variation between people

Answer 40

• Tucker et al found large differences between participants in terms of the duration of each sleep stage particularly 3 and 4
• Tucker et al suggests that theses differences are likely to be biologically determined
• difficult to describe ‘normal sleep’ in any meaningful way

Question 41

Ultradian rhythms evaluation: significant variation between people

Answer 41

• Tucker et al found large differences between participants in terms of the duration of each sleep stage particularly 3 and 4
• Tucker et al suggests that theses differences are likely to be biologically determined
• difficult to describe ‘normal sleep’ in any meaningful way

Question 42

Why can SAD be classed as a circadian rhythm?

Answer 42

the experience may be due to disruption to the sleep/wake cycle and this can be attributed to prolonged periods of daily darkness during winter