Lesson 11 - Ultradian and Infradian Rhythms

Question 1

Ultradian Rhythms

Answer 1

Span a period of less than 24 hours
E.g. Five Sleep Stages

Question 2

Ultradian Rhythm
Five Sleep Stages

Answer 2

Repeats every 90 minutes
Each stage shows a distinct EEG pattern
As person enters deep sleep, brainwaves slow and breathing and hear rate decrease
During fifth stage, EEG pattern resembles that of an awake person => dreaming
Example Study => Kleitman (1969)

Question 3

Ultradian Rhythm
Five Sleep Stages
Kleitman (1969)

Answer 3

Refers to 90 minute cycle as the basic rest activity cycle
Suggests this cycle continues when awake
During the day, instead of moving through sleep stages, we move from alertness into physiological fatigue
Studies suggest human mind can focus for about 90 minutes and then body runs out of energy resulting in loss on concentration, fatigue and hunger

Question 4

Ultradian Rhythm Evaluation Points

Answer 4

Ericsson et al. (2006) - Violinists
Tucker et al. (2007) - Individual Differences

Question 5

Ultradian Rhythm Evaluation
Ericsson et al. (2006) - Violinists
Positive

Answer 5

Supports BRAC cycle
Studied group of elite violinists
Found amongst this group practise sessions were limited to 90 minutes at a time
Frequently napped to recover from practise, with best violinists napping more
Same pattern found among athletes, chess players and writers

Question 6

Ultradian Rhythm Evaluation
Tucker et al. (2007) - Individual Differences
Negative

Answer 6

Suggests individual differences in ultradian rhythms which are biologically determined and may even be genetic in origin
Participants were studied over 11 consecutive days and nights in a lab environment
Researchers assessed sleep duration, time taken to fall asleep and amount of time in each sleep stage
Found differences in all of these characteristics

Question 7

Infradian Rhythms

Answer 7

Span a period longer than 24 hours
E.g. menstrual cycle

Question 8

Infradian Rhythms
Menstrual Cycle

Answer 8

Lasts around a month
Hormones regulate menstrual cycle
Ovulation occurs roughly halfway through cycle, when oestrogen levels are at their peaks and usually last 16-32 hours
After ovulation, progesterone levels increase in preparation for possible implantation of an embryo in uterus

Question 9

Infradian Rhythm Evaluation Points

Answer 9

Penton-Voak (1999) - Behaviour
Menstrual Cycle

Question 10

Infradian Rhythm Evaluation
Penton-Voak (1999) - Behaviour

Answer 10

Found women express a preference for feminised male faces when choosing a partner for a long-term relationship
However, they showed a preference for masculinised faces during ovulation

Question 11

Infradian Rhythm Evaluation
Menstrual Cycle
Negative

Answer 11

Not only governed by infradian rhythms
When several women of childbearing age live together, do not take oral contraceptives, their menstrual cycles become synchronised
In one study, samples of swear collected from women and rubbed onto upper lip of other women and cycles became synchronised
Suggests synchronisation is affected by pheromones => chemical substances produced and released into environment by an animal which affects behaviour of others of the same species