Infradian Rhythms Evaluation of Infradian & Ultradian Rhythms
-less than 1 cycle in 24 hours
-lasts longer than 24 hours P+ research support, E Stern and McClintock (1998) studied how menstrual cycles synchronise
menstrual cycle, seasonal affective disorder (SAD) pheromones, 68% of women experienced changes to their cycle which brought them closer to t
donor’, E exogenous zeitgebers influence infradian rhythms, increased validity
Menstrual Cycle
> monthly changes in hormone levels that regulate ovulation P+ research support E evolutionary psychologists argue females menstruate together to fall pre
> takes approximately 28 days to complete that babies are cared for collectively & increases the chances of survival E increases validity
> endogenous system, some psychologists argue that it may be influenced by exogenous factors
such as the cycle of other women P- research support for REM E Dement and Kleitman (1957) studied 9 participants sleep pattern
was recorded on an EEG and the researchers controlled the effects of caffeine and alcohol, REM
SAD correlated to dreaming, participants woken during this time had very accurate recall of their dr
> depressive disorder that has a seasonal pattern of onset of ultradian rhythms
> persistent low mood, lack of activity & interest in life, triggered when daylight hours become
shorter P- small scale study E only studied 9 people which means that the study lacks generalisability a
> circannual rhythm- happens as a yearly cycle can’t be applied to a wider population E lowers validity of studies
> lack of light during winter, melatonin secretion lasts longer, affects production of serotonin in
brain (a chemical linked to depression) P- invasive procedures, E must be a level of control & participants are attached to monitors tha
lead to them sleeping in a way that does not represent their ordinary sleep cycle, E lack of ecolo
Ultradian Rhythms false conclusions being drawn.
-more than 1 in 24 hours
-shorter than 24 hours (e.g. sleep cycle)
Sleep Cycle
> 5 distinct stages of sleep that altogether last 90 minutes- cycle continues throughout night
> each stage gas a different level of brainwave activity which is monitored using an EEG
Biopsychology- Biological Rhythm
Endogenous pacemakers
-internal processes/ body clock (biological)
- biology plays a significant role in the sleep/wake cycle
Key area= Superchiasmatic nucleus (SCN)
> above the optic chiasm (crossover of light)
> receives info about light & passes it to pineal gland, this then produces melatonin (chemical in
little light
Exogenous zeitgebers
-external factors (environment) that reset the biological clock/ affect our biological rhythms
Key cues= light, social cues
> light- resets SCN & indirectly influences processes controlling hormone secretion and blood c
> social cues- used to entrain babies at about 16 weeks, influences circadian cycle
Biological Rhythms Evaluation
-less than 1 cycle in 24 hours
-lasts longer than 24 hours P+ research support, E Stern and McClintock (1998) studied how menstrual cycles synchronise
menstrual cycle, seasonal affective disorder (SAD) pheromones, 68% of women experienced changes to their cycle which brought them closer to t
donor’, E exogenous zeitgebers influence infradian rhythms, increased validity
Menstrual Cycle
> monthly changes in hormone levels that regulate ovulation P+ research support E evolutionary psychologists argue females menstruate together to fall pre
> takes approximately 28 days to complete that babies are cared for collectively & increases the chances of survival E increases validity
> endogenous system, some psychologists argue that it may be influenced by exogenous factors
such as the cycle of other women P- research support for REM E Dement and Kleitman (1957) studied 9 participants sleep pattern
was recorded on an EEG and the researchers controlled the effects of caffeine and alcohol, REM
SAD correlated to dreaming, participants woken during this time had very accurate recall of their dr
> depressive disorder that has a seasonal pattern of onset of ultradian rhythms
> persistent low mood, lack of activity & interest in life, triggered when daylight hours become
shorter P- small scale study E only studied 9 people which means that the study lacks generalisability a
> circannual rhythm- happens as a yearly cycle can’t be applied to a wider population E lowers validity of studies
> lack of light during winter, melatonin secretion lasts longer, affects production of serotonin in
brain (a chemical linked to depression) P- invasive procedures, E must be a level of control & participants are attached to monitors tha
lead to them sleeping in a way that does not represent their ordinary sleep cycle, E lack of ecolo
Ultradian Rhythms false conclusions being drawn.
-more than 1 in 24 hours
-shorter than 24 hours (e.g. sleep cycle)
Sleep Cycle
> 5 distinct stages of sleep that altogether last 90 minutes- cycle continues throughout night
> each stage gas a different level of brainwave activity which is monitored using an EEG
Biopsychology- Biological Rhythm
Endogenous pacemakers
-internal processes/ body clock (biological)
- biology plays a significant role in the sleep/wake cycle
Key area= Superchiasmatic nucleus (SCN)
> above the optic chiasm (crossover of light)
> receives info about light & passes it to pineal gland, this then produces melatonin (chemical in
little light
Exogenous zeitgebers
-external factors (environment) that reset the biological clock/ affect our biological rhythms
Key cues= light, social cues
> light- resets SCN & indirectly influences processes controlling hormone secretion and blood c
> social cues- used to entrain babies at about 16 weeks, influences circadian cycle
Biological Rhythms Evaluation
