Biopsychology Flashcards
What two systems is the nervous system split into?
Peripheral nervous system
Central nervous system
What is the peripheral nervous system split into?
Somatic nervous system
Autonomic nervous system
What is the central nervous system made up of?
Spinal chord
Brain
What is the autonomic nervous system split into?
Sympathetic nervous system
Parasympathetic nervous system
What is the role of the nervous system?
To collect, process and respond to information in the environment. Also, to co-ordinate the working of different organs and cells in the body.
What is the role of the peripheral nervous system?
Transmit messages to the whole body from the brain.
What does the autonomic nervous system control?
-Involuntary movements.
-Internal organs and glands of the body - transmits and receives information from them.
-It is important for survival, affects reaction to threat, returns the body to normality (homeostasis) after a reaction.
What does the somatic nervous system control?
-Voluntary movement (conscious control)
- Controls skeletal and muscle movement
- Transmits sensory information from the body to the CNS
What is the role of the brain in the central nervous system?
- ensure life is maintained
- centre of all conscious awareness
What s the role of the spinal chord in the central nervous system?
- responsible for reflex actions
- facilitates transferral of messages to and from the brain to the PNS
What are the two main components of the endocrine system?
Glands and hormones
What are the main functions of the endocrine system?
- communicate messages to organs of the body
- secretes hormones from a series of glands into the bloodstream throughout the body
The endocrine system is ________ than the nervous system.
Slower
What hormone does the adrenal gland release?
Adrenaline
What is the function of the adrenal gland?
Facilitates the release of adrenaline.
It is an important part of the fight or flight response (stimulates the heart rate, contracts blood vessels, dilates air passages)
Which gland release adrenaline?
The Adrenal gland
What is the function of the pituitary gland?
‘The master gland’.
It controls the release of hormones from all other endocrine glands in the body.
What gland releases testosterone?
Testes
What is the role of the testes glands?
Facilitates the release of testosterone (a male hormone) which has been implicated in aggression.
What hormones do the ovaries release?
Oestrogen and progesterone
What is the role of the ovaries?
Facilitates the release of oestrogen and progesterone (female hormones) implicated in menstruation
What part of the nervous system is the fight or flight response generated from?
Autonomic nervous system (sympathetic branch)
What is the fight or flight response?
A reflex response to help a individual manage physically when under threat.
It can also be activated in times of stress as the body perceives it as a threat.
Facilitates optimal functioning (fight the threat or run away).
Describe the process of the fight to flight response.
- A stressor is perceived
- Hypothalamus triggers activity in the sympathetic branch of the ANS
- ANS changes from its normal resting state (parasympathetic state) to the physiologically aroused sympathetic state
- The stress hormone adrenaline is released from the adrenal medulla (part of the adrenal gland) into the bloodstream
- Adrenaline triggers physiological changes in the body (see table below) which creates the physiological arousal necessary for the fight or flight response
- Once the threat has passed, the parasympathetic nervous system returns the body to its resting state.
Name two physiological changes to the body caused by adrenaline?
Increased heart rate - To speed up the blood flow to vital organs & improve the spread of adrenaline around the body
Muscle tension - To improve reaction time and speed
Pupil dilation - To improve vision
Sweat production - To facilitate temperature regulation
Reduced functioning of digestive & immune system - To save energy for prioritised functions e.g. running
What is the function of a neurone?
Receives information and transmits it to other cells
What is the role of the sensory neurone?
Sends messages from the PNS to the CNS
What is the role of the relay neurone?
Connects the motor and sensory neurone
CNS to CNS
What is the role of the motor neurone?
CNS to effector (muscle or gland)
Describe the reflex arc.
A stimulus such as a hammer hits the knee. This is detected by the sense organs in the PNS which coveys a message along a sensory neurone.
The message reaches the CNSwhere it connects with a relay neurone. This then transfers a message to a motor neurone. This then carries the message to an effector such as a muscle, which causes the muscle to contract, causing the knee to move.
What does the cell body in a neurone contain?
The nucleus
What do the dendrites on a neurone do?
Carry nerve impulses from neighbouring neurones towards the cell body
What is the axon on a neurone covered by?
A myelin sheath
What is the role of the axon in a neurone?
Carries impulses away from the cell body down the length of the neurone.
What does the myelin sheath in a neurone do?
Protects the axon and speeds up electrical impulses.
What do the nodes of ranvier do in a neurone?
Speed up the transmission of an impulse by forcing it to ‘jump’ across the spaces along the axon.
What do the terminal buttons do in a neurone?
The nerve impulse becomes a chemical message to be passed to the dendrite of another neurone.
Contains vesicles that store neurotransmitters ready for the next stage.
Describe the process of an electrical transmission.
- when a neurone is in resting state, the inside of the cell is negatively charged.
- when a neurone is activated by a stimulus the inside of the cell become positively charged.
- this cause an action potential to occur.
- this creates an electrical impulse that travels down the axon to the end of the neurone.
What is synaptic transmission?
The process of transmitting chemical messages from neurone to neurone across the synapse (synaptic gap/cleft)
Describe the process of synaptic transmission.
- neurotransmitters are released into the synaptic gap
- the receiving neurone must then quickly take up the neurotransmitters
- it converts to an electrical impulse to travel down the neurone to the next pre-synaptic terminal.
What is reuptake?
- unused neurotransmitter molecules are absorbed back into the presynaptic neurone to be reused
- reuptake regulates the amount of neurotransmitters in the synapse and this regulates how ‘much’ message there is
- when the neurotransmitter is no longer in the synaptic gap, the message will stop
Each neurotransmitter has its own _______ molecular structure that is ______________ to a post-synaptic receptor site.
Specific
Complimentary
What is inhibition and excitation?
Neurotransmitters have either an excitatory or inhibitory effect on the neighbouring neurone.
What is an excitatory potential?
If the neurotransmitter is excitatory then the post synaptic neurone is more likely to fire an impulse as it increases its positive charge making it more likely to fire.
What is an inhibitory potential?
If the neurotransmitter is inhibitory the post synaptic neurone is less likely to fire an impulse
Neurones can only transmit information in ___ direction at the synapse.
One
Describe the process of synaptic transmissions.
Electrical impulses (action potentials) reach the presynaptic terminal
Electrical impulses (action potentials) trigger release of neurotransmitters in the presynaptic neuron
Neurotransmitters cross the synaptic cleft from the vesicles
Neurotransmitters combine with receptors on the postsynaptic membrane
Stimulation of the postsynaptic receptors by neurotransmitters result in either excitation or inhibition of the postsynaptic neuron
Unused neurotransmitter molecules are absorbed back into the presynaptic neuron to be reused
Name the 4 lobes in the brain.
Frontal lobe
Parietal lobe
Temporal lobe
Occipital lobe
What is localisation of function?
During the 19th century, scientists e.g Paul Broca and Karl Wernickle discovered that specific areas of the brain are associated with particular physical and physiological functions.
Different parts of the brain performing different tasks are involved with different parts of the body.
What is the holistic theory of the brain?
All parts of the brain were involved in the processing of thought and action.
What was the holistic theory of the brain replaced by?
The localisation of function.
What is the cerebral cortex?
The outer protective layer of both hemispheres.
3mm thick.
The human cortex is highly developed compared to other animals.
Where is the motor cortex located in the brain?
The back of the frontal lobes in both hemispheres
What is the motor cortex?
Controls voluntary movement in the opposite side of the body. It send messages to muscles via the brain stem and spinal chord.
Controls complex movements.
Damage to this area of the brain may result in a loss of control over fine movements.
Where is the somatosensory cortex located?
The font of both parietal lobes (next to the motor cortex)
what is the somatosensory cortex?
Where sensory information from the skin is represented and processed.
The amount of somatosensory area devotes to a particular body part denotes its sensitivity.
Where is the visual cortex located?
The occipital lobe
What is the visual cortex?
Main visual centre - processes information such as colour and shape
Each eye sends information from the right visual field to the left visual cortex, visa versa.
Damage to left hemisphere can produce blindness in part of the right visual fuels in both eyes
An area called area VI seems recessed for visual perception
Patients with damage to this area repot no vision of any kind: conscious vision, visual imagery while awake or in dreams.
Where is the auditory cortex located?
The temporal lobe in both hemispheres
What does the auditory cortex do?
Analyses speech bases information.
Processes information such as pitch and volume.
Damage may produce partial hearing loss, the more extensive the damage the more extensive the loss.
Which hemisphere in the brain controls language?
Left hemisphere
What are the two elements of the ‘language area’ in the brain?
Broca’s area
Wernickle’s area
What does damage to the Broca’s area cause?
Broca’s aphasia
What does damage to Wernicke’s area cause?
Wernicke’s aphasia
What are the symptoms of Broca’s aphasia?
Speech is slow, laborious and lacks fluency
what are the symptoms of Werncike’s aphasia?
Cannot comprehend langue
Speech is fluent but meaningless (produce neologisms)
Where in the brain is Broca’s area?
Left frontal lobe
Where in the brain is Wernicke’s area?
Left temporal lobe
What is lateralisation of function?
The idea that both hemispheres are functionally different and certain mental processes and behaviour are mainly controlled by one hemisphere
What does contralateral mean?
Each hemisphere controls the opposite side of the body and visual field.
What does it mean if a function is lateralised?
A function is dealt with by one hemisphere.
Name 3 left brain functions.
Language
Analytic thought
Numerical skills
Name 3 right brain functions.
Creativity
Intuition
Imagination
Which hemisphere is the site of language processing?
Left hemisphere
Which hemisphere is dominant in recognising faces?
Right hemisphere
What is the corpus callosum?
The section that joins the two hemispheres. Messages travel between the two hemispheres via the corpus callosum so if this is damaged the two hemispheres cannot communicate.
Explain Sprerry’s (1968) study into split brain research.
He studied a group of 11 individuals who had their corpus callosum severed to control their epilepsy.
Participants were shown a screen and were instructed to focus on the centres black dot.
An image will be shown in their right field of view and they could verbalise what they saw (as the image seen in the right visual field was processed in the left hemisphere which controls Language).
An image will then be shown in their right field of view. This image is processed by the right hemisphere, however language is not processed in this hemisphere and the message of the image cannot be passes through the corpus callosum for the left hemisphere to process. Therefore the participants report not seeing anything.
However, if asked to draw what they saw with their left hand (controlled by the right hemisphere) they can draw the image.
What are the strengths of split brain research?
Reliability- highly standardised procedure in a lab so replication is possible.
Applicability- produced an impressive and sizeable body of research findings. The more we understand about how out brain is lateralised, the more we can help with brain damage.
What are the weaknesses of split brain research?
Generalisability - unusual and small sample (11 people with a history of epileptic seizures)
Validity - (low ecological validity). In a real life situation, information would be entering both eyes so this can compensate for having no corpus callosum.
Ethics - no major ethical issues, however it is drawing attention to how the patients are different.
How does Phineas Gage provide support for localisation of function?
He suffered an accident in which a tampering iron took out a portion of his frontal lobe which resulted in a dramatic change in his personality.
This suggests that these areas of the brain have different functions. This therefore supports the idea that many neurological functions are localised.
Give the name of a study that provides support for lateralisation of function.
Heller and Levy (1981)
Found that if a photo of a face is split so that half is smiling and the other is neutral is shown to someone, the emotion displayed in the right-hand side of the picture is the emotion recognised by the participant. This suggests that the right hemisphere seems to be dominant in recognising emotions.
Give the name of a case study that provides evidence against lateralisation and localisation of the brain.
Danelli Et Al (2013)
Reported the case of a boy who had virtually all his left hemisphere removed, however managed to regain most of his language abilities.
This implies that there is no lateralisation an localisation of function.
What is meant by brain plasticity?
The brain has the ability to change through life.
When does the brain experience a rapid growth in the number of synaptic connections?
Ages 2-3
Peaks at about 15,000
What happens to the synaptic connections in our brain asa we age?
Rarely used connections are deleted and frequently use connections are strengthened (synaptic pruning).
What is synaptic pruning?
Rarely used connections in the brain are deleted and frequently used connection are strengthened.
Before the idea of brain plasticity, what was believed about the development of the brain?
It used to be thought that the brain was restricted to developing in childhood. It was believed that the adult brain would remain fixed and static in terms of function ad structure.
What factors can result in our brains changing?
Occupation
Leaning experiences
Hobbies
Drug use
How can new synaptic connections be formed in the brain?
As a result of learning and experience
Describe the functional recovery of the brain after trauma?
The brain is able to redistribute or transfer functions e.g. healthy brain areas may take over function of those that are damages, destroyed or missing. The brain does this by reviving and reorganising itself, forming new synaptic connections close to the area of damage.
What are the 3 possible structural changes in the brain during recovery after trauma?
Axon sprouting
Recruitment of homologous areas on the opposite side of the brain
Denervation suspersensitivity
What is axon sprouting in brain recover after trauma?
The growth of new nerve endings which connect with other undamaged nerve cells to form new neurological pathways. This is because when an axon is damages, to connections with a neighbouring neurone is lost
What is the recruitment of homologous areas on the opposite side of the brain when the brain is recovering after trauma?
This is done to perform specific tasks e.g. if Broca’s area was damaged on the left side of the brain, the right sided equivalent would carry out its functions.
What is denervation supersensitivity in brain recovery after trauma?
Axons that do a similar job become aroused to a higher level to compensate for the ones that are lost. This may cause over-sensitivity to messages such as pain, increase an individuals pain levels.
What factors effect brain recovery after trauma?
Perseverance
Physical exhaustion
Stress
Alcohol consumption
Age
Gender
How does perseverance effect brain recovery after trauma?
A function may appear to be lost but this may be because the individual thinks it is unrecoverable and therefore doesn’t try. This means perseverance is key to recover.
How does physical exhaustion, stress and alcohol consumption effect brain recovery after trauma?
When a function is recovered, the function is used with considerable effort from the individual. Factors such as stress and alcohol consumption can affect the ability to use any regained function.
How does age effect brain recovery after trauma?
There is deterioration of the brain in old age. This effects the extent and speed of recovery.
How does gender effect brain recovery after trauma?
Research suggests that women recover better from brain injury as their function is not as lateralised. However, overall conclusions are unclear.
What is a strength of brain plasticity?
Practical application
Understanding the processes involved in plasticity has contributed to the field of neuro-rehabilitation. The more we understand, the more effectively we can help those who need it.
What is a weakness of brain plasticity?
Factors effecting recovery
The ability of the brain to recover varies according to the extent of the damage, the location of the damage and the individual. Generalisations are difficult to make from case studies.
Validity of findings
In some cases there is no record of functioning level prior to the trauma. It is therefore difficult to know the extent to which a brain has e covered to pre-trauma levels. The inability to come to these conclusions lowers validity.
What research supports plasticity?
Maguire et al (2000)
Studied London taxi drivers and found that they had a larger posterior hippocampus than the matched control group. This part of the brain is associated with the development of spatial and navigational skills. The longer they had been in the job, the more pronounced the structural difference.
The result of this learning experience is to alter the structure of the taxi driver’s brains. This supports the idea of brain plasticity - the brain having the ability to change throughout a person’s life.
Describe the features of an fMRI scan.
- uses a magnetic field and radio waves to detect the changes in blood oxygenation and flow that occur as a result of brain activity in specific parts of the brain. (When a brain area is more active, it consumes are oxygen. To meet this demand, blood flow is directed to this active area).
- gives a moving picture of the brain.
- produces 3D images (activation maps) which show which parts of the brain are involved in mental processes.
Name 2 strengths of using an fMRI scan.
- doesn’t rely on radiation (risk free).
- images have a high spatial resolution (mm)
- captures dynamic brain activity
What are two weaknesses of fMRI scans?
- low temporal resolution
- can only capture a dealer image if the person is completely still.
- fMRI data is complex and can be open to interpretation
- expensive (leads to small sample sizes which leads to decreased validity)
Outline what a Post-Mortem is.
- analysis of a person’s brain following their death
- a person having a post-mortem is likely to have had a rare disorder/ experienced an unusual deficit in mental processes
- areas of damage within the brain after death establish likely cause of the affliction
- psychologists may compare this brain to a neurotypical brain to ascertain the differences
Name 2 strengths of post - mortem.
- the evidence found provided a foundation for early undertaking of key processes in the brain eg Broca and Wernike
- allows deeper regions of the brain to be studies
- helps generate hypothesis for future studies
Name 2 weaknesses of post-mortem.
- causation - observed damage may not be linked to the deficits under review but to unrelated trauma or decay
- requires special permissions which leads to a small sample size
- shows purely physiology (no dynamic brain activity)
Outline what an EEGG scan is.
- measures electrical activity within the brain via electrodes fixe to the scalp using a scull cap to detect neuronal activity directly below where the electrodes are placed
- the scan recording represents brain wave patterns that are generated from the action of millions of neurones, providing an overall account of brain activity
- may indicate neurological abnormalities e.g epilepsy or sleep disorders
Name two strengths of using an EEG scan.
- contributed into out understanding of the stages of the stages involved in sleep
- extremely high temporal resolution (millisecond)
- cheaper than fMRI, larger sample used, increased validity
- observe/ investigate the active brain
Name 2 weaknesses of using EEG scans.
- generalised nature of the information revive (from thousands of neurones)
-poorer spatial resolution than fMRI’s - not useful for pinpointing the exact source of neurone activity
Outline the features of an ERP scan.
- uses the same apparatus as EEG’s, but records when there is activity in response to a stimulus introduced by the researcher
- within EEG data are all the neutral responses associated with different events. Researchers have developed a way of tearing out and isolating their responses using a statistical averaging technique, all extraneous brain activity from the original EEG recording is filtered out
- what remains in the ERP: types of brain waves triggered by events
Outline the features of an ERP scan.
- uses the same apparatus as EEG’s, but records when there is activity in response to a stimulus introduced by the researcher
- within EEG data are all the neutral responses associated with different events. Researchers have developed a way of tearing out and isolating their responses using a statistical averaging technique, all extraneous brain activity from the original EEG recording is filtered out
- what remains in the ERP: types of brain waves triggered by events
Outline 2 strengths of using a ERP scan.
- bring much more specificity to the measurement of neural processes than could never be achieved using raw EEG data
- researchers have been able to identify many different types of ERP and describe the precise role of these in cognitive functioning
Outline 2 weaknesses of using an ERP scan.
- lack of standardisation in ERP methodology between the different research studies makes it difficult to confirm findings
- in order to establish pure data in ERP studies, background noise and extraneous material must be completely eliminated and this may not always be easy to achieve
What are the 3 types of biological rhythms?
Circadian rhythm, infradian rhythm, ultradian rhythm
What is a biological rhythm?
Distinct patters in changes in body activities that conform to cyclical periods.
What are endogenous pacemakers?
-The body’s internal ‘biological clock’
- mechanisms within the body that govern the internal biological bodily rhythms
What is an example of an endogenous pacemaker?
Supechiasmatic nucleolus (SCN)
What is an exogenous zeitgeber?
- an environmental cue such that helps to regulate the biological clock in organisms e.g. light and sound
How long is a circadian rhythm?
24 hours
What is an example of a circadian rhythm?
The sleep/wake cycle.
What case study supports exogenous zietgebers and endogenous pacemakers?
Sifter’s cave study.
Explain Siffre’s cave study.
- Micheal Siffre spent 2 months in a cave, deprive of exposure to natural light or cue as to the day or time (but had access to sufficient food and drink and supplies etc).
- he had an artificial light to help navigate the cave
- his free-running biological rhythm was just beyond 24 hours (25-30 hours)
- he continued to fall asleep and wake up on a regular schedule but lost track of how many days he’d been in the cave (thought it had been a month or less)
- THIS SUGGUESTS:
- the natural seep/wake cycle may be longer than 24 hours
- natural light sources in the environment are vital for keeping the individual to a 24 hour cycle
- the natural sleep/wake cycle is adjusted but exogenous zeitgebers associated with our 24 hour day
Name the primary endogenous pacemaker which is influential in maintaining the sleep/wake cycle.
The superchiasmatic nucleus (SCN)
Describe how the superchiasmatic nucleus works.
-The SCN lies above the optic chiasm in the hypothalamus (in each hemisphere)
- it receives information about light (even when eyes are closed)
- this enables ou biological clock to adjust to changing patters of daylight when we sleep
- the SCN passes information on day length and light that it receives to the pineal gland
- during the night, the pineal gland increases production of melatonin- a chemical that induces sleep and is inhibited during periods of wakefulness
Why is animal research used when investigating the superchiasmatic nucleus?
- human research would be difficult and unethical.
- it is argued that generalisation can be made to humans.
Explain the study of DeCoursey (2000)
- they destroyed the connections in the rains of 30 chipmunks and returned them to their natural habitat for 80 days for observation
- they found that their sleep/wake cycle disappeared and a significant number had been killed by predators as they were awake when they should have been sleeping and were therefore vulnerable to attack
- this shows that the superchiasmatic nucleus has a key role in the sleep/wake cycle
What case study supports the superchiasmatic nucleus?
DeCoursey
What is entrainment?
Where there is an adjustment of the body clock in line with the environment.
Explain how entrainment may effect someone crossing a time zone.
When a traveller crosses a time zone pacemakers are no longer synchronised to the environment. Zeitgebers therefore act as cues, allowing the person to adjust.
What case study supports exogenous zeitgebers?
Campbell and Murphy (1998)
Explain the case study of Campbell and Murphy (1998)
- they monitored 15 volunteers who slept in a lab
- they shone a beam of light onto the back of their knees during the night at a series of intervals
FOUND:
- they found their circadian rhythms were disrupted by up to 3 hours
- this shows that it is not necessary for light to just enter the eyes to have a physical effect on biological rhythms
What are the advantages of understanding circadian rhythms?
- practical application- shift work - night shift workers experience a period of reduced concentration around 6am, this means mistakes are more likely to happen. Employers can adjust their workers timetable according to this to increase economical benefit.
- practical application - drug treatments - research into circadian rhythms have revealed that there are peak times when drugs are most effective, this could influence when doctors tell patients to take their medication.
- supporting evidence - DeCoursey, Campbell and Murphy.
What are the disadvantages of research into circadian rhythms?
- validity - research is often carried out in artificial conditions, the fore resulting in artificial behaviour
- generalisability - animas are often used in research and research, based off unique case studies(not representative), individual differences(individual cycles can vary).
- ethics- ethics involved in animal studies (exposed to considerable harm and risk when returned to their natural habitat).
How long is an ultradian rhythm?
Less than 24 hours
What is an example of an ultradian rhythm?
Stages of sleep
How many distinct stages of sleep are there?
5
How long do the 5 stages of sleep approximately span?
90 minutes
What method of studying the brain is used to investigate ultradian rhythms?
EEG scans
How long is an ultradian rhythm?
Less than 24 hours
What is an example of an ultradian rhythm?
Sleep cycles
What happens to the body in the 5th/REM stage of the sleep cycle?
The body is paralysed yet brain activity speeds up significantly. There is fast “jerky” activity of the eyes under the eyelids. Irregular breathing and heart rate.
In which stage of the sleep cycle do we dream?
The 5th/REM
Name the symptoms of sleep deprivation.
Memory and attention problems.
Weakening of immune system.
Increased risk of depression and substance abuse.
Increased risk of motor vehicle accidents do to loss of focus.
Explain a strength of research into ultradian rhythms.
Research evidence
‘Dement and Kleitman (1957)’
Which case study provides evidence about the sleep cycles? Explain what is discovered and how.
‘Dement and Kleitman’ (1957)
- monitored the sleep patterns of 9 adult participants in a sleep lab.
- brainwave activity was recorded on an EEG.
- researched controlled the effects of caffeine and alcohol.
- REM activity during sleep was highly correlated with dreaming.
- brainwave activity varied according to ow vivid dreams were.
- participants woken during dreaming reported a very accurate recall of their dreams.
- replications of this have noted similar findings.
- this suggests that sleep follows a typical pattern throughout the night and dreams mostly occur during REM sleep.
What is a weakness of research into ultradian rhythms.
problems with sleep research
Sleep research such as Derment and Kleitman lack validity.
E.g. self report - may lie or be inaccurate.
Lacks ecological validity - not a usual task to be woken up and report dreams.
Electrodes/lab may disrupt sleep - an experimental setting may have caused the results produced.
Dreaming is difficult to measure.
It also lacks generalisability due to a small sample of 9 people which limits the extent to which we can generalise results to other people.
How long is an infradian rhythm?
More than 24 hours
What is an example of an infradian rhythm?
The menstrual cycle
The menstrual cycle is part of the ______________ system.
Endocrine
how long does the menstrual cycle last?
Approximately 28 days
What are some exogenous factors that can effect an infradian rhythm such as the menstrual cycle?
Light, odours, pheromones
what is a pheromone and how does it relate to the menstrual cycle?
Chemicals produced by an individual, changing the behaviour of others.
They can change the length of a woman’s menstrual cycle.
What is a case study that shows how light is an exogenous factor that can effect the menstrual system? Explain this case study.
‘Reinberg (1967)’
- a woman spent 3 months in a cave with only the light of a small lamp
- her days lengthened to 24.9 hours and her menstrual system shortened to 25.7 days
This shows that levels of light could have effected her menstrual cycle.
Name two strengths of research into infradian rhythms.
menstrual synchronicity
- the effect of pheromones can help explain menstrual synchronicity of groups of women living together such as nuns.
evolutionary basis of the menstrual system
- menstrual synchrony means they can fall pregnant at he same time so babies can be cared for collectively, increasing survival OR it could increase competition for the highest quality males.
State two weaknesses of research into infraian rhythms.
methodological issues
- other factors such as stress, diet and exercise may effect a woman’s menstrual cycle (confounding variables).
- small samples in research - decreases validity
- self report - subjective
animal studies
- much of the knowledge of the effects of pheromones on behaviour is derived from animal studies which lacks generalisability to humans.
