Biopsychology Flashcards
1
Q
What is the nervous system and what does it consist of?
A
The nervous system is a specialised network of cells in the human body and is our primary internal communication system;
It consists of the central nervous system and the peripheral nervous system.
2
Q
What are the two main functions of the nervous system?
A
To collect, process and respond to information in the environment;
To coordinate the working of different organs and cells in the body.
3
Q
What is the Central Nervous System (CNS) made up of?
A
The brain and spinal chord
4
Q
Describe the structure and role of the brain.
A
The brain is the centre of all conscious awareness;
The cerebral cortex is the outer layer of the brain and is what distinguishes human mental functions from those of animals;
The brain is divided into two hemispheres - the left and the right;
Each hemisphere has 4 lobes - frontal, parietal, occipital and temporal.
5
Q
Describe the structure and role of the spinal chord.
A
The spinal chord is an extension of the brain;
It is responsible for reflex actions;
It passes messages to and from the brain and connects nerves to the Peripheral Nervous System (PNS)
6
Q
What is the role of the PNS?
A
Transmit messages via millions of neurons to and from the central nervous system.
7
Q
What is the PNS subdivided into?
A
The autonomic nervous system and the somatic nervous system.
8
Q
Describe the role of the autonomic nervous system.
A
Governs vital functions in the body such as breathing, heart rate, digestion - involuntary effect.
9
Q
What is the autonomic nervous system subdivided into?
A
The sympathetic nervous system - it activates internal organs and increases bodily activities
The parasympathetic nervous system - it relaxes internal organs and decreases bodily activities.
10
Q
Describe the role of the somatic nervous system.
A
Transmits information from receptor cells in the sense organs to the CNS;
It receives information from the central nervous system that directs muscles to act - voluntary effect.
11
Q
State the role of a sensory neuron.
A
Carry nerve impulses from sensory receptors (PNS) to the spinal chord and brain (CNS)
12
Q
State the role of a relay neuron.
A
Allow sensory and motor neurons to communicate with each other.
13
Q
State the role of a motor neuron.
A
Carry nerve impulses from the spinal chord and brain (CNS) to effectors which are muscles and glands (PNS).
14
Q
Describe the three neurons in terms of axon and dendrite length.
A
Sensory - Short axon and long dendrites
Relay - Short axon and short dendrites
Motor - Long axon and short dendrites
15
Q
What is the function of the cell body.
A
The factory of the neuron;
Contains the nucleus and produces the proteins that a neuron requires to function.
16
Q
What is the function of a nucleus.
A
Contains the genetic material within the neuron.
17
Q
Describe the structure and role of dendrites.
A
Branch-like features protruding from cell body;
They carry nerve impulses from neighboring neurons towards the cell body.
18
Q
Describe the structure and role of axons.
A
Covered in myelin sheath;
Carries the electrical impulse from the cell body down the length of the neuron.
19
Q
Describe the structure and role of myelin sheath.
A
Fatty layer which surrounds and protects the axon;
Helps to speed up electrical transmission of the impulse.
20
Q
Describe the structure and role of the nodes of Ranvier.
A
Gaps between the myelin sheath;
Their purpose is to speed up the transmission of the impulse, by forcing it to jump across the gaps along the axon
21
Q
Explain the role of the terminal buttons.
A
Located at the end of the axon;
Communicate with the next neuron that is on the other side of the synaptic cleft.
22
Q
Explain the process of synaptic transmission.
A
An electrical impulse travels down a pre-synaptic neuron along its axon and to the terminal buttons;
The electrical impulse stimulates synaptic vesicles which contain neurotransmitters;
Neurotransmitters are released from synaptic vesicles and travel across the gap - electrical impulse changes to a chemical impulse;
Receptors on the post-synaptic neuron are complementary in shape to specific neurotransmitter;
The connection between the neurotransmitter and receptor either produces an excitatory or inhibitory effect;
If the neurotransmitter is excitatory it is more likely that the electrical impulse will travel along the post-synaptic neuron;
If the neurotransmitter does not fit receptor there will be no electrical impulse.
23
Q
Describe the two effects neurotransmitters can have.
A
Increase of the likelihood of a neuron firing - excitation
Decrease the likelihood of a neuron firing - inhibition
24
Q
Give an example of an excitatory neurotransmitter and its function.
A
Adrenaline - causes excitation of the post-synaptic neuron by increasing its positive charge and making it more likely to fire.
25
Give an example of an inhibitory neurotransmitter and its function.
Serotonin - causes inhibition in the post-synaptic neuron as neuron becomes negatively charged and less likely to fire.
26
Whether or not a post synaptic neuron fires is decided by what?
Summation
27
What is meant by summation?
The excitatory and inhibitory influences are summed up;
If the net effect on the post-synaptic neuron is inhibitory it is less likely to fire;
If the net effect is excitatory it is more likely to.
28
Describe the two impacts drugs can have on synaptic transmission.
Increase the amount of neurotransmitter by blocking reuptake channels
OR
Decrease the amount of neurotransmitter by blocking the receptors.
29
Information can only travel in one direction at a synapse.
Explain why neurons can only transmit information in one direction at a synapse.
[3 marks]
1. Receptor binding sites are only found on the post synaptic neuron.
2. Neurotransmitters can only diffuse across synapse down a concentration gradient from a high concentration in the pre-synaptic neuron to a low concentration in the post-synaptic neuron.
3. The synaptic vesicles containing neurotransmitters are only released from the pre-synaptic neuron.
30
What is the role of the endocrine system?
Instructs glands to release hormones directly into the blood stream.
31
Where are hormones carried towards?
Target organs.
32
What is a gland?
An organ in the body that produces hormones.
33
Give two examples of glands and the hormones released from each gland.
Describe their impacts.
1. Ovaries - release oestrogen;
Controls the regulation of the female reproductive system, including the menstrual cycle and pregnancy.
2. Adrenal gland - releases adrenaline;
Responsible for the fight or flight response - stimulates the heart rate, contracts blood vessels etc.
34
What is the main endocrine gland and where is it located?
Pituitary gland, located in the brain.
35
Why is the pituitary gland often called the 'master gland'?
Because it controls the release of hormones from all of the other endocrine glands in the body.
36
Describe the fight or flight response.
1. The hypothalamus recognises that there is a threat in the environment.
2. The ANS activates the sympathetic nervous system.
3. The sympathetic nervous system tells the pituitary gland to release ACTH.
4. This sends a message to the adrenal gland.
5. The adrenal gland responds by releasing adrenaline.
6. The adrenaline travels via the bloodstream and targets organs in the body which have adrenaline receptors.
7. Causes many physical changes e.g. stimulating the heart rate.
8. Once the threat has passed, the parasympathetic nervous system brings the body back to normal, resting functions.
37
Give 6 responses to the body when adrenaline is present - sympathetic state.
1. Increased heart rate
2. Increased breathing rate
3. Dilates pupils
4. Inhibits digestion
5. Inhibits saliva production
6. Contracts rectum
38
Give 6 responses to the body when adrenaline is not present - parasympathetic state.
1. Decreased heart rate
2. Decreased breathing rate
3. Constricts pupils
4. Stimulates digestion
5. Stimulates saliva production
6. Relaxes rectum
39
Evaluate the fight or flight response. [10 marks]
1. TEND AND BEFRIEND - females adopt a 'tend and befriend response. Taylor et al.
2. BETA BIAS - research was typically conducted on males - androcentric. This is an example of beta bias. Cannot be applied to all individuals.
3. MALADAPTIVE RESPONSE - Stressors of modern day life can repeatedly activate the fight or flight response. Leads to increase in blood pressure which can damage blood vessels and cause heart disease.
4. BIOLOGICALLY REDUCTIONIST - attempts to explain behaviour based on the role of adrenaline and the effect of the nervous system. Does not take into account other elements such as cognitive processes. It may be too limited.
40
What are the four scanning techniques to study the brain?
1. fMRIs
2. EEGs
3. ERPs
4. Post Mortem
41
Describe fMRIs. (4 POINTS)
1. fMRIs work by detecting blood oxygenation and blood flow that indicate increased neural activity.
2. People are asked to do a task and it is observed where the brain activity is.
3. When a brain area is more active it consumes more oxygen and to meet this increased demand, blood flow is directed to that area.
4. Produces 3D images showing which areas of the brain are involved in particular processes which is important for establishing localisation of function.
42
Evaluate fMRIs. (8 marks)
1. fMRI is NON-INVASIVE - unlike other scanning techniques it does not rely on radiation so it is safe.
2. Produces images with HIGH SPATIAL RESOLUTION - so can provide a clear picture.
3. EXPENSIVE - limits the appropriateness.
4. POOR TEMPORAL RESOLUTION - 5 second lag - not truly represent moment-to-moment brain acitivity.
43
Describe EEGs. (3 POINTS)
1. EEGs record changes in electrical activity using electrodes attached to the scalp.
2. The scan recordings represents the brainwave patterns that are generated from the action of millions of neurons, providing an overall account of brain activity.
3. It is often used as a diagnostic tool as unusual arrhythmic patterns may indicate neurological abnormalities e.g. epilepsy.
44
Evaluate EEGs (8 marks)
1. VALUABLE IN DIAGNOSING CONDITIONS - identified epilepsy and used to understand the stages of sleep.
2. HIGH TEMPORAL RESOLUTION - more able to represent moment-to-moment brain activity.
3. GENERALISED SIGNAL - difficult to know the exact source of neural activity.
4. DO NOT provide a complete picture of brain activity - cannot reveal electrical activity in deeper brain sites.
45
Describe ERPs. (3 POINTS)
1. It records changes in electrical activity using electrodes attached to the scalp but uses a SPECIFIC STIMULUS to see where activity is.
2. Using a statistical averaging technique, all extraneous brain activity from the original EEG recording is filtered out, leaving only those responses that are related to a specific stimulus or task.
3. Research has revealed many different forms of ERP and how these are linked to cognitive processes.
46
Evaluate ERPs (8 marks).
1. VERY SPECIFIC - better method of investigating brain activity.
2. EXCELLENT TEMPORAL RESOLUTION - can detect brain activity as a resolution of a single millisecond.
3. LACK STANDARDISATION - makes it difficult to confirm findings - decreases the reliability.
4. Background noise and extraneous material must be completely eliminated - this may be hard to achieve which limits its appropriateness.
47
Describe Post Mortems. (2 POINTS)
1. Post Mortems examine abnormalities in the structure of the brain which try to explain psychological abnormalities that people have before death.
2. They may also involve comparison with a neurotypical brain in order to determine the extent of the difference.
48
Evaluate Post Mortems. (8 marks)
1. Provided the foundation for understanding the brain - Broca and Wernicke both relied on post mortem studies.
2. Allow for in-depth study of the brain - examinations and measurements of deep brain structures e.g. hypothalamus.
3. Causation may be an issue - observed damage may be due to another cause related to trauma or decay - limits the appropriateness.
4. Raise ethical issues - patients need to give informed consent before death - may not be able to be provided e.g. HM.
49
Summarise what happened to Phineas Gage.
-He had a meter-long iron pole through his left cheek, passing behind his left eye, and exiting his skull from the top of his head taking a proportion of his brain with it - most of his left frontal lobe.
-He survived the damage but his personality changed from someone who was calm and reserved to someone who was quick-tempered, rude and 'no longer Gage'.
50
Briefly describe the two different theories of the brain.
The holistic theory argues that all parts of the brain are involved in the processing of thoughts and action;
The localisation of function theory argued that specific areas of the brain are associated with particular physical and psychological functions - damage to these areas cause consequences for behaviour.
51
Where is the motor cortex located and state its function.
At the back of the frontal lobe;
Controls voluntary movement in the contralateral (opposite) side of the body.
52
What happens as a result of damage to the motor cortex?
Loss of fine movement
53
Where is the somatosensory cortex located and state its function.
At the front of the parietal lobe;
Represents sensory information from the skin;
The more sensitive an area, the more space it takes up in the somatosensory cortex.
54
What happens when the somatosensory cortex is damaged?
Loss of senses.
55
Where is the visual cortex located and state its role.
In the occipital lobe;
Information from the right visual field is sent to the left visual cortex and vice versa.
56
What happens if there is damage to the visual cortex?
Loss of specific areas of the visual field.
57
Where is the auditory cortex located and state its role.
In the temporal lobe;
Analyses speech-based information.
58
What happens if there is damage to the auditory cortex?
Partial hearing loss.
59
Where is the Wernicke's area located and state its function.
In the left temporal lobe;
Responsible for language comprehension.
60
What happens if there is damage to the Wernicke's area?
People produce nonsense words i.e. they can speak fluently but the words are meaningless to them.
61
Where is the Broca's area located and state its role.
Small area of the left frontal lobe;
Responsible for speech production.
62
What happens if damage is done to the Broca's area?
Slow speech that lacks fluency.
63
What are Broca and Wernicke's Area examples of and what does this mean?
Localisation i.e. they are located within specific areas of the brain.
64
What is meant by laterlisation?
When something is specialised to one hemisphere.
65
Evaluate localisation of function.
BRAIN SCANNING EVIDENCE - Peterson et al used brain scans to demonstrate Wernicke's area was active during a listening task and Broca's area was active during a reading task - increases validity (impact)
CASE STUDY EVIDENCE - Phineas Gage - suggests that personality and temperament are localised within the frontal lobe.
NEUROSURGICAL EVIDENCE - Dougherty et al reported on 44 OCD patients who had undergone cingulotomy - after 32 weeks a third of patients had successful response and 14% had partial response - suggests symptoms of OCD are localised.
FUNCTIONAL RECOVERY SHOWS THAT LOCALISATION OF FUNCTION CAN CHANGE - a girl who lives with half a brain as after illness/accident the brain appears to reorganise itself in an attempt to recover the lost function - this supports the holistic view.
66
What is meant by plasticity?
Plasticity describes the brains tendency to change existing neural connections and adapt new neural connections as a result of experience and new learning.
67
What is meant by synaptic pruning?
As we age, rarely used connections are deleted and frequently used connections are strengthened.
68
Describe Maguire et al's study for plasticity.
- Studied the brains of London taxi drivers and found significantly more volume of grey matter in the posterior hippocampus than in a matched control group.
69
What is the posterior hippocampus? (Maguire et al)
The part of the brain associated with the development of spatial and navigational skills.
70
How does London cabbies training affect grey matter?
- They must take a test called 'The Knowledge' to assess their recall of the city streets and possible routes, which appears to alter the structure of the taxi driver's brains.
-The longer they had been in the job the more pronounced the structural difference.
71
Describe Kuhn's study for plasticity.
- A control group was compared to a video game group, who had to play Super Mario for at least 30 minutes a day for 2 months.
- They found a significant increase in the grey matter in a number of brain areas of the video game group which were associated with spatial navigation, strategic planning etc which are all involved in playing video games.
- The increase was not found in the control group which demonstrates plasticity within the brain.
72
Describe how mediation provides evidence for plasticity.
- Monks who meditated were compared to student volunteers who had no previous experience with meditation.
- Monks were found to have greater gamma wave activation, which coordinate neuron activity within the brain, than the controls whilst meditating.
- They were also found to have greater gamma wave activation before mediation compared to controls.
- This shows that meditation can have both short term and permanent changes.
73
What is meant by functional recovery?
- A form of plasticity that occurs following damage to the brain in which the brain reorganises itself to compensate for the area that has lost the function.
- The brain has the ability to transfer functions usually performed by a damaged area to other undamaged areas.
74
Which three processes support the structural changes in the brain during functional recovery?
1) Axonal sprouting: The growth of new nerve endings which connect with other undamaged nerves to form new neuronal pathways.
2) Reformation of blood vessels.
3) Recruitment of homologous areas on the opposite side of the brain to perform specific tasks.
75
What are the 6 factors affecting functional recovery?
1) How much people want to recover.
2) How tired people are.
3) How stressed people are.
4) How much alcohol/drugs people are having.
5) Age - younger individuals recover more quickly.
6) Gender - women recover more quickly.
76
Evaluate plasticity and functional recovery of the brain after trauma.
1. ANIMAL STUDIES - Hubel and Wiesel sewed the eye of a kitten shut and analysed the brains cortical response. HOWEVER, questioning the ability to generalise findings to humans due to complexity of the human brain.
2. MALADAPTIVE CONSEQUENCES - 60-80% of amputees develop phantom limb syndrome - these are unpleasant due to cortical reorganisation in the somatosensory cortex.
3. REDUCTION WITH AGE - Brain has greater prosperity for reorganisation in childhood as it is constantly adapting to new experiences and learning - those who are older may need additional support.
4. INDIVIDUAL DIFFERENCES - Schneider et al discovered the more time patients spent in education the greater the chance of a disability-free recovery - shows educational attainment may influence how well the brain adapts after injury.
77
What is meant by hemispheric lateralisation?
Some mental processes in the brain are mainly specialised to the left of right hemisphere e.g. language is lateralised to the left hemisphere.
78
What is meant by contralateral?
The right hand side of the body is controlled by the left hemisphere;
The left hand side of the body is controlled by the right hemisphere.
79
What is the corpus callosum?
Broad band of fibres that join the two hemispheres together which allows communication between the two hemispheres.
80
What happens as a result of cutting the corpus callosum?
Information cannot be passed between hemispheres.
81
Describe how information is processed by the right and left hemispheres.
Information from the left visual field is processed by the right hemisphere.
Information from the right visual field is processed by the left hemisphere.
82
What is meant by a split brain patient?
Split brain patients have had their corpus callosum cut meaning information cannot be passed between the two hemispheres.
This means the two hemispheres operate independently.
83
Describe Sperry's research on split brain patients.
- Sperry wanted to investigate hemispheric lateralisation.
- The individual focuses on a central dot which means information can either be presented to the left (processed by the right hemisphere) or the right visual field (processed by the left hemisphere).
- This means that the information is only processed by one hemisphere so we can see what functions are controlled by each hemisphere.
84
Describe the how split brain patients describe what they see.
If an image is shown to the right visual field, the patient could easily describe what is seen. This is because information is processed by the left hemisphere which is responsible for speech and language as it has language centres.
If it is presented in the left visual field, they cannot because of the lack of language centres in the right hemisphere.
If the patient draws what is presented to them in the left visual field, they can let the left hemisphere in on the 'secret' and the word can be said.
85
Describe how split brain patients deal with composite words e.g Key - Ring.
If two words are presented simultaneously, one on either side of the visual field, then the patient would write with their left hand which is controlled by the right hemisphere, the word key.
They would then say the word ring from their speaking left hemisphere so that the left hand knows what to write as the right hemisphere is in on the 'secret'.
86
Evaluate split brain research into hemispheric lateralisation.
1. METHODOLOGICAL STRENGTHS - highly standardised procedure - ensured only one hemipshere was receiving information - meant he had developed a well controlled procedure.
2. SPARKED THEORETICAL AND PHILOSOPHICAL DEBATE - Pucetti suggested the two hemispheres represent a form of duality however others argue they form a highly integrated system.
3. GENERALISABILITY ISSUES - only 11 patients took part all who had a history of epileptic seizures - reduces validity of the conclusions.
4. DIFFERENCES IN FUNCTION IS OVERSTATED - verbal and non-verbal labels can be applied to summarise differences between hemispheres, modern day neuroscientists argue the actual distinction is less clear cut - some behaviour typically associated in one hemisphere can be performed by the other when necessary - plasticisty and functional recovery findings have shown lateralisation is not always clear or permanent.
87
What are the three biological rhythms?
1. Circadian
2. Infradian
3. Ultradian
88
Describe circadian rhythms.
A circadian rhythm is any cycle that last about 24 hours;
These rhythms optimise an organism's bodily functions and behaviour to best meet the varying demands of the day and night cycle;
The rhythm is regulated by an internal system such as the release of hormones, metabolic rate and body temperature.
89
Give an example of a circadian rhythm.
Sleep-wake cycle
90
Describe the sleep-wake cycle.
Light and dark provide signals about when we should be awake and when we should be asleep;
Our strongest sleep drive occurs between 2-4 am and 1-3 pm.
91
What else controls our need to sleep?
Homeostasis - if we need more energy our body tells us we need to sleep.
92
Describe Siffre's cave study.
Siffre spent several extended periods underground to study the effects on his own biological rhythms;
He was deprived of exposure to natural light and sound but with access to adequate food and drink;
His 'free running' biological rhythms did extend to around 25 hours but he did continue to fall asleep and wake up on a regular schedule.
93
How does hormone production effect the sleep-wake cycle?
Melatonin is produced and released from the pineal gland and peaks during hours of darkness;
Melatonin encourages feeling of sleep;
When it is dark more melatonin is produced, when it is light, less melatonin is produced.
94
How does body temperature effect the sleep-wake cycle?
Sleep occurs when the body temperature drops;
Temperature rises during the last few hours of sleep and this causes people to feel alert in the morning.
95
Evaluate circadian rhythms.
1. SHIFT WORK APPLICATION - Boivin et al found shift workers experience a lapse of concentration around 6 am - may have economic implications - shift changeovers could occur before a circadian trough to reduce mistakes (impact)
2. DRUG TREATMENT APPLICATION - has had implications for pharmacokinetics - research shows there are times during the day and night when drugs are more effective - guidelines have been developed for the timing of doses e.g cancer and epilepsy (impact)
3. USES CASE STUDIES + SMALL SAMPLES - Siffre's study involved a case study of himself - not representative of the wider population which limits the ability to generalise - even when the same participants are used there are factors that may prevent general conclusions e.g Siffre observed that his internal clock ticked more slowly at 60 than when he was younger (impact)
4. POOR CONTROL - Siffre had a lamp turned on from when he woke up until he went to bed - assumed artificial lighting would have no effect - Czeisler et al adjusted participants' circadian rhythms from 22 to 28 hours using dim lighting - artificial lighting may be like a drug that resets the participants' biological clocks. (impact)
96
What is meant by an endogenous pacemaker?
Internal body clocks that regulate many of our biological rhythms such as the influence of the SCN on the sleep-wake cycle.
97
What is meant by an exogenous Zeitgebers?
External cues that may affect or entrain our biological rhythms such as the influence of light on the sleep-wake cycle.
98
Describe how the SCN regulates the sleep-wake cycle.
It receives information about light, even when eyes are closed;
Passes information on day lengths and light to pineal gland;
During the night the pineal gland produces melatonin.
99
Describe one piece of research into endogenous pacemaker.
Decoursey et al - destroyed the SCN connections in the brain of 30 chipmunks - they were then returned to their natural habitat for 80 days.
Findings - significant proportion had been killed by predators as they were awake and vulnerable when they should have been asleep. The sleep wake cycle disappeared.
Conclusions - SCN maintains the circadian sleep-wake cycle.
100
How do exogenous zeitgebers set our body clocks?
Through entrainment which is the synchronisation of our body to the environment.
101
Why do external and internal cues work together?
To determine our 24-hour cycle.
102
How does light affect the sleep-wake cycle?
It resets the SCN and affects hormone secretion and blood circulation.
103
Describe a piece of research into light as an exogenous zeitgeber.
Campbell and Murphey - showed light can be detected by skin receptor sites on the body not just the eyes.
15 participants were woken at various times and a light pad shone on the back of their knees.
Participant's sleep-wake cycles were up to 3 hours in some cases.
This suggests that light is a powerful exogenous zeitgeber that influences our brain and body.
104
Evaluate research into endogenous pacemakers.
ETHICAL ISSUES - Decoursey's research - the animals were exposed to great harm - what we learn from investigations on biological rhythms may not justify the harmful procedures involved.
ANIMAL RESEARCH ALLOWS CAUSE + EFFECT - Decoursey's research involved destroying SCN connections which cannot be done on humans - without this research we would not know about the effect of the SCN on the sleep-wake cycle (impact)
105
Evaluate exogenous zeitgebers.
INFLUENCE MAY BE OVERSTATED - individuals who live in arctic regions where the sun does not set during the summer months show normal patterns of sleep - suggests there are occasions where exo. ziet. have little relation to our internal rhythms.
METHODOLOGICAL ISSUES - Campbell and Murphy's study has yet to be replicated and is criticised because there may have been some light exposure to participant's eyes - isolating one exo. ziet. does not give insight into other zeitgebers that influence the sleep/wake cycle - suggests that some studies have underplayed or ignored the way in which different exogenous zeitgebers interact. (impact)
106
Which rhythm is menstrual cycle an example of?
Infradian rhythm.
107
Describe each cycle of the menstrual cycle.
Increase in oestrogen levels causes the ovary to develop and release an egg, which is ovulation.
After ovulation, progesterone levels increase and helps the womb lining grow thicker, readying the body for pregnancy.
If fertilisation does not occur, the egg is absorbed into the body and the womb lining disintegrates.
108
Describe research into the menstrual cycle.
Stern and McClintock - suggested menstrual cycles may synchronise as a result of pheromones.
Used 29 women with a history of irregular periods and took samples of 9 of their pheromones at different stages of their menstrual cycles via a cotton pad placed under their armpits.
Treated with alcohol and frozen to be rubbed on the lips of the other participants.
68% of women experienced changes to their cycle which brought them closer to their 'odour donor'.
This shows pheromones do influence women's menstrual cycles
109
Evaluate infradian rhythms.
EVOLUTIONARY PERSPECTIVE - advantangeous for female ancestors to menstruate together - means offspring would be cared for collectively, increasing chance of survival. HOWEVER, Schank argues too many females cycling together would produce competition for highest quality males - this would lower genetic fitness of potential offspring - therefore, avoidance of synchrony would be advantageous and selected.
OTHER FACTORS IN CHANGES TO MENSTRUAL CYCLE - stress and change in diet - pattern of synchronisation in McClintock's study occurred by chance - lacks validity (impact)
ROLE OF PHEROMONES IS SPECULATIVE AND INCONCLUSIVE - pheromones in McClintock and Stern's study was taken from armpits - not reflective of how pheromones work in the real world - questions validity of study + questions the role of pheromones (impact)
110
What is an ultradian rhythm?
Biological rhythms that last less than 24 hours, so there is more than one cycle within the 24 hour period such as the sleep cycle and the wake cycle.
111
Describe the stages of the sleep cycle. (ultradian rhythm)
Stages 1 and 2 are light sleep where the person can be easily woken - brainwave activity becomes slower and more rhythmic as sleep becomes deeper. (alpha waves into theta waves)
Stages 3 and 4 involve delta waves which are slower and have a greater amplitude than earlier wave patterns - this is deep sleep.
Stage 5 is REM sleep where the body is paralysed yet brain activity speeds up. Rapid eye movement occurs. REM activity is highly correlated with the experience of dreaming.
112
Evaluate ultradian rhythms.
EVIDENCE TO SUPPORT QUALITATIVELY DIFFERENT STAGES IN SLEEP - Dement and Kleitman monitored sleep patterns of 9 participants in a sleep lab - found REM activity correlated with dreaming - suggests REM sleep is a distinct ultradian rhythm
INDIVIDUAL DIFFERNCES IN SLEEP STAGES - Tucker assessed sleep in controlled conditions focusing on sleep duration - individual differences in deep sleep was particularly significant - shows differences were driven by biology - difficult to generalise results to wider population (impact)
113
Compare infradian rhythms to ultradian rhythms.
Infradian rhythms take more than 24 hours to complete whereas ultradian rhythms take less than 24 hours to complete.
An example of an infradian rhythm is the menstrual cycle whereas an example of an ultradian rhythm is the sleep cycle.
