biopsychology A03 Flashcards
(8 cards)
Fight or flight
reductionist - assumes only 2 elements to FoF.
- Ev - freeze effect - hypervigilant to threat, avoid confrontation, take time to decide best course of action
- Ex - cognitive process - decision making element in processing danger - not just instinctive bio response to threat.
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L - But ‘freeze’ still evolutionary survival instinct - playing dead to ensure survival (instinctive response to survive an attack rather than decision making cog process).
FF or freeze still reductionist = solely attributing beh to evolution.
criticised for being beta biased
- Ev - assumes men + women use same FoF response.
Taylor et al - women tend and befriend. seek out social support in threat.
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Ex - Bio/evolutionary process = Oestrogen enhances the effects of oxytocin (‘love hormone’), creating a bond with groups and the need for social support. Provides safety in numbers, protect offspring which FoF wouldn’t do.
testosterone inhibits it, and linked to aggression (fight). so FoF = gender biased. -
L - but this exaggerated diff - alpha bias - assumes aggression from FoF only male.
Research found males tend and befriend - seek out others when stressed for social support. FoF too reductionist - humans need number of diff ways to cope with threats.
outdated explanation - maladaptive in modern times
- Ev - Modern day stressors = chronic + long lasting (e.g. lack of money, job stress) rather than acute stressors with ancestors.
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Ex - not situations where FoF can be used quick then put into parasympathetic state of R+D.
body would be in constant FoF mode - increased HR, inhibited digestion etc = heart attack, stroke, stomach ulcers etc. - L - still some situations where FoF can be used such as in an attack but mostly maladaptive, decreasing life span rather than being adaptive for survival. If evolutionary, should de-evolve over time.
localisation of function in the brain
research support from case study
-Ev - Tan - could only say ‘tan, tan’ (expressive aphasia) - lesion in Broca’s area. could do other functions such as maths
-Ex - Therefore Broca’s area is localised in its function for speech production. He had language comprehension and mathematical ability, so brain lobes have specific functions.
-L - but unique case study.
can’t see function whilst alive - only after in post mortem - correlational - may not be precise damage to Broca’s - modern fMRI scans used on other patients with expressive aphasia found low activity in other brain areas so other areas involved in speech production, so maybe not as localised as thought.
gender differences
-Ev - women have a larger Broca’s and Wernicke’s area than men
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Ex - not all individuals brains are localised in the same way - not innate, created by env.
Brian becomes more localised due to plasticity - primary socialisation (girls = language dev, boys = active playing - spatial areas)
-L - doesn’t criticise theory - specialised areas of brain are responsible for certain functions, but specialism = adaptive to a persons environment/ nurture.
brain only localised for simplistic functions
-Ev- higher mental functions, e.g. decision making and problem solving aren’t localised. Simpler functions such as language are more localised.
-Ex - this suggests brain isn’t intended to be localised and all parts of brain are used equally for a function.
more important to consider how diff areas work together rather than sep
-L - summary: useful in understanding basic localised functions of brain.
but unless we fully understand how areas communicate, we can’t understand complex mental processes e.g. memory, perception, attention.
This can be done through use of new technology (fMRI scans)
lateralisation
highly scientific research suppor -
-Ev - lots of controls, e.g. 1/10th sec, hands in box, blindfolded in one eye, control group
- Ex - strongt causation, can be sure LH is for language and RH is for object and face rec as not possible for other hemisphere to have seen the objects/words flashed.
-L - but sample- only 11 so more or case study. Had diff brain surgeries so unique brain damage in each pp.
Also the epilepsy could have changed the localisation of functions of their brain, therefore can’t say that ‘normal’ brains are lat.
L - study has been heavily replicated with different samples, finding same lateralisation of function so valid and reliable and can be generalised - true concept.
further research support for lateralisation
- Ev - Roger’s et al: chickens - lateralisation of hems associated with enhanced ability to perform two tasks simultaneously: finding food and being vigilant for predators.
- Ex - Proves lateralisation is evolutionary and necessary for survival and that all mammals have this function.
-L - however, chickens lower on ev scale. humans aren’t prey but apex predators and don’t need such threat detection. So only certain humans (epilepsy) and chickens have lat?
HOWEVER
humans are lateralised but in a different specialism. Need language in order to have safely in numbers/coordinate actives, develop medicine etc.
need object and face rec to attach to caregivers, for warmth, food and safety. So lat is necessary in humans and is bio
lateralisation changes with age
-Ev - over age of 25, brain becomes more de-lateralised and loses its specialism in lang and object rec.
-Ex - Suggests lat of brains only required in childhood due to new experiences, ppl and lang. Not necessary in adulthood (new exp less common) If brain lat should stay lat.
but brain has plasticity - as brain decays it lacks capability to efficiently remain lateralised so brain has recruitment of homologous areas, where both areas of brain take on the function. Hence we need de lateralisation as we age.
also, simplistic to assume each hemisphere only does one function, more complex functions, e.g. problem solving needs both hemispheres to function together, not independently.
plasticity
Criticism of Maguire’s Taxi Drivers research support
-Ev - sample bias (androcentric) and no before and after the knowledge test.
-Ex - can’t be certain if plasticity is same in women, or if ‘the knowledge test’ cause structural plasticity, or if they passed the test as their posterior hipp was already larger, hence better at remembering maps.
But, Maguire did further research to overcome criticism
-Ev - Same study but compared hipp before and after knowledge test.
Result: Posterior hipp did increase.
-Ex - learning mental map of london structurally and functionally changed their brains.
so brains do have plasticity and continue to develop as we learn.
but individual differences in level of plasticity ppl have
- Ev - gender - women have more plasticity in Broca’s + Wenicke’s area than men.
Education- undergraduate students that suffered brain damage had more plasticity than those without any qualifications (recovered more function)
Age - over 40 years plasticity decreases. takes longer to recover from brain damage.
-Ex - so, plasticity dependant on age, gender and education, suggesting it’s both env. and bio.
circadian rhythms (EP + EZ)
research to support role of EP’s in circadian rhythms
-Ev - 30 chipmunks had SCN removed and observed for 80 days. All chipmunks sleep-wake cycle ceased.
By end of study, significant proportion had been killed by weasels.
-Ev - The EP is responsible for keeping time to our circadian rhythm and ensures our survival.
-L - But humans are apex predators unlike chipmunks. EZ may be more important in humans, as less EP less needed for survival as we pray on other animals. E.g. Light from mobile phones interrupts the circadian rhythm of adolescents, affecting academic performance.
research to show EP important in human circadian rhythms
-Ev - Michael Siffre in cave for 2 months. No EZ - no light, clock, communication to outside world. Only could call out to his team. Found his circadian rhythm stayed at around 24.5hrs.
- Ex - EP (SCN) can hold humans to a 24hr circadian rhythm without any EZ. Therefore, our bio clock more
important.
- L- But case study of caver who was used to being underground. Was cold and wet, reducing his body temp, increasing sleepiness. So cannot
assume circadian rhythm is purely down to EP when living on the surface of earth.
real life application for role of EP
-Ev - Eskimos in arctic circle have daylight all summer and dark all winter. They maintained a 24hr circadian rhythm.
-Ex - Suggests humans don’t need an EZ (e.g. light) to regulate the circadian rhythm. EP = most important factor.
-L - But eskimos used blackout curtains during summer months and UV light during winter. Therefore stimulating the EZ to help maintain the circadian rhythm to 24hrs.
ways of studying the brain
P: post mortems = longitudinal case study of abnormal person when alive. triangulation of methods used to study them. Post mortem when dead - dissection of brain to see if correlation between brain damage to neural areas and difficulties in life.
Ev: Tan - Expressive Aphasia in life, found Lesion in Broca’s area in post mortem.
L: not functional brain activity. Correlation between brain area and difficulty in life.
Flawed - fMRI used in other patients with expressive aphasia and found low activity in other areas of brain, not just Broca’s.
So fMRI = better - person can be given task whilst in machine so functional brain activity is recorded whilst doing task.
more objective data, high causation. Before and ater task can be compared as control.
Criticism of fMRI
Ev: lacks temporal resolution compared to EEG and ERP’s.
fMRI scanners measure brain activity indirectly from blood flow.
One image is taken every few secs
Ex: delay between brain activity and it showing up on a scanner through blood flow.
But EEG’s show direct real time activity with no delay. The EEG skill cap with electrodes recoreds neuronal activity - action potentials from the cortex just below surface of skull.
e.g. in sleep studies, pps wired up to EEG’s which gives direct readout of brainwaves during each stage of sleep.
Not possible using fMRI - impractical and noisy to sleep in and lack of brainwave info directly from AP’s.
Criticism of EEG
Ev: lacks the special resolution that post mortems and fMRI scans have.
Ex: can’t see imagine of brain with EEG’s/ERP’s - only general readout of brainwaves.
fMRI/PET scan - can see actual brain size. This can be seen in Maguire’s study on plasticity where she was able to measure the volume of the hippocampus from the images.
Even better in post mortem - actual brain can be investigated on a microscopic and cellar level (highest special res).
L: therefore, triangulating many methods to study the brain gives us the most valid understanding of how the brain works and increases our knowledge of cognitive neuroscience.
ultradian rhythms
research support for ultradian rhythms being biologically controlled by EPs
-Ev - 9 pps stayed in a sleep lab and were woken every time the EEG brainwaves changed, using a doorbell sound. Pps asked to report what they remever. Only recalled dream in REM sleep.
-Ex - so, SCN regulates any basic rest activity cycle in the body, such as the sleep stages. We go from active to rest to active every 90 mins which is bio controlled.
-L - But small sample of 9 and have been reports of dreaming in stage 4 of sleep (non-REM), so activity isn’t specific to REM sleep.
Also, time taken to go through sleep stages can change depending on env. factors, e.g. mobile phone light.
infradian rhythms
research support for infradian rhythms being controlled by EZ’s
- Ev - Study- collected pheromones (EZ) in the sweat from the armpits of women who were due or ovulating. The sweat was placed on the upper lip of other women. Their menstruation cycle synced to ‘odour donor’.
-Ex - so, external factors such as pheromones from other women can alter the infradian menstruation cycle. Hence, EZ play a part in them.
-L - But pheromones are bio chemical messengers and syncing the inf. rhythm of menstruation could be considered evolutionary, as it ensures women give birth around the same time so can look after each others children to provide safety in numbers, ensuring a higher survival rate.
