biological AO1s

• Raine et al

  AIM: study brain activity in NGRI killers by using PET scans - hypotheses = NGRI killers will show abnormal activity in brain areas associated with violence eg PFC, amygdala, hippocampus

  METHOD: 2 groups - control and experimental, 41ppts in each - 39male, 2 female, 6 schizophrenic, similar average age, independent groups design (despite ppts being matched by age and gender), opportunity sample, all 2 weeks medication free

  PROCEDURE: each ppt injected with the radioactive PET tracer, then completed a continuous performance task for 32 minutes, PET scan conducted

  RESULTS: NGRIs had lower activity in corpus collosum, left amygdala and left temporal lobe, has higher activity in right amygdala, right temporal lobe and right thalamus

  CONCLUSION: is a link between brain structure and aggression, murderers have impaired function in brain areas identified previously as involved in violence, dysfunction of a single brain area can't explain violence on its own
• bredgen

  AIM: investigate aggression in MZ and DZ twins to find - extet social and physical aggression is explained by genetic an environmental influences

  METHOD: twin study, correlation study, 234 pairs of twins from QNTS used

  PROCEDURE: ratings taken from 1- teachers who rates social and physical aggression of each child on a three point scale and 2 - peer ratings where classmates chose three photos from a book of all children who best matched descriptions of behaviours. correlation test then performed

  RESULTS: higher correlation between MZ pairs on physical aggression than DZ airs in teach and peer ratings, social aggression roughly equally correlated in both. teachers rated boys more physically aggressive and girls more socially,, girls rated boys more on both

  CONCLUSION: physical aggression more genetic, social is more due to environmental factors. physical aggression may lead to social aggression but not the other way round
• psychodynamic theory

  . three areas in the mind: the conscious (thought s we are aware of and control). preconscious (thoughts we may be aware of due to dreams and slips of tongue), and unconscious (thoughts we are unaware of and repressed material - these can directly influence our behaviour and lead to underlying causes of aggression

  . have innate drives from the Eros (life instinct) and Thanatos (death instinct) - aggression occurs when we direct the Thanatos away from us to protect ourselves and onto others

  - are 3 parts to personality - Id, Ego, Superego:

  Id = operates on pleasure principle, demands immediate gratification, no moral principle, present from birth.

  Ego = works on reality principle, is rational and logical to mediate desires of Id and superego, develops around 2 yrs. Superego = operates on morality principle, represents our moral sense of right and wrong, develops around 5 yrs

  . developmental issues of ego or superego means urges no longer remain in unconscious mind as Id is in control = aggression

  . ego has defense mechanisms to control this eg displacement, reaction formation, denial, repression

  .Catharsis = process of releasing negative energy from mind by venting and satisfying our violent impulses in a safer way - preventing catharsis can cause a build up of energy which results in destructive aggression.
• evolutionary theory

  . certain behaviour eg aggression has developed due to evolutionary factors

  .evolutionary psychologists look at fossils to understand the EEA to find out what type of behaviours may have been adaptive to match them to current behaviours

  . in the EEA aggression may have been useful for humans to have as it increased survival and reproductive success

  . natural selection = the process where organisms better adapted to their environment survive and reproduce more successfully due to better genes so these good genes are passed on (survival of the fittest)

  . sexual selection = a form of natural selection where individuals that are successful in attracting mates out-reproduce others in population

  . evolution = the changes in the heritable characteristics of biological populations over successive generations

  . aggression may have been used for gaining territory and resource so the more aggressive would survive, or in mate selection where females chose good, strong, aggressive mates = competition for mates has driven masculine attraction

  . explains higher aggression n men as they needed to protect family and fight, lower in woman as would have been an evolutionary disadvantage and needed to stay home look after offspring
• brain structure


  .brain made up of many lobes and structures some of which have links to aggression

  . prefrontal cortex regulates behavior and governs social interaction, can delay gratification of an impulse by inhibiting messages from amygdala - damage to it reduces levels of inhibition of amygdala = high aggression

  .Hypothalamus regulates responses to emotional circumstances, maintains homeostasis + regulation of hormones - damage to it results in inappropriate responses to perceived threat, more testosterone released

  . Amygdala is center for emotions, behaviour + motivation, recognises threats and triggers aggressive responses to them - damage to it can make some
• hormones

  hormones are biochemical messengers that have a slow but widespread effect.

  . testosterone is an androgen and is found to cause aggression, dominance, competitiveness. prenatal and around birth exposures are found to affect brain development eg in amygdala = aggression more likely as adult,
• synaptic transmission

  . neurons are separated by a synaptic cleft

  1) process starts with an action potential - electrical impulse triggers release of NTs from vesicles in axon

  2) NTs diffuse as chemicals across the synapse

  3) fit into the matching receptor sites on the post synaptic neuron and signal gets converted back to electrical

  4) NTs remaining in synapse are reabsorbed into presynaptic neuron (reuptake) and process repeats
• effect of drugs

  . we have the mesocorticolimbic pathway - causes to feel rewarding feelings and encourages repeating behaviours, operates on dopamine - drugs hijack the system

  . stimulants eg cocaine = increases NT activity by increasing dopamine in synaptic cleft by blocking their reuptake = prolonged effect of the NT on postsynaptic neuron

  . depressants eg alcohol = decreases NT activity, increase activity of GABA which binds to glutamate receptors, prevents glutamate binding = deceased effect of glutamate

  . Hallucinogens eg LSO = act on serotonin receptors, release more serotonin in different brain areas
• addiction withdrawal system

  drug taken = increases dopamine in reward pathway = feel good - brain reactions to increase of D and downregulates its own natural production of it

  drug effects wear off - person has less dopamine than normal = fells down and depressed = motivates them to take more

  person takes more to reproduce first feeling - repeated use = further downregulation of D production - brain adapts so now doesn't operate normally without the drug

  stop taking drug = lack of dopamine = depressed and low = withdrawal = keeps taking drug to avoid this - addiction
• neurotransmitters


  . are chemical messengers that act between neurons

  . can be excitatory on inhibitory depending on effect they have on neighboring NTs

  . serotonin = causes inhibition in postsynaptic neuron = makes neuron more negatively charged and less likely to fire

  . dopamine = causes excitation on postsynaptic neuron by increasing its positive charge = more likely to fire

  . summation = the adding together of signals - the firing of the postsynaptic neuron depends on the summation of the charges received
• twin studies


  . twins ae compared to see if behaviour is genetically or environmentally based

  . psychologists compare behaviour between groups of monozygotic twins and dizygotic twins using concordance rates or correlation

  . assumption that both tin types grew up in same environment so only difference is how genetically related they are

  . if behaviour is entirely genetic we expect MZ twins to have 100% concordance rate

  EXAMPLE: Gottesman and shields - investigated genetic basis of schizophrenia - 57 twin pairs used (opportunity sample), found if one MZ twin had schizophrenia the other would be 42x more likely to have it than someone in general pop and if one DZ twin had it the other same sex twin would be 9x more likely
• adoption study


  . adopted children are compared with their biological relative and adoptive relative - if more similar to biological the behaviour is likely more genetic, of more similar to adoptive then behaviour is likely more environmental

  EXAMPLE: Heston - aimed to see how many adopted children of biological mothers with schizophrenia would also develop it, took 47 adults adopted at birth with schizophrenic mothers and 47 with mentally healthy mothers, were assessed to see for development of it, found 10% of adopted had developed it - matched data which showed risk of developing it if one parent had it was 10% - concluded findings support influence of genes in schizophrenia
• CAT scans


  . a scanner slowly rotates around person, x rays and multiple beams pass into body

  . information gathered is interpreted by a computer

  . detailed cross section images are produced

  . useful for detecting brain damage and finding position of tumors, doesn't give info on brain functioning
• PET scans


  . patient injected with small amount of radioactive material - tracer

  . once absorbed into blood stream a continuous performance task is given to stimulate brain and encourage activity

  . as brain works tracer is used up as energy in brain and emits positrons

  . this creates gamma rays which the scanner picks up

  . coloured image produced - red and warm = high activity, blue and cool = low activity
• fMRI


  . brain activity is associated with blood flow in the brain - this activity is used to gather info and produce image

  . head placed in scanner (large powerful electromagnet)

  . inside magnetic field the nuclei within H atoms in water align themselves with direction of magnetic field

  . as neural activity in brain increases, blood flow also increases to keep up with O2 demands

  . O2 carried in Hb which repels a magnetic field but when deoxygenated it follows direction of field - these changes are detected to make image

  . scanner sends info to computer, generates map of activation