Biological psychology

Central Nervous System
brain and spinal cord
Send messages
Brain responsible for different parts

Send and receive messages
Neurotransmitters pass messages
Cell body has ions they differ and cause action potential, goes down axon protected by myelin sheath
Voltage speeds up along the nodes de ranvier

gaps between neurons
Dendrite receptors have certain shape
Neurotransmitters only pass message if they fit shape
If blocked it is reuptaked absorbed back into the presynoptic neutron

Chemical messages between neurons
Electrical impulses travel down the axon and triggers release of neutransmitters
Dopamine – pleasure
GABA blocks messages

Recreational drugs
Cocaine – blocks reuptake of dopamine more in the synaptic gap make person feel extremely happy and pleasurable

Cannabis – blocks pre synaptic neurons so messages can’t get through effects activity of the hippocampus and impacts memory

Occipital lobe – visual

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Temporal lobe – memory
Parietal lobe – percemption
Pre frontal lobe – emotions
Limbic system – amygdala – emotions. Hippocampus – memory. Hypothalamus – motivated behaviours

Brain and aggression
Prefrontal cortex – raine et al found difference of activity between murders and non
– Bechara and VanDerLinden damage to prefrontal cortex makes someone impatient and more aggressive

Limbic system – hermans et al electrical stimulation of the hypothalamus leads to aggression
– Swantje et al smaller the amygdala the more aggressive

Brain and aggression – VESTROAR
V – lacks internal validity cannot establish cause and effect
E – raine et al murderers
S – brain scans can be subjective
A – hormones and aggression
R – only looks at the brain
A – aggression and crime
R – brain scans are reliable measures

Evolution and aggression
Selection of partner – males evolved to be bigger and stronger to hunt and protect
– infidelity can cause jealousy and aggression

Living in groups – groups allow protection to fight off a threat

Evolution and aggression – VESTROAR
V – doesn’t explain why some aren’t aggressive
E – Buss and Shackleton men try and imitate others
A – freuds psychodynamic
A – domestic abuse
R – difficult to prove scientifically
R – doesn’t explain why some aren’t aggressive

Hormones and aggression
Testosterone – aggression
Found greater in men than women
High levels links to aggression

Hormones and aggression – VESTROAR
V – cannot establish cause and effect – internal validity
E – Chang et al – fish
S – interpretation of animal behaviour
A – brain and aggression
R – only looks at one aspect
O – levels of hormones can be tested
A – why people are aggressive
R – can be tested using scientific measures

Freuds psychodynamic
Conscious level – aware of thoughts and feelings
Pre-conscious level – sometimes aware
Unconscious level – unaware of sexual desires
ID – born with/ pleasure and satisfaction – in control = psychotic
EGO – 18 months/ juggles demands to satisfy person – in control = healthy
Superego – 4 years/ morals – In control = neurotic / depressed
Catharsis – satisfying urges without violence brings emotions from unconscious to conscious
Eros – enjoy life and sexual pleasure
Thantos- death drive destruction of self and others

Freuds psychodynamic – VESTROAR
V – no supporting evidence to make scientific
E – only tested on friends and family’s
S – collected qualitative date – interpretations
A – evolution and aggression
R – only looks at the unconscious mind
A – help treat those with anger issues
R – cannot be tested

individual differences and developmental psychology
Individual – freuds notes everyone’s personalities vary
– neurotransmitters function the same but are specific

Developmental – survival of the fittest
– hormones effect development

Bio vs non bio theories of aggression
Bio = scientific , Raine et al shows brain and aggression, chang et al shows hormones and aggression
Non bio = non scientific, no solid data to support, conducted on friends and family
Both = neither says why people aren’t aggressive, both argue born with aggression, not generalisable

brain scans
CAT – X-ray of brain. Section slices, iodine injected, moving platform
– more ethical than PET, good for brain damage however fMRI better picture, injections is invasive

fMRI – brain activity/function, detects changes in blood oxygenation
– measures blood flow, non invasive however may suffer claustrophobia, may not measure what it says

PET – brain activity, radio active isotopes, measures radiotic levels, perform task
– measures what it claims, very reliable however radioactive tracer is invasive, difficult to isolate parts of the brain

Classic study – Raune et al 1997
Difference of brain activity between murderers
41 murderers, 41 non 4 females – matched pairs on age, gender and mental illness
23 brain damage, 3 drug abuse, 6 schizophrenics, 2 epileptics
Carried out a task, injected with fdg tracer, continued with 32 min task after injection then PET scans
Murderers had reduced activity In amygdala and prefrontal cortex
Links to brain and aggression- amygdala is about emotions and aggression. Prefrontal cortex is about rational thinking

Classic study – GRAVE
G – used a large sample however mostly men
R – matched pairs reduces participant variables, PET scans give reliable measures
A – applied to functioning of an individual murderer
V – lacks ecological validity artificial setting and task. Lacks internal validity cannot establish cause and effect
E – informed consent gained however injection cause cause harm

Contemporary study – Brendgen 2005
Social aggression is nature or nurture and does it lead to physical aggression
234 pairs of twins , Quebec born between 95/98
Longitundal study – 6 years
Data from peers and teachers – peers link description to child, teachers rank behaviour
Physical aggression leads to social not the other way
Physical – genes social – environemtn

Contemporary study – GRAVE
G – large sample however from same region and age
R – bias because teachers give opinion however collects quantitative data from ranks
A – help aggression in schools
V – high ecological validity done at school
E – informed consent gained from parents

Adoption studies – Mednick 2008
Criminal behaviour affected by nature or nurture
14427 adoptees I. Denmark between 1924/1947
Bio/ non bio parents examined used to work out socioeconomic status and criminal activity
20% committed crimes if bio parents did
Link between crime and genes

Adoption studies – GRAVE
G – uses a large sample however from same region
R – objective measures and standardised procedure
A – prevent adoptees committing crime
V – no internal validity hard to establish cause and effect
E – invasion of privacy

Should aggressive people be punished for their behaviour even thought they can’t help it?
Nature vs nurture
Aggression- emotion can be triggered by environment
Depressed get treated aggressive get punished

Raine et al – damage to the prefrontal cortex can’t help aggression
Social learning theory – we observe and learn behaviour so should be punished
Chang et al – high levels of testosterone lead to aggression

Correlations between age and attitude to drugs
Opportunity 15 participants both open and closed questions
Many young done drugs, above 35 don’t recommend drugs
There is a correlation

Practical – GRAVE
G – used a small sample however range of ages
R – participants could guess aim
A – change teenagers attitudes
V – high internal validity more than one interpreter
E – gained informed consent

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