Biological psychology

The central nervous system

• Made up of brain and spinal chord

• Nerves in our body send information via the spinal chord to the brain

• The brain processes this information and sends a message to the body through the spinal chord

Lobes in the brain and their function

• Frontal lobe - higher order thinking, emotional control and decision making

• Temporal lobe (side) - sound and memory

• Occipital lobe (back) - visual info

• Parietal lobe (top/back) - physical sensation

Function of neurons

• Dendrites pick up signals from sense organs/ other neurones

• The cell body collects these into one stronger signal (or not if not enough dendrites activate)

• The axon carries the electrical nerve impulse down the length of the cell

• Myelin sheath acts as an insulation to speed up the conduction of the impulse and keep it travelling in one direction

• The axon terminal is where the synapse passes the message on to the next neuron

Synaptic transmission

1. Action potential comes down axon to terminal

2. Vesicles full of neurotransmitters move to the edge of the cell and release neurotransmitters into the gap

3. The NT drifts across the gap and binds to a receptor

4. When enough are filled then a new AP/ nerve impulse starts on the next cell

5. Any used/ excess NT are reabsorbed to the pre synaptic membrane

Process of an action potential

1. Nerve cell starts at a resting period of -70mv

2. If a signal passes the threshold at -55mv it starts depolarisation (charge inside becomes positive)

3. At +40mv the action potential fires

4. After this it begins to repolarise and goes through a refractory period

Neurotransmitters

Chemicals used to carry messages across the synaptic gap but different ones do different things

Functions of neurotransmitters

• Acetylcholine - linked to memory and cognitive thought. Low levels linked to Alzheimer’s. Important for motor control and emotions such as anger and sexuality.

• Norepinephrine - responsible for fight or flight, treats ADHD. Involved in sleeping and dreaming.

• Dopamine - associated with pleasure. Linked to addiction. Linked to illnesses like schizophrenia and many other things in the body, eg controlling the menstrual cycle.

• Serotonin - happiness and good mood, along with melatonin it regulates sleep/ wake, hunger and pain. Low levels linked with depression and anxiety. Low serotonin linked to aggression, assault, arson, murder and child beating.

• GABA - suppresses the activity of the neurons it contacts, reducing the probability that they will fire

• Glutamate - involved in most aspects of normal brain function including cognition, memory and learning. Helps to increase the probability of neurons firing. Works almost like the opposite of GABA.

Addiction (world health organisation) definition

State of periodic or chronic intoxication produced by repeated consumption of drug, natural or synthetic

Signs of addiction

• Cravings

• Tolerance

• Withdrawal symptoms

• Financial trouble

• Poor judgement

The dopamine pathway

In our brain we have a reward pathway (or pleasure centre) eg the limbic system. This is sensitive to dopamine, GABA and glutamate. Whenever we do something which is pleasurable these chemicals are released and activate this area, which is what makes us enjoy them.

Olds and Milner

• Showed that there were probably pleasure centres in the brain which are part of our normal motivation system

• Rats would press a lever to receive a reward of mild electrical stimulation to this part of the brain

• They would continue to press the lever in preference to other possible rewards such as food, drink or sexual activity and would even cross a grid with a painful electrical current passing through it to reach the lever and receive the pleasurable stimulation

How drugs work in general

They cause a change to how neurotransmitters work either:

• Increasing dopamine levels in the reward areas/ blocking reuptake (so more dopamine hovers around increasing the levels)

• Increases/decreases some other neurotransmitters eg GABA

Desensitisation to drugs

If the receptor is constantly stimulated by extra neurotransmitter than it will have diminished responsiveness (caused by down regulation). This means you end up having to take more drugs.

Drug withdrawal

Group of symptoms that occur upon the abrupt discontinuation or decrease in intake of medications or recreational drugs, eg anxiety, shaking, sweating, depression, headaches

Cocaine and effects

• Blocks reuptake of dopamine and so the dopamine builds up in the synapse

• Effects -depressed, anxious, paranoia

Heroin and effects

• Binds to opioid receptors and increases dopamine release, increases euphoria

• Effects - numbing effect, decreases breathing

Alcohol and effects

• Is a depressant, increases GABA - ‘turns off nerve cells’ which increases dopamine

• Effects - balance issues, slurring, blurred vision, effects emotions

PCP and effects

• Blocks glutamate receptors which causes increase in dopamine

• Effects - anaesthetic, numbness, hallucinations, paranoia

Aggression definition

Psychological or physiological expression of anguish or anger, showing forms of anti-social behaviour

The limbic system

• Role in self preservation, eg fight or flight response

• If someone was faced with a confrontation the limbic system might lead to them creating an anger response to the perceived threat

Brain parts in the limbic system

• Amygdala - ‘source’ of emotions such as aggression. It takes in information and decides on an emotional response. People who have more activity in the amygdala tend to be higher in aggression.

• Hypothalamus - controls homeostasis in the body particularly levels of hormones such as testosterone. Aggression can be influenced by hormones such as testosterone therefore the hypothalamus controlling this ties it into the cause of aggressive behaviour.

• Pre-frontal cortex - controls emotions, self control and regulates our behaviour. Those who have less activity/ under developed/ smaller/ damaged PFC are less able to control their behaviour and emotions.

Brain activity as an explanation of aggression strengths

• Use brain scans to study areas like the amygdala which are standardised and empirical → can repeat brain scans to see if the results about brain activity and aggression are reliable

• Supported by Raine which showed that the NGRI murderers had higher activity in the right amygdala and lower activity in the PFC → theory is credible as we have evidence that differences in brain activity can effect behaviour like aggression

• Kluver-Bucy syndrome showed removing part of the temporal lobes (destroying amygdala) in rhesus monkeys led to them becoming more tame → since removing the amygdala reduced their aggression it suggests that the brain region is linked to aggression

Brain activity as an explanation of aggression weaknesses

• Too reductionist, it is too simplistic to put it down solely to biology and it can be influenced by things such as environment and the persons upbringing → activity in the brain isn’t the only factor in aggression meaning that this isn’t a complete explanation of where aggression is from.

• Social learning theory suggests that we learn our aggression through observing and imitating others → lowers the validity of the biological explanation which only looks at brain activity

• Animals aren’t the same as humans, eg differences in the PFC → results we get about aggression don’t apply to humans making explanations of how the brain influences aggression less credible

• Brain scans low in ecological validity because they use labs and scanners → results of brain activity in a lab might not tell us about how it links to aggression in a real world setting

Hormones

• Hormones are chemical messengers that transmit information around the body, carried in blood.

• Hormones are produced by glands. These glands make up the endocrine system e.g. the pituitary gland creates growth hormone and the adrenal gland creates adrenaline

Hormone explanation of aggression

• Testosterone is a male sex hormone that can influence areas of the brain such as the frontal cortex, amygdala and hypothalamus associated with aggression

• Testosterone lowers the activation threshold of the Amygdala – it takes less to activate it, so make it more active. On the level of individual neurones/action potentials it shortens the refractory period meaning that more signals can fire (more signals = more aggressive)

• Cortisol is a hormone primarily involved in stress but it has an impact on testosterone and aggression. Cortisol seems to inhibit aggression, the same way that testosterone increases it. Cortisol mediates the effects of testosterone (so your aggression is about the ratio between the two)

• Cortisol is produced when faced with stressors and low levels of cortisol have been associated with aggression.

• Adrenaline is a hormone linked to a ‘flight or fight’ reaction to a stimuli that triggers a need to be physically fast or strong - higher adrenaline might lead to someone fighting

• Serotonin is for calmness/ mood regulation - low levels might lead to higher aggression

Strengths of hormone explanations of aggression

• This explanation is measuring hormones in the blood so is empirical and objective because they can be directly measures → explanation is credible because you can directly measure the levels of hormones to see their relationship with aggression

• Beeman - castrated male mice and found that aggressiveness reduced. He later injected the mice with testosterone which re-established their aggressiveness → provides evidence that there is a correlation between testosterone and aggression.

• Edwards - Injecting female rats with testosterone made them much more aggressive compared to a control group → This provides evidence that there is a correlation between testosterone and aggression.

• Dabbs et al - measured testosterone in the saliva of 692 adult male prisoners. They found higher levels in violent offenders than in burglars and thieves (non-violent offenders) → This provides evidence that there is a correlation between testosterone and aggression.

• We can do research on animals we wouldn’t be able to on humans (and they have many similarities to us) → This is good because we can find out the influence of different hormones on aggression through specific surgery interventions we couldn’t conduct on humans.

• This theory can explain individual differences why some people are more aggressive than others through variations in hormone levels → makes it a more useful and credible explanation of where aggression comes from because it accounts for how hormones might influence people differently.

Weaknesses of hormone explanation of aggression

• Mazur et al: playing a non-aggressive game, such as tennis or chess, increases the testosterone levels of the winners and decreases the testosterone levels of the losers. Testosterone seems to be more about dominance/success than it does aggression so it might not be a direct cause of aggression

• Berman: Had people compete in a competition and the winner was allowed to give the loser an electric shock. Those who had been given a drug to increase their serotonin, however, showed significantly reduced aggression levels during the game compared to those given a placebo. Therefore Serotonin is also involved and looking at testosterone / cortisol levels isn’t the whole picture

• Cause and effect issues with the theory as most of the research about hormones and aggression are just correlational. We’re not sure whether testosterone causes increased aggression or whether increased aggression causes an increase in testosterone which means this is possible not a cause of aggression but a result.

• Reductionist- ignores other explanations such as upbringing e.g. SLT says we learn through observing others and imitating them. If this explanation is true it questions the credibility of this explanation as inherited genes aren’t the only cause of aggression

• Animals aren’t the same as humans (e.g. brain differences) e.g. differences in how hormones effect brain activity → This means the results we get about aggression don’t apply to humans making explanations of how hormones influence aggression less credible as much research might not apply to humans

Evolution

• Evolution is the impact of how inherited characteristics change throughout generations.

• ‘Survival of the fittest’ means that organisms who are suited to their environment will survive in order to reproduce e.g. the fittest genes, like those involving aggression, were passed on to aid human survival

• It is the combination between the genotype and environment that lead to the phenotype which is what is passed on through time to subsequent generations.

Evolutionary reasons humans are aggressive

• Aggression could be an evolved solution to adaptive problems so individuals act aggressively to protect themselves.

• Fighting is an evolved strategy to assert dominance on a rival.

• Aggression is useful because it deters our partners from infidelity and can scare rivals away to ensure children below to the aggressor

• Aggression has evolved to increase status against competing males to make the aggressor more attractive to the female.

• Appropriating resources like hunting, to provide food for others so they have a survival advantage.

• Aggressive behaviour may be due to inheritance of an aggressive gene combined with situational factors such as abusive upbringing.

Strengths of evolutionary explanation of aggression

• Daly & Wilson – 58 / 214 cases of murder motivated by sexual jealousy, confidence in paternity and warning to potential rivals → provides some evidence that evolution and Inheritance of aggression promoting genes might provide a credible explanation of aggression.

• Dobash and Dobash who found that violence against woman often came about through jealousy, which is an aggressive trait that could lead to gene survival → This provides some evidence that evolution and inheritance of aggression promoting genes might provide a credible explanation of aggression.

• Mazur - Males show an increase in fighting behaviours around puberty because of an increased focus on attracting mates → This provides some evidence that evolution and inheritance of aggression promoting genes might provide a credible explanation of aggression.

• Daly, Wilson, Weghorst (1982): Domestic abuse to dissuade romantic partners from infidelity. This provides some evidence that evolution and inheritance of aggression promoting genes might provide a credible explanation of aggression.

• Buss found that when men give in to women (debasement) and threaten any males around them it aids their survival of the gene pool and ensures their human development.

Weaknesses of evolutionary explanations of aggression

• There are alternative explanations behaviour is learned and not biological so evolution might not be a credible explanation → may have learned aggressive behaviour from observing and imitating other people fighting rather via social learning theory rather than an instinctive survival characteristic

• Explanations are ‘post-hoc’ (you’re looking backwards at behaviour and therefore you might see patterns which aren’t true but just look like they make sense). This means it might not be a credible explanation of aggressive behaviour as you cannot directly test the behaviours of our ancestors so can be hard to provide evidence

• The evolutionary perspective also fails to explain why some cultures such as the Yanomamo of South America seemingly require violent behaviour to achieve social status while other such as the Kung San of Kalahari see aggression as being unforgivable (Buss and Shackelford) → evolutionary theory can’t explain these differences well as all humans have evolved from shared ancestors therefore it cannot account for cultural differences

• This theory is deterministic as it suggests people have little free-will and choice in their own behaviour if it is all due to inherited genes → reduces the credibility of the theory because it doesn’t account for the full range of human behaviour e.g. choice in deciding how to behave.

Drives and motivations for behaviour

• Eros- The life instinct- The preservation and enjoyment of life.

• Thanatos- The Death Instinct- This is most commonly directed out towards other people as aggression/anger.

The topographic structure of the mind

• The conscious: part of your mind that you are aware of e.g. your thoughts at the moment and is the little part of your experience you are aware of (like the top of an iceberg)

• The preconscious: part of your mind which can be called upon e.g. memories where you can be aware of them but are not at all times

• The unconscious: largest part of your mind and contains things like unacceptable urges and desires e.g. sexual and for violence

Three parts of personality

• The Id is the INSTINCTIVE aspect of the personality. It operates on the PLEASURE PRINCIPLE. It demands immediate satisfaction and doesn't care about REALITY.

• The Super-ego is the MORAL aspect of the personality. It operates on the Morality Principle. It develops due to the moral and ethical restraints placed on us by our parents/caregivers

• The ego, It is the LOGICAL aspect of the personality. It operates on the REALITY PRINCIPLE. It can make conscious and rational decisions that reflect the demands of instinct (Id), morality (Superego) and external reality (Environment)

• The ego balances the Id and the Super-egos demands

Aggression according to psychodynamic approach

• Freud believes that your unconscious is an active entity and is constantly influencing your behaviour.

• You have a drive called Thanatos (death instinct) which is the source of aggression/destruction within you.

• You have three parts of your personality the Id which is responsible for your instinctual behaviours and wants to please itself (pleasure principle), in the case of aggression it would like to give in to the aggressive impulses.

• Aggression can also be caused by frustration of its desires, if it doesn’t get what it wants then it gets aggressive.

• The Super-ego is your conscience (morality principle) and tries to control your aggressive impulses, you get this from your relationship with your parents at a young age and would be the thing which tries to stop you acting aggressively.

• The ego is the part of your mind in the middle which balances the two out, one of the ways it does this is through defence mechanisms like displacement e.g. you have been arguing with your parents and when you are on a driving lesson go into a bout of road rage.

• Catharsis is a way of venting aggression, it involves releasing internal emotions such as anger or frustration.

• Displacement is when a person uses an alternative object to satisfy an impulse, such as a punch bag to displace aggression

Strengths of psychodynamic approach

• Verona and Sullivan support this theory when they found that when participants administered either aggressive or non aggressive responses (after being made angry), heart rate was found to have reduced in those administering the aggressive responses → shows evidence that catharsis is a credible explanation of aggression as by being aggressive they produced a calming effect.

• Bresin et al. found that adaptive forms of aggression could create a calming effect and empower participants with the skills to regulate anger in the future. So psychodynamic explanations have practical application so it is useful- it also means that since this works the psychodynamic explanation is a credible one for the cause of aggression.

• This theory can explain individual differences why some people are more aggressive than others through variations in Id and Superego → makes it a more useful and credible explanation of where aggression comes from because it accounts for how differences in these components might influence people differently

• Takes into account both nature and nurture (nature-everyone has these things e.g. the Id develops naturally but your life events e.g. how strict your parents are shapes the superego). This makes it a more complete explanation of aggression since the Id and Superego take both facets into account so it is less reductionist.

Weaknesses of psychodynamic approach

• The concepts like the Id, Superego etc cannot be empirically tested as they do not exist as a specific region of the brain → we can question its credibility since the components used to explain aggression cannot be measured so Freud’s ideas lack scientific credibility.

• Bushman: Those who took part in a ‘cathartic’ activity (venting) were actually more aggressive than those who didn’t have a chance to release their aggression. This means that catharsis is not supported as a role in aggression meaning this theory is a credible one.

• Largely determinist- unconscious processes you have no control over cause our aggression. This makes it less credible as it ignores the influence of free-will on your decisions of aggression by only focusing on unconscious processes like the Id.

• Biological psychology provides evidence that aggression is not a death instinct but has biological roots, e.g. Dabbs found high levels of testosterone in male prisoners → shows that looking at the unconscious is not a complete explanation of what causes aggression.

• It ignores other explanations such as upbringing e.g. SLT says we learn through observing others and imitating them. If this explanation is true it questions the credibility of this explanation as the Id, Superego etc aren’t the only cause of aggression

PET scans

• Investigate brain activity when a human is doing a task

• Involves injecting a radioactive tracer into the participant

• This irradiates the glucose supply in the brain

• When an area is active it gives off more gamma rays which are detected

• Areas of high energy will be red/ orange

• Areas of low energy will be blue/ green

PET scans strengths

• Valid measurement of brain activity as they provide a detailed image of brain activity during the completion of a task → we can get a valid measurement of the brain activity when in use making it useful and valid

• Raine found differences in murderer brain activity using PET scans showing their contribution

• Brain scans can be repeated easily as they use standardised procedures and technology → able to test for reliability in findings about human behaviour

• Brain scans are empirical as they are directly measuring things about the brain which can be measured, eg glucose metabolism → makes them more valid as we are directly measuring brain activity/ structure

PET scans weaknesses

• Involve injecting a radioactive glucose tracer into participants which could be dangerously → limits the number of times that it can be used with the same participants because it could be harmful

• Lacks ecological validity as it takes place in an artificial setting of a scanner → results we get about the brain might not be representative of how it would function in a real life setting (as the scanner/ process might influence the brain)

fMRI scans

• Records brain activity and produces an anatomical picture of the brain

• Uses magnetic and radio waves

• Person lies in a large cylinder in which they must lie perfectly still

• Magnetic and radio waves are then sent through the body

• Blood flow increases in active areas and requires more oxygen

• Oxygen is carried to the areas via haemoglobin in red blood cells

• Haemoglobin when it is full of oxygen repels the magnetic field but follows the field when it is deoxygenated and it uses these changes to build up an image

fMRI scans strengths

• fMRI is a non invasive method of looking at the brain → ethically more acceptable than for surgery or any other forms of invasive treatment

• Can be repeated easily as they use standardised procedures and technology → able to test for reliability in findings about human behaviour

fMRI scans weaknesses

• Involve magnets and radio waves which could be dangerously to those with pacemakers → limits the use of fMRI scans to certain people as it could be harmful due to it effecting their heart functioning

• Lacks ecological validity as it takes place in an artificial setting of a scanner → results we get about the brain might not be representative of how it would function in a real life situation

CAT scans

• Use multiple x-rays to produce a cross sectional image or brain regions

• Done at many angles which can then be put together into a full picture

• Lets us see the structure of the brain such as if there is damage/ tumours

CAT scans strengths

• Valid measurement of brain structure as they provide a detailed image of the brain → we can get a valid measurement of the brain structure when in use making it useful and valid

• Non invasive method of looking at the brain → ethically more acceptable than surgery or any other forms of invasive treatment

• Brain scans can be repeated easily as they use standardised procedures and technology → able to test for reliability in findings about human behaviour

• Brain scans are empirical as they are directly measuring things about the brain which can be measured, eg structure → makes them more valid as we are directly measuring brain structure

CAT scans weaknesses

• Involve x-ray radio waves into participants which could be dangerously → limits the number of times that it can be used with the same participants because it could be harmful

• Can be difficult for those with claustrophobia because of the enclosed space → could be upsetting and this would make it difficult to get a good picture meaning it might not be effective/ applicable for everyone

• Brain scans lack ecological validity as it takes place in an artificial setting of a scanner → results we get about the brain might not be representative of how it would function in a real life situation

Aim of Raine

Aimed to see if the brain activity of murderers/ people pleading not guilty of murder through diminished responsibility was different to that of non-murderers

Sample of Raine

• 41 murderers pleading not guilty by reason of insanity

• 41 controls

• Matched on age, gender and 6 in each had schizophrenia

• 39 men, 2 women in each group

Procedure of Raine

• Each participant carried out a practice test (a visual targeting test)

• 10 minutes later a FDG tracer was injected then completed the visual targeting task again

• PET scan was carried out after 32 minutes when the task was finished to see how active the brain had been in the prefrontal cortex

Cortical results of Raine

• Prefrontal lobe - lower glucose metabolism in murderers

• Parietal lobe - lower glucose metabolism in murderers

• Temporal lobe - no significant difference

• Occipital lobe - higher glucose metabolism in murderers

Sub-cortical results of Raine

• Corpus callosum - lower glucose metabolism in murderers

• Amygdala - reduced activity in the left amygdala and more activity in the right amygdala in murderers

• Medial temporal lobe including the hippocampus - reduced activity in the left amygdala and more activity in the right in murderers

• Thalamus - greater right thalamus activity in murderers

Raine conclusion

Areas that had abnormal activity were associated with lower self control/ increased aggression. Brains of murderers were significantly different from the brains of non-murderers.

Raine strengths

• Reliable standardised procedure, eg same timings and machines → brain scans of NGRI participants with similar PET scans can be repeated to test for reliability of findings about brain differences

• Matched pairs design with the NGRI and control group being matched on things like schizophrenia which reduces participant variables → makes a more valid comparison between the NGRI and normal participants without things like schizophrenia impacting the results so we can get a better understanding of the key brain differences

• PET scans used on the NGRI participants are empirical as they directly measure the glucose metabolism of the brain → makes the results about NGRI brain activity differences more valid as it can be directly measured

• 41 is a large sample for this sort of study (PET on NGRI) which makes it more representative than most which have been conducted

Raine weaknesses

• Small sample if 41 NGRI makes it less generalisable → their results about differences in brain activity eg. lower amygdala activity may not be applied to a wider population

• All NGRI - doesn’t apply to ‘non-insane’ criminals so it is less generalisable → results we get about brain differences may not be that useful in explaining aggressive behaviours in others

• Some things which cannot be matched in the NGRI and control eg. brain damage → makes it less valid because these factors might influence the brain activity which was recorded in the NGRI participants lowering validity

• Low ecological validity due to the PET scanning process which doesn’t reflect what the brain would be doing in a real life setting → results they find about the NGRI brain activity may not be applicable to real world brain functioning when committing their crime in real life

• Might be ethical issues like informed consent and withdrawal as the participants are NGRI murderers → their ‘insanity’ might mean that they can’t fully comprehend and agree to take part in the study, making the study less ethical

• Ethical issue with protection from harm due to the NGRI patients being given an injection and being off meds for two weeks → could cause issues with the NGRI patients mental health and the injection is invasive making the study less ethical

• Subjective interpretation on some of the brain scans was needed at the time, several areas might ‘light up’ at any time, eg from physical sensation and so Raine has to make interpretations on the importance and meaning of the results from PET scan → this makes the results about brain activity less valid

Aim of Brendgen

To find out what extent the variance of social aggression is explained by genetic, shared environment, or non-shared environmental factors

Sample of Brendgen

• 322 twin pairs from Quebec

• 234 completed the full study, physical resemblance was used to identify them as MZ or DZ at 18m of age

• For 123 twin pairs we obtained DNA and showed a 94% agreement with their assignment

• They were followed from birth until the age of 6 (5, 18, 30, 48 and 60 months and 6 years) gathering data which is when the main part of the study took place with the remaining 234 twin pairs

Procedure of Brendgen

• Questions were given in either English or French as needed for that teacher (across 409 classrooms)

• Teachers rated the children’s level of social aggression and physical aggression. With questions like ‘‘tries to make others dislike a child,’’ ‘‘becomes friends with another child for revenge,’’ and ‘‘says bad things or spreads nasty rumours about another child.’’

• With regard to physical aggression, the teachers indicated to what extent the child ‘‘gets into fights,’’ ‘‘physically attacks others,’’ and ‘‘hits, bites, or kicks others.’’ Responses were given on a 3-point scale (never, sometimes, often). These were from Preschool Social Behaviour Scale (PSBS-T)

• The children were then asked to circle the photos of three children who best fit a behavioural descriptor

• Two behavioural descriptors were used for social aggression (‘‘tells others not to play with a child’’ and ‘‘tells mean secrets about another child’’) and two others for physical aggression (‘‘gets into fights’’ and ‘‘hits, bites, or kicks others’’).

Results of Brendgen

• There is a much higher correlation (nearly double) from MZ to DZ twins on Physical aggression - down to genetics

• MZ and DZ twins had similar ratings on social aggression - down to environment

• The correlation seen between Physical and Social aggression (0.79) in twins was mainly due to genetics rather than shared environment.

• MZ have a higher concordance than DZ for physical aggression

Conclusions of Brendgen

• Genetic and environmental influence - About 50-60% of the difference in physical aggression was due to genes and the rest non-shared environment. In Social aggression this was only 20% genes and 60% non-shared environment.

• Children seem to move from physical to social aggression as they age (possibly to avoid punishment, possibly because of developing skills).

Strengths of Brendgen

• There was a 94% agreement between zygosity based on physical likeness and gene markers showing reliability for testing genetic links to aggression → makes their findings more valid as they were making accurate comparisons between the concordance of aggression between MZ and DZ twins

• Large sample for twin studies of 234 twin pairs so is more generalisable → the results about physical and social aggression are more generalisable to a wider population.

• It was good they used measures by both the teacher and the students because it allows them to check the scores against each other getting inter-rater reliability → we can check the reliability of the results comparing the teacher and child scores.

• Children were told not to share their answers which reduces demand characteristics → makes the results about the concordance of aggression between the twins more valid.

• A study which is standardised (questions on the PSBS-T, procedure etc) and so is easy to repeat → we could repeat the procedure to test the results about physical and social aggression for reliability

• Consent was gained from responsible adults (the teachers)

• Quantitative data was gathered in the ratings by the teachers and the number of times chosen by the kids which allows statistical analysis → we can check if the results about aggression differences were due to chance

• Brendgen et al. (2005) used a creditable questionnaires like the Preschool Social Behaviour Scale (PSBS-T) to measure the aggression in the twins → This means the measure had already been established as a valid measure of aggression

Weaknesses of Brendgen

• Sometimes, often and never is subjective judgement which might lower the validity as different teachers may interpret these words differently

• The study is on 6 year olds which makes it not generalisable → results about genes/ environment on aggression might not apply to adults

• Quantitative data doesn’t provide lots of depth e.g. reasons for aggression in different situations etc. This means we don’t get a lot of understanding on how/why the children demonstrated their aggression

• In Brendgen study not all the twins were DNA tested for identicalness. This means some of the twins may have been in the wrong group making the results less valid (they weren’t comparing MZ compared to DZ correctly.

Aim of Kety

To find out if there is a genetic basis for schizophrenia and to see if there is a higher rate of schizophrenia-related illness among biological relatives than adoptive relatives.

Variables of Kety

• IV: Schizophrenia sufferers and a Control Group with no history of mental illness.

• DV: The researcher's measured the prevalence of schizophrenia-related mental illness among family members

Sample of Kety

• Group 1: 34 schizophrenic patients (two of them MZ twins) taken from the Danish Adoption Register for Copenhagen. They were aged 20-43.

• Control: 33 mentally-healthy Controls were selected from the Danish Adoption Registry. They were matched to the schizophrenic patients on age, gender, the age at which they were adopted and the social class of the adoptive family.

Procedure of Kety

• Kety used the Danish family records to locate adoptive and biological relatives of all the participants.

• He tracked down 463 relatives and used the mental health register to assess their mental status.

• A panel of 4 Danish psychiatrists used the medical records to diagnose the family members.

• This was a "blind test" because the psychiatrists did not know whether the records were from an adoptive or a biological family member.

• Once the diagnoses had been made, the identities were revealed and they were assigned to adoptive family groups (IA and CA) or to the biological family groups (IB or CB).

• In 4 cases, they couldn't reach a conclusion and these relatives were dropped from the study.

Results of Kety

• Found more signs of schizophrenic spectrum disorders in the index participants biological family than their adoptive family

• Found more spectrum disorders in the index participants biological families than in the controls biological families 8.7% vs 1.9%

Conclusion of Kety

There seems to be a genetic component to schizophrenia. Schizophrenic adoptees were more likely to have schizophrenia in their biological family than their adoptive family. Their biological families were more likely to have schizophrenia than the families of Controls.

Strengths of Kety

• This study has a fairly large sample for an adoption study on Schizophrenia (as adoptees with Schizophrenia are rare) and covers a range of ages, from teenagers to men and women in their 40s → makes the results about the nature and nurture of Schizophrenia more generalisable

• Kety developed a very reliable procedure (of having the doctors rate the patients) and they replicated it many times. Since they got similar findings, this is test-retest reliability about the influence of genetics on Schizophrenia.

• The study has high inter-rater reliability as there were 4 Psychiatrists doing the ratings for Schizophrenia in family medical records. Relatives were assigned to categories when these psychiatrists agreed. There were only 4 cases where the psychiatrists could not agree and these were removed from the study.

• The participants in this study were not directly approached: only their data was analysed by the researchers and this could be done under Danish laws without needing consent from the participants.

Weaknesses of Kety

• Ethnocentric- all of the SZ adoptees and their families from one location and culture (Denmark) → the results about how genetics influences Schizophrenia might not apply to a wider population from other places

• “Schizophrenia spectrum“ is a catch-all category / umbrella term that doesn’t measure Schizophrenia directly → This reduces the validity of the findings as we might not be really measuring Schizophrenia any more.

• Their medical records of the family members were accessed without their approval and their data used in the study. There are issues with informed consent since the family members didn’t agree to be studied making this unethical.

• Kety may have created the impression that schizophrenia is genetically heritable so it is socially sensitive. This may have led to stress, anxiety and prejudice for people from families with a history of mental illness

Individual differences in brain activity

Some people have a damaged/ less active pre-frontal cortex which leads to issues controlling behaviour

Individual differences in psychodynamic

People have differing strengths in things like superego from parents or differences in id → this leads to differences in behaviour like aggression

Individual differences in hormones

Levels of testosterone can lead to differences in aggression, some people have higher levels which has a relationship with higher aggression

Individual differences in drug addiction

Some people are more prone to addiction due to biological factors

Individual differences in Kety

Genetic differences between people might influence their proneness to developing schizophrenia

Human development in hormones

During puberty, hormones have an effect on behaviour, eg more testosterone. It changes physical structure of the body and has an impact on reproductive systems.

Human development in evolution

Evolution via natural selection where traits beneficial for survival have been passed on/ shape the species, eg language development, larger brains for more intelligence

Human development in brain structure

Prefrontal cortex doesn’t develop into later in life and as such effects behaviour - people get better at self control and emotional regulation etc as they age

Human development in psychodynamic

Superego develops during early childhood

AO1 of key question: how effective is drug therapy for treating addiction

• Addiction to drugs costs society in terms of crime and NHS costs so needs to be treated.

• In the UK theres approx 610,000 people addicted to drugs

• Substitute prescribing- giving some medication or another which reduces the physical effects of the heroin

• Methadone is a replacement drug that reduces cravings for heroin so could stop addicts offending for access to heroin.

• Methadone reduction programmes can discourage abstinence from the heroin so cost society more in economic and social costs.

• Buprenorphine is a common one. It helps avoid the withdrawal effects of coming off the drug but provides less of a ‘high’ so it is less addictive

• Heroin changes the brain and body so any treatment needs to also have a biological basis.

• The national institute for drug abuse calls addiction an illness and explains that there are many features of drug addiction which could be seen as a symptom like cravings and compulsion to seek drugs

• An alternative argument we might want to think about is counselling: It is very beneficial to engage in counselling to determine why you began abusing drugs in the first place. If those issues are not addressed the chronicity of drug misuse is reinforced at the expense of your long-term recovery It is very beneficial to engage in counselling to determine why you began abusing drugs in the first place.

AO2 of key question

• Heroin binds to opioid receptors in the brain which suppresses physical pain. This chemical effect of heroin slows the motor functions which is why you feel so relaxed and out of it when you’re taking heroin.

• Over time you get a tolerance because your receptors desensitise (need more heroin to get the same feeling)

• If you try and stop, you get cravings and withdrawal which makes you want to take more

• Methadone mimics the action of heroin at the synaptic level through dopamine and endorphins.

• Reduction of the methadone doses means the user will experience withdrawal symptoms such as cramps and vomiting so can lead to relapse.

• Buprenorphine binds to the opioid receptors, however, without a perfect fit. As a result the Buprenorphine tends to occupy the receptors without all of the opioid effects (without the euphoria). Over time, the dose of buprenorphine is gradually reduced until it can be stopped completely

• PCP blocks glutamate receptors - causes psychosis

AO3 of key question

• It has been shown to be effective in treating heroin addiction (West et al, 2000)

• Jones (2004) Buprenorphine prevents withdrawal, allows for a more individual treatment process and has less chance of overdose

• Marteau et al found it 6 times safer than methadone

• Alexander et al (1978) showed that substitute prescribing may not be needed. Rat park took drug addicted animals and put them into a lush and exciting social cage, over time they weaned themselves of their addiction because their environment replaced the euphoria they got from the drugs

• However, this is an animal study and therefore the results gained from the animals may not be applicable to humans

Aim of practical

To conduct a correlation to the relationship between testosterone (shown by 2D:4D ratio) and aggression (shown via aggression questionnaire).

Procedure of practical

• Sample of 16 student via opportunity sample from a psychology class in Newcastle

• Completed questionnaire asking 12 questions about aggression and measured on a 7 point scale

• Measured the length of ring finger and index finger and measured the ratio between the two

Conclusion of practical

No significant relationship between finger ratio and aggression score/84

Strengths of practical

• The sample used both males and females in the finger ratio measures/aggression questionnaire making it more generalisable. This means the results would be more representative about the correlation between finger ratio and aggression in a wider population.

• The questionnaires about aggression and the finger measures are standardised which means it can be easily repeated. This is good because the procedure can be repeated to see if the results about the correlation with finger ratio and aggression would be the same.

• A strength is it used quantitative data from the aggression questionnaires which allows for statistical testing/analysis. This is good because we can to see if the results about aggression and finger ratio are due to chance

• The study is ethical as participants knew we were measuring their aggression levels and their finger ratio as a proxy for testosterone when they consented. This means we have consent for the research as participants were fully aware of the purpose and that we would discuss their aggression

Weaknesses of practical

• This has small opportunity sample from the same sixth form college in the north east completing the aggression questionnaire so not generalisable because they might share characteristics. This is a problem because the results about the relationship between aggression and finger ratio might not be applicable to non-teenagers.

• A problem is there might be social desirability and demand characteristics in the questionnaire (about aggression). This is an issue because the results about the correlation between finger ratio and aggression might be less valid if people lie about their aggression

• 5 point scales used on the aggression questionnaire can be subjective in interpretation e.g. ‘4’ might mean different things to different people. This is an issue because the results about the correlation between finger ratio and aggression might be less valid if people interpret the aggression scores differently

• Finger ratios may not be a valid measurement of testosterone as it is just a correlation itself. This might mean that the results about the correlation might not really be telling us about testosterone and aggression making the findings less valid.

• Taking part in the study might have been upsetting for some participants to answer questions about their own temper/aggression. This means the study has breached the ethical guideline of protection from harm because of the psychological harm linked to understanding their aggression