Biological Psychology

Edexcel

STRENGTHS OF EFFECTS OF RECREATIONAL DRUGS

Weinshenker & Schroeder (2007): Empirical Support

• Lesioning the mesocorticolimbic pathway in mice brains means neurons are unable to produce levels of dopamine normally associated with reward.

• Showed cocaine’s effects are due to dopamine activity in brain’s reward system of mice brains.

Application to better treatments for addiction:

• Scientific knowledge of heroin being an agonist that binds to opiate receptors led to the development of Naloxone, an antagonist drug that does not produce the rewarding euphoria associated with heroin use.

Youngentob et al. (2007) also show that children born with FAS are also more likely to grow up to be alcohol users; they acquire a predisposition towards alcohol addiction. Heroin is even more addictive than alcohol and babies of heroin-users can be born addicted.

WEAKNESSES OF EFFECTS OF RECREATIONAL DRUGS

Validity of non-human animal studies:

• Human brain is more complex than animals

• Isolating the effects of one neurotransmitter oversimplifies the process as the effect of recreational drugs on transmission can’t only be explained by one mode of action

Competing Argument → Effect of recreational drugs: Volkow et al. (1997)

Used PET scans to track the activity of dopamine transporters during a cocaine-induced high. Subjective experience intensified as more dopamine transporters were occupied by cocaine and declined as they became less active.

This supports the idea of CNS transmission for drug effects on humans.

Papez (1937) & MacLean (1952)

Link between limbic structures and aggression:

Role of the limbic system and amygdala plays a central role in assessing & responding to environmental threats by regulating emotional behaviour.

Coccaro et al. (2007)

Studied people with IED (Intermittent explosive disorder) and fMRI scans showed high levels of amygdala activity when viewing angry faces.

• Explains the association between amygdala reactivity and aggression because an angry facial expression can be seen as a threat

Role of the OFC:

• Amygdala functions in tandem with the OFC, which is responsible for higher cognitive functions like rational thinking and decision-making.

• In aggressive patients - activity in the OFC is reduced, which disrupts its impulse-control function.

Raine et al. (1997)

• Found greater glucose metabolism in amygdala and abnormally low metabolism in OFC and PFC from PET scans of murderers with reactive aggression.

Denson et al. (2012)

Proved that decreased serotonin reduces self-control, causing more impulsive behaviour.

Virkkunen et al. (1994)

Levels of serotonin breakdown product in cerebrospinal fluid of violent impulsive offenders was significantly lower than non-impulsive offenders. This could be from sleep irregularities.

Seo et al. (2008)

Serotonin hypo-function and dopamine hyper-function causes aggression and impulsivity.

STRENGTHS OF STRUCTURE OF THE BRAIN AND AGGRESSION

Pardini et al. (2014) - Support from Longitudinal Research

Strength for structure of brain & aggression: Found that 56 males consistently behaved aggressively like engaging in serious criminal violence for 20 years since 6 or 7 years of age. fMRI brain scans found a strong negative correlation between levels of aggression and amygdala volume, supporting the influence of amygdala.

Verhoeven & Tuinier (2007) - Application to understanding aggression

Serenics (type of serotonin agonist drugs) had significant anti-aggressive effects in animals and humans. Can reduce aggressive behaviour with minimal side effects, benefiting society.

Gao et al. (2010) - Highlighted the role of the amygdala in fear conditioning. Amygdala impairments can lead to dysfunctional fear conditioning so individuals may be unusually aggressive.

Wong et al. (1997) - used MRI scans with 19 violent male criminals, they found the volume of the amygdala was smaller in the violent criminals compared to controls, supporting brain structure as a factor involved in violent offending (1).

Egger and Flynn (1963) - introduced a rat to the cat's cage and found that the two animals would ignore each other. However, when the amygdala was electrically stimulated, the cat immediately attacked and killed the rat. This is predatory aggression. Egger & Flynn found that stimulation of a different part of the amygdala caused the cat to ignore the rat and attack the experimenter! This is affective (emotional or fear-based) aggression.

WEAKNESSES OF STRUCTURE OF THE BRAIN AND AGGRESSION

Correlational Research

Impossible to establish whether a particular structure or function is a cause or effect of aggression.

Competing Argument → Researchers use drugs to increase serotonin activity. Berman et al. (2009) - participants given paroxetine gave fewer and less intense electric shocks to others.

Darwin (1859)

Process of natural selection and survival of the fittest where environment selects desirable traits for survival and reproductive success. Only organisms best able to adapt to demands of the environment can transfer their genes to offspring for successive generations.

Wilson & Daly (1996)

Guarding partner:

Direct guarding involves male vigilance over a partner’s behaviour

Steiner (2016)

Protecting offspring where females are just as aggressive as males.

STRENGTHS OF EVOLUTION AND NATURAL SELECTION THEORY

Manson & Wrangham (1991) - Gender Differences

Chimpanzees - Explained why males are more aggressive than females, which was desirable.

• Males are better hunters

• Cooperative females helps them protect themselves and their offspring

Competing Argument → Correlational research cannot rule out effects of other factors on aggressive behaviour, so cause-and-effect conclusions cannot be drawn.

Buss (1989) - Application to reproductive behaviour

Across 33 countries, males preferred younger, more attractive and chaste women. Women preferred older, wealthier and ambitious men.

WEAKNESSES OF EVOLUTION AND NATURAL SELECTION THEORY

Wolfgang & Ferracuti (1967) - Cannot explain cultural differences

Kalahari aggression was discouraged whereas aggression was encouraged in Yanomami (accepted behaviour to gain status in their structured society).

Sigmund Freud

Psychodynamic theory:

Iceberg analogy - unconscious mind, urges and desires.

1. The conscious mind is that part of the mind we are aware of. It can be compared to the part of an iceberg that is above the water. It contains the thoughts we are currently thinking at any given moment.

2. The pre-conscious mind is the part of the mind we are occasionally aware of. It contains remembered dreams, feelings that haven't been put into words and memories that can be recalled into the conscious mind without help.

3. The unconscious mind contains instincts and desires, fears, motives, most of our dreams and memories that have been repressed because they are too painful.

Personality:

1. ID - Instincts, pleasure principle (sex, thirst, hunger): The id resembles the function of the limbic system in the human brain: this is the brain's "emotion centre" and the source of our appetites, fear and aggression.

2. Superego - morality principle: The ego resembles the function of the pre-frontal cortex in the human brain: this is the brain's "decision-making centre" which handles messages from the limbic system and decides how to act on them.

3. Ego - Reality principle, satisfies desire of id and superego realistically: The super-ego straddles the conscious and the unconscious mind. It is based on "the morality principle" and acts as "the voice of conscience". It tells the ego whether its thoughts are morally acceptable or not.

Life instinct (Eros) - aggression occurs when Eros is blocked

Death instinct (Thanatos) - annihilation and the tendency to destroy. Psychological mechanisms release it outwards in the form of aggression.

Weaknesses of psychodynamic theory

Bushman (2002)

Found venting worsened anger while Graham et al. (2008) found ranting was a better alternative found, as it allows an individual to gain control over their feelings, by having confederates criticise essays of 600 college students.

The main criticism of psychoanalysis is that it is time-consuming, expensive and not at all certain to work. Since it is not scientifically-based, it is difficult to measure how effective it is and whether or not it is working for any particular client.

Giammanco et al. (2005)

As testosterone increases, aggression in males of different species increases.

Dolan et al. (2001)

Positive correlation between testosterone levels and aggressive behaviors of 60 male offenders in maximum security hospitals.

Strengths of psychodynamic theory

Explains different types of aggression:

• Hot-blooded: impulsive, angry, no purpose

• Cold-blooded: deliberate, rational and has a purpose

Application to reducing aggression:

• Harmless ways of releasing anger - displacement using an object

• Catharsis of bringing unconscious memories into the conscious mind

Psychoanalysis is not a miracle cure, but it aims to make the client's emotions seem less confusing and frightening, producing a greater sense of acceptance and more self-control.

Eisenegger et al. (2011)

Women with a dose of testosterone were more generous and social in a lab-negotiating game. This showed hormonal effect of testosterone in females was more complex but this was done in an artificial setting.

STRENGTHS OF ROLES OF HORMONES

Dabbs & Hargrove (1997) - Empirical Support

Testosterone level was positively correlated with the degree of violence and aggressiveness used by 87 female inmates of a maximum security prison. Measured using their saliva.

Maletzky et al. (2006) - Application to controlling aggression

Testosterone lowering drug (Depo-Provera) which reduced sexual aggression without widespread effects on bodily systems and behaviour. This can reduce the frequency of serious crimes.

McBurnett et al. (2000)

Found that boys who had lower levels of cortisol in their saliva were three times more aggressive than boys with higher levels of cortisol, so cortisol does seem to play a role in aggressive behaviour.

Dabbs et al. (1987)

Measured male prisoners involved in crime and found they had higher levels of testosterone, suggesting a link between aggression and testosterone changes.

Wagner et al. (1979)

Castrated mice and observed that aggression levels dropped. When the castrated mice are injected with testosterone, their aggression levels (measured by biting attacks on other mice) rose back to pre-castration levels. This clearly suggests that testosterone is a cause of aggression in mice and may cause aggression in humans too.

WEAKNESSES OF ROLES OF HORMONES

Carré et al. (2011) - Difficult to measure testosterone levels

• Baseline testosterone levels are more important in animal than human research.

• Many studies using baseline measure may not provide a valid indicator of testosterone in relation to aggression.

Competing Argument → Elevated testosterone may be the outcome of aggression or the dysfunctional regulation of other hormones

Classic study: Raine et al. (1997)

Aim: Investigate brain dysfunction in murderers who pleaded not guilty by reason of insanity (NGRI). Researchers hypothesised that brain scans would show dysfunctions in areas linked in previous research to violence - the PFC, angular gyrus, amygdala, hippocampus, thalamus and corpus callosum.

I.V. - 41 murderers and 41 non-murderers (each group contained 39 males and 2 females)

D.V. - Glucose metabolism in specific brain areas with PET scans

Procedure:

1. Participants were medication free 2 weeks prior to PET scan

2. Control group: Similar gender, age, sex, ethnicity and 6 people with schizophrenia

3. All gave consent for ethics and had satisfactory general physical and mental health

4. Continuous performance task - identify targets on a screen and pressing a button 32 minutes after injection to encourage uptake of radioactive tracer into certain areas of the brain. 10 images at 10mm intervals.

Findings:

CORTICAL REGIONS:

1. Murderers had significantly lower glucose metabolism than controls in lateral and medial prefrontal areas, left angular gyrus and left and right superior parietal areas.

2. Murderers had higher metabolism than controls in occipital lobe.

SUBCORTICAL REGIONS:

1. Murderers had lower glucose metabolism in left amygdala, left medial temporal lobe, hippocampus and corpus callosum.

2. Greater activity in right amygdala and right medial temporal lobe.

Conclusion:

1. Brain differences are associated with behavioral changes related to violence.

2. Criminals may be unable to modify their behavior due to dysfunction in PFC causing impulsivity and lack of self-control.

Double Dissociation → murderers and non-murderers differed significantly in brain activity in aggressive areas but no significant differences in areas not linked to violence.

Contemporary Study: Brendgen et al. (2005)

Aim: TWIN STUDIES

1. Whether social and physical aggression are explained by genes and environment

2. Overlap between social and physical aggression is explained by direct effect of one type over the other.

Sample: 44 pairs of male MZ twins, 50 female MZ pairs, 41 male MZ pairs, 32 female DZ pairs.

Procedure:

1. Teacher ratings - three-point scale

2. Peer ratings - given a booklet of photographs of classmates and asked to nominate the three children on one page who best matched the descriptions for social and physical aggression

The teachers’ questionnaires asked them to rate each child on a 3-point scale (0 = never, 1 = sometimes, 2 = often) on these 6 statements:

• tries to make others dislike a child

• says bad things or spreads nasty rumors about another child

• becomes friends with another child for revenge

• gets into fights

• physically attacks others

• hits, bites or kicks others

The scores for social aggression and physical aggression were added together to produce two overall scores.

For the peer ratings, the children were given a simpler task. They were shown photos of their classmates and asked to circle the photos of 3 children who best fit these 4 descriptions:

• tells others not to play with a child

• tells mean secrets about another child

• gets into fights

Findings:

1. Only 20% (teacher) to 23% (peer) of social aggression is explained by genes. - More affected by nurture.

2. Nature - physical aggression mostly explained by genes and partly by non-shared environmental influences.

3. There was also a “moderate” correlation between teacher and peer ratings for physical aggression (r=0.25) and for social aggression

4. The MZ twins' correlations for social aggression were similar to the DZ twins' correlations. This suggests social aggression is less linked to genetics, because both types of twins seemed to be equally affected by their surroundings, unlike with physical aggression.

Conclusion:

1. Genes predispose some children to aggressive behavior in general.

2. Specific type of aggression depends on environment.

3. Brendgen concludes that about 50-60% of physical aggression can be linked to genes, since it was shared by MZ twins but not so much by DZ twins. For social aggression, genes only seem to account for about 20%.

The central nervous system (CNS)

Consists of brain and spinal cord, origin of all complex commands & decisions.

Nervous system:

1. Collects, processes & responds to information in environment.

2. Coordinates working of different organs and cells in the body.

Spinal cord

Functions:

1. Central Processing

2. Reflex actions

3. Transmits messages between brain and PNS

Thalamus

Functions:

1. Brain’s relay station

2. Receives sensory information - auditory, visual, tactile but not olfactory

Hypothalamus

Functions:

1. Motivational behaviors

2. Body stress response

3. Maintains balance in bodily functions

4. Regulates activity of endocrine system with pituitary gland

Limbic system

Functions:

1. Contains Amygdala - regulates emotional responses

2. Memory & Learning

Cerebellum

Functions:

1. Little brain

2. contains 50% of brain’s neurons

3. Coordinates posture, balance & movement

4. Receives & integrates information from spinal cord & other areas

Corpus callosum

Functions:

1. Connects 2 near-symmetrical hemispheres.

2. Allows communication between hemispheres through transmission of signals - contralateral control.

Lateralisation

Functions:

1. Language - left hemisphere

2. Contralateral control

Localisation

Functions:

1. Certain areas are responsible for specific functions & behaviors

Cerebral cortex

Functions:

1. Covers inner brain

2. divided into cortical and subcortical regions

3. Ridges increase surface area for higher processing power

Frontal lobe

Functions:

1. At front of the brain

2. High-level cognitive functions: thinking, planning, problem-solving and decision making

3. Motor cortex - controls voluntary movements on opposite side of the body

Parietal lobe

Functions:

1. On either side of central sulcus, further back in brain

2. receiving and processing sensory input - touch, pressure

3. Perception of environment and bodily awareness

Temporal lobe

Functions:

1. Auditory cortex - processes location, volume and pitch of sounds from opposite ear.

Occipital lobe

Functions:

1. Back of the brain

2. Each lobe contains primary visual cortex and several secondary areas

3. Contralateral field of visions

Broca’s area

Functions:

1. Left frontal lobe responsible for speech production

2. Damage causes Broca’s aphasia, slow and laborious speech lacking fluency

Wernicke's area

Functions:

1. Left temporal lobe

2. Difficulty understanding language (fluent but meaningless speech)

Volk et al. (2012)

Bullying is more attractive to the opposite sex.

Males:

• Physical fights show dominance and led to greater reproductive success.

Females:

• Verbal abuse shows authority and more reproductive success as males are more committed to relationship.

Narabyashi et al. (1972)

43/51 patients had reduced aggression once amygdala was removed.

Hill & Hurtado (1996)

Aggression leads to increase in social status of Yanomami tribe in Venezuela.

Chester et al. (2015)

Low of functioning of MAOA (Warrior) gene was linked to greater aggression.

Brain

Functions:

1. Conscious awareness and decision making

2. Consists of corpus callosum and cerebral cortex.

3. Lateralisation and Localisation

Somatosensory cortex

Functions:

1. Processes sensory information from the skin

Carré and Mehta (2011)

Hormones regulating human behavior:

• Claimed that high levels of testosterone only lead to aggressive behavior when cortisol levels are low, as violent drive is not blocked.

• Van Goozen et al. (2007) - Cortisol is released to help the body deal with stress, so there is a link between regulating aggression and the stress response.

• Popma et al. (2007) also proved this dual-hormone hypothesis with a positive correlation of physical aggression in adolescent males, suggesting how this is a good predictor for human aggression.

Effects of Recreational Drugs

Drugs - biochemicals that have specific effects on functioning of body systems. Physiological or psychological purposes.

Examples: stimulants, sedatives, hallucinogens and opioids.

Serotonin - Inhibition in postsynaptic neuron, making it negatively charged and less likely to fire.

Dopamine - excitation of postsynaptic neuron by increasing positive charge and making it more likely to fire.

1. Cocaine - stimulant effect on CNS. Blocks reuptake of dopamine by binding with dopamine transporter molecules on terminal buttons of presynaptic neuron. Synapse flooded with high amounts of dopamine causes euphoric high.

2. Heroin - depressant effects on the CNS. Slows down CNS activity, including activity of neurons involved in pain. Processed into morphine after reaching the brain, binds with the receptors of natural opioid to enhance natural response.

Bardo et al. (2013)

Genes affect how sensitive or responsive an individual’s nervous system is to recreational drugs.

STRENGTHS OF RAINE CLASSIC STUDY

High degree of experimental control:

• Participants matched across experimental and control groups on three confounding variables

• Standardised procedures - the same CPT (continuous performance task) was used for 32 minutes

• High internal validity

• Well-established protocol of PET scans

Competing Argument → The participants were not randomly allocated to experimental or control groups which could have confounded some results.

Application to understanding biological evidence:

• Brain structures only play a partial role in aggression so brain structures should not be changed through medication or surgery unless necessary.

WEAKNESSES OF RAINE CLASSIC STUDY

Inappropriate PET Scanning Technique:

• Scanned the brain in 10mm slices on the canthomeatal line which varies significantly between individuals so it is hard to precisely locate certain brain areas.

• Limitation - reduces internal validity and accuracy of findings.

STRENGTHS OF BRENDGEN CONTEMPORARY STUDY

Multiple Data sources:

• Valid and reliable measure of aggressive behaviour

• A main advantage of the present study is it assessed behavior not only by teachers but also by peers, who are rarely employed as a reporting source in twin studies

Application to reducing aggression:

• Effective interventions - identify factors that block the path from physical to social aggression to reduce both types.

Generalisability:

• Brendgen uses a large sample (234 twin pairs), so unusual children (anomalies) with very high or low levels of aggression out to be “averaged out” by the size of the data. This makes the sample representative.

• The study only looked at 6-year-olds. In some ways, this is a representative age group because they are going through the shift from physical aggression towards social aggression.

Reliability:

• Brendgen uses established questionnaires to measure aggression. These can easily be replicated, making the study reliable.

• Two researchers visited each classroom, suggesting the study has inter-rater reliability.

• There was a strong correlation between teacher- and peer- ratings, suggesting the scores are reliable.

Application:

• If social aggression is strongly linked to environment, it must be possible to reduce the worst effects of verbal bullying, gossiping and “trolling” in social media by children, by using early intervention.

Ethics:

• The parents of the twins agreed for their children to be in the study, so presumptive consent was given by a responsible adult. The teachers also agreed and this is presumptive consent too.

WEAKNESSES OF BRENDGEN CONTEMPORARY STUDY

Invalid Assumptions:

• States that MZ and DZ twins experience the same treatment (environmental) but this may not be true.

Competing Argument → Many of the ways MZ similarity occurs are irrelevant to the behaviour being investigated.

Derks et al. (2006) conducted a study of aggression in adolescent twins and used statistical methods to show the assumption that MZ and DZ twins experiencing the same treatment was not violated.

Generalisability:

• The researchers themselves complain that their sample was too small. They looked at 409 classrooms, but argue future studies that replicate their procedure should use larger samples.

• Some children will be slow developers and others will be fast developers. For example, more mature children may have more non-shared environmental influences (they do more things away from home).

Reliability:

• The language differences might make the study less reliable. Questions translated into another language might have slightly different meanings or become confusing. Brendgen’s original questionnaires were in French, meaning the English translations might be unreliable.

• The allocation of zygocity (MZ and DZ categories) was based largely on their appearance and wasn’t 100% reliable. In particular, it is possible there were DZ twins in the MZ condition.

Validity:

• Correlations like Brendgren’s do not prove causation. Something else could be affecting the MZ twins. For example, MZ twins tend to be physically identical and get mistaken for one another. It might be that one twin gets stereotyped based on the other twin’s behaviour (if one twin is naughty, both get a bad reputation).

• In Brendgen’s study, teacher- and peer- ratings might have been influenced by stereotypes, with both children being given the same rating regardless of their behaviour.

• The study avoids taking a reductionist view of human behaviour: it looks at genetics but also at environmental factors. It links in with the findings about aggression by Bandura (who claims it is learned) and Raine et al. (who suggest it is due to brain structure).

Ethics:

• The study does get children to look at pictures of their classmates and judge them. This might have a bad impact on friendships, especially if the children told each other afterwards who they had selected as the “hitter and biter” or the “tale-bearer”. This could lead to hurt feelings or worse – revenge! This goes against the social responsibility of ethical research and might create risk for the children who participated.

Describe the areas of the brain and their functions (lobes)

Frontal lobe- conscious planning, thinking, organisation, language
pre-frontal cortex- self-control, decision making, delayed gratifaction
Temporal Lobe- memory, understanding, facial and object recognition

Prosopagnosia- can't recognise faces/memory loss
Occipital lobe- vision, colour- McCarley- Sz- abnormalities
Parietal Lobe- abstract thinking, perception, spatial awareness
Corpus Collosum- large bundle of fibres connecting hemisphere

left hemisphere contains language centre- contralateral- couldn't describe object in left hand- could in right

Describe the process of neurotransmission

An electrical impulse(action potential) is transmitted along the axon of the pre-synaptic neuron to the axon terminal. Electrical impulses cannot travel across the synaptic gap, so the electrical impulse is carried by neurotransmitters, which are contained in vesicles. Vesicles release the neurotransmitters to diffuse across the synaptic gap, so they can activate the receptors of the post-synaptic neuron. When enough receptors are activated, a new action potential is sent to the next neuron. Remaining neurotransmitters are degraded by enzymes released by the post-synaptic neuron or are absorbed through re-uptake back into the vesicles of the pre-synaptic neuron to be reused.

EFFECT OF CULTURE ON AGGRESSION

Gordon Ingram (2014)

• Showed that young children show more physical aggression than social aggression, but, as they grow into adolescence, this reverses and social aggression (gossiping, rumour-spreading) dominates.

• Brendgen thinks this is because young children don’t have the verbal or social skills to practise social aggression, but they acquire these once they start school.

• This supports the influence of social background and culture on aggression.

Rogoff & Mosier (2003)

• Compared US families with Mayan Indian families in Guatemala. Among the Mayans, the "terrible twos" are unknown. Rogoff & Mosier gave children an interesting object to play with (an embroidery hoop). US mothers would make the toddler share the toy with an older brother or sister; the Mayan mothers would insist that the toddler kept the toy, telling older brothers or sisters to wait for their turn 97% of the time.

• Mayan mothers expect an older sibling to defer to the toddler for the sake of good relations and the toddler grew up without tantrums. The Mayan parenting-style may seem as if you are "spoiling" the toddler. However, the Rogoff & Mosier found that 61% of the interactions of Mayan children were cooperative, whereas 68% of the American children's reactions were competitive.

• This suggests that some childhood aggression is more cultural than biological.

EVALUATING PSYCHODYNAMIC THEORY

Supporting Research:

• The limbic system is the brain's "emotion centre" and the pre-frontal cortex handles rational decision-making, just like the id and the ego.

• There is also a link between the right hemisphere and the unconscious mind. The right hemisphere is linked to emotional intelligence and procedural memories (how to do things).

• Divino & Moore (2010) - explain how the growing influence of the left hemisphere might link to Freud's idea of the growth of the ego in children: Only the right hemisphere is fully functional at birth; it remains dominant for the first 2 to 3 years of life, thus, infants develop patterns of emotional communication prior to developing left-hemisphere-based verbal skills when that hemisphere becomes fully functional around the 3rd year

• Crucial memories from early childhood may be stored in the right hemisphere but cannot be "put into words" by the left hemisphere, even though they still affect our emotions. This ties in very closely with Freud's idea of the unconscious mind influencing the conscious mind.

Opposing Research:

• Freud depends on case studies and gathering qualitative data. There is very little quantitative data in any of his research. This makes his findings hard to analyse and dependent upon his own interpretation.

• Other psychologists have offered very different interpretations of what was wrong with Freud's patients. They may have had biological problems or their behaviour might have been learned from role models or conditioning. Little Hans' phobia of horses could be explained using classical conditioning.

• Popper argued that true scientific theories are falsifiable. This means you can state what circumstances would prove the theory false. It is very difficult to falsify Freud's ideas but the unconscious mind is completely inaccessible. This means there's no way of proving that it doesn't exist or that some behaviour isn't caused by it.

Different Theory:

• The biological/evolutionary approach also uses case studies (such as Phineas Gage and Charles Whitman) but it uses other more objective methods too, such as twin studies and adoption studies. Since the 1990s, it has also used brain imaging techniques which provide detailed, quantitative data about the structure of the brain.

• Another difference is the use of animal studies. Ethology is a part of the biological approach that studies animals to learn about humans. The psychodynamic approach rejects this; although he focuses on instinct, Freud claims to study what makes us distinctively human, not what we share with other animals.

Applications:

• Psychoanalysis can help treat emotional problems by exploring their unconscious causes. The psychoanalyst helps the client explore their own dreams and childhood memories and work out what they mean. Hopefully, the client will learn about the defence mechanisms they are using and the unresolved conflicts going on in their unconscious. They may come to self-knowledge.

• A recent study by Jonathan Shedler (2010) drew together research into the effectiveness of psychoanalysis from all over the world. He concluded that, despite its lack of scientific support, psychoanalysis has about the same outcomes as other therapies like Cognitive Behavioural Therapy (CBT) which are more scientifically-based.

Key Question: WHAT ARE THE IMPLICATIONS FOR SOCIETY IF AGGRESSION IS FOUND TO BE CAUSED BY NATURE NOT NURTURE?

A01:

• Aggression: the intentional use of physical force or power, threatened or actual, against oneself, another person, or against a group or community

• Relational (or social) aggression, which includes gossiping and name-calling but which falls short of actual violence.

• A different view is that humans evolved to be violent as self-defence.

• Warrior Gene - MAO-L is found on the X chromosome so men are more likely to be affected by it (because if women have MAOA-L on one chromosome, they might still have the normal MAO-A on their other X chromosome).

• Frydman et al. (2010) made 83 young men compete at gambling $25 in 140 different games. Each man had to choose between a sure option (100% no profit, no loss) and a risky option (various risks of loss and chances of profit). The carriers of the MAOA-L gene variant were more likely to take financial risks that were beneficial to them (as opposed to pointless risk-taking).This suggests that evolution favours creatures who "push their luck" by taking risks, but only if they have something to gain. When there's nothing to gain by being aggressive, the "Warrior Gene" shouldn't encourage violence

A02:

• ​A 2013 UN study created a World Homicide Map; this showed that a third of the world's murders happen in Latin America, despite Central America, South America and the Caribbean having less than a tenth of the world's population. Specifically, you are 25 times more likely to be murdered in Brazil than in the UK.

• The differences in violence between different places and times suggest there is nurture involved as well as nature. There may be explanations for violence from the Social Approach or the Learning Approach. For example, obedience to leaders, intergroup discrimination and violent role models may explain why people in some areas are more aggressive than people in other areas. It would also explain why violence declines over the centuries.

• Darwin’s theory of evolution: The discovery that chimpanzees engage in organised violence suggests that humans and chimps both evolved these behaviours before their species diverged 6 million years ago.

• The limbic system in humans and chimps is very similar and this includes the amygdala that regulates aggression. However, the big difference between a chimp brain and a human brain is in the cerebral cortex and this includes the pre-frontal cortex that restrains aggression.

• The solution to violence would be to improve the environment people (and chimpanzees) live in, by cleaning up cities, improving policing, creating jobs and building schools (and, to help the chimpanzees, banning logging!).

• However, if violence IS part of human (and chimp) nature, none of these strategies will work 100%. There will always be violence.

• Cases et al. (1995) used genetic engineering to breed mice with the MAOA-L mutation. The mice pups were much more fearful than normal mice but they grew up to be much more aggressive. This suggests that MAO-A is linked to the "fight or flight" response and that adult aggression is linked to finding the world to be a scarier place than it really is. Interestingly, the amygdala, which regulates aggression, also regulates fear.

• The important thing about genetic explanations like this is that genes only give us predispositions or tendencies.

• Education may be the key here. Boys with the MAOA-L mutation could be identified early and given more help with problem-solving, personal skills and careers advice. Cognitive Behavioural Therapy (CBT) works by getting people to recognise their faulty ways of thinking and Freud's psychoanalysis helps people overcome the fear and aggression in their childhoods.

NEUROTRANSMITTERS & AGGRESSION

Higley et al. (1996) - studied rhesus monkeys living wild on an island. The researchers used behavioural observations of the monkeys fighting and leaping from trees. They also took samples of spinal fluid from the monkeys to measure 5-HIAA levels. 5-HIAA is a chemical that is produced by the re-uptake of serotonin, so high levels of 5-HIAA means high levels of serotonin.

Ferrari et al. (2003) studied the link between neurotransmitters and aggression in rats. They allowed a rat to fight every day for 10 days at approximately the same time. This was done by introducing an "intruder rat" into the test rat's cage. On the 11th day, no intruder rat was introduced. The researchers measured the levels of serotonin and dopamine in the test rat's brain. The test rat’s dopamine levels had increased and serotonin levels decreased, because it was anticipating a fight.

• This study also links in with Classical Conditioning. The rat had been conditioned to fight at a certain time each day and its brain chemistry had altered to prepare it for aggressive action. It also illustrates brain plasticity, since the rat's brain chemistry changed, showing that the brain adapts to what we experience.

APPLICATION OF AGGRESSION TO REAL LIFE

Sexual Jealousy: Mazur & Booth (1998) showed how testosterone rises in men who need to show their dominance; this includes single males and males in failing relationships. If jealousy makes men feel insecure in a relationship, their body will start to produce more testosterone to prepare them to assert their dominance and this can make them aggressive.

Gordon Ingram (2014) shows that young children show more physical aggression than social aggression, but, as they grow into adolescence, this reverses and social aggression (gossiping, rumour-spreading) dominates.

EVALUATING THE BIOLOGY OF AGGRESSION

Supporting Research:

• Ferrari's research on rats illustrates how dopamine and serotonin are linked to aggression in rats. These animal studies are backed up by human studies, like Raine et al. (1997) which also suggests the amygdala and pre-frontal cortex are linked to murder, and case studies like Charles Whitman whose brain tumour may have produced his uncontrollable aggression.

Opposing Research:

• Animals do not have the same pre-frontal cortex as humans (it is smaller, for example) and may not be capable of planning or self-awareness.

• Animals also express their behaviour through dominance or submission. It is possible that researchers are confusing dominant behaviour with aggressive behaviour. This would be a validity problem with the animal model if one sort of behaviour is being mistaken for another. In fact, there may be very little aggression in animal behaviour

Different Theory:

• Classical Conditioning shows that aggression is an unconditioned response to some stimuli (like threat) but may become a conditioned response to a neutral stimuli (like social embarrassment, unfamiliar people or drunkeness). This ties in with the Biological Approach because it assumes that unconditioned aggression is an instinctive response, but conditioned aggression is learned.

• Operant Conditioning shows that aggression is learned through reinforcement, either positive reinforcement (aggressive behaviour may bring you admiration and respect) or negative reinforcement (aggressive behaviour may make unpleasant things stop, by scaring people away).

Applications:

• Another application of the nativist view of aggression is the use of drugs to control behaviour and reduce aggression. For example, young people with ADHD (Attention Deficit Hyperactivity Disorder) can behave aggressively. They are often treated with drugs like Ritalin to control their behaviour.

• Brendgen (2005) - education at an early age may help children control their behaviour better.