Aggression

Question 1

which two of the following statements are true

Answer 1

-aggression involved low MAOA gene activity
-MAOA gene influences levels of serotonin

Question 2

MAOA gene

Answer 2

-determines the production of MAOA enzyme

-MAOA enzyme breaks down neurotransmitters in the brain after a nerve impulse has been transmitted from one neuron to another

-it breaks down neurotransmitters such as serotonin and dopamine

-Humans have various forms of the MAOA gene e.g MAOA-L (Warrior gene) leading to low levels of the MAOA enzyme

-low levels of this enzyme lead to abnormal levels of serotonin = more impulse and aggressive behaviour

Question 3

Brunner et al

Answer 3

Brunner et al (1993):

-28 male members of a large dutch family involved in impulsive aggressive behaviours such as rape, attempted murder and physical assult

-found an association between MAOA deficiency and increased impulsive aggression

Question 4

Twin studies

Answer 4

-herediability account for 50% of the variance in aggressive behaviour

-Emil Corraco et al (1997) = studied adult male MZ and DZ twins = concordance rates of aggression is 50% in MZ twins and 19% in DZ twins = physical aggression

Question 5

adoption studies

Answer 5

-Rhee and Waldwin (2002) = carried out meta-analysis of adoption studies of direct aggression and antisocial behaviour = 41% of genetics = variance of aggression

Question 6

gene-environment interactions

Answer 6

-low MAOA gene activity is only related to adult aggresison when combined with early life traumatic events

-Frazetto et al (2007) = found an association between higher levels of antisocial aggression and low activity of MAOA gene in adult males = diatheiss stress

Question 7

strengths = genetic explanations of schizophrenia

Answer 7

-research support for role of MAOA gene in aggression (empirical evidence) = Brunnert al al (1993)

-twin studies + adoption studies

-self-report method of measuring aggression

-There is evidence supporting a positive correlation between increasing MAOA activity levels and increasing levels of prosocial behaviour, as demonstrated by Mertins et al (2011) who found that participants with high MAOA activity levels behaved more compassionately in a money-lending game, often with fewer provocations or refusals of offers. Therefore, this suggests that the link between MAOA and aggression is valid because correlations in both directions (increasing and decreasing MAOA levels) are supported by research evidence.

-There is also evidence supporting the strong link between MAOA activity levels and concentrations of serotonin, which has been based upon animal studies where researchers are able to ‘switch off’ or prevent the expression of the gene coding for the MAOA enzyme, thus allowing the researchers to study its effects in isolation. For example, Godar et al (2014) found that when the MAOA gene was switched off in mice, these mice were ‘hyperaggressive’, potentially due to the increased stimulation of postsynaptic neurons due to an increased concentration of serotonin in the synaptic cleft. Therefore, alongside additional evidence that the serotonin agonist ‘fluoxetine’ reverses this effect, increases the validity of the MAOA-aggression link.

Question 8

limitations = genetic explanations of schizophrenia

Answer 8

-interactionism approach should be adopted

-deterministic

-gender bias = Brunner = only male + testosterone

-socially sensitive research = reduce impact of serious crimes due to genetics = make Victims harm feel inferior and unimportant

-diathesis stress

-— However, a major problem with the use of the diathesis-stress model is the difficulty in distinguishing between the effects of nature (MAOA genetic mutations) and nurture (childhood trauma), as well as determining which has a larger influence. For example, McDermott et al (2009) found that provocation in a money-lending game was key to triggering aggressive behaviour in individuals with low MAOA activity levels, whereas previously they displayed the same levels of aggression as the healthy, neurotypical control group. This suggests that although the interactionist approach may be a better explanation for aggression compared to biological determinism, there is still a lack of clarity over the role of the stressor.

Question 9

aggression + reactive aggression

Answer 9

-Reactive aggression –> meaning they consistently overact to perceived threats

-greater activity in the amygdala is linked to fear

-lower activity in the prefrontal cortex is linked to reasoning and decision making

Question 10

limbic system

Answer 10

-The limbic system (subcortial structures) is part of the brain involved in regulating our behavioural and emotional responses, especially when it comes to behaviours and we need for survivial; feeding, reproduction etc. The limbic system includes the hypothalamus, amygdala and parts of the hippocampus

Question 11

amygdala

Answer 11

-the reactivity of the amygdala in humans and other mammals is an important predictor of aggression.

-the amygdala has a key role in how animals assess and respond to environmental threats. When it is stimulated electrically, animals respond with aggression

-if the amygdala is removed then animals would not long respond to things that would have caused a fight or flight response (aggression) before

Question 12

Gospic et al 2011

Answer 12

-lab method of assessing aggression known as the ultimatium game

-involves 2 ppts where one is given money and can decide how the split between the two

-an unfair offer was seen as a provocation. If the offer was rejected this was seen as an aggressive reaction

-when ppts rejected (acted aggressively) fMRI scans showed a fast and heightened response in the amygdala

-found that benzodapine drug (Reduces arousal in the autonomic nervous system) taken before the game had 2 effects on responses to unfair answers – it halved the number of rejections (reduced aggesssion)

Question 13

orbitofrontal cortex and serotonin

Answer 13

-OFC is the area of the brain involved with decision making and regulation of behaviour

-serotonin is a neurotransmitter that allows the communication of impulses between neurons at the synapse

-it has inhibitory effects (slows and calms neural activity)

-normal levels of serotonin in the OFC are linked with reducing firing of neurons which in turn leads to greater behavioural self control

-low levels of serotonin disrupt this mechanisms, reducing self-control and leading to an increase in impulsive behaviour

Question 14

Serotonin research

Answer 14

Virkkunen et al 1994:

-compared levels of serotonin breakdown product in the cerebrospinal fluid of violent impulsive and violent non-impulsive offenders. The levels were significantly lower in impulsive offenders

Question 15

testosterone

Answer 15

-Testosterone is an androgen (male sex hormone) responsible for the development of masculine features such as facial hair, muscle mass etc. Has other roles as well on male typical behaviours such as regulating sex drive and increasing libido. Also been shown to play an important role in social behaviours such as cooperation and aggressive behaviours

Question 16

testosterone research

Answer 16

Giammanco et al 2005:

-castration studies removing testes of animals reduces aggression in many species. Giving injections of testosterone to the same animal then restores aggressive behaviour

Question 17

Dolan et al 2001

Answer 17

Dolan et al 2001:

-evidence of the role of testosterone comes from studies of prison populations and violent offenders. Dolan found a positive correlation between testosterone levels and aggressive behaviour in a sample of 60 offenders in a UK maximum security prison. These men mostly has personality disorder such as psychopathy and histories of impulsively violent behaviours

Question 18

strengths = neural to aggression

Answer 18

-effects of drugs on serotonin –> drugs that increase serotonin also reduce levels of aggressive behaviour. Berman et al 2009 = gave their ppts either a placebo or dose of paroxetine. Ppts then took part in a lab-based game in which electric shocks of varrying intesnity were given and received in response to provocation. However, this was only true in ppts who had a history o aggressive behaviour.

Question 19

limitations = neural to aggression

Answer 19

Limitations – neural:

-role of other brain structures –> amygdala does not operate in isolation in determing aggression. Appears in tandem with the OFC which is not part of the limbic system. Coccaro et al 2007 = in people with psychiatric disorders OFC activity is reduced. — There may be an over-reliance on the limbic system as an explanation for aggressive behaviour. For example, the orbitofrontal cortex (OFC) may also play a significant role, due to its link with the action of serotonin, as shown above. Therefore, as suggested by Gospic et al, it may be more effective to focus on the neural connections between the OFC and the limbic system, as opposed to looking at the two in isolation.

Question 20

strengths hormonal to aggression

Answer 20

-Testosterone is an androgen (male sex hormone) present in significantly larger concentrations in men, compared to women, and is responsible for the production of male facial characteristics and reproductive organs, being secreted from the pineal gland. There may be a link between decreased testosterone levels and decreased levels of aggressive behaviour, a positive correlation demonstrated by castration studies.

Question 21

limitations hormonal to aggression

Answer 21

-— Carre and Mehta (2011) suggest that, through their dual-hormone hypothesis, testosterone does not work alone in determining aggression, but rather has an antagonistic relationship with the stress hormone cortisol, where increased levels of aggression are associated with increased testosterone levels but only when cortisol is low. Therefore, this implies that different hormones have different predictive values for aggression and are part of a system when developing aggressive behaviour.

Question 22

ethology

Answer 22

-Ethology is the scientific and objective study of animal behaviour, usually with a focus on behaviour under natural conditions, and viewing behaviour as an evolutionary, adaptive trait

-ethologists study aggression in non-human animals and generalise their findings to humans because they assume we are all subject to the same evolutionary forces (natural selection)

Question 23

adaptive function of aggression

Answer 23

-describes aggression as an adaptive behaviour = contributes to an individuals survival or reproductive success and is thus subject to the forces of natural selection

Question 24

why is aggression adaptive

Answer 24

1) aggression wins fights which leads to dominance and rising up in the hierarchy. This leads to mating rights and greater access to resources

2) A defeated animal is rarely killed and usually has to find territory somewhere else. Losers spread out over a wider area, discover new resources which reduces competition

Question 25

ritualsitic aggression

Answer 25

-disocvered by Lorenz

-ethologists observe very little physical damage done in fights between animals. It is suggested that aggression is ritualistic

-usually involves signalling – baring teeth, threatening behaviour, voacalisation

-aggressive confrontations between animals often end is appeasement displays. These displays indicate acceptance of defeat, submissiveness and inhibit aggressive behaviour in the winner of the fight

Question 26

research = ritualistic aggression

Answer 26

–> aggression acts as a method of increasing one’s social status within a hierarchy, as demonstrated by Pettit et al (1988) who found that young children use aggressive tactics in playgrounds to assert their authority, lead the others and have their way

-aggression increases the chance of survival of a species - through appeasement following an aggressive confrontation, the ‘loser’ will seek out new territory, increasing the scope of the resources of the species and so increasing their chances of survival

Question 27

innate releasing mechanisms (IRM)

Answer 27

-biological structure or process in which the brain is activated by an external stimulus than in turn triggers a fixed action pattern

-aggression can be the result of an evolved automatic biological response in the brain

-animals have a built in neural structure which when exposed to specific stimuli such as teeth being shown will cause the release of an automatic behavioural response.

-animals studies are able to separate biological and social processes when studying aggressive behaviour

Question 28

Fixed action pattern (FAP)

Answer 28

-A sequence of stereotyped pre-programmed behaviours triggered by an innate releasing mechanism

-universal = same in every individual of the species

-stereotypes = predictable and unchanging

-unaffected by learning

-ballistic = once triggered, follows its course and cant be changed before completitin

-single purpose = only used for one specific stimulus

-consequential aggressive behavioural sequence is called the FAP

-an environmental stimulus triggers the IRM which then released a specific sequence of behaviours

Question 29

Stickleback research = ethological

Answer 29

Tinbergen (1951) - Stickleback research:

-sticklebacks highly territoral during mating seasons and develop red spot under their belly. If male enters territory, highly seterotyped sequence of behaviours aggressive initiated (FAP)

Procedure = presented wooden models with red spots and end observed reactions

Findings = regardless of shape, if a model had a red spot the other male would aggressively display and even attack. No red spot = no aggression. FAPS didn’t change from encounter once triggered he FAP always run its course.

Question 30

strength of ethological explanations to aggression

Answer 30

-There is evidence to suggest that ritualistic aggression may not be displayed by all species and in all situations. For example, Goodall’s (2010) observation of chimpanzees in the Gombe Stream National Park found that rival communities slaughtered each other in a systematic fashion, despite appeasament and ritualistic signals being displayed by the victims. This supports the idea that once a releaser has triggered the IRM, this will always lead to a FAP, and so the releaser is a stronger predictor of aggressive behaviour than appeasement.

-+ There is also evidence supporting the biological, innate basis of IRM and FAP systems. For example, researchers have pointed to Brunners work (1993) on the link between the low MAOA activity and levels of aggression, as evidence for the heritability of IRM and FAP systems. This is due to aggressive behaviour being triggered by increased levels of testosterone which must have been preceded by exposure to a releaser or signal, which had triggered the IRM. Therefore, the role of the limbic system and the IRM can be considered as valid explanations of aggression. Innate bias + aggression is genetically determined and heritable

Question 31

limitations of ethological explanation to aggression

Answer 31

-reductionist = human aggression may be more complex than animals. Cannot generalise animals and humans = over-simplify

-However, a more accurate description of FAPs may be ‘modal’ rather than ‘fixed’, as suggested by Hunt (1973). The researcher provided evidence that the duration of each behaviour within each FAP may vary between individuals as well as the specific other animal towards which it is targeted. Hence, environmental and social factors may have significant influences on the course of the FAP, resulting in lower validity of the universal nature of FAPs as part of an explanation for aggression.

-cultural differences in aggressions = Nisbett (1993) = found north-south divide in US for homocide rates. Killings more common for males in north. Culture overrides innate influences

Question 32

aggression as adaptive

Answer 32

-Aggression is an adaptive behaviour bc it serves an important function in terms of both individual survival as well as reproductive potential

-Males who used aggression would have been successful in securing and retaining mates as they could fight any rivals and prevent their mates from sexual infidelity; consequentially they would be more likely to pass on their genes

Question 33

male sexual jealousy

Answer 33

-greater in males because it is an evolved psychological mechanism to prevent cuckoldry

-cuckold = husband of an adulterous wife + males who are unwittingly investing parental effort in offspring that arent genetically their own

-females have 100% paternity certainty. Males have paternity uncertainty

-if a female cheats and becomes pregnant the male will end up wasting his resources raising another mans child

Question 34

male retention strategies

Answer 34

-Wilson and Daly (1996)

-men have evolved strategies to avoid cuckoldry

-direct guarding –> males monitor their partners behaviour e.g stalking

-negative inducements –> threaten them to prevent them straying

-All these strategies are adaptive and helped in aiding males to pass on their genes to the next generation.

-IPV = intimate partner violence

-Wilson et al = women who reported mate retention strategies agreed their partners who want to be with them at all times. 53% women said they feared for their lives.

Question 35

evoltuionary explanatiosn fo aggression

Answer 35

Evolutionary explanations of aggression suggest that aggression serves an important function in terms of reproductive potential. Evolved as it was beneficial for our survival. Sexual jealousy (more experienced in males than females) = evolved psychological mechanism in preventing female infidelity. Ensures male paternity so he can pass his genes on to the next generation.

Question 36

evolutionary explanation of bullying

Answer 36

-Bullying occurs bc of a power imbalance (more powerful individual uses aggression deliberatly against a weaker person)

-Tony Volk et al 2012 = argue that the characteristics associated with bullying behaviour are attractive to females and has the benefit of warding of potential rivals.

Question 37

strengths of evolutionary characteristics to aggression

Answer 37

-Research support –> Shackleford (2005) studied intimate partner violence in heterosexual couples. He gave questionnaires to couples and found a strong positive correlation between male reports of their mate retention strategies and female reports of their partners use of physical violence against them

-Evolutionary theories are useful because they can provide an explanation for gender differences in aggression. For example, Campbell (1999) suggested that females are more likely to engage in acts of verbal, as opposed to physical, aggression as this ensures that their own survival, as well as the survival of their offspring, is not endangered. Such tactics also prevents females from being involved in life-threatening physical confrontations with their partners, and so further increases their chance of survival through the use of non-aggressive methods of resolving conflicts (Bess and Shackleford). This utility increases the validity of the evolutionary explanation of aggression.

-However, there is research supporting the link between sexual jealousy and aggression. The main example of this would be Shackleford’s 2005 study which found that male retention strategies are a method of expressing sexual jealousy, which leads to aggressive behaviour both towards females and other partners. This increases the reliability of evolutionary theories as a method of explaining aggression, due to this supporting evidence.

-real world applications –> change bullying = deflect aggressive behaviours into activites and sports rather than against other people

Question 38

limitations of evolutionary characteristics to aggression

Answer 38

-methodological issues = evolutionary hypotheses are difficult to test bc behaviours evolved in the past. Therefore evolutionary psychologists must rely on correlational research e.g finding an association between mate retention strategies and aggression in Shacklefords study.

• There are methodological issues associated with the use of evolutionary theories to explain current examples of aggression. For example, predominantly such studies are correlational, meaning that there is only a correlation between aggression and the use of male retention strategies. This means that the research may suffer from the ‘third factor problem’, where there may be a third contributory factor which has not been studied. These studies may also jump to make causal conclusions, when really correlations can never demonstrate a ‘cause and effect’ relationship.

-cultural differences = aggressive behaviour can be accepted or rejected in different cultures