A Level Psychology- Aggression key studies & explanations

The limbic system responds to primative functions, which contains the amygdala that responds to threats & challenges in the environment, intiating the flight-or-fight response.

• Phineas gage had a pipe go through his skull, destroying the majority of his left frontal lobe. After suffering the injury, he became more aggressive and short-tempered as he prefrontal cortex was damaged and could no longer inhibit the amygdala.

Serotonin is a neurotransmitter that influences mood impulsivity & behaviour through an inhibitory effect. When serotonin levels become abnormal/ overractive/ low, the communcation with the amygdala no longer occurs, which causes a loos of control & increase in impulstivity, causing the individual to act more aggressively.

• Berman et al. (2009) had ppts. administer electric shocks to another ppt. in an agrument & found that ppts. who were given paroxetine (increases serotonin levels) gave fewer/ less intense electric shocks than the group who were given a placebo.

Testosterone is a hormone that activates the amygdala, which increases emotional reactions to stimuli; high testosterone levels are associated with higher aggression levels.

The presence of the Y chromosome has been associated with more aggressive tendancies in men.

• Court Brown (1965) discovered that 314 patients with XXY chromosome were more likely to be hosptalised due to their aggressive tendancies.

Twin study focus on whether aggression corcordance rates are higher in MMZ or DZ twins. Differences in corcordance of aggression between the two sets of twins have indicated that aggressions has a genetic element.

• Coccaro (1997) looked at MZ & DZ twins corcordance rates of criminal behaviour and found that MZ were 50% where DZ were 19%. Shows that other factors are at play at corcordance rates aren't 100%.

MAOA gene/ warrior gene: responsible for release of monoamine oxidase protein; metabolises nonadrenalin, serotonin & dopamine. If there's a dysfunction in the protein, adrenaline isn't metabolised, which can cause a hypersensitivity to external stimuli where we percieve a threat that doesn't exist.

• Goddar et al. (2014) found that the removal of the MAOA gene resulted in increased aggression & higher serotonin levels.

Ethologists propose that aggression is an adaptive trait that promotes survival as animals are 'defeated' rather than killed to enhance the species' survival (ritualistic aggression).

Tinbergen (1951) investigated IRMs in male sticklebacks during mating season, where they develop a red underbelly & become more aggressive towards males entering their territories. He found that when they were presented with wooden models with a red underbelly, they would act aggressively & attack it.

Innate releasing mechanism: hard-wired brain networks that are triggered by an external stimuli. Fixed action patterns: set sequence of behaviours that occur automatically due to an IRM.

• low activity of MAOA gene promotes aggression which is an innate bias, relating to ethological ideals.
• generalising this to human aggression reduces the reliability of the explanation as these findings have been extrapolated from animals.

Evolutionary explanation: the need to ensure the survival of one's genes; mating is crucial for survival, meaning there's a greater tendancy for aggressive behaviours.

Buss (1988) created aggressive mate retention strategies to prevent cuckoldry. (1) direct guarding- restricing partner's independance, (2) negative inducement- actual violence/ threats to prevent unfaithful behaviour, (3) emotional manipulation.

• Shackleford et al. (2005) surveyed 461 men & 560 women who were in committed heterosexual relationships, where the men were asked about retention strategies & how often they were aggressive to their partner; female ppts. were asked about their partner's behaviour. Male retention strategies positively correlated with aggression towards partners.
• reductionist as it excludes individual differences & environmental factors.
• social sensitivity- reduces explanation's credibility as findings are self-repot & are against the legal system.

Dispositional explanation: the personalities of the prisoners make the prisons violent places (Importation Model).

Irwim & Cressey (1962) the social traits/ histories of prisoners are imported into prisons; someone who's in prison for violent/ aggressve crime will act accordingly.

(1) Criminal/ theif subculture: sterotypical criminal traits, (2) Convict subculture: raised within system/ seek positions of power/ most aggressive, (3) Straight subculture: one-time offenders that just want to get on with their sentence.

• DeLisi (2011) found that men who were prior gang members members were more likely to be involved in violent offences in prison.
• DeLisi (2004) found no difference in violence between gang members & non-gang members.

Situational explanation: the prison's environment makes people act out aggressively (Importation Model).

Sykes (1958) described specific deprivations that prisoners may encounter that causes them to act out aggressively: loss of freedom, opportunity for heterosexual relationships, boredom, loneliness & isolation.

• Wilson altered the prison conditions to be less claustrophobic, play music on the radio & cooler temperatures; found that assaults on staff were virtually eradicated.
• Nijman (1999) found that giving psychiatric patients more personal space didn't lower levels of violence.

(1) Deindividuation: psychological state where person loses personal identity & takes on idenity of social group- Gustave LeBon (1895). Public & private self-awareness is reduced/ self-idenity & sense of personal responsibilty is lost;  more likely to act aggressively.

• "The Baiting Crowd" Mann (1981) analysed 21 suicide leaps were a crowd gathered; 10 cases crowd urged individual to jump due to it being a larger crowd & at nighttime.

(2) Fustration-aggression hypothesis, Dollard et al.: where aggression may not be directed at the fustrating stimuli & instead is displaced. Catharsis: process of engaging in aggression to get rid of their fustration.

• Berkowitz (1967) conducted an experiment where ppts. were given an opportunity to shock a confederate that angered them. Con. 1: aggressive cue (gun), Con. 2: non-aggressive cue (badminton racket) & Con. 3: control group/ no cue. Ppts. with aggressive cue gave higher shock level (average= 6.07V) to no aggressive cue (4.67V)

(3) SLT, Bandura (1961): when individuals act aggressively by imitating role models through observational learning & vicarious reinforcement (witnesssing a model being rewarded for aggressive behaviour, increasing the likelihood of reproduction). 

Four mediationtional prcoesses occur during SLT: attention, retention, reproduction & motvation.

Frequent seeing of aggression in the media is thought to lead to increased aggression in the individual viewing the media.

SLT suggestes that identification with the model increases the likelihood of the behaviour being imitated through vicarious reinforcement.

Operant conditioning via computer games rewards/ praises the player for actively being aggressive, which increases the likelihood of this behaviour being repeated.

Desensitisation: after repeated exposure to extreme aggression, it reduces a person's strong reaction and increases more aggressive tendancies (as it reduces normal levels of physiological/ sympathetic nervous system's functions).

Disinhibition: our normal moral restraints are loosned after exposure to media violence & it becomes normalised

• Berkowitz & Alioto (1973) found that ppts. who saw an aggressive film gave more & longer aggressive electic shocks to a confederate.

Cognitive priming: the effect the media has on past learnt behaviours & schemas, which makes agggressive behaviours more likely.