Aggression

The limbic system plays a key role in emotional responses to threats. The amygdala attaches emotional significance to sensory information, and increased activity in this area is associated with aggressive behaviour. The hypothalamus regulates the autonomic nervous system and emotional responses, and damage to this area can lead to heightened aggression.

Genetic Factors

Genetic explanations suggest aggression is inherited. Coccaro et al. (1997) found higher concordance rates for aggression in monozygotic twins than dizygotic twins, indicating a genetic influence.

Rhee and Waldman (2002) found that genetic factors accounted for a significant proportion of variation in aggression in adoption studies. 

The MAOA gene produces an enzyme that regulates neurotransmitters such as serotonin and dopamine. The low-activity variant, MAOA-L, leads to poor regulation of these neurotransmitters and is linked to aggressive behaviour. Brunner et al. (1993) found that males with this variant showed impulsive and aggressive behaviour. 

The XYY genotype has also been suggested as a factor in aggression, although evidence is limited. 

The diathesis-stress model suggests that genetic predispositions, such as MAOA-L, only lead to aggression when combined with environmental stressors such as early trauma. 

Evaluation of Genetic Factors

Godar et al. (2014) found that mice lacking the MAOA gene showed increased aggression, supporting a biological basis.

Rhee and Waldman (2002) found that genetic influences appear stronger when using self-report measures, suggesting issues with measurement. 

Theilgaard (1984) found that the XYY genotype does not reliably predict aggression, challenging this explanation. 

Twin studies may overestimate genetic influence because monozygotic twins are often treated more similarly than dizygotic twins.

 

Ethological Explanation of Aggression

The ethological explanation suggests aggression is innate and adaptive. Lorenz (1966) argued that aggression helps secure resources and establish dominance, and that most aggression within a species is ritualistic rather than harmful. 

Aggression can be triggered by an innate releasing mechanism, which responds to specific environmental stimuli and produces a fixed action pattern. These are universal behavioural sequences within a species.

Tinbergen (1951) demonstrated this in sticklebacks, showing that male fish became aggressive when exposed to a red stimulus during mating season, even when the stimulus was artificial. 

Evaluation of the Ethological Explanation

Nisbett (1993) found cultural differences in aggression, suggesting that aggression is influenced by social norms rather than being purely innate.

Research suggests that behaviour is not completely fixed and can change depending on context, challenging the idea of fixed action patterns. 

Goodall (2010) observed chimpanzees engaging in lethal aggression, suggesting that aggression is not always ritualistic or adaptive. 

 

Evolutionary Explanations

Evolutionary explanations suggest aggression has survival value. One example is sexual jealousy, where males may use aggression to prevent infidelity and ensure reproductive success. 

Mate-retention strategies include direct guarding, such as monitoring a partner’s behaviour, and negative inducements, such as threats. 

Aggression may also function in bullying, where it signals dominance and strength, potentially increasing attractiveness to mates. 

Evaluation of Evolutionary Explanations

Evolutionary explanations can explain gender differences, as males are more likely to use physical aggression due to reproductive pressures.

However, cultural differences, such as low aggression in the Kung San tribe, suggest environmental factors also play a role. 

These explanations may also oversimplify behaviour by focusing too heavily on biological factors. 

 

Social Psychological Explanations of Aggression

Frustration-Aggression Hypothesis

Dollard et al. (1939) proposed that aggression is an innate response to frustration. When individuals are prevented from achieving a goal, frustration builds and leads to aggression. 

Aggression may be directed at the source of frustration, displaced onto another target, or expressed through socially acceptable activities such as sport, known as sublimation. 

Berkowitz (1969) suggested that aggression only occurs when environmental cues, such as weapons, are present. 

Evaluation of the Frustration-Aggression Hypothesis

Green (1968) found that participants who were frustrated through insults or difficult tasks showed increased aggression.

Berkowitz (1967) demonstrated the weapon effect, where participants were more aggressive when a gun was present. 

However, the research often relies on artificial tasks, which may reduce ecological validity. 

Social Learning Theory

Bandura (1961) proposed that aggression is learned through observation and imitation. Individuals observe role models and imitate their behaviour, particularly when the behaviour is rewarded.

Vicarious reinforcement occurs when individuals imitate behaviour they see being rewarded in others.

Bandura (1961) proposed four mediational processes: attention, retention, reproduction and motivation. 

Bandura et al. (1961) showed in the Bobo doll study that children imitated aggressive behaviour after observing an adult model. 

Evaluation of Social Learning Theory

The theory has real-world applications, such as understanding the influence of media on behaviour. 

Phillips (1986) found an increase in homicide rates after televised boxing matches, suggesting imitation in adults.

However, the theory cannot fully explain reactive aggression that occurs without prior observation or reward. 

Deindividuation

Deindividuation occurs when individuals lose their sense of identity in a crowd. This leads to behaviour that is more impulsive, emotional and often aggressive. Le Bon (1895) first suggested that crowd behaviour changes individual behaviour. [

Zimbardo (1969) argued that anonymity, crowd size and reduced accountability contribute to deindividuation. 

Prentice-Dunn and Rogers (1982) suggested that reduced private and public self-awareness leads to less concern about behaviour and its consequences. 

Evaluation of Deindividuation

Dodd (1985) found that people were more likely to engage in antisocial behaviour when anonymous. 

Mann (1981) found that crowd conditions such as darkness and large group size increased aggressive behaviour. 

However, Spears and Lea (1992) argued in the Social Identity Model of Deindividuation Effects that people conform to group norms rather than lose control completely.

 

Institutional Aggression

Dispositional Explanation

The importation model, proposed by Irwin and Cressey (1962), suggests that prisoners bring their own aggressive tendencies into prison based on personal characteristics and past experiences.

Situational Explanation

The deprivation model, proposed by Clemmer (1958), suggests that aggression is caused by the conditions of prison life, including lack of freedom, autonomy, possessions, relationships and security. 

Evaluation of Institutional Aggression

Camp and Gaes (2002) found similar levels of aggression across different prison environments, supporting the importation model. 

Cunningham et al. (2010) found that conflicts over resources in prison contribute to aggression, supporting the deprivation model. 

Jiang and Fisher-Giorlando (2002) suggested that both models are needed to explain aggression, indicating an interactionist approach. Dobbs and Waid (2004) also argued that deprivation and imported characteristics interact. 

Media Influences on Aggression

Effects of computer Games

Research suggests that violent computer games may increase aggression. Experimental studies have shown that those who play violent games display more aggressive behaviour in laboratory settings.

Bartholow and Anderson (2002) found that participants who played a violent computer game selected higher levels of white noise than those who played a non-violent game. 

DeLisi et al. (2013) found a positive correlation between violent game play and aggressive behaviour in offenders. 

Anderson et al. (2010) found in a meta-analysis that violent game exposure was linked to aggressive thoughts, feelings and behaviour across genders and cultures. 

Evaluation of Effects of Computer Games

Laboratory tasks may not reflect real-world aggression, reducing ecological validity. 

Correlational studies cannot determine cause and effect. 

Publication bias may lead to overestimation of the relationship between violence and aggression. 

Desensitisation, Disinhibition and Cognitive Priming

Desensitisation occurs when repeated exposure to violence reduces emotional responses and increases acceptance of aggression. 

Disinhibition occurs when media portray aggression as acceptable, reducing restraint against aggressive behaviour. 

Cognitive priming suggests that exposure to violent media activates schemas that guide aggressive behaviour in future situations. 

Evaluation of Media Effects

Krahe et al. (2011) found reduced physiological responses to violence in habitual viewers, supporting desensitisation.

Berkowitz and Alioto (1973) found that justified violence increased aggressive behaviour, supporting disinhibition.

Fischer and Greitemeyer (2006) found that exposure to aggressive content increased aggressive thoughts and behaviours, supporting cognitive priming. 

However, alternative explanations suggest media may act as a safe outlet for aggression rather than increasing it.