Aggression 1

Neural Mechanisms (AO1)

The Limbic System: Comprises subcortical structures (including the hypothalamus and amygdala) that govern emotional behaviors. The amygdala assesses environmental threats; heightened reactivity reliably predicts increased aggressive behavior.

• Orbitofrontal Cortex (OFC): A non-limbic structure responsible for impulse control and rational decision-making. Decreased neural activity in the OFC disrupts its ability to inhibit aggressive impulses from the limbic system.

• Serotonin: A neurotransmitter with widespread inhibitory effects in the brain. Normal levels in the OFC are linked with controlled, regulated firing of neurons. Deficient levels of serotonin reduce self-control, leading to impulsive, reactive aggression.

Neural Mechanisms (AO3)

1. Research Support for the Amygdala: Katarina Gospic et al. (2011) used fMRI scans during the Ultimatum Game. When participants rejected unfair monetary offers (an aggressive reaction), they showed a fast, heightened response in the amygdala. Administering a benzodiazepine halved the number of rejections and decreased amygdala activity. Link: This strongly supports the validity of the neural explanation by providing objective, biological evidence that amygdala hyper-reactivity directly drives behavioral aggression. 2. Research Support for Serotonin: Mitchell Berman et al. (2009) found that participants given paroxetine (an SSRI that enhances serotonin activity) gave fewer and less intense electric shocks in a lab-based game compared to a placebo group. Link: This establishes a critical causal relationship, demonstrating that increasing serotonin activity directly reduces aggressive behavior, thereby strengthening the explanatory power of neurotransmitter models. 3. Limitation - Reductionism vs. Complexity: Isolating aggression to individual brain structures ignores complex structural interactions. Evidence shows the OFC works closely with the amygdala to regulate emotional responses; focusing solely on one structure fails to capture how holistic networks function. Link: Therefore, this narrow focus reduces the completeness of the neural explanation, as it fails to account for the interconnected network systems required to successfully regulate human impulses.

Hormonal Mechanisms (AO1)

Testosterone: An androgen (male sex hormone) produced mainly in the testes. It is responsible for the development of masculine characteristics and regulates social behavior. High levels of testosterone are positively correlated with dominance and aggressive behaviors, particularly in young males.

• Progesterone: A female ovarian hormone that plays an inhibitory role in aggression. Levels fluctuate during the ovulation cycle; research (e.g., Ziomkiewicz, 2012) shows a negative correlation where the lowest levels of progesterone (just before/during menstruation) are linked to heightened aggression in women.

Hormonal Mechanisms (AO3)

1. Support from Correlation Studies: Research in prison populations (e.g., Dabbs and Hargrove, 1997) shows that inmates with the highest levels of testosterone frequently had histories of violent crimes and more disciplinary infractions. Link: This positive correlation increases the ecological validity of the hormonal explanation by demonstrating that elevated testosterone levels consistently align with severe, real-world violent behaviors. 2. Limitation - Animal Research Generalisability: Much supporting evidence comes from non-human animals (e.g., studies showing testosterone increases mouse-killing behavior). Human aggression is far more complex, governed by higher-order cognitive processing, social norms, and cultural expectations. Link: Consequently, this reliance on animal models limits the generalisability of the findings, meaning the explanation cannot fully account for the unique cognitive and social parameters of human violence. 3. The Dual-Hormone Hypothesis: Carre and Mehta (2011) argue that testosterone's influence is moderated by cortisol. High testosterone only leads to aggression when cortisol levels are low; when cortisol is high, the body's stress response blocks testosterone’s influence. Link: This dynamic shows that a single-hormone approach is oversimplified, meaning the explanation lacks the necessary scope to predict aggression without measuring broader endocrine interactions.

Genetic Factors & The MAOA Gene (AO1)

Twin and Adoption Studies: Twin studies reveal higher concordance rates for aggressive behavior in monozygotic (MZ) twins (approx. 50%) than dizygotic (DZ) twins (approx. 19%), suggesting a strong heritable component. Adoption studies show a significant correlation between an adopted child's aggressive behavior and their biological parents' criminal history.

• The MAOA Gene: This gene produces the enzyme monoamine oxidase A, which breaks down and recycles neurotransmitters (serotonin, dopamine, noradrenaline) in the brain.

• MAOA-L Variant: A low-activity genetic mutation (the "warrior gene") causes an initial buildup of these neurotransmitters during development, leading to dysfunctional receptor wiring and subsequently lower levels of serotonin activity in adulthood, driving impulsive, violent behavior.

• Gene-Environment (GxE) Interactions: The diathesis-stress model suggests the MAOA-L variant only triggers adult aggression if paired with early childhood trauma (e.g., physical or sexual abuse).

Genetic Factors (AO3)

1. Research Support for MAOA-L: Han Brunner et al. (1993) studied 28 male members of a large Dutch family who were repeatedly involved in impulsively aggressive crimes (arson, rape, assault) and discovered all of them possessed the rare MAOA-L genetic variant. Link: This provides powerful direct evidence for the "warrior gene" hypothesis, substantially increasing the internal validity of genetic origin explanations for violent behavior. 2. Strong Support for GxE Interactions: Frazzetto et al. (2007) found an association between high aggression and the MAOA-L variant, but only if the individual had experienced significant trauma in their first 15 years of life. Link: This supports a diathesis-stress framework, proving that genetic factors cannot be viewed in isolation and that the validity of the explanation depends on accounting for environmental triggers. 3. Limitation - Methodological Issues in Twin Studies: Twin studies assume equal environments, but identical (MZ) twins often look the same and are treated far more similarly by society than non-identical (DZ) twins. Link: Because the environment is not a controlled constant, the higher concordance rates found in MZ twins may reflect shared environmental treatment rather than pure heredity, confounding the reliability of genetic data.

Ethological Explanation (AO1)

Adaptive Functions: Ethologists (like Konrad Lorenz) argue aggression is an innate, instinctual drive that is adaptive because it ensures survival. It helps distribute a species evenly over a wider territory to reduce resource competition, and establishes dominance hierarchies, granting top-ranking males access to mates and food.

• Ritualistic Aggression: Animal encounters rarely end in death. They rely on stylized, ritualistic signaling (e.g., baring teeth, chest beating, submissive postures like a wolf exposing its jugular) to prevent physical injury and preserve the species' population.

• Innate Releasing Mechanisms (IRM) & Fixed Action Patterns (FAP): An IRM is an inbuilt neural network triggered by an environmental "sign stimulus." The IRM then releases a Fixed Action Pattern (FAP)—a sequence of stereotyped, universal, unchangeable, and ballistic behaviors (once started, it must be completed).

• Tinbergen’s Stickleback Research: Male sticklebacks aggressively attack any model fish, regardless of shape, as long as it features a red underbelly (the sign stimulus triggering the aggressive FAP).

The Ethological Explanation (AO3)

1. Research Support for Innate Mechanisms: Genetic and evolutionary studies reinforce the idea that basic structural mechanisms for survival are hardwired. Brunner’s work on the MAOA gene demonstrates a biological baseline for aggression that aligns with ethological premises. Link: This biological overlap provides cross-disciplinary corroboration, boosting the theoretical credibility of the ethological claim that aggression is rooted in innate drives. 2. Limitation - Ritualistic Aggression is Not Universal: Jane Goodall (2010) observed a "four-year war" where a community of chimpanzees systematically and violently slaughtered all members of a neighboring rival group. Link: This lethal, deliberate violence directly undermines Lorenz’s core assumption that non-human aggression is purely ritualistic and self-limiting, weakening the empirical foundation of the model. 3. Limitation - FAPs are Not Entirely Fixed: Modern ethologists have replaced "Fixed Action Patterns" with "modal behavior patterns" because environmental factors and learning can significantly alter these sequences. Link: This shift demonstrates that the original ethological view is too rigid, making it an inaccurate framework for explaining highly flexible and choice-driven human behaviors.

Evolutionary Explanations (AO1)

Sexual Jealousy & Cuckoldry: Human males face evolutionary pressure regarding paternity uncertainty. Unlike females, a male can never be 100% certain a child is biologically his, risking cuckoldry (raising another man's offspring, wasting his resources and failing to pass on his own genes).

• Mate Retention Strategies: To prevent cuckoldry, males evolved psychological mechanisms to retain their mates:

  • Direct Guarding: Monitoring a partner's behavior, tracking their whereabouts, or checking their communications.

  • Negative Inducements: Issuing threats of violence or financial ruin for infidelity.

• Physical Violence Against Partner: Evolutionary theory argues that mate retention strategies can escalate into physical abuse to intimidate partners and prevent them from straying.

• Evolutionary Explanation of Bullying: Bullying behavior historically allowed ancestors to dominate rivals, secure resources, and signal strength or reproductive fitness to prospective mates, making it an adaptive strategy for survival and gene transmission.

Evolutionary Explanations (AO3)

1. Real-World Application & Support: Margo Wilson and Martin Daly (1996) found that women who reported their partners using high levels of direct guarding and negative inducements were twice as likely to have experienced physical domestic violence. Link: This strong predictive link confirms the real-world utility of evolutionary concepts in identifying behavioral warning signs that precede physical relationship abuse. 2. Limitation - Cultural Differences: Aggression varies wildly across cultures; for example, the !Kung San people of the Kalahari actively discourage aggression from childhood, resulting in exceptionally low levels of violence. Link: Because aggression is not universal, this cultural variation severely compromises the evolutionary claim that violent behavior is a universal, hardwired adaptation mandatory for human survival. 3. Debate - Determinism vs. Free Will: The evolutionary argument is biologically determinist, suggesting that males are pre-programmed to be violently possessive to protect their genetic lineage. Link: By suggesting violence is an inescapable genetic drive, this explanation creates a dangerous social loophole that excuses criminal behavior and ignores human free will and personal accountability.

Social Learning Theory (AO1)

Direct vs. Indirect Learning: Albert Bandura argued aggression is learned through direct experience (operant conditioning via positive/negative reinforcement) and indirectly through observational learning of role models.

• Vicarious Reinforcement: Children observe the consequences of a model’s aggressive actions. If the model is rewarded (e.g., gets a toy by hitting someone), the child experiences vicarious reinforcement and is highly likely to imitate the behavior. If punished, imitation drops (vicarious punishment).

• Four Cognitive Mediational Processes: 1. Attention: Noticing the aggressive model. 2. Retention: Creating a mental representation/memory of the behavior. 3. Reproduction: Possessing the physical capability to replicate the actions. 4. Motivation: Having a reason or expected reward to perform the act.

• Self-Efficacy: The child's growing confidence in their ability to perform aggressive acts successfully. High self-efficacy forms when past aggression has successfully yielded rewards.

• Bandura’s Bobo Doll Studies: Children exposed to an adult model beating, kicking, and screaming at an inflatable Bobo doll imitated the exact physical and verbal behaviors when left alone with the doll, whereas the control group showed virtually zero aggression.

Social Learning Theory (AO3)

1. Strong Practical Applications: SLT explains how aggression can be reduced by introducing non-violent role models in media and ensuring aggressive behaviors are explicitly punished to provide vicarious punishment. Link: This practical utility gives the theory immense value, as it provides actionable, non-invasive strategies for parents, schools, and media policies to actively reduce societal violence. 2. Limitation - Underestimates Biological Factors: Bandura noted that boys were consistently more physically aggressive than girls across all experimental conditions, a difference SLT cannot explain on its own. Link: By ignoring the role of hormones like testosterone, the theory offers an incomplete account, demonstrating that social learning cannot fully explain aggression without incorporating biological variables. 3. Counterpoint to Lab Evidence: Bandura's Bobo doll experiments were conducted in artificial laboratory settings where the doll was explicitly designed to be hit and bounce back. Link: This artificial design means children may have simply been responding to demand characteristics rather than displaying genuine interpersonal aggression, weakening the ecological validity of the supporting research.

De-individuation (AO1)

Crowd Behavior: Gustave Le Bon (1895) proposed that individuals transform when submerged in a crowd. We lose our normal psychological constraints, personal identity, and sense of individual responsibility, taking on a collective "group mind."

• Conditions Promoting De-individuation: Anonymity is driven by being in a large crowd, wearing uniforms, disguises, masks, or operating under the cover of darkness. This reduces the fear of social disapproval and negative consequences.

• Reduced Self-Awareness: Prentice-Dunn and Rogers explained that anonymity reduces two types of self-awareness:

  • Private Self-Awareness: We focus less on our own internal thoughts, morals, and values.

  • Public Self-Awareness: We realize we are just one face in a crowd, meaning others cannot identify or judge us, causing a drop in behavioral restraint.

• Dodd’s Classroom Study: David Dodd (1985) asked psychology students what they would do if they could commit any act with complete assurance of not getting caught. 36% of responses involved antisocial behaviors (e.g., robbing a bank), and 26% were actual criminal acts, supporting the anonymity-aggression link.

De-individuation (AO3)

1. Real-World Observational Support: Leon Mann (1981) analyzed 21 instances of suicidal "baiting crowds" and found that when the crowd was large, far away, and it was dark outside, people regularly taunted the person to jump. Link: This dark real-world phenomenon provides strong empirical validation for the theory, proving that anonymity directly erodes typical moral constraints within large groups. 2. Limitation - Prosocial Outcomes: Gergen et al. (1973) placed strangers in a completely darkened room and found that instead of becoming aggressive, they began to hug, touch, and share intimate secrets. Link: This indicates that anonymity does not automatically trigger hostility, showing that the de-individuation theory is limited unless it accounts for the specific situational cues present. 3. Methodological Challenge (The Uniform Issue): Research shows that when participants are de-individuated using uniforms (e.g., Ku Klux Klan gowns vs. nurse outfits), their behavior shifts based on the social meaning of the clothing. Link: This proves that aggression is mediated by the social roles and expectations tied to anonymity, rather than being an automatic, unguided consequence of losing one's identity.

Institutional Aggression (AO1)

The Dispositional Explanation (The Importation Model): John Irwin and Donald Cressey (1962) argue that inmates bring (import) their pre-existing subcultures, criminal values, histories of violence, and personal traits (e.g., race, gang memberships, subcultural norms) from the outside world into the prison. Prison aggression is therefore a reflection of the individual's disposition, not the prison environment itself.

• The Situational Explanation (The Deprivation Model): Donald Clemmer (1958) argues prison aggression is caused by the stressful environment of the institution itself. Inmates are forced to cope with structural deprivations ("The Pains of Imprisonment"): deprivation of liberty, autonomy, goods/services, heterosexual relationships, and security. This creates immense frustration, which erupts into violence.

Institutional Aggression (AO3)

1. Support for the Importation Model: Matt DeLisi et al. (2011) studied juvenile offenders with pre-existing negative dispositional traits (e.g., childhood trauma, gang ties) and found they committed significantly more acts of physical violence in prison. Link: This research strongly confirms the validity of the importation model by proving that individual personal histories dictate institutional misconduct. 2. Support for the Deprivation Model: Benjamin Steiner (2009) investigated 512 US prisons and found that inmate-on-inmate violence was significantly higher in facilities characterized by structural overcrowding and high staff turnover. Link: This large-scale study confirms the reliability of situational explanations, proving that institutional environment design directly impacts safety and behavioral outcomes. 3. Interactionist Conclusion: Treating importation and deprivation as separate models is an oversimplification; dispositional traits determine who is vulnerable, but situational deprivations act as the trigger. Link: Therefore, a purely independent view of either model reduces explanatory power, meaning a holistic interactionist framework is required to fully understand prison violence

Effects of TV and Computer Games (AO1)

Excessive TV Viewing: Longitudinal studies (e.g., Robertson et al., 2013) show that the absolute quantity of TV watched during childhood, regardless of content, is a reliable predictor of aggressive behavior and criminal convictions in early adulthood due to reduced real-world social interaction.

• Violent Film Content: Bandura's follow-up studies showed children readily imitate aggressive models on screens if the content features violent acts rewarded or unpunished.

• Computer Games: Gaming may have a more powerful effect than TV for two reasons:

  1. Active Role: The player actively takes on the persona of an aggressive character rather than remaining a passive viewer.

  2. Operant Conditioning: The game actively rewards aggressive acts (e.g., points, leveling up for kills), reinforcing violent choices through positive feedback loops.

Media Influences (AO3)

Support from Meta-Analyses: Craig Anderson et al. (2010) conducted a meta-analysis of 136 studies and found that exposure to violent video games was significantly associated with increases in aggressive behaviors, thoughts, and feelings globally. Link: This widespread statistical consensus provides massive confirmation for the theory, showing that media exposure has a globally reliable effect on aggressive psychology. 2. Limitation - Methodological Issues (Correlation vs. Causation): Many studies are correlational, meaning they cannot establish whether violent media causes aggression or if naturally aggressive individuals simply choose to consume violent media. Link: This selection effect creates a major issue with internal validity, leaving the underlying causal direction of the media-aggression theory unproven. 3. Limitation - Artificial Measures of Aggression: Lab experiments cannot use actual violence, relying instead on surrogate measures like blasting an opponent with white noise in the Taylor Competitive Reaction Time Task. Link: Because these measures lack mundane realism, it remains highly questionable whether laboratory gaming data can validly predict physical, real-world criminal violence.

Media Mechanisms (AO1)

Desensitisation: Normally, witnessing violence triggers physiological arousal (activation of the sympathetic nervous system: sweating, increased heart rate). Repeated exposure to media violence numbs this natural response. The physiological shock diminishes, leading to lowered empathy for victims and a higher willingness to engage in real-world aggression.

• Disinhibition: Society conditions us with powerful internal moral and social restraints against using violence. However, media often portrays aggression as normal, justified, or rewarded. This alters cognitive schemas, lifting social constraints (disinhibiting the individual) and making aggressive outbursts seem acceptable.

• Cognitive Priming: Watching or playing violent media provides us with an internal "cognitive script" stored in memory. When we encounter a real-world conflict that mimics the media scenario, the script is automatically primed (triggered), causing us to react aggressively without thinking.

Media Mechanisms (AO3)

1. Research Support for Desensitisation: Barbara Krahe et al. (2011) measured skin conductance and found that regular consumers of violent media showed lower physiological arousal and less anxiety when watching violent clips. Link: This physiological data provides objective evidence supporting desensitisation theory, confirming that routine media consumption alters basic physical responses to violence. 2. Research Support for Cognitive Priming: Peter Fischer and Tobias Greitemeyer (2006) found that men who listened to misogynistic song lyrics later recalled significantly more negative qualities about a female confederate and behaved more aggressively toward her. Link: This successfully illustrates the mechanism of cognitive priming, proving that media exposure can immediately activate stored aggressive schemas to direct social behavior. 3. Alternative Explanation (Catharsis): The psychodynamic approach counterargues that viewing media violence is cathartic, allowing individuals to safely purge their aggressive impulses through a screen, which actually reduces real-world violence. Link: The existence of this viable, opposite explanation shows that the desensitisation and disinhibition models are contested, meaning alternative psychological pathways must be evaluated.