Aggression

Which subcortical structure of the limbic system, whose electrical stimulation in animal studies raises attack behaviour, is most strongly associated with reactive aggression?

• AThe cerebellum
• BThe amygdala✓
• CThe corpus callosum
• DThe substantia nigra

Answer: The amygdala is the limbic structure central to evaluating sensory information and generating an aggressive/threat response; stimulation tends to increase aggression and damage tends to reduce it. The cerebellum coordinates movement, the corpus callosum links the hemispheres, and the substantia nigra is involved in dopamine and motor control.

How does the neurotransmitter serotonin most plausibly relate to aggression according to the neural explanation?

• AHigh serotonin activity causes aggression by over-exciting the limbic system (the amygdala and the hypothalamus in particular)
• BSerotonin drives aggression through the pituitary gland, which converts it into a hormone that triggers attack
• CSerotonin raises circulating testosterone, and this surge of testosterone directly triggers attack behaviour
• DLow serotonin reduces inhibitory control of the orbitofrontal cortex, increasing impulsive aggression✓

Answer: Serotonin normally exerts an inhibitory, calming effect via the prefrontal/orbitofrontal cortex. Low serotonin activity reduces this top-down inhibition, so impulses are less controlled and impulsive aggression rises. The other options reverse the direction or invent unsupported mechanisms.

Studies such as those reviewed by Dabbs report that prison inmates with the highest testosterone levels are more likely to have committed violent crimes. What is the main limitation in concluding that testosterone causes aggression here?

• ASalivary assays cannot detect testosterone accurately enough for the reported levels to be trusted
• BTestosterone shapes physical development, but leaves social or emotional behaviour untouched
• CThe data are correlational, so aggression or social dominance could raise testosterone rather than the reverse✓
• DThe samples were adolescents in youth custody (not adult prisoners), so the findings cannot be generalised

Answer: Such studies are correlational; a relationship between testosterone and violence does not establish causal direction. Aggressive or dominant behaviour may itself elevate testosterone (reciprocal influence), so cause and effect cannot be separated.

Brunner et al. (1993) studied a large Dutch family in which several males showed impulsive aggression. What genetic feature did the affected men share?

• AA point mutation producing a low-activity (deficient) variant of the MAOA gene✓
• BAn extra Y chromosome (XYY syndrome)
• CA duplication of the serotonin transporter gene (5-HTT)
• DA trinucleotide repeat expansion on chromosome 4

Answer: Brunner identified a point mutation in the MAOA gene leading to MAOA deficiency (the low-activity, MAOA-L form) in affected males. MAOA breaks down neurotransmitters such as serotonin; low activity is linked to impulsive aggression. This low-activity variant later became popularly known as the warrior gene.

The MAOA gene is often described as the 'warrior gene'. Which finding best captures why a purely genetic account of aggression is considered incomplete?

• AThe MAOA gene sits on the X chromosome and is expressed in women alone, so it cannot explain male violence
• BCaspi et al. (2002) found the low-activity MAOA variant predicted antisocial behaviour mainly in those who had also been maltreated in childhood✓
• CTwin studies show that identical and non-identical pairs share aggressive tendencies at exactly the same rate, ruling out genes
• DThe MAOA gene codes for an enzyme (MAOA) that builds serotonin up rather than breaking it down

Answer: Caspi et al. (2002) showed a gene-environment interaction: the low-activity MAOA genotype predicted later antisocial/aggressive behaviour largely in men who had been maltreated as children. This diathesis-stress pattern shows genes act in concert with environment, not alone.

In the ethological explanation of aggression, what is a 'fixed action pattern' (FAP)?

• AA stereotyped, innate behaviour sequence that, once triggered by a sign stimulus, runs to completion✓
• BA learned sequence of behaviour acquired through reinforcement
• CA conscious decision to attack a rival
• DA temporary increase in testosterone, released just before a fight

Answer: Lorenz described FAPs as innate, stereotyped, universal behaviour sequences released by a specific sign stimulus via the innate releasing mechanism; once started they typically run to completion (ballistic). They are not learned and are not conscious choices.

Tinbergen's classic study of the male three-spined stickleback supports the ethological account because the fish attacked any model showing a red underside, regardless of shape. What does the red belly act as?

• AA fixed action pattern, the stereotyped attack sequence itself
• BAn unconditioned response, never learned but present from birth
• CA sign stimulus (releaser) that triggers the innate releasing mechanism✓
• DA form of displacement activity, such as redirected nest-building

Answer: The red underside of a rival male is the sign stimulus (releaser) that activates the innate releasing mechanism, triggering the aggressive fixed action pattern. Even crude models with a red belly were attacked, whereas accurate models without red were not.

According to evolutionary explanations, why might male sexual jealousy have evolved as a driver of aggression?

• AIt increases the number of offspring a female can produce
• BIt lowers the level of conflict between rival males competing for a mate
• CIt is a by-product (a spandrel) of low serotonin in the cortex, amygdala and hypothalamus
• DIt functions as a mate-retention strategy guarding against cuckoldry and the resulting loss of paternal investment✓

Answer: Because paternity is uncertain, a man risks investing in offspring that are not his (cuckoldry). Sexual jealousy and associated mate-retention behaviours (including aggression and mate-guarding, as studied by Wilson and Daly) are argued to have been adaptive in reducing this risk.

The original frustration-aggression hypothesis (Dollard et al., 1939) was reformulated by Berkowitz (1989). What was Berkowitz's key modification?

• AFrustration creates only a readiness for aggression (negative affect), which becomes actual aggression in the presence of aggressive cues✓
• BFrustration always and inevitably leads to aggression
• CAggression arises from an innate ethological drive that accumulates until it is discharged, making frustration irrelevant to whether attack occurs
• DPhysical obstruction produces aggression, whereas psychological frustration does not

Answer: Berkowitz argued frustration produces negative affect, creating a readiness to aggress rather than guaranteed aggression. Whether aggression occurs depends on environmental cues (e.g. the weapon effect, Berkowitz and LePage 1967). This addressed the original claim's over-determinism.

Deindividuation theory explains aggression in crowds primarily through which mechanism?

• AA reduced sense of individual identity and lowered self-awareness, weakening normal restraints on behaviour✓
• BIncreased private self-awareness, personal accountability and concern for reputation within the crowd
• CA surge in serotonin (normally a calming neurotransmitter) brought on by the physical presence of a large group
• DClassical conditioning, in which fear responses learned earlier are triggered again by the sight of a crowd of people

Answer: Deindividuation involves a loss of personal identity and reduced public/private self-awareness in situations such as crowds or anonymity, which loosens the internal restraints that normally inhibit antisocial behaviour. Zimbardo and the Stanford prison study are often cited in support.

What role does the limbic system play in aggression?

• AThe cerebellum and brain stem regulate aggressive responses
• BThe amygdala and hippocampus regulate aggressive responses✓
• CThe frontal cortex alone controls all aggressive behaviour
• DThe limbic system has no established role in aggression

Answer: Amygdala reactivity predicts aggressive responses, and the hippocampus provides the context that lets a threat be interpreted. Serotonin normally inhibits the response, so low levels are linked to impulsive aggression.

What does the frustration-aggression hypothesis propose?

• AAggression is learned entirely by observing aggressive models
• BAggression is an innate drive that must be released periodically
• CBlocked goals create frustration which is displaced onto a target✓
• DFrustration always leads directly to aggression against its cause

Answer: Dollard argued that frustration causes aggression, often displaced onto a safer substitute when the source is unavailable or too powerful. Berkowitz revised it, arguing frustration creates readiness which cues then trigger.

What is deindividuation?

• ALoss of memory for aggressive acts committed in a group
• BThe tendency to identify strongly with a chosen group
• CThe process of being singled out from a larger crowd
• DLoss of personal identity and restraint within a group✓

Answer: Anonymity reduces private self-awareness and accountability, so behaviour becomes governed by group norms. Zimbardo's hooded participants gave longer shocks, and online anonymity is the modern application.

What did the importation model of institutional aggression propose?

• APrison conditions themselves generate the violent behaviour
• BAggression is imported through contact with visiting families
• CAggression is learned from prison staff rather than inmates
• DPrisoners bring their existing violent characteristics inside✓

Answer: Irwin and Cressey argued dispositional characteristics predict violence, so gang membership before prison predicts violence inside. The deprivation model is the situational alternative, blaming overcrowding and lost freedoms.

What is the ethological explanation of aggression?

• AAggression is learned by observing and then imitating other people
• BAggression results from frustration at goals which have been blocked
• CAggression is caused by high testosterone levels alone
• DAggression is innate and ritualised, ending in appeasement✓

Answer: Lorenz argued that intra-species aggression is largely ritualistic, with innate releasing mechanisms and fixed action patterns, so real damage is rare. Human warfare is difficult to reconcile with the account.

What is a genetic explanation linked to aggression?

• AHigh MAOA activity associated with higher aggression
• BThe presence of an extra X chromosome in males
• CLow MAOA activity associated with higher aggression✓
• DAbsence of the serotonin transporter gene entirely

Answer: The MAOA-L variant breaks down neurotransmitters less efficiently and is associated with aggression, particularly when combined with childhood maltreatment. That interaction is itself evidence for diathesis-stress.

What does desensitisation explain about media influence?

• ARepeated exposure increases the emotional response to violence
• BExposure temporarily removes normal social restraints
• CRepeated exposure reduces the emotional response to violence✓
• DExposure creates mental scripts for handling conflict

Answer: Physiological arousal to violence falls with repeated exposure, so it is perceived as more normal. Disinhibition concerns loosened restraints and cognitive priming concerns stored scripts — three distinct mechanisms.

What is a criticism of the evolutionary explanation of aggression?

• AIt has no supporting evidence at all from any animal species
• BIt cannot account for aggression in males of the species at all
• CIt relies entirely on laboratory experiments with humans
• DIt struggles to explain why many people are never aggressive✓

Answer: If aggression were universally adaptive it should be far more consistent, and the account offers little explanation for cultural variation or for non-violent societies. It also risks being used to excuse violence as natural.

What did Bandura's Bobo doll studies demonstrate?

• AChildren imitate aggression they have observed in a model✓
• BChildren only imitate aggression when they are rewarded
• CChildren become less aggressive after watching aggression
• DAggression in children is unrelated to what they observe

Answer: Children who saw an adult attack the doll reproduced the specific behaviours. The doll is designed to be hit, so the study may measure novelty rather than genuine aggression, and demand characteristics are likely.