3.4.1, 3.4.2 - Aggression and social responsibility

What a biological contribution means

A biological contribution can help explain vulnerability to aggression without making an aggressive outcome inevitable.

The prefrontal cortex contributes to regulating behaviour, while networks involving limbic regions contribute to emotional responding. Changes in their functioning may affect inhibition or reactions to threats. Raine’s PET study found a pattern of regional differences in a selected NGRI sample, consistent with a possible predisposition. It did not show that every aggressive person has that pattern, that the differences were inherited or that they preceded the offences.

Hormones provide another possible influence. Testosterone can be related to status-seeking and responses to challenge, with effects depending on circumstances and other characteristics. A higher hormone level is not a direct instruction to attack. Competition and behaviour can themselves affect hormones, so a relationship between testosterone and aggression does not automatically establish one causal direction.

Evolutionary explanations propose that dispositions could have affected survival or reproductive success in ancestral conditions. This can generate predictions about competition, but it does not mean that current violence is beneficial, justified or unavoidable. An explanation of why a disposition might have developed is different from a decision about how people should treat one another today.

Brendgen’s twins provide a further qualification. Physical-aggression variation showed more genetic contribution than social-aggression variation, with substantial environmental contribution in both. Heritability concerns differences in a population under particular conditions, not the proportion of one person’s acts caused by genes. Experiences can shape a developing brain as well as influence the use of aggressive strategies.

The social question should therefore be discussed as one about contributing mechanisms and risk. Framing it as “nature instead of nurture” can conceal interaction and lead society to overlook modifiable circumstances.

Support and prevention in society

Biological understanding can direct attention towards support while also explaining why intervention must address more than biology.

Consider a fictional adult who develops difficulty controlling angry responses after a brain injury. Recognising a possible contribution from injury could encourage professional assessment, rehabilitation and practical adjustments, such as reducing confusing demands and providing strategies for pausing during conflict. It may also encourage compassion rather than assuming that every difficulty is deliberate. A scan alone cannot prescribe an intervention; assessment needs the person’s functioning, circumstances and preferences.

The same reasoning supports combined prevention. Help with emotional regulation, safe social environments and changes in reinforcing consequences may reduce the occasions on which a vulnerability becomes harmful. Brendgen’s greater environmental contribution to social aggression makes peer and classroom experiences particularly relevant hypotheses for prevention. The study did not test a programme’s effectiveness, so a school would still need evidence that its chosen intervention helps.

Biological accounts could guide research into treatments aimed at identified mechanisms. However, it would be unjustified to assume that changing a hormone or brain signal reliably removes aggression. Treatments require professional oversight, evidence of benefit and consideration of adverse effects, consent and alternatives. Behavioural improvement is an outcome to assess, rather than something guaranteed by changing a biological measure.

Resources also involve social choices. Providing assessment and support may prevent harm, but expensive screening without useful individual prediction could divert funds from effective services. The relevant question is whether a proposed use adds a demonstrated benefit and treats people fairly.