How is aggression biologically influenced

In animals, testosterone is linked to social aggression. Reducing testosterone in the alpha male by castrating him eliminates his dominant social status, and restoring testosterone through injection causes him to regain his social status. However, administering testosterone to males with less social status does not usually allow them to take over the alpha male position, indicating that there is not a direct relationship between testosterone and position in the dominance hierarchy.

There is some evidence in humans that high testosterone males are more likely to be socially aggressive, but no evidence that they are necessarily more violent. Often they are successful in professions that thrive on competition, such as successful leading of a company, running for president, or pursuing a sports career. Also, a few psychologists have suggested that females are not necessarily less aggressive than males; rather, they display a different kind of aggression.

Females are more likely to show non-violent types of aggression such as ostracizing their peers or spreading false rumors with the intent to cause pain. Several lines of converging evidence indicate that the neurotransmitter serotonin plays a key role in mediating aggressive and violent behavior. Mice with a selective knockout of the serotonin 1B receptor show an increase in aggression.

Similarly, depleting serotonin levels in vervet monkeys increases their aggressive behavior, whereas augmenting serotonin levels reduces aggression and increases peaceable interactions like grooming. Serotonin has also been implicated in human aggression. For example, pharmacological interventions that augment serotonergic efficacy have been shown to reduce hostile sentiment and violent outbursts in aggressive psychiatric patients.

Also, people with a history of impulsively violent behavior, such as arsonists, violent criminals, and people who die by violent methods of suicide show low levels of the serotonin in their cerebral spinal fluid.

These findings represent an interesting correlation, but it is important to remember that the direction of effect is unclear.

It may be that aggressive behavior induces low serotonin levels in the cerebral spinal fluid rather than vice versa. Adrian Raine and colleagues have conducted the largest and most thorough study to date, in which they used positron emission tomography commonly called a PET scan to compare brain activity in 41 convicted violent offenders to activity in 41 age matched control subjects.

They found that the people convicted of murder had reduced activity in the prefrontal cortex and increased activity in subcortical regions such as the thalamus. This finding fits nicely with previous research showing that the damage to the prefrontal cortex impairs decision making and increasing impulsive behavior.

However, it is important to remember that his subjects lie at the extreme end of a spectrum and may not be typical of most aggressors.

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Performance on indirect measures of race evaluation predicts amygdala activation. Journal of Cognitive Neuroscience, 12 5 , — Raine, A. The psychopathology of crime: Criminal behavior as a clinical disorder. If you're experiencing feelings of aggression, you can learn to manage your anger and cope in a more constructive way. Developing an anger management plan ahead of time can give you a roadmap to use when your emotions feel out of control.

That plan should include ways to reduce your stress levels, like:. If someone in your life is behaving aggressively toward you, it's important to protect your own mental health and physical safety. Try to stay calm and avoid escalating the conflict, and walk away if it's safe to do so. If you're facing aggression at the hands of an intimate partner, look out for warning signs that the relationship is becoming dangerous, and reach out for help and support.

If you or a loved one are a victim of domestic violence, contact the National Domestic Violence Hotline at for confidential assistance from trained advocates. For more mental health resources, see our National Helpline Database. Aggression involves several different regions of the brain.

The amygdala, hypothalamus, and periaqueductal gray are involved in recognizing an acute threat and generating an emotional response, while the prefrontal cortex plays a role in whether or not we act based on those emotions. Passive aggression is a way to express aggression indirectly. This kind of behavior is still intended to harm others, but it's often harder to identify and address.

Deliberately avoiding someone else or "forgetting" to complete assigned tasks can be examples of passive-aggressive behavior.

Reactive aggression, also known as impulsive aggression, happens in response to a specific trigger. This form of aggression isn't planned and is often associated with feelings of intense anger.

Hitting someone in response to an insult is an example of reactive aggression. Microaggressions are subtle behaviors that discriminate against a marginalized group of people.

Microaggressions can be intentional or they may reflect someone's implicit bias ; either way, they can have a cumulative, negative effect on the person being targeted. The goal of aggression is to harm someone who doesn't want to be harmed.

The motivation behind this varies from person to person. Someone may act aggressively as a response to pain or fear, while someone else may use aggression to achieve another goal, like taking another person's money or property. Aggression is often the byproduct of another underlying factor. Exploring and addressing that root cause can often help reduce aggressive behavior. If you're troubled by aggression, seeking professional mental health care may benefit you.

Anger management classes can help you learn how to avoid responding to intense emotions and how to manage aggression in a healthy, safe way. Ever wonder what your personality type means? Sign up to find out more in our Healthy Mind newsletter. Blair RJR. The neurobiology of impulsive aggression. J Child Adolesc Psychopharmacol.

The general aggression model. Curr Opin Psychol. The neurobiology of aggression and violence. He added: "Our findings also corroborate those of other studies, demonstrating that programs designed to prevent reactive aggression should focus on reducing experiences of victimization, whereas those meant to counter proactive aggression should be based on the development of pro-social values.

Materials provided by University of Montreal. Note: Content may be edited for style and length. Science News. Twins under the microscope The study's cohort of Quebec twins, which included sets of monozygotic twins with an identical genetic code and sets of fraternal twins, made it possible to determine whether the individual differences observed in proactive and reactive aggression were due to genetic or environmental factors.

Story Source: Materials provided by University of Montreal. Heterogeneity in the development of proactive and reactive aggression in childhood: Common and specific genetic - environmental factors. ScienceDaily, 20 December