Why Do People Become Radicalized and Commit Violent Acts?

By Dr. LaLanya Fair  |  07/16/2025

Why do normal people become radicalized and become violent extremists? It is an age-old question and one that continues to stir concern because it’s difficult to find answers. What is the catalyst – the trigger or the significant event – that attracts someone to extremist ideas and behaviors?

Most people often seek companions who have similar views or backgrounds, such as friends with shared values. For people who hold radical beliefs, this need to feel part of a group is especially strong.

This tendency toward joining a group of like-minded people enables extreme ideologies related to either domestic terrorism or international terrorism to take root and flourish within tight-knit communities. While social dynamics are powerful, it can also be argued that biological factors – not just environmental factors – can influence radicalization.

The truth is that various factors can have a lot to do with how and why a person becomes motivated to have extreme views and commit extremist acts.

What Biological Factors Contribute to Aggression and Violence?

There have been numerous studies that provide evidence to support that genetic factors can influence aggressive and antisocial behavior. While there is no single gene that can be identified as an “aggression gene,” research has found that people prone to extremism may share identifiable psychological identifiers, including violent tendencies.

However, there are many factors that may heighten a person’s likelihood to acting on their aggressive impulses. They include:

• Neurochemical imbalances
• Neuroanatomical factors
• Hormonal influences
• Genetic influences

Neurochemical Imbalances

Dopamine and norepinephrine are neurotransmitters that can increase aggressive responses when they are not regulated. Similarly, a low serotonin level is associated with poor emotional regulation and impulsivity.

Neuroanatomical Factors

Heightened aggression is associated with overactivity of the amygdala, which processes emotional responses like anger and fear. Also, the prefrontal cortex is responsible for decision-making and impulse control. When its function is impaired, it can cause increased aggression.

Hormonal Influences

Stress can cause people to have abnormal cortisol responses, which trigger aggressive behavior. Similarly, increased male aggression has been linked to elevated testosterone levels.

Genetic Influences

Some genetic studies that focus on twins and adoption have suggested that there can be a variance of up to 50% in aggressive behavior attributed to genetics, which could include traits linked to extremist groups.

When combined with early-life trauma, low-activity variants of the monoamine oxidase A (MAOA) gene, also known as the warrior gene, may increase the likelihood of aggression and susceptibility to recruitment from extremist or terrorist groups.

Social Factors Can Accelerate the Radicalization Process

However, biology does not act in isolation, and environmental influences may also play a role in forming aggressive behavior. Social factors can be strong motivators to quell or strengthen certain predisposed behaviors when someone is given the right opportunities.

There are many social factors, including exposure to extremist messages, that can play a critical role in people becoming radicalized more quickly. They include:

• Structural and environmental factors
• Perceived injustice and grievances
• Peer influence and social networks
• Ideological indoctrination and charismatic leadership
• Identity crises and a need to belong

Structural and Environmental Factors

Political instability and institutional distrust within a country can be fertile breeding grounds for domestic terrorism. Also, factors such as a lack of education, socioeconomic deficiencies, and exposure to conflict or violence can play a part in influencing extremists’ thinking.

Perceived Injustice and Grievances

Political and social grievances – including discrimination, perceived oppression, and inequality from a government – may influence the decision to turn from a normal citizen to a terrorist. Propaganda that frames violence as a legitimate response to right certain wrongs committed by government leaders or certain social groups can often be spread through the internet, making it much easier for recruiters to find people who are vulnerable to the messages of extremism.

Peer Influence and Social Networks

Close-knit social groups, online communities, and real-life peer groups can serve as echo chambers for terrorists. Often, radical ideas and extremism are reinforced and supported through social bonding.

Ideological Indoctrination and Charismatic Leadership

Recruiters working for terrorist groups have been known to manipulate vulnerable individuals by using ideological framing and emotional appeals to justify violence. Often, terrorist groups are led by highly charismatic leaders who are appealing to their followers.

Identity Crises and a Need to Belong

People feeling marginalized or alienated, perhaps after a personal crisis involving family members, sometimes seek out similar people or groups to feel a sense of family and belonging. Sometimes, those groups are very good at identifying individuals who believe in extreme ideologies and are highly effective in convincing others to get involved in extremist groups.

Environmental Factors Can Amplify Biological Factors

Biological predispositions and social factors may lay the foundation for aggression, but environmental influences often determine whether those tendencies are suppressed or intensified.

One example is that individuals with a biological vulnerability, such as neurochemical imbalances or certain genetic markers, may be more prone to environmental stressors such as:

• Early-life trauma
• Socioeconomic adversity
• Exposure to violence

Environmental stressors can alter brain function and development, predominantly in areas like the prefrontal cortex and amygdala. These parts of the brain are crucial for impulse control and emotion regulation.

Environmental influences like cultural norms, family dynamics, and media exposure can strengthen aggressive behaviors, especially if individuals are already predisposed toward aggression. Similarly, hormonal responses (e.g., elevated testosterone or cortisol) and neurotransmitter systems (e.g., serotonin and dopamine) are also modulated by environmental experiences, further influencing aggression.

Examples of Environmental Factors That Can Lead to Violent Extremism

There are numerous examples that validate how environmental factors can impact biological mechanisms contributing to aggression and violence, such as:

• Gene-environment interactions – Research has shown that individuals with certain genetic predispositions (e.g., MAOA gene variants) are more likely to exhibit aggressive behavior when exposed to early-life stressors such as abuse or neglect. This interaction between genes and the environment significantly increases the risk of antisocial behavior.
• Stress and brain development – Chronic exposure to stressful environments, such as poverty, violence, or family dysfunction, can alter the development of brain regions like the amygdala and prefrontal cortex. These areas are crucial for emotional regulation and impulse control, and their dysregulation is linked to increased aggression.
• Neuroendocrine responses – Environmental stressors can influence hormonal systems, such as cortisol and testosterone levels, which are associated with aggressive behavior. For example, children exposed to domestic violence often show altered cortisol rhythms, which may predispose them to reactive aggression.
• Social learning and neuroplasticity – Observing aggressive behavior in one’s environment (e.g., through media or family members) can shape neural pathways through repeated exposure, reinforcing aggressive responses as learned behaviors.

How Extremist Ideologists Escalate to Commit Violent Acts

A study by the RAND Corporation, Violent Extremism in America, provides an excellent example of why radicalization occurs. The study analyzed 32 individuals – 24 white supremacists and 8 Islamic extremists. Most of the subjects had histories of abuse, bullying, or emotional trauma, and several struggled with isolation or identity crises.

The Four Stages of the Radicalization Process

There are four commonly known stages of the radicalization process:

• Stage One: This stage happens when an individual is first exposed to internet material describing radical ideals from extremist groups. The person feels disconnected, alienated, or disenfranchised from mainstream society, so the extremist messages are compelling.
• Stage Two: In these early stages, repeated exposure to extremist material can lead the individual to adopt radical thoughts.
• Stage Three: This stage occurs when a person moves from expressing hate through speech or internet content to actively planning to commit a crime. This stage is known as the “acceptance of violence” stage, when the terrorist starts conducting research, chooses a location, and obtains weapons.
• Stage Four: Preparations for a violent act intensify, and the individual moves toward carrying out the organized crime.

Early Intervention Can Prevent Children from a Predisposition to Violence

When people are surrounded by positive, supportive environmental influences, that can help deter individuals who are genetically predisposed to violence and terrorism. It is crucial to act early to support anti-terrorism efforts.

First, supportive parenting and stable home environments can be helpful. Studies show that when children who have genetic risk factors for aggression (such as low-activity MAOA gene variants) have a supportive home life and parents, they are significantly less likely to develop violent behaviors. Children thrive in a nurturing, structured, and emotionally supportive environment.

Second, communities and local authorities seeking to prevent terrorism can adopt early intervention programs. Programs that focus on emotional regulation, conflict resolution, and social skills, especially in early childhood, can reduce violent intentions and mitigate personal vulnerabilities.

Third, education and community engagement can lessen the sense of social isolation and make joining terrorism groups less attractive. Young people who have access to mentoring, quality education, and positive peer influences can reshape their behavioral trajectories, even for high-risk youth.

The brain’s ability to adapt means that positive experiences, like consistent caregiving, therapy, and social support, can alter neural pathways associated with aggression and impulse control. In other words, positive experiences can reshape people’s behavior, even later in life.

Young people growing up in aggressive or violent households can benefit significantly from early and sustained support to deter them from future violence or terrorism.

Some useful techniques for preventing violence include:

• Early intervention – The brain is most malleable in early childhood (ages up to 5 years). Intervening during the early stages can shape children’s emotional regulation, empathy, and impulse control. Also, high-quality early childhood education, nurturing caregiver relationships, and structured environments help children develop self-control and social skills.
• Safe, stable, and nurturing relationships – Consistent, supportive relationships buffer the effects of toxic stress and trauma. Parenting programs, home visits, and caregiver training can teach non-violent discipline, emotional coaching, and conflict resolution.
• Life skills development – Acting early and teaching children how to manage emotions, solve problems, and communicate effectively reduces aggression. School-based social-emotional learning (SEL) programs and community mentoring initiatives can have long-term benefits.
• Community and school engagement – Positive peers and adult role models outside the home can reinforce prosocial behavior. For instance, after-school programs, such as sports, arts, and civic engagement activities, provide children with structure and a sense of belonging.
• Trauma-informed care – Many children in aggressive households experience Adverse Childhood Experiences (ACEs), which increases the risk of mental health challenges, violence, and extremism. As a result, access to mental health services, trauma-informed schools, and resilience-building interventions are critical.

Preventing Radicalization and Violent Extremism Is a Shared Responsibility

Why do people join extremist groups and become terrorists? The true answer lies in a complex web of biological predispositions and environmental influences. No single factor causes individual radicalization, but genetics, trauma, social conditions, and early experiences can all set the stage for violent extremism.

Adults – especially parents, educators, and mentors – play a vital role in guiding young people away from extremist beliefs and discouraging the reading of extremist content. They can be highly influential in helping children and teenagers to build their resilience against harmful influences and potentially dissuade future acts of terrorism.

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American Military University (AMU) provides an online Bachelor of Arts in Homeland Security for adult learners seeking to improve their knowledge of terrorism, homeland security, and other related topics, This degree program offers a variety of courses, including critical infrastructure protection, border and coastal security, and intelligence and homeland security. Other courses include the mind of a terrorist, risk communications, and homegrown violent extremism.

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