What makes a criminal a criminal?

Q: Why do some people commit crimes? What does science say about it?

Krishna: It is easy to blame people. But did you know that the way your brain wires or rewires because of different situations it encounters dictates its processing and results in a person's behaviour?

Personality is a major factor in many kinds of behavior, one of which is criminal behavior. To determine what makes a criminal “a criminal,” we must understand his/her personality.

Are criminals born or made? This question has baffled psychologists, sociologists, and criminologists for many years, and efforts have been made to establish the nature of criminality. The born or made argument, known as the “nature versus nurture” debate, arises the question, whether criminality is due to genetic factors, biochemistry, neurobiology and therefore unavoidable, or whether it is the product of social, situational, environmental surroundings, and other external factors.

Earlier it was thought that home life, upbringing, inconsistent affection, physical abuse, and inconsistent discipline could result in criminality. Another area that may suggest an individual's personality is likely to cause criminal behaviour is that of psychopathy.

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Brain circuits play a significant role in regulating behaviour, and abnormalities in specific brain regions and pathways have been linked to criminal behaviour. Key areas of interest include the prefrontal cortex, which is involved in decision-making and impulse control, and the amygdala, which is crucial for processing emotions like fear and aggression. Damage or dysfunction in these areas can lead to traits often associated with criminal behaviour, such as impulsivity, poor judgment, and aggression. 

Research has been conducted on this aspect which shows Key Brain Areas and Their Roles in abnormal behaviour:

Prefrontal Cortex: This area is responsible for executive functions like planning, decision-making, and impulse control. Damage to the prefrontal cortex can impair these functions, leading to increased impulsivity and difficulty regulating behaviour, which can increase the risk of criminal behaviour, according to experts.

Amygdala: The amygdala plays a central role in processing emotions, particularly fear and aggression. Abnormalities in the amygdala can lead to heightened aggression, difficulty regulating emotional responses, and increased risk-taking behaviour, all of which are relevant to criminal behaviour. 

White Matter Tracts:White matter tracts, such as the uncinate fasciculus, connect different brain regions, allowing for communication and coordinated activity. Damage to these tracts, particularly the right uncinate fasciculus, has been linked to criminal behaviour, especially violent offenses, according to News-Medical. 

Research Findings:

Brain Injury and Criminality: Studies have shown that brain injuries, particularly to the prefrontal cortex and white matter tracts, can be associated with a higher likelihood of engaging in criminal behaviour. 

Specific Brain Regions:Research has identified specific brain regions, including the orbitofrontal cortex, anterior cingulate cortex, and dorsolateral prefrontal cortex, that are significantly reduced in size and function in individuals with antisocial and violent behaviour. 

Neuroimaging Evidence: Neuroimaging techniques, such as MRI and fMRI, are increasingly used to study brain structure and activity in individuals with criminal behavior, providing valuable insights into the neural underpinnings of these behaviors. 

Cautions and Considerations: 

Causation vs. Correlation: While studies have identified correlations between brain abnormalities and criminal behaviour, it is crucial to distinguish between correlation and causation. It's not always clear whether the brain abnormalities are a cause or a consequence of criminal behaviour. 

Individual Variability: Brain structure and function vary significantly between individuals. Not everyone with brain abnormalities will engage in criminal behaviour, and many individuals with criminal behaviour do not have identifiable brain abnormalities. 

Ethical Implications:The use of neuroimaging evidence in legal settings raises ethical considerations about free will, responsibility, and the potential for bias. 

Need for Further Research: More research is needed to fully understand the complex relationship between brain circuits and criminal behaviour, including the interplay between biological, psychological, and social factors. 

Recently I read an interesting research paper* which says ....

Injury to specific brain connections could explain some people's criminal behaviour.

Over the past decades, some lawyers have started using brain imaging scans as evidence during criminal trials, to provide a possible explanation for the criminal behavior of defendants. This was justified by recent neuroscientific studies, which found that some people who commit crimes present differences in specific parts of the brain. Yet a key question remains: are these brain changes causal, compensatory or incidental to the behaviour?

To answer this question, researchers analyzed the locations of brain injury temporally associated with a new onset of criminality.

They found evidence suggesting that lesions to a specific white matter tract could be causally implicated in the behavior of individuals who start committing crimes after injury.Their findings, published , could help inform future juridical and medical practices, helping lawyers, judges and neurologists to identify individuals who might have been prompted to commit crimes as a result of injuries, strokes or other diseases.

While it is generally accepted that brain injury can lead to problems with memory or motor function, the role of the brain in guiding social behaviors like criminality is more controversial as it touches on the concepts of moral culpability and free will.

 Researchers wanted to pin-point specific patterns of brain injury that are associated with newly exhibited violent and criminal behaviour, particularly in individuals that were previously unaggressive and law-abiding.

 To unveil these patterns, they studied rare clinical cases, specifically those from patients who started committing crimes after a brain injury.

They mapped the locations of brain injury from 17 cases of lesion-induced criminality and calculated the structural connections from a large brain atlas derived from 178 healthy controls. They then compared the connections associated with criminality to 706 control lesions from brain injuries associated with other symptoms such as memory loss or depression.

When they analyzed the imaging data of the 17 patients and compared it to that of individuals with no history of criminality, the researchers uncovered a pattern of brain injury that appeared to be most strongly linked to the emergence of criminal behaviour, particularly violent offenses. This pattern was characterized by lesions to a specific white matter tract known as the right uncinate, which connects brain regions responsible for emotion processing with other regions involved in decision-making.

A key question in the courtroom is often whether a specific white matter brain injury identified on a brain scan is incidental, correlated or causal to a behaviour. These new results suggest that if an individual has a new brain injury to specific white matter locations, especially to the right uncinate fasciculus, and has new onset criminal behavior, there is an increased likelihood that the injury plays a causal role in the behaviour

The results of this recent study suggest that lesions to the right uncinate fasciculus, whether as a result of physical trauma or a disease, can help to explain why some injured individuals suddenly start committing crimes.

Further research could examine the link between these specific lesions and criminal behaviour, potentially examining an even larger pool of clinical cases.

These findings can help assess whether focal brain injuries may be implicated in new-onset criminality and contribute to our growing knowledge about how social behaviour is mediated by the brain

(* Isaiah Kletenik et al, White matter disconnection in acquired criminality, Molecular Psychiatry (2025). DOI: 10.1038/s41380-025-03076-z )

Now let me ask you a question. A schizophrenic hallucinates that his mother standing in front of him is his enemy trying to kill him. His brain tells him to kill the person standing in front of him. Then he kills his mother. 

Such things happen. Who do you blame then? When your brain goes haywire, your brain circuits malfunction, who or what is responsible for your behaviour? 

Therefore, before blaming someone, you have to fully study and understand what made the person such a criminal.

Criminals? Their brains are differently wired!

Why? When several factors dictate outcomes, the results are  the display of interplay of scientific rules and reaction realities!