Can a youth overcome life in a dysfunctional, drug-abusing household to become a contributing member of society? Making the switch isn’t easy. Streetwise once told me that he preferred to go to jail, where he’d have a warm bed and food, rather than spend the rest of his life on the streets.
Do people have a genetic predisposition toward being evil? When I look at conflicts around the world and growing divisions in our own country, I can’t help but revisit the old nurture vs. nature question. With human rights abuses mounting, I wonder whether science has learned more since the completion of the Human Genome Project.
Psychologists identify sadistic or callous individuals as those who score high on measures of lying, manipulativeness, lack of empathy, aggression, and criminality. Large twin studies suggest that traits associated with psychopathy are moderately to highly heritable. This means genetics plays a significant role. Individuals with stronger genetic predispositions showed higher levels of callousness and emotional detachment.
Psychopaths and sociopaths both disregard social norms, customs, and the rights of others without remorse. Sociopaths tend to be more impulsive and emotionally volatile. Their crimes are often spontaneous actions that may later cause them distress. Psychopaths are outwardly controlled and more elusive to recognition. They often lead outwardly normal lives, manipulating others by mimicking emotions they do not truly feel.
There is evidence that psychopathy has a stronger biological component, while sociopathy is more closely linked to trauma and neglect. Still, most researchers agree that behavior emerges from gene–environment interaction, not from genetics alone.
This question became personal for me when I learned of ongoing bullying in my granddaughter’s fourth-grade class. I wondered whether those children had been subjected to violence or neglect at home. That instinct aligns with research showing that early adversity is one of the strongest predictors of later aggression. I felt the school needed to address it immediately so the children wouldn’t carry unresolved trauma into adulthood, potentially harming others.
What my intuition didn’t fully consider was how biology can influence those experiences. One gene I read about is MAOA, sometimes called the “warrior gene.” Certain variants of MAOA affect how the brain regulates neurotransmitters linked to mood and impulse control. Research suggests these variants are associated with increased risk of aggressive or antisocial behavior, especially when combined with childhood trauma. Children without that genetic vulnerability appear more likely to overcome early abuse. Those with both the gene variant and early trauma were more likely to be convicted of violent crimes later in life.
When neuroscientist Christian Jarrett was asked whether there is evidence-based therapy for individuals with psychopathic traits, his answer was cautious. Recently, New Zealand psychologists have called the belief that psychopathy cannot be treated a myth. New evidence suggests that intensive cognitive behavioral programs can reduce violent behavior and help some individuals experience empathy and regret, even though their core personality traits remain unchanged.
Another emerging field, epigenetics, further complicates the story. Severe stress or trauma can leave chemical markers on genes involved in stress regulation, altering how those genes are expressed. Research involving Holocaust survivors and other victims of political violence suggests these effects may persist across generations, allowing violence and neglect to continue beyond a single lifetime.
Unfortunately, cruelty can also feel rewarding in the short term. For some, fighting and hurting others is exciting, giving a sense of power. Since the neurochemicals responsible for those feelings don’t last, it often leads to repeated acts of cruelty in search of stimulating this pleasure response. The cycle most often has a negative impact on the perpetrator’s health.
By contrast, good deeds such as helping, cooperating, and caring activate brain systems linked to long-term well-being. Kindness and generosity are associated with lower stress, better health, and sustained happiness. Goodness reinforces itself, also propelling a cycle that makes people want to do more.
When we look at today’s political landscape, the violent treatment of immigrants, waiting for deportation, the killing of drug suspects willing to surrender, and the disproportionate incarceration of people based on skin color, I feel fear. I am tempted to wonder whether sociopaths or psychopaths are at the helm, knowing that what they are doing is a crime against humanity.
Though genes matter and trauma matters, having a trustworthy leader matters more. If we want a future with less fear and violence, we must focus on electing leaders who reduce harm, protect children and citizens, and build environments that reward empathy rather than cruelty.
References:
Stokstad,E. (2002) Violent Effects of Abuse Tied to Gene. Science. Retrieved from https://www.science.org/content/article/violent-effects-abuse-tied-gene
Jarrett,C. (2025). Can people have a genetic predisposition towards being evil? BBC Science Focus. Retrieved from https://www.sciencefocus.com/the-human-body/can-people-have-a-genetic-predisposition-towards-being-evil
Jarrett,C. (2025) Is there a cure for evil? BBScience Focus. Retrieved from https://www.sciencefocus.com/the-human-body/is-there-a-cure-for-evil
(2025) Violence alters human genes for generations, researchers discover. Science Daily.
Viding, E., & McCrory, E. (2019). Towards understanding atypical social affiliation in psychopathy. The Lancet Psychiatry, 6(5), 437–444.
Glenn, A. L., & Raine, A. (2014). Neurocriminology: Implications for the punishment, prediction and prevention of criminal behaviour. Nature Reviews Neuroscience, 15, 54–63.
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