Can you make a sociopath—either through brain injury or other types of trauma?

— Chris Daly
, via e-mail

Jeannine Stamatakis, an instructor at various colleges in the San Francisco Bay Area, explains:

Psychologist John Watson, the founder of behaviorism, once said, “Give me a dozen healthy infants, well formed, and my own specified world to bring them up in, and I'll guarantee to take any one at random and train him to become any type of specialist I might select.”

If we take Watson's logic one step further, it may be possible to mold someone into a psychopath. Psychopathy, also called sociopathy, is defined by a lack of empathy, deceitfulness and complete selfishness. Current thinking is that although certain genes may predispose people toward psychopathy, their environment seems to provide the ultimate catalyst. Thus, a person who possesses the particular genes associated with this malady and is brought up in an abusive or neglectful household will be at a higher risk of exhibiting the traits associated with this disorder.

Severe trauma to specific regions of the brain can cause a person to undergo marked personality changes, such as in the famous case of Phineas Gage. While working as a railroad construction foreman in Vermont in 1848, he survived an accident in which a large iron rod was driven through his head, damaging much of his brain's left frontal lobe. Although he did not become a sociopath, the reported effects on his personality and behavior were so profound that friends saw him as “no longer Gage.”

An incident two decades ago supports the idea that brain trauma can lead to psychopathic behaviors. In 1991 convicted sex offender Phillip Garrido kidnapped 11-year-old Jaycee Dugard and kept her as a prisoner in his home for 18 years. Experts believe that Garrido experienced severe brain damage after a serious motorcycle accident as a teenager, which was compounded by intense drug use. Garrido's father said that his son had been a “good boy” as a child but that he had changed radically after the accident and had become unstable.

Recently neuroscientists have identified areas of the brain related to psychopathic behaviors. Subtle damage to the amygdala, a brain region that helps us process our emotions, may explain why psychopaths act so cruelly and cannot express emotions properly. Psychopathic behaviors are also associated with injury to the cerebral cortex, which regulates memory and self-awareness, and the frontal lobe, which is responsible for self-control and judgment.

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