'Fearless' 3-Year-Olds Might Be Tomorrow's Criminals

Nov. 18 -- TUESDAY, Nov. 17 (HealthDay News) -- Children who are fearless at 3 years of age might just be poised for a life of crime.

According to a new study, poor fear conditioning at the tender age of 3 can predispose that person to break the law as an adult. Yet other factors, such as education of the parents, large family size, nutrition, physical activity, configuration of the household and other elements also play a role, the researchers concluded.

"There's no 100 percent correspondence between conditioning deficits and crime: Not all poor conditioners will become criminals and not all criminals have the early fear conditioning deficits," explained study author Yu Gao, a research associate in the department of criminology at the University of Pennsylvania. His findings are published in the Nov. 16 online issue of the American Journal of Psychiatry.

Specifically, what Gao and his associates set out to determine is whether dysfunction of the amygdala, an almond-shaped mass that resides deep in the human brain and is linked to fear conditioning as well as emotions and mental state, leads to an inherent intrepidness and disregard for the law.

Twenty years ago, the research team tested almost 1,800 children who were 3 years old from Mauritius, an Indian Ocean island off the coast of southeastern Africa, by exposing them to two sets of sounds, one with a short shrill noise, and the other deeper in pitch and with a pleasant tone, and then measuring the children's physical responses through an electrode attached to their index and middle fingers. Sweating upon hearing the loud noise indicated a sense of fear, while no sweat meant the child lacked fear -- that is, had poor fear conditioning.

Two decades later, using court records, Gao and his team tracked down 137 study participants -- 131 males and six females -- who had committed serious crimes involving property, drugs, violence and driving. These individuals had shown an absence of fear during testing at age 3, whereas 274 study participants who had grown to adulthood without a criminal record had displayed typical fear responses.