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.

Experts agreed that the findings don't constitute a cause-and-effect
situation, but hailed the study for its longevity and what the work adds
to what is known about how childhood factors influence adult behavior.

"Any time you have a 20-year study, that's significant," said Dr.
Elissa P. Benedek, an Ann Arbor, Mich.-based psychiatrist who has worked
in private practice with children and adults for more than 40 years and is
a past president of the American Psychiatric Association.

"It's good for putting another link in the chain in terms of what is
early brain dysfunction, and what increases the risk for such behaviors as
attention-deficit disorder and criminal activity. It's another link back
to whatever we all ready know about early brain dysfunction that may cause
problems later in life," Benedek added.

So what do the results mean for individuals with fear conditioning
deficits and their loved ones, and for society at large? It's a wake-up
call about potential problems, said Gao and other experts in the field. To
enhance the proper working of the amygdala, which is believed to reduce
criminal behavior in later life, enrichment programs are essential.

In fact, according to Gao, some at-risk children between the ages of 3
and 5 who have benefited from those programs, which include sound
nutrition, adequate physical exercise and cognitive brain stimulation, had
shown an improvement in brain functioning by age 11 that reduced the
chances of criminal behavior by 35 percent 20 years later.

Addressing parental concerns, Benedek added: "Don't be discouraged if
your child has early brain dysfunction. It doesn't mean that he or she is
going to grow up and be a criminal. The brain can change and grow."

More information

For more on the causes of violent behavior among children, go to the U.S. National Institute of Mental Health.