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Roots of Murder
of a Killer: Is it in the Brain?
For years police and psychologists have been trying to get inside voilent minds.
As this ScienCentral News video reports, they are now getting closer than ever.
Bad Brain, Bad Behavior
Ted Bundy, Jeffrey Dahmer, David Berkowitz. The names of well-known
serial killers elicit chills and horror. What were they thinking? What
could have been going on in their heads? Are their brains wired differently?
professor of psychology
at the University of Southern California, has been trying to find answers
to these questions by watching killersâ€™ brains at work. To do this he
is using two scanning techniques: positron emission tomography (PET), which
allows him to see how their brains function; and magnetic resonance imaging
(MRI) which helps him study the structure of their brains.
Raine compared the function and structure of the brains of 41 murderers and
41 control subjects and found that there was lower activity in the pre-frontal
cortex (an area located above the eyes and behind the forehead) of the
brains of murderers when compared to that of normal control subjects. Raine
explains that the prefrontal cortex acts as the “brakes” in our
brains, and since these individuals have poor prefrontal functioning, they
are unable to control and regulate their emotions. However, Raine says that
although there are many associations between poor prefrontal function and
violence, brain dysfunction cannot be the only reason for violent behavior.
There are larger societal and environmental reasons that lead to an individual
becoming a murderer.
He further divided the murderers into two groups of “affective”
and “predatory” killers to study the differences, if any, in their
brains. (Affective being those who kill on impulse; predatory being those
who kill with prior intent.) Although some of them could not be strictly assigned
to either one of the groups, Raine was able to assign 15 of the 41 murderers
to the predatory group and 9 to the affective group. He found that while affective
killers had poor pre-frontal functioning, predatory killers had intact prefrontal
activity. Both groups had higher than normal activity in the sub-cortex
region of the brain, which is a deeper, more primitive part of the brain.
“This is the part of the brain that gives rise to more aggressive feelings
and may stimulate aggressive behavior,” says Raine. “The one difference
between the two groups of killers is that the impulsive, emotional individuals
[affective killers]—who have a lot of emotional, aggressive feelings—are
not able to control their behavior because they have poor frontal function.
In contrast the planned, regulated killers [predatory killers] may feel aggressive
and angry. But they have sufficient pre-frontal resources to be able to regulate,
control and channel their aggressive behaviors into activities that may give
them a lot of pleasure.” And according to Raine, since they carefully
plan their activities, it is harder to nab the predatory, cold-blooded killers.
Early Brain Development
“Its likely that the seeds of violence are sown very early on in life,”
says Raine. “Of course social factors are also critically important.
We know for example that individuals
who have suffered birth complications but who are also rejected by their mother
in the first years of life are especially likely to grow up to be violent
Raine also points out that they donâ€™t know for certain whether the poor
brain functioning they find in killers was there before the homicide, whether
it was there early in life and predisposed them to crime, or whether living
a violent way of life actually caused the brain damage. “Nevertheless”,
he says, “there is increasing evidence from child brain studies that
suggests that poor brain functioning can indeed cause a predisposition to
violent and anti-social behavior.” But there are no studies as yet proving
that poor brain functioning early in life is a pathway to later violence.
He believes that early enrichment of the lives of those with a biological predisposition
to violence may help to reduce violence in society in the future. But although
they have ideas about what may be the root causes of violent behavior, he
says, “at the moment itâ€™s simply too early to apply those findings.
Weâ€™ll be criticized for doing that. What we really need is a lot more
research in this area, but research of the type that can ultimately be applied
in practice so that we can do something about treating violent offenders in
prison, and do something about taking juvenile delinquents off the street.”