FRIDAY, Nov. 5 (HealthDay News) -- Impaired understanding of how
social contracts work and why people need to take precautions may
explain why psychopaths cheat and take risks even though they know
right from wrong, a new study suggests.
Although less than 1 percent of people in the United States are
psychopaths, they account for 20 percent of the prison population
because of their tendency for impulsive, destructive and harmful
behavior, noted the University of New Mexico researchers.
Previous studies have shown that psychopaths know the difference
between right and wrong and give typical responses when presented
with an example of a moral dilemma. This study examined another
type of reasoning -- thinking about precautions and social
The researchers presented 67 prisoners -- some psychopaths, some
not -- with a series of problems based on three types of rules:
descriptive rules (for example, "If a person is from California,
then that person will be patient"); social contracts ("If you
borrow my motorcycle, then you have to wash it"); and precautions
("If you work with tuberculosis patients, then you must wear a
The non-psychopath prisoners did about as well as non-prisoners
on all three kinds of reasoning. While the psychopaths did fairly
well on straight logical reasoning, they scored lower than
non-psychopaths on problems that involved social contracts and
The study was published in the October issue of the journal
"This work suggests that psychopaths don't understand cheating in the normal way, so they might not realize when they're cheating other people or when other people would react badly to cheating," study co-author Elsa Ermer said in an Association for Psychological Science news release.
She added that psychopaths' inability to reason about
precautions may explain why they take risks and commit impulsive
acts that land them in trouble. It appears they have difficulty
"understanding when they can avoid negative consequences of a risk
by taking a precaution," Ermer said.
Oregon Counseling has more about
the psychopathic personality.