Testosterone makes men less likely to question
their impulses
California Institute
of Technology
Hotheaded, impulsive
men who shoot first and ask questions later are a staple of Westerns and 1970s
cop films, but new research shows there might be truth to the trope.
A study conducted by
researchers from Caltech, the Wharton School, Western University, and ZRT
Laboratory tested the hypothesis that higher levels of testosterone increase
the tendency in men to rely on their intuitive judgments and reduce cognitive
reflection -- a decision-making process by which a person stops to consider
whether their gut reaction to something makes sense.
The researchers found
that men given doses of testosterone performed more poorly on a test designed
to measure cognitive reflection than a group given a placebo.
The research will
appear in an upcoming issue of the journal Psychological Science.
"What we found
was the testosterone group was quicker to make snap judgments on brain teasers
where your initial guess is usually wrong," says Caltech's Colin Camerer,
the Robert Kirby Professor of Behavioral Economics and T&C Chen Center for
Social and Decision Neuroscience Leadership Chair.
"The testosterone is either inhibiting the process of mentally checking your work or increasing the intuitive feeling that 'I'm definitely right.'"
The study, which is one of the largest of its type ever conducted, included 243 males who were randomly selected to receive a dose of testosterone gel or placebo gel before taking a cognitive reflection test.
A math task was also
given to control for participant engagement, motivation level, and basic math
skills.
The questions included
on the cognitive reflection test are exemplified by the following:
A bat and a ball cost
$1.10 in total. The bat costs $1 more than the ball.
How much does the ball
cost?
For many people, the
first answer that comes to mind is that the ball costs 10 cents, but that's
incorrect because then the bat costs only 90 cents more than the ball. The
correct answer is that the ball costs 5 cents and the bat costs $1.05.
An individual prone to
relying on their gut instincts would be more likely to accept their first
answer of 10 cents. However, another person might realize their initial error
through cognitive reflection and come up with the correct answer.
Participants were not
limited on time while taking the test and were offered $1 for each correct
answer and an additional $2 if they answered all the questions correctly.
The results show that
the group that received testosterone scored significantly lower than the group
that received the placebo, on average answering 20 percent fewer questions
correctly.
The testosterone group
also "gave incorrect answers more quickly, and correct answers more slowly
than the placebo group," the authors write.
The same effect was
not seen in the results of the basic math tests administered to both groups.
The results
"demonstrate a clear and robust causal effect of [testosterone] on human
cognition and decision-making," they conclude.
The researchers
believe that the phenomenon they've observed can be linked to testosterone's
effect of increasing confidence in humans.
Testosterone is
thought to generally enhance the male drive for social status, and recent
studies have shown that confidence enhances status.
"We think it
works through confidence enhancement. If you're more confident, you'll feel like
you're right and will not have enough self-doubt to correct mistakes,"
Camerer says.
Camerer says the
results of the study raise questions about potential negative effects of the
growing testosterone-replacement therapy industry, which is primarily aimed at
reversing the decline in sex drive many middle-aged men experience.
"If men want more
testosterone to increase sex drive, are there other effects? Do these men
become too mentally bold and thinking they know things they don't?"