WHAT MAKES THRILL SEEKERS TICK?

Researchers Go Along For The Ride

The roller coaster that plunges 98 meters. The log flume that leaves you
staggering. The free-fall ride that separates you from your stomach. Some
people love them. Some people would rather be boiled in the oil over at the
Belgian waffle stand.

With summer approaching, amusement parks are bracing for a flood of
visitors, and visitors are bracing for the flood of adrenaline lost through
thrill rides. Meanwhile, a cottage industry of psychologists, psychiatrists
and even geneticists has started to work in pursuit of an explanation for
why some people are sensation-seekers and others sensation-duckers.

Who will ride the Millennium Force and who will hide out at the Sno-cone
concession isn't a burning research question. But it sheds light on
important, related ones -- such as who will drive 150 kilometers per hour,
try heroin or play "chicken" on train tracks.

"There is a common temperament that underlies the attraction to many kinds
of risky behavior," says Marvin Zuckerman, a professor of clinical
psychology at the University of Delaware who has studied sensation-seeking
for 40 years. "Sensation-seekers tend to drive recklessly, to do drugs and
drink. They are drawn to people who are exciting but not too reliable. They
typically have many unstable relationships with lots of sexual partners. In
every aspect of their lives, they're looking for the latest thing."

Early on, explanations of the innocuous, roller-coaster sort of
sensation-seeking focused on "vicarious fear." The idea is that the mind
knows that making hairpin turns in a little car 60 meters up is actually
less dangerous than driving (0.61 deaths per 100 million passenger miles in
roller-coasters compared with 0.91 in automobiles, say the latest U.S.
statistics). "So we can master that fear," explains Dr. Zuckerman. "And we
take pleasure in mastering it."

But clearly something more is going on in people who truly dare death, as
in that game of railroad chicken. Not to put too fine a point on it, but
what the heck is wrong with these people's brains?

When in doubt, look to testosterone poisoning. "It had long been assumed
that high testosterone levels are associated with sensation-seeking," says
David Quadagno, a psychology professor at Florida State University. After
all, more men than women drive fast and scale K2. But when his research
team recently measured testosterone in men and women, and then checked the
levels against answers to questions such as, "would you like to jump out of
an airplane (with or without a parachute)?," they got a surprise.

Men who copped to preferring a nice Bronte novel had testosterone levels no
lower than those who opted for more adventure. "Testosterone levels are not
associated with sensation-seeking in either sex," Dr. Quadagno says.

Another culprit, the stress hormone cortisol, tells a different story. "Low
cortisol levels were associated with sensation-seeking in men," Dr.
Quadagno says. A low-cortisol man, he suspects, isn't stressed by the same
things as other people. He is therefore willing and able to "up the ante
and look for excitement."

Are low-cortisol guys born or made? That is a mystery, but genes almost
surely play a role. In 1996, geneticists announced the discovery of a
"novelty-seeking" gene. It codes for a receptor in the brain that acts as a
molecular docking site for dopamine. This brain chemical can produce a rush
of pleasure and its release seems to underlie addiction.

In people hooked on thrills, empty dopamine receptors make them almost as
edgy as a smoker with empty nicotine receptors. As with any addiction, the
dopamine rush from, say, Disney's spinning teacup ride eventually wears
off. "To stimulate the system, you have to do something more," Dr.
Zuckerman says. "That's why sensation-seekers need riskier and riskier
thrills to get the same kick."

Psychologists who deal with problem kids say sensation-seeking is more
ingrained than aggression or impulsiveness. "It's less malleable because
it's a trait of temperament, which has a strong genetic basis," says
Deborah Capaldi of the Oregon Social Learning Center. "You might affect the
associated behavior, but you won't change the underlying temperament."

Still, there are thrills and there are thrills. A sensation-seeker who also
is persistent and optimistic might become a star options trader; one who is
resentful and impulsive might turn to crime. Nature deals the hand -- how
we play it is up to us.

Me, I'll be at the Sno-cone stand.