What do pigeons have in common with problem gamblers?
Expecting a cash bonanza from buying lottery tickets or
playing slot machines in a casino might brand someone a dupe
or pigeon. That comparison, in fact, is much more accurate
than meets the eye. In a new study, University of Kentucky
psychologists found that pigeons and problem gamblers seem
to have a particular trait in common — impulsive behavior.
The findings are important because they suggest that training
in impulse control could help people with gambling problems.
The researchers’ previous work showed that pigeons do
gamble. In experiments that trained pigeons to choose to peck
keys for food pellets, the birds placed high-stakes bets. They
consistently pecked a key that would give them a big jackpot —
10 pieces of food — but only paid out 20 percent of the time,
rather than a key with a more modest payoff of three food
pellets 100 percent of the time. So, the jackpot would give them
an average of two food pellets per trial, whereas the optimal
alternative would give them three food pellets per trial.
The findings piqued the researchers’ curiosity. Could
the pigeons’ tendency to risk no payoff most of the time for
the rare possibility of winning a big jackpot be related to
impulsivity? To find out, they added another procedure to their
A time-honored test for impulsivity looks at the ability to
delay gratification. If a gambler, or a pigeon, could have a small
reward now or a heftier payoff later, which would either of
them choose? The less time they’re willing to wait for the large
prize, the more impulsive they are.
So, lead author Jennifer Laude, a doctoral psychology
student, and her colleagues tested the pigeons for their
impulsivity as indexed by the delayed reward task. They found
that the more impulsive birds — those that were more partial
to pecking keys that gave them a little food immediately instead
of a larger number of pellets for which they’d have to wait up
to 20 seconds — were more likely to choose the gambling-like
alternative associated with the jackpot than the sure thing.
The results suggest that the pigeons gave more weight to
winning the jackpot and less weight to losing than optimally
they should have, says Thomas Zentall, PhD, a co-author of
the study and senior researcher in the psychology department’s
Comparative Cognition Laboratory. That is, the birds weren’t
wary enough about pecking keys that usually didn’t provide
food, he says.
It’s the same phenomenon seen in pathological or problem
gambling, which is clinically recognized as an impulse control
disorder. “Not surprisingly, pathological gamblers are relatively
unaffected by their losses and attend almost exclusively to their
seldom occurring gains,” says Zentall.