DOMINATIONway and the willpower that gets us there. Usually the two work together,
but when desire fixates on things that will bring us harm in the long
run—a third piece of cake, an extramarital affair, or an IV injection of
heroin—dopaminergic willpower turns around, and does battle with its
companion circuit.
Willpower isn’t the only tool control dopamine has in its arsenal
when it needs to oppose desire. It can also use planning, strategy, and
abstraction, such as the ability to imagine the long-term consequences
of alternate choices. But when we need to resist harmful urges, will-
power is the tool we reach for first. As it turns out, that might not be
such a good idea. Willpower can help an alcoholic say no to a drink
once, but it’s probably not going to work if he has to say no over and
over again for months or years. Willpower is like a muscle. It becomes
fatigued with use, and after a fairly short period of time, it gives out.
One of the best experiments that demonstrated the limits of willpower
was the famous radishes-and-cookies study. This study relied on decep-
tion. Volunteers were told that they were signing up for a food-tasting
study. Here is how one scientist described it:
The laboratory room was carefully set up before participants in the food
conditions arrived. Chocolate chip cookies were baked in the room in a small
oven, and, as a result, the laboratory was filled with the delicious aroma of
fresh chocolate and baking. Two foods were displayed on the table at which
the participant was seated. One display consisted of a stack of chocolate
chip cookies augmented by some chocolate candies. The other consisted of a
bowl of red and white radishes.When the participants arrived, they were hungry. They had been told
to skip a meal before coming to the laboratory. The sight and smell
of the freshly baked chocolate chip cookies were very tempting under
these conditions. One at a time the participants were ushered into the
laboratory where the chocolate chip cookies had just come out of the
oven, and they were told to sample two or three cookies or two or three
radishes, depending on which group they had been assigned to. Before