The Molecule of More

participant that she must only eat the food she was assigned to.
None of the participants assigned to the radishes broke the rules and 
ate a cookie, but they were obviously tempted. The researchers peeked 
around a curtain to watch what they did. “Several of them [looked] 
longingly at the chocolate display and in a few cases even pick[ed] up 
the cookies to sniff at them.”
After about 5 minutes, the scientist returned, and told the partic-
ipant that the next step in the study was something completely unre-
lated: it was a test of problem-solving ability. What the participants 
weren’t told was that the problem couldn’t be solved. The question was, 
how long would each participant persevere at this impossible task?
The participants who had been allowed to eat cookies worked 
on the problem for about 19 minutes. The ones who had been only 
allowed to eat radishes, those who had to exert self-control to counter-
act their desire for cookies, persisted at the task for only 8 minutes—less 
than half the time—before they gave up. The researchers concluded, 
“Resisting temptation seems to have produced a psychic cost, in the 
sense that afterward participants were more inclined to give up easily 
in the face of frustration.” If you’re on a diet, the more times you resist 
temptation, the more likely you are to fail the next time around. Will-
power is a limited resource.
THE WILLPOWER EXERCISE MACHINE
If willpower is like a muscle, can it be strengthened through exercise? 
Yes, but it requires some high tech “exercise equipment,” the kind of
equipment that scientists at the Center for Cognitive Neuroscience at 
Duke University used to see if they could enhance the part of the brain 
people use for willpower.
First they made things easy. They paid participants money if they 
completed a task successfully. It’s easy to get motivated when there is an 
immediate reward. Using a brain scanner, they were able to see activa-
tion of the ventral tegmental area of the brain, the place where both 

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DOMINATION
the desire and control circuits originate. Next they asked the partici-
pants to find ways to motivate themselves. They suggested a number of
strategies, such as telling themselves, “You can do it!” They encouraged 
the participants to be creative and use whatever they thought would be 
most motivating. Some people imagined coaches encouraging them. 
Others imagined situations in which their efforts were rewarded. All 
the while, they lay in the brain scanner, and the scientists watched what 
happened in the motivation region of their brains. They were surprised 
at what they saw: nothing happened. Although getting money worked, 
when participants tried to do it on their own, they failed.
Next, the scientists gave them a little help in the form of biofeed-
back, which is when a person is provided information on how their 
body and brain are functioning. This information helps them find effec-
tive ways to take control of things that are usually unconscious. The 
best-known form of biofeedback is for relaxation. A device that mea-
sures tiny amounts of sweat is attached to a person’s finger. The less 
sweat, the greater the relaxation. The signal is expressed as a tone, and 
the user tries to manipulate the tone in the direction of relaxation. It 
works.
In the motivation experiment, the participants were shown a ther-
mometer with two lines. One showed the current level of activity in 
the motivation region, and the other represented a higher target they 
should try to achieve. Now they could see which strategies worked and 
which ones didn’t. After a while, they built up a collection of imagined 
scenes that effectively boosted motivation activity. These strategies con-
tinued to work even when the thermometer was removed. Strength-
ening willpower was possible, but it required a high-tech window that 
allowed the test participants to look deep inside their brains.
DOPAMINE VERSUS DOPAMINE
Even though it’s possible to strengthen willpower, it’s still not the answer 
to long-term, enduring change. So what does work? That question is 
of great interest to clinicians who help people struggling to overcome 

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THE MOLECULE OF MORE
addictions. You can’t beat drugs with willpower alone. It takes more 
than that. There are medications that help with some addictions, but 
they don’t work when they’re given alone. They have to be combined 
with some form of psychotherapy.
The goal of addiction psychotherapy is to pit one part of the brain 
against another. Part of the dopamine desire circuit becomes malignant 
in drug addiction, pushing the addict into compulsive, uncontrollable 
use. It has to be opposed by an equally potent force. We know willpower 
won’t do it. What other resources can be called on to win this fight?
This question has been studied extensively, and the knowledge 
gained has been formalized into a variety of different psychothera-
pies. Among the best studied are motivational enhancement therapy, cognitive