The Molecule of More

partners tend to become less frequent and less satisfying. One young 
man gave up dating completely. He said that he’d rather look at por-
nography than go out with a real woman because the women in the 
pictures never demanded anything of him, and never said no.
4 Raising the price of cigarettes and alcohol is controversial, though, especially with 
regard to cigarettes. Fewer and fewer people smoke. Those who persist tend to be 
poor and less educated. As a result, increases in cigarette taxes hit them the hard-
est. This is the opposite of a tax system that shifts more of the burden onto those 
who are better able to afford it. Advocates who defend this strategy argue that the 
pain caused by raising taxes on the poor is counterbalanced by reducing their risk 
of getting cancer, emphysema, and heart disease.

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53
DRUGS
As with drugs, habituation can also occur with pornography, in 
which the starting “dose” no longer works as well. When sex addicts 
were repeatedly shown the same sexual images, their interest dimin-
ished. The activity measured in their dopamine circuits also decreased 
as the images were shown over and over. The same thing happened 
to healthy males who were repeatedly shown the same pornographic 
video. When they were shown a new video, their dopamine systems 
revved up again. This experience of a dopamine rush, followed by a 
dopamine drop (repeated images), followed by another dopamine rush 
(new images), pushes addicts to continually seek out fresh material, 
which may explain why browsing internet sex sites can become com-
pulsive. It’s hard to resist the demands of dopamine circuits, especially 
with something as evolutionarily important as sex. The researchers who 
performed the study also identified a wanting/liking divide similar to 
what is seen in drug addiction: “Sex addicts showed higher levels of
desire when watching pornography, but did not necessarily rate the 
explicit videos higher in their ‘liking’ scores.”
ARE VIDEO GAMES ADDICTIVE, TOO?
It’s not just pornography that can ensnare computer users. Some scien-
tists claim that video games can also be addicting. In certain ways, video 
games are similar to casino games. Like slot machines, video games 
surprise players with unpredictable rewards. They do more than that, 
though, which can make them even more potent agents of dopamine 
release. In researching this problem, psychologist Douglas Gentile of
Iowa State University found that nearly one in ten gamers ages eight 
to eighteen are addicted, causing family, social, school, or psychological 
damage because of their video game playing habits—a rate of addic-
tion more than five times higher than that among gamblers, accord-
ing to the National Research Council on Pathological Gambling. What 
accounts for this large difference in how many users get addicted?