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Figure 1
This dopamine circuit evolved to promote behaviors that lead to sur-
vival and reproduction, or, to put it more plainly, to help us get food and
sex, and to win competitions. It’s the desire circuit that’s activated when
you see the plate of donuts on the table, and it’s activated not by need,
but by the presence of something attractive from an evolutionary or
life-sustaining standpoint. That is, at the moment such a thing is seen,
the circuit is activated whether or not you’re hungry. That’s the nature
of dopamine. It’s always focused on acquiring more of everything with
an eye toward providing for the future. Hunger is something that hap-
pens here and now, in the present. But dopamine says, “Go ahead and
eat the donut, even if you’re not hungry. It will increase your chance
of staying alive in the future. Who knows when food will be available
next?” That made sense for our evolutionary ancestors, who lived most
of their lives on the brink of starvation.
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DRUGS
For a biological organism, the most important goal related to the
future is to be alive when it comes. As a result, the dopamine system
is more or less obsessed with keeping us alive. It constantly scans the
environment for new sources of food, shelter, mating opportunities,
and other resources that will keep our DNA replicating. When it finds
something that’s potentially valuable, dopamine switches on, sending
the message Wake up. Pay attention. This is important. It sends this message
by creating the feeling of desire, and often excitement. The sensation
of wanting is not a choice you make. It is a reaction to the things you
encounter.
The man walking past the burger place smelled food, and although
other priorities may have been floating around in his mind, dopamine
gave him a near-overwhelming urge—he wanted that burger. Although
the focus was different, this is the same mechanism that was working
in our brains thousands of years ago. Imagine one of our ancestors
walking along the savanna. It’s a clear morning. The sun is coming up,
the birds are singing, and everything is as it usually is. She walks along,
looking without seeing, her mind wandering, when suddenly she stum-
bles upon a clump of bushes that are covered with berries. She’s seen
these bushes a dozen times before, but they never had berries on them.
In the past her eyes slipped over these bushes, her thoughts somewhere
else, but now she’s paying attention. Her concentration sharpens as her
eyes scan back and forth across the bushes, taking in all the details.
Excitement wells up inside her. The future just became a little more
secure because the bush with the dark green leaves makes fruit.
The desire circuit, powered by dopamine, has sprung into action.
She’s going to remember this place where the berry bushes grow.
From now on, whenever she sees this bush, a little dopamine will be
released to make her more alert and to give her a hint of excitement,
the better to motivate her to acquire this thing that can help her stay
alive. An important memory has been formed: important because it’s
linked to survival, important because it was triggered by the release of
dopamine. But what happens when dopamine gets out of control?
32
THE MOLECULE OF MORE
WHY WE LIVE IN A WORLD OF PHANTOMS
When Andrew saw an attractive woman, getting her into bed became the
most interesting thing in his life. Everything else faded into dull gray. He typ-
ically met women in bars, and when he wasn’t working, bars were where he
wanted to be. Sometimes he told himself he was going to just relax and have
a few beers. He liked the ambience, and there were times when he fought hard
against the temptation to pick someone up. He knew that as soon as the sex
was over, he would lose interest in the young woman, and he disliked that feel-
ing. But in spite of knowing how things would turn out, he usually gave in.
After a while things got even worse. He was losing interest the moment
the woman agreed to go home with him. The chase had come to an end,
and everything was different. To his eyes, she even looked different, a trans-
formation that occurred in the blink of an eye. By the time they got to his
apartment he no longer wanted to have sex with her.
In a broad sense, saying something is “important” is another way of
saying it’s linked to dopamine. Why? Because among the many things
it does, dopamine is an early-warning system for the appearance of
anything that can help us survive. When something useful to our con-
tinued existence appears, we don’t have to think about it. Dopamine
makes us want it, right now. It doesn’t matter if we’re going to like it, or
if we even need it at the moment. Dopamine doesn’t care. Dopamine
is like the little old lady who always buys toilet paper. It doesn’t matter
if she has a thousand rolls stacked in the pantry. Her attitude is you can
never have too much toilet paper. So it is with dopamine, but instead of toilet
paper, dopamine urges you to possess and accumulate anything that
might help keep you alive.
This explains why the man on the diet wanted that hamburger even
though he wasn’t hungry. It explains why Andrew couldn’t stop pursu-
ing women even though he knew that in just a few hours, maybe in just
a few minutes, it would make him unhappy. But it also explains more
nuanced things; for instance, why we remember some names but not
others. There are all sorts of tricks one can use to make remembering
easier, such as using the person’s name in conversation a few times.
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DRUGS
But even if the name seems committed to memory, it almost always
fades quickly. Important names—those of people who can affect our
lives—are easier. The name of the person who flirted with you at the
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