The Molecule of More: How a Single Chemical in Your Brain Drives Love, Sex, and Creativity―and Will Determine the Fate of the Human Race

by Daniel Z. Lieberman

This dopamine circuit evolved to promote behaviors that lead to survival 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 happens 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.