Dopamine is about wanting, not liking

The book's foundational correction to popular belief: dopamine isn't the brain's pleasure chemical, it's the desire chemical. Experiments on rats and, later, humans showed that dopamine spikes not when a reward is consumed, but when it's anticipated — the actual enjoyment of eating, resting, or embracing someone runs on entirely different neurochemicals.

This distinction resolves a puzzle: why does getting what you wanted so often feel less thrilling than wanting it did? Because the wanting and the liking are handled by separate systems, and dopamine only cares about the gap between here and there.

Lieberman and Long call this the difference between the "desire circuit" and what they term the H&N (here-and-now) circuit. Dopamine fires hardest for what's uncertain and not-yet-had; the moment you have it, the job is done and dopamine moves on to the next target.

Takeaway: if satisfaction feels hollow after getting what you wanted, that's dopamine working exactly as designed.