A slot machine triggers the brain’s learning and curiosity pathways while teaching nothing, and that one-way exchange is what makes it contemptuous of the player.

curiosity Wanting to know for its own sake: what it does for good work, learning, creativity and a long life, and what happens to it with age.

Addiction Compulsive use that continues through the harm it causes — and the argument about whether it is a disease, a choice, or a response to pain.

motivation What makes effort feel worth it: the neuroscience of wanting to act, apathy, dopamine, and habit.