incentive

Notice how a sale sign pulls shoppers in, how a fine makes drivers slow down, how a bonus makes salespeople work weekends. People do not act at random; they respond to the rewards and punishments around them. An incentive is anything that motivates a person to act one way rather than another — a carrot or a stick. Economists half-joke that their whole field boils down to one sentence: people respond to incentives.

An incentive can be a reward (a prize, a discount, a wage, praise) or a penalty (a fine, a tax, a loss, shame). When the payoff of an action rises, people tend to do more of it; when the cost rises, they do less. Incentives can be financial or not — reputation and convenience are powerful too. A worked picture: if a city charges five dollars to drive downtown at rush hour, some drivers will switch to the train, not because they were ordered to, but because the changed incentive made driving less attractive at the margin.

Incentives matter so much because they shape behaviour even when no one intends it, and they often bite back. Well-meant rules can create perverse incentives — paying people per snake killed once led a city to breed snakes for the bounty. Designing good policy is largely about asking, honestly, 'how will people actually respond to this?' rather than 'what do we wish people would do?'. The answer is usually: they will do whatever the incentives reward.