The environment is critical not only in our development, but in determining almost all of our behaviors; why we act the way we do all the time. Incentives are those stimuli in the environment, both positive or negative, that motivate our behavior. These things pull us to behave in certain ways (as opposed to drive which pushes us from within). For example, if you are offered money to perform a certain behavior, the money is the incentive to perform that behavior.