Figure 1

Pleasure cycles. One way to view the difference between pleasure 'liking' and other components of reward is as cyclical time course common to many everyday moments of positive affect. Typically, rewarding moments go through a phase of expectation or wanting for a reward, which sometimes leads to a phase of consummation or liking with the reward that can have a peak level of pleasure (e.g. encountering a loved one, a tasty meal, sexual orgasm, drug rush, winning a gambling bet). This can be followed by a satiety or learning phase, where one learns and update our predictions for the reward. These various phases have been identified at many levels of investigation of which the recent research on the computational mechanisms underlying prediction, evaluation and prediction error are particularly interesting (Friston and Kiebel 2009; Zhang et al. 2009). Note, however, that some rewards might possibly lack a satiety phase (suggested candidates for brief or missing satiety phase have included money, some abstract rewards and some drug and brain stimulation rewards that activate dopamine systems rather directly).