Why the brain talks to itself: sources of error in emotional prediction.

People typically choose pleasure over pain. But how do they know which of these their choices will entail? The brain generates mental simulations (previews) of future events, which produce affective reactions (premotions), which are then used as a basis for forecasts (predictions) about the future event's emotional consequences. Research shows that this process leads to systematic errors of prediction. We review evidence indicating that these errors can be traced to five sources.