An Analysis of Retrospective Utility In prior research, the PI has examined how experienced utility/disutility - the pleasure/pain of an activity as it occurs - relates to the retrospective or recalled utility of that activity. To date the PI has examined this relationship in the context of unpleasant activities. He has found that the retrospective disutility of an activity is accurately predicted by a simple average of the most extreme discomfort reported during the activity and the level of discomfort experienced at the end of the episode, a finding referred to as the `peak/end` effect. The duration of the activity has little effect on retrospectively reported disutility. A paradoxical consequence of this finding is that an activity can be made less aversive simply by adding a period of diminishing discomfort to what would have been the end of the experience. The current research involves the conduct of an extensive series of experiments to further explore and gain additional insights into this phenomenon.