Episodic memory
Critiques of the peak–end rule typically derive from its conflation of a complex mental evaluation into a simplistic framework. A 2008 study found some support for the peak–end rule, but also found that it was "not an outstandingly good predictor" of remembered experiential value, and that the happiness of the most memorable part of an experience predicted remembered happiness better than did the happiness of the peak or of the end. Additionally, the extreme effect of peaks fades more rapidly over time, causing peaks to be recalled less positively and troughs recalled less negatively over time. Episodic memory endures for only a few weeks; at some point, mental accounting shifts over to semantic memory, leading to potential over-valuation of the "end" and diminished weighting of the peak. Additionally, memories that are available for evaluation may change due to the fading affect associated with memory or differing goals in recall. Goal orientation or initial expectations can also affect the weighting of a peak or an end, causing an end to be over-weighted as the culmination of a goal. Finally, Ariely and Carmon have theorized that evaluations of past events are affected by feelings at the time of evaluation.