Memory is not a recording but a reconstruction, and reconstruction is biased in predictable ways. Recency bias overweights recent events when forming judgments, while the primacy effect gives the first information received disproportionate influence over overall impressions. Together they shape everything from hiring decisions to product reviews. The availability heuristic, discussed earlier, doubles as a memory bias: easily recalled examples feel more numerous, regardless of true base rates. The contrast effect similarly shows that judgments shift depending on what was seen immediately before, which is why a $500 watch seems reasonable after a $5,000 one.
Recall of past experience is particularly rosy. Rosy retrospection describes past events remembered more positively than they were experienced, and the Pollyanna principle notes that pleasant information is recalled more accurately than unpleasant. The peak-end rule, demonstrated in Kahneman's colonoscopy study, shows that judgments of past experiences are dominated by peak intensity and how they ended rather than total duration, a phenomenon called duration neglect. The impact bias and the broader affective forecasting error lead people to overestimate how long and how intensely future events will affect them. The focusing illusion sums this up with Kahneman's quip that nothing in life is as important as you think it is while you are thinking about it.
Several biases tie emotion, repetition, and identity to perceived truth. The Forer (Barnum) effect is the acceptance of vague, general personality descriptions as uniquely accurate, the basis of horoscopes. The illusory truth effect shows that repeated false statements are rated more true with each exposure, while the mere-exposure effect makes repeated stimuli increasingly likable. Mood-congruent memory causes sad moods to retrieve sad memories, and the affect heuristic lets current emotion shape risk and benefit judgments. The empathy gap, sometimes called the hot-cold empathy gap, captures the difficulty of predicting one's future emotional state, while projection bias assumes future preferences will mirror current ones, as in planning meals while hungry. Finally, post-decisional dissonance and choice-supportive bias lead people to remember chosen options as better and rejected ones as worse than they were at decision time, reducing the discomfort of trade-offs.