Now THAT'S a good article
I stumbled across a journal article in Psychonomic Bulletin and Review, a pretty well-respected journal, called "When the Red Sox Shocked the Yankees: comparing negative and positive memories." Here's the abstract:
The present study examined whether positive or negative valence affects the amount of detail remembered about a public event, and whether positive or negative valence alters other memory characteristics (consistency, vividness, and confidence). Memory for the final game of the Boston Red Sox-New York Yankees 2004 American League playoff series was assessed in individuals who found the event highly positive, highly negative, or neutral (i.e., Red Sox fans, Yankees fans, and fans of neither team). Valence did not affect the number of personal details recalled, but it did affect memory consistency (greatest for the negative-event group) and memory overconfidence (apparent only in the positive-event group). These results indicate that positive events can be remembered with the same types of distortions that have been shown previously for negative events. Moreover, it appears that, in comparison with negative valence, positive valence sometimes can be associated with decreased memory consistency and increased memory overconfidence.
Not surprisingly, a couple of researchers from BC and Harvard wrote it.