“For researchers who study memory, the ease with which people forget jokes is one of those quirks, those little skids on the neuronal banana peel, that end up revealing a surprising amount about the underlying architecture of memory. And there are plenty of other similarly illuminating examples of memory’s whimsy and bad taste — like why you may forget your spouse’s birthday but will go to your deathbed remembering every word of the ‘Gilligan’s Island’ theme song.”