Natalie Angier in The New York Times:
A simple melody with a simple rhythm and repetition can be a tremendous mnemonic device. “It would be a virtually impossible task for young children to memorize a sequence of 26 separate letters if you just gave it to them as a string of information,” Dr. Thaut said. But when the alphabet is set to the tune of the ABC song with its four melodic phrases, preschoolers can learn it with ease.
And what are the most insidious jingles or sitcom themes but cunning variations on twinkle twinkle ABC? Really great jokes, on the other hand, punch the lights out of do re mi. They work not by conforming to pattern recognition routines but by subverting them. “Jokes work because they deal with the unexpected, starting in one direction and then veering off into another,” said Robert Provine, a professor of psychology at the University of Maryland, Baltimore County, and the author of “Laughter: A Scientific Investigation.” “What makes a joke successful are the same properties that can make it difficult to remember.”
This may also explain why the jokes we tend to remember are often the most clichéd ones. A mother-in-law joke? Yes, I have the slot ready and labeled. Memory researchers suggest additional reasons that great jokes may elude common capture. Daniel L. Schacter, a professor of psychology at Harvard and the author of “The Seven Sins of Memory,” says there is a big difference between verbatim recall of all the details of an event and gist recall of its general meaning.
“We humans are pretty good at gist recall but have difficulty with being exact,” he said. Though anecdotes can be told in broad outline, jokes live or die by nuance, precision and timing. And while emotional arousal normally enhances memory, it ends up further eroding your attention to that one killer frill. “Emotionally arousing material calls your attention to a central object,” Dr. Schacter said, “but it can make it difficult to remember peripheral details.”