Why jokes are hard to remember.

Natalie Angier has a nice piece on foibles of our memory in last Tuesday's science section of the NYTimes. Some edited clips:

The ease with which people forget jokes is one of those quirks...that ends up revealing a surprising amount about the underlying architecture of memory....We have our version of a buffer...a short-term working memory of limited scope and fast turnover rate...our equivalent of a save button: the hippocampus, deep in the forebrain is essential for translating short-term memories into a more permanent form...what really distinguishes the lasting from the transient is how strongly the memory is engraved in the brain...The deeper the memory, the more readily and robustly an ensemble of like-minded neurons will fire...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, but when the alphabet is set to the tune of the ABC song with its four melodic phrases, preschoolers can learn it with ease.

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...What makes a joke successful are the same properties that can make it difficult to remember.

As frustrating as it can be to forget something new, it’s worse to forget what you already know... Behind the tying up of tongues are the too-delicate nerves of our brain’s frontal lobes and their sensitivity to anxiety and the hormones of fight or flight. The frontal lobes that rifle through stored memories and perform other higher cognitive tasks tend to shut down when the lower brain senses danger and demands that energy be shunted its way....For that reason anxiety can be a test taker’s worst foe.