Cornell University professors Valerie Reyna and Charles Brainerd find that people do a poorer job of remembering negative experiences.

"You may not remember the specifics of what happened to you, but boy, do you remember it was negative," said Brainerd. "And that allows you to fill in the blanks with 'memories' of negative events that didn't really happen."

Brainerd is the lead author of a study published in Psychological Science (Vol. 19, No. 9); co-authors include his wife, Valerie Reyna, also a Cornell professor of human development, and colleagues from Brazilian universities.

The researchers conducted experiments in which about 120 participants -- half in Brazil and half in the United States -- were asked to read lists of words that had either positive, negative or neutral connotations. They were then asked to identify which words had been listed. When remembering negative words -- such as mad, sad, rage, temper, ire and wrath -- they were much more likely to be inaccurate and "falsely remember" such unlisted words as anger. When identifying positive words, their memories were much more accurate.

The findings challenge traditional ideas about how emotion affects memory, Brainerd says. "Historically the belief has been that negative events are really pretty easy to remember, that negative emotion creates very distinctive memories. What we found was exactly the opposite. Negative information really tends to distort your memory."

This might mean that witnesses to crimes are memory-impaired. Well, if you witness a crime try not to feel unhappy about it and write up your memories while they are still fresh. Do not trust your memories.