Past Perfect: Why Bad Memories Fade

Remember how you felt in the not-so-good times? While we certainly
remember what happened, our emotional recall dims with time. Researchers
have found that the mind is biased toward positive emotional
memories—as negative emotions fade faster. This isn't universal,
however, as mild depression can skew emotional memory toward the
negative.

"People have an inherent bias to view their experiences in a
positive light," says study author Richard Walker, Ph.D., assistant
professor of psychology at Winston-Salem State University in North
Carolina. For one, the positive bias can be explained simply because
there are more positive events than negative ones, explains
Walker.

In his research, he found that happier emotions have a longer shelf
life in our memories. In a review of 12 studies, he found that people
consistently report experiencing more positive events.
Negative emotions tended to fade faster than positive ones.

This "fading effect" works differently for those with depression.
The researcher tracked the emotional recollection of 330 participants and
found that their positive and negative emotions fade at the same rate.
"The folks who are mildly depressed tend to report more negative life
events," says Walker. "And they tend to have more difficulty dealing with
negative emotions. This is likely to be one of the contributing factors
[to depression]."