Worrying too much about an unpleasant task you will face an hour down the road will burn that experience more deeply into your brain, making it much more difficult for you to forget how badly you blundered, according to new research.
And that memory of your failure could make it more difficult for you to face the same task later, thus sending you into a downward spiral of self-fulfilling prophecies.
The research, conducted by psychologists at the University of Wisconsin-Madison, shows that simple anticipation of an emotional event, whether good or bad, will reinforce the memory of that event.
"That finding was a bit of a surprise to us," said Jack Nitschke, assistant professor of psychiatry and psychology at the university, and a clinical psychologist.
It suggests that anticipating a bad situation may kick-start an "arousal or fear circuitry" in the brain, says Kristen Mackiewicz, lead author of a report on the research in the current issue of the Proceedings of the National Academy of Sciences.
Mackiewicz has since moved on to the University of Colorado, where she is a doctoral candidate in psychology.
Nitschke and his colleagues used functional magnetic resonance imaging -- a scanner that allows researchers to study the effects of various stimuli on the human brain -- to see whether anticipation of an event had any impact on subsequent memories of that event.
Two areas of the brain, the amygdala and the hippocampus, both associated with memory, lit up when 36 student volunteers were shown a series of photographs, including photos of gruesome scenes.
The pictures were preceded by a symbol moments before each photo flashed on a monitor. The participants knew the symbol indicated the emotional nature of the pictures.
The symbols varied, depending on whether the upcoming photo was "neutral" or "aversive."
All of the photos came from an international repository established 20 years ago to provide psychologists with a standardized set of images that would have a predictable impact on viewers.
The neutral photos are "really neutral," Nitschke said, like a picture of a spoon, a plate, a fire hydrant or a chair.
A circle, symbolizing a neutral picture, appeared on the screen moments before the photograph, so participants knew the next photo was neutral.
If they saw an X, they knew it wasn't going to be fun.
When Nitschke culled through the photos for aversive pictures, he picked the ones that were extremely negative.
"I maxed out," he said. "I got the pictures that were as arousing and as negative as possible. A lot of them are really gory. There's one of a guy whose arm has been cut off, and he's bleeding. There's a picture of a child with a tumor on its face that is bright red and has disfigured the face. There's a vicious dog, and a snake, and one where a person is attacking another with a knife."
During the scanning, as soon as the X flashed on the screen, the amygdala and hippocampus became very active.
That shows that the simple anticipation of an emotional experience fires up the memory machine, Nitschke says.
"Just the X results in activation of these areas," he said. "I would not have predicted that six [years] or eight years ago when I got into this."
That anticipation of the negative image also had a dramatic impact on memory.