Why do we remember emotional events so well? One memory researcher says it’s not just because they’re important to us.

As this ScienCentral News video reports, the findings suggest that we can manipulate emotion to help improve our memory.

Drilling for memory

Students don’t expect their teachers to encourage them to stop studying at night to watch their favorite TV show. But when Kristy Nielson tells her students at Marquette University it’s okay to do just that, she has a good reason why.

“I tell them, ‘Yeah, you can use me as an excuse for why you stopped studying last night and watched Friends,’” she says. “Because it may not be a bad thing to do to take that break, have that positive emotional experience. Of course the only catch is, can we get them to get back to studying afterwards?”

Nielson has been researching the connection between emotion and memory for more than a decade, and her work is disproving some previously held theories. It was assumed that we remember emotional events so well because they are important to us and we replay them in our minds over and over. But her work shows that emotional events can help you remember things that are not related to the event itself, as long as the two things occur within a close timeframe.

In her most recent study, which was presented at the 2002 Society for Neuroscience conference, Nielson showed a group of students a list of common, unrelated nouns. Then she showed the students either a video illustrating proper tooth brushing technique, or one with uncensored footage of someone undergoing a tooth extraction.

“It was unpleasant,” she says. “You see some blood and you hear some drilling, and it's—people kind of describe it as giving them the creepy crawlies.”

When she brought the students back 24-hours later, she asked them to recall the words they had been shown the day before. Those who saw the gory dental surgery video remembered, on average, 10 percent more of the words than those who saw the tooth brushing video.

How it works

This work builds on previous studies on animals and humans, showing how “arousal” can enhance memory. The chemical mechanism is adrenaline, which studies suggest helps encode memories in our brain. The idea is that when something emotional happens, you get a jolt of adrenaline that helps you remember the moment, and even unimportant details around the moment, better than usual.

“We think that's a pretty natural biological mechanism to help differentiate important from unimportant memories,” says Nielson. “I'm just trying to manipulate that.”

That is, she wants to show how to use emotion or arousal to your own advantage, and “take control of [your] own memory, and learn to enhance it when you want to.” While watching a disturbing dental procedure can do the trick, so can many other (and much less gross) things.

The adrenaline response can be elicited by positive emotional experiences. One of Nielson’s previous studies showed that students who received a dollar after learning the word list remembered the words better than those who got nothing, a full week after the words were presented. She thinks a funny event would also work, and she is currently recreating her experiment using a clip from Saturday Night Live. But arousal is not restricted to emotional events.

In one of her very first studies, Nielson showed people a word list, and had some of them squeeze a “hand dynamometer”-sort of a fancy stress ball that also measures muscle tension. That simple muscle tension caused enough arousal, and therefore adrenaline, in the subjects to help them remember the words better.

What it means for you

While manipulating arousal to help memory can apply to anyone who cares to try, Nielson has three specific groups in mind: students, teachers (who can manipulate the environment in which their students learn), and the elderly, who lose control of their memory as the aging process wears on their brains.

Watching your favorite TV show, taking a jog around the block, listening to your favorite album, squeezing a stress ball, or even eating a candy bar—all these things might work. But Nielson cautions to use them in moderation. That is, extremes of emotion or arousal tend to have a negative effect on memory.

“The video that I showed was unpleasant,” she says. “But it wasn't what you would call traumatizing. If there were something that was extremely violent or very traumatizing, then you might expect that it could actually impair memory.”

She also does not yet know how long the window of opportunity is between the learning experience and the emotional event. She hopes to tease that out in future studies.

Her current work is funded by Marquette University.