The Science Behind 'Stop Me If I've Told You This'

We've all said the equivalent of, "Stop me if I've told you this before," but now scientists have figured out why we can be so unsure what tales we've told to whom.

Turns out, our brains are better at recalling the source of information than whom we give information to, and the more self-focused a person is, the worse he is at so-called destination memory.

Scientists have classified memory as short-term and long-term, but this is arguably one of the first times anyone has looked at incoming and outgoing information and how it's stored in our noggins. While remembering both types is likely important in everyday lives, this new research suggests we're not as good at some aspects of the outgoing garble.

And that could get us into trouble, say the researchers. For instance, managers need to remember to whom they told certain information or delegated responsibilities in order to monitor progress. Even liars, or perhaps particularly liars, need to keep track of what they've told people so they don't get caught telling incompatible stories.

The finding will be published in a forthcoming issue of the journal Psychological Science.

Memory game

Nigel Gopie of the Rotman Research Institute in Toronto and Colin MacLeod of the University of Waterloo ran two experiments to tease out whether there's a difference between our incoming and outgoing recollections and if so what's to blame.

In the first experiment, 60 undergraduates were split into two groups. In one group tested for source memory, participants looked at the faces of well-known famous people on a computer screen. After they viewed each of the 50 faces, a random fact appeared on the screen. In the destination group, participants told each fact to the face on their computer screen.

Then, to test students' memory, the researchers showed them 20 faces and 20 facts, half of which the participants had studied and the others they had not studied. Participants had to indicate whether they had seen each during the initial part of the study. No matter the group, the students didn't seem to have trouble recalling which separate facts and faces they had seen.

That changed when the researchers tested the participants on remembering face-fact pairs. The students who were giving information out (destination memory) scored about 15 percent lower on memory performance compared with the students receiving information on the face-fact pairings.

Self-absorbed

Something must be hindering participants from linking up the person with the fact when doling out the information, the researchers figured. They knew that when providing information to others you are generally preoccupied with thinking about what you're saying and how you look, among other factors.

So a second experiment tested whether that something was self-focus. The researchers had 40 undergraduates complete the same task for destination memory as the first experiment. The only difference here was that some participants dealt with personal facts while others doled out interesting facts about other things (non-self facts).

"When you start telling these personal facts compared with non-self facts, suddenly destination memory goes down more, suggesting that it is the self-focus component that's reducing the associative memory," Gopie told LiveScience. The difference was about 15 percent, he said.

Brain drain

Perhaps, the researchers suggest, focusing on oneself drains mental resources, leaving fewer reserves for storing information about the fact-giving situation.

"Psychologists think there is a limited set of resources available and so there's one central pool of resources, so when we take away from that pool there's fewer left to do things with," Gopie said.

The findings may not hold in all situations. "If you were telling something that was highly emotional then maybe you would remember that information better," Gopie said.

As for whether the narcissists among us would have an even tougher time recalling to whom they relayed certain information, Gopie said, he'd expect to find in an experiment, "that people who are self-focused would have worse destination memory."

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