What was the best day of your life? Think about it for a moment, and try to recollect some details about it. The sights, sounds, smells and emotions of the day come bubbling up to the surface without a lot of effort. Chances are, you remember a lot of it pretty well.
Or do you?
The way your brain works, what you’re actually recalling is the memory of the memory. And if you’ve spent a lot of time thinking about it, there’s a good chance that what is locked in your brain now is different than what actually happened.
Memories are not static. For example, if you bring something up from the depths of childhood while you’re in a sour mood, you might think of the event in a more negative way. And then that negativity gets stuck with the memory. So the next time you retrieve that information, it won’t seem as nice as it actually was. You won’t know the difference, though. To you, it will still be the same memory.
Do it enough times, and you could even end up with a completely false version of the event.
This phenomenon recently was proven for the first time in an experiment conducted by Donna Bridge, a postdoctoral fellow at Northwestern University’s Feinberg School of Medicine. In her experiment, Bridge put participants through a two-hour session where they learned a series of 180 unique object-location associations on a computer screen. The next day, they were asked to recall the information by moving some of the images from the middle of the screen to the correct location. This was repeated on day three, though some of the objects were different between the two recall sessions.
As you might expect, people did better with images on day three that they were tested on during day two. However, people never recalled the exact location correctly. And on day three, they tended to place the object closer to the incorrect location they recalled on day two rather than the actual correct location they learned on day one.
What’s more, their brains created a stronger electrical signal when they placed the image closer to the incorrect location from day two than when they placed it closer to the correct location on day one. That signal seems to indicate that a new memory was being laid down. And that new memory caused people to continue to have a bias towards the wrong location.
Of course, if you asked them, they’d swear they were right on target.
Besides just being kind of cool, the study has a lot of real world implications, not the least of which is eye witness testimony in criminal trials. How sure can we be that people are recalling actual events, rather than slightly different versions of the events that their brain has created out of thin air?
How sure are you about those five minutes?