One of the strangest conversations I have witnessed happened when I was at a party at a friend's house several years ago. He was regaling me with a story about making breakfast in high school and covering the dog with pancake mix. He got to the end of the story (which was funnier than you might think) when his brother piped in. "Great story," he said, "but that was me, not you. You were on the sofa watching." The next 20 minutes devolved into an argument over whose life it really was.
I had forgotten about that story until I read a paper in the September 2010 issue of Psychological Science by Isabel Lindner, Gerald Echterhoff, Patrick Davidson, and Matthias Brand. They were interested in how observing actions influences your memory for those actions.
Previous research has shown that if people imagine performing an action, they can later believe that they did it. I know I have had this happen to me. I have thought about bringing the garbage can to the street on the day when garbage is collected. Later, I am surprised that it isn't out on the street; I mis-remembered thinking about taking out the garbage as actually taking it out.
These authors were interested in whether observing an action can lead you to think later that you actually performed it. To test this possibility, they first had people read about a variety of simple actions like shaking a bottle or tapping with a pencil for 15 seconds. Some of the actions they only read about, while others they read about and also performed.
After a short break, people saw videos of other people carrying out some actions they actually performed, some they just read about, and some that were not a part of the first phase of the experiment at all.
Two weeks later, the participants were shown a list of actions and were asked whether they had performed them in the first session of the study.
Across three studies, people were consistently more likely to believe that they had performed actions that they had only seen someone else perform than actions they had not seen someone else perform. That is, watching someone else perform an action led people to believe later that they themselves had performed the action. This finding held up even when participants were told at the beginning of the study to pay careful attention to the actions they performed.
In a particularly interesting condition, this finding was observed even when participants were warned that people often mis-remember actions they see other people perform as things they did themselves. Knowing about this effect does not make it go away.
Why does this happen?
As I have written about previously in this blog, when you see someone perform an action, you often adopt the goals of the people you are watching. This phenomenon is called goal contagion. Goal contagion is useful in social groups, because it can lead an entire group to want to work together. A side effect of this goal contagion, though, is that you may later think you were more involved in an action than you actually were. The most extreme version of this effect is a false memory that you performed an action that you actually did not.
Findings like this reinforce the point that our memories are not designed to provide a truthful readout of the events of our lives. Memory is designed to help us act in the future. Seeing an action performed gives you some confidence that you understand how to perform the action yourself. Your memory is really trying to tell you that you understand how to perform an action.
For example, when I first bought a house, a wasp built a nest in ceiling of my back porch. I went to the local hardware store and bought a can of spray to take down the nest. I was really worried about getting stung. The sales guy at the hardware store took me outside with a bottle and sprayed it to show me how it was done. After that, I went home and did it myself. Just seeing someone else do it helped me to understand how to do it myself.
It is only because our culture cares a lot about exactly who performed particular actions that this facet of memory is seen as an error rather than a benefit.
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