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 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.

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 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 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 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 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.

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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