This is a question that has been bugging me for a very long time.
Let me illustrate with a silly example.
Suppose that a study finds out that the majority of the population associate the number 1 with the colour blue (again, this is is a very silly example). Suppose this study becomes very popular and the result comes to be known to most people.
How will this knowledge of the experiment change behaviour?
Will the result still be the same after the study is known to the entire population?
I am not talking about the kind of results where we do not have influence on our behaviours, like our heart rate during a tense situation or how we react when our life is threatened. I am talking about experiments where we can make a conscious choice and is apparently "inconsequential" (so, nothing that poses harm to us).
The use of canned laughter in sitcoms -- Many of us by now have realised that laugh tracks are used in sitcoms to direct how the audience should react and make them think that what they are watching is funnier than it actually is (Example of Social Proof, which is nicely explained by Robert Cialdini). After I knew this, I actually found TV shows employing the technique to be less funny and in some cases, even annoying. (I assume that many people reacted the same way after finding out about it).
So the study of this particular behaviour actually made me react in the opposite way that the TV show producers intended and how the study says I should be behaving. Thus, changing the results of the study.
Are there other studies like this? How do we design experiments that are tolerant to this?