10 people in a room. 9 actors and 1 test subject. They are asked a question with an obvious answer. The actors answer are the same and it´s completey and obviously wrong. The test subject will most likely also then give the same wrong answer.
Henk, in most experiments like that, they include a part where they afterward ask the subject for the reasons why
they responded as they did. That can be extremely important.
A quick example . . .
In an experiment, young children, one at a time, were put into a chair at a table in a room by themselves. A piece of candy was placed on the table, and the child was told, "You can eat the candy right now if you want, or you can wait a few minutes and I'll bring you another so you will have two
pieces of candy instead of just one." The child was then left alone.
The experiment showed that white children usually waited for that second piece of candy, while black children tended to go ahead and eat the single piece. The psycologists' conclusion was that blacks tend to want things immediately, while whites are more patient.
But another group of psychologists questioned that conclusion and performed the exact same experiment. But this time, they asked
the children why
they either ate the candy or waited for more. The black children said that they were afraid that the adult was lying to them about bringing that second piece of candy and might even come back and take away the single piece. So, the real
reason the black children went ahead and ate the single piece was because they were brought up around adults who often lied to them. It was a societal
problem. It had nothing to do with being "impatient."
So, asking why
is a very important part of human experimentation.