NOTE: Below is the complete question
In Solomom Asch's classic obedience experiment, participants were asked which of three lines matched a reference line. When participants were tested alone, there performance was approximately 99% correct in the main experiment, the participants were tested in a group that contains several confederates. A confederate is someone who is working for the experimenter but appears to be just another participant. Starting on the third trial of the group testing condition, all the confederates gave the wrong answer on most trials. On these trials, most participants at least occasionally gave the same wrong answer as the confederates. However, it’s clear that the participants knew that this answer is incorrect because
ANSWER AND EXPLANATION:
It is obvious that the participants knew that the answer is incorrect because virtually all of them got it right when they were tested individually. They sometimes gave incorrect answers because they conformed to group pressure, which is the basis of Solomon Asch's experiment.
Based on Solomon Asch's conclusion, people conform for two main reasons: because they want to fit in with the group (normative influence) and because they believe the group is better informed than they are (informational influence).
The participants gave the wrong answers in this experiment because they allowed group pressure to rob them of their own individual or personal convictions.