Asch conducted an experiment to determine the extent social pressure from the majority of a group affected conformity on an individual.
Asch used a lab experiment, where he took 123 male American undergraduates and asked them to take part in a 'vision test' using a line judgement task. Asch put 7 confederates in a room(those who knew the true intentions of the experiment) and one naive participant( did not know it was a study of conformity). in every trial there would be 3 lines on one board and another target line on another board, the participants were asked which line (A,B or C) was most like the target line.
Why did you say the wrong answer even though you knew it wasn't right??
In total there were 18 trial, in 12 of those the confederates deliberately gave the wrong answer, even though the correct answer was easily visible. The naive participant would always go last or second to last in the line of participants. Asch asked all participants in turn to say allowed which line they thought best matched the target line, when the confederates all answered incorrectly, Asch wanted to see if this made the naive participant to also say the wrong answer.
Throughout the trials around 35% of participants conformed with the group and 75% conformed at least once in the 12 critical trials. just 25% of the participants didn't conform at all.
When they were interviewed after the experiment, the participants explained that they conformed either because they feared being ridiculed from the group for saying a different answer (distortion of action) or they started to see the lines the same way as the majority (distortion of perception) or finally the were doubtful/unsure of their answer so conformed (distortion of judgement)
One limitation of this experiment is that is a highly biased sample as all participants were white American male undergraduates , which means the experiment lacks population validity. Also another problem was that the environment was very artificial so the experiment lacks generalisability. Another problem was deception as participants were not aware of the true intentions of the experiment and therefore at the end could become embarrassed which is not protecting from harm.