Conformity can be split into two.
Compliance: To go along with the majority, even if you don't share their views. If you do this to appear normal, this is normative influence.
Internalisation: An actual embracing of the exposed view. For example, if I lived with a vegan, I may become a vegan after time and exposure, believing the same reasons as my house mate. You fully believe these views yourself. In terms of internalisation, if you find yourself in a strange situation and you are unsure of how to behave, (ie, at a formal dinner, with the choice of cutlery) you may observe others showing the correct behaviour and copy this. This is informational influence.
ASCH studied Normative Influence.
This was a Lab Experiment with an Independent Groups design.
What are the Pro's and Con's with these methods?
Asch formed groups of eight participants, 7 were actors, 1 was the real participant, the true participant was either sat last or 7th so they heard the answers of the 7 actors before them.
In the experiment, the participants were shown 3 lines and an unlabeled line, the participants had to shout out what line was the unlabeled, in the image here, the correct answer is C, however, participants 1-7 answered B to see if Number 8 conformed to appear normal. The test was repeated.
Asch concluded that in control trials, ie, trials where the subject was on his/her own, the participant gave the wrong answer 0.7% of the time, this could be due to error or investigator effects. However, in the 8 participant trial, conformity levels were as high as 37% and 75% of participants conformed at least once.
Also note that this study was an ambiguous task, people don't usually conform if they are tested in a task they are specialized in, ie, a brain surgeon won't accept advice from a 5 year old.
Zimbardo studied Conformity to Assigned Roles.