In wrong answer. The ‘learner’ was to act

In 1962, Stanley Milgram
shocked the entire world with his study on obedience and personal conscience.
He was a psychologist at Yale University who devised an experiment famously
known as ‘The Milgram Experiment’. Milgram selected volunteers by advertising
in the newspaper asking for male participants to be a part in a study about
learning and memory. The real motive behind the experiment was not disclosed to
these participants as he wanted to get genuine behaviors from them.  
When these participants arrived at the lab, they were told that they were going
to be taking part in a study that was trying to look at the effects of
punishment on learning.
There were two participants involved in the study who were to randomly select
from a hat to decide who would be the ‘learner’ and who would be the ‘teacher’.
However, one of the participants was working with the experimenter and choosing
the roles from the hat was not so random since he was given a fixed role as the
‘learner’. This means that the actual participant always got the ‘teacher’
role. While the ‘teacher’ was watching, the experimenter connected a shock
generator to the ‘student’ . The ‘teacher’ was then taken to another room with
no visual contact with the ‘learner’ and were introduced to a shock box with a
number of switches in ascending order where the first switch was labelled 15
volts and the last 450 volts which was considered to be extremely intense
shock. He was then asked to teach the ‘learner’ some word pairs where learner
would be shocked every time he gave a wrong answer. If the ‘learner’ gave
correct answer, the ‘teacher’ was to continue and if not, he was to announce
the voltage and then give them a shock at increasing increments for every wrong
answer. The ‘learner’ was to act as he was in pain by screaming loudly and
begging the ‘teacher’ to let him out of there. The experimenter stood behind
the subject encouraging them to continue with the punishments even if they seem
distressed and was to give a series of prods to make sure that the subjects
continue with the test.