In 1951 Solomon Asch carried out what was to become a classic psychology experiment. He showed that people are hugely susceptible to the choices of the people around them. In both an effort to fit in and because they believe others in the group are better informed, people will conform to the group in their choices.

1. Conformity
We conform to the choices of the people around us

2. Participants are told they are taking part in a vision test
They are seated in a room with other ‘participants’ taking
part in the same test
These people are actually stooges

3. Participant
StoogeStoogeStooge
Stooge

4. Every participant is shown a line…

5. Every participant is shown a line…
…and then asked to choose the matching line from a group of
three lines of different lengths
A B C

6. Each participant is asked to individually select the matching
line and give their answer out loud to the group…
A B C

7. I think it’s ‘C’
I think it’s ‘C’I think it’s ‘C’I think it’s ‘C’
I think it’s ‘C’

8. Occasionally the stooges unanimously declare a
different line is the correct match…

9. I know it’s ‘C’ I think it’s ‘B’
I think it’s ‘B’I think it’s ‘B’I think it’s ‘B’

10. Err… I think
it’s ‘B’ too
I think it’s ‘B’
I think it’s ‘B’I think it’s ‘B’I think it’s ‘B’

11. Participants conform to the group answer about a third
of the time, even when they report afterwards that they
knew the answer was wrong
In a control group where everyone writes down their
answers privately, participants chose the correct line
98% of the time

12. Why?
1. People want to fit in with the rest of the group — giving a
different answer puts them at risk of being singled-out
2. Some people also believe the group is better informed
than they are, so they change their mind

13. Reference
Effects of group pressure on the modification and distortion of judgements; Asch, S. E.
in H. Guetzkow (ed.) Groups, leadership and men. (1951)
Pittsburgh, PA: Carnegie Press.