IB Psychology HLTopic 3 — Group BehaviourPaper 1 & 2Sociocultural approach~10 min read
Why People Conform to a Group
Seven people in a row look at two obviously different lines and calmly say they are the same length. You are eighth. Your eyes are working perfectly. What do you say? Around a third of the time, people said what the group said — and the reasons why turn out to be two completely different things.
📘 What you need to know
Conformity is a type of social influence involving changing, adapting or taking on new behaviours to fit in with a group.
It is also called majority influence, because people tend to conform to larger groups. Minority influence happens too, but it is less common.
There are two motivations. Normative social influence (NSI) is the need to be liked and accepted — a fear of rejection.
Informational social influence (ISI) is the need to know what to do — a fear of getting it wrong or being humiliated.
NSI is emotional and links to compliance: you change what you say, not what you believe.
ISI is cognitive and links to internalisation: you change what you actually believe.
Asch (1951): conformity ran at 32% on critical trials; 74% conformed at least once; with no confederates present, errors fell below 1%.
Two very different reasons to agree
Ask yourself one question to tell them apart: would this person still agree if nobody was watching? If yes, it was informational.
ISI tends to appear in a crisis, when a decision is needed fast and you assume the group knows what it is doing — even when that assumption is wrong. Someone collapses in the street, nobody stops, so you conclude it is not serious. Nobody has told you anything; you read the group as information.
Asch’s line task (1951)
Aim: to investigate the effect of majority influence on behaviour.
Participants: 50 male students at a US university. They believed they were taking part in a vision test, so they were naive participants.
Procedure: the real participant sat at the end of a row with seven confederates. Each person in turn said which of three comparison lines matched a target line. In the critical trials the confederates all gave the same wrong answer. The dependent variable was the number of times the participant matched that wrong answer.
The task had to be this easy. If it had been ambiguous, a wrong answer could have been a genuine mistake rather than conformity.
Finding
Figure
What it tells you
Conformity on critical trials
32%
About a third of answers followed the wrong majority
Conformed at least once
74%
Most people caved at some point, even if not often
Never conformed
26%
A quarter held out every single time
Errors with no confederates
under 1%
The task itself was easy; the group caused the errors
Conclusion: people will conform to giving an answer they can see is incorrect, largely because of normative social influence.
The 26% is as interesting as the 32%. A quarter of participants never conformed once. Any theory of conformity has to explain the people who resist as well as the people who fold, and neither NSI nor ISI does that well.
Evaluation
Strengths
Real practical value. Understanding majority influence helps make sense of crowd behaviour, including anti-social acts during protests, and of why nobody helps in an emergency — the diffusion of responsibility.
Well controlled. The IV was manipulated while everything else was held constant: the same line stimuli, the same number of confederates, the participant always in the same seat. That makes it high in reliability.
The no-confederate control condition proves the errors were not caused by a difficult task.
Limitations
Neither explanation accounts for resisters. Freedom fighters, rebels and people who simply do not care what a group thinks are not covered, so the theory cannot be generalised to everyone and does not handle individual differences.
Low mundane realism. The task is artificial and lab-based, which limits external validity. It is rare for NSI and ISI to be tested in real conditions.
Demand characteristics. The task was strange enough that participants may have felt self-conscious, and easy enough that some may have thought “what do they know that I don’t? Is this a trick?” — following the group out of wariness rather than conformity.
Gender and culture bias. An all-male, all-American sample tells us nothing about how NSI works for women or in other cultures.
EXAM QUESTION
Discuss two explanations of conformity. [22]
Step 1: define conformity and majority influenceChanging behaviour to fit in with a group.Step 2: explain NSI and ISI as different mechanismsNSI: emotional, fear of rejection, compliance. ISI: cognitive, uncertainty, internalisation.Step 3: use Asch, including the control condition32% / 74% / 26% / under 1%. The control is what makes the rest meaningful.Step 4: discuss both explanations criticallyNeither explains resisters; demand characteristics; artificial task; gender and culture bias.Best line: Asch shows conformity happens, not which motivation caused it
Link to concepts
Causality
The key question is how far demand characteristics invalidate the findings. Participants were doing an unusual, contrived task in front of strangers, which invites self-consciousness. And because the task was so unambiguous, some may have suspected a trick and gone along with the group out of caution. Either reading undermines the claim that the group’s opinion caused the change.
Bias
Beyond the all-male US sample, there is participant bias: people behave differently because they are in a study, often because they want to fit in with the situation. So the participants who conformed to a wrong answer in a laboratory might not conform anything like as much in ordinary life.
💡 Exam tip
Pair each explanation with its outcome: NSI with compliance, ISI with internalisation. Examiners look for that link.
Always quote the control condition figure. Without it, 32% could just mean the task was hard.
Use the 26% who never conformed as your evaluation of both explanations.
Explain why the task had to be easy. It shows you understand the logic of the design.
Diffusion of responsibility is a useful real-world application — name it.
This page sets up the next one: if conformity is social, cultures should differ in how much of it there is.
⚠ Common mix-up
Swapping NSI and ISI. Normative = norms and being liked. Informational = information and being right.
Saying 32% of participants conformed. It is 32% of critical-trial answers. 74% of participants conformed at least once.
Calling the confederates participants. There was one real participant per group.
Treating conformity as obedience. No authority figure gave an order here.
Assuming conformity is always bad. ISI is often sensible — copying the group on your first day at work is efficient.
Forgetting that Asch cannot separate NSI from ISI. The study shows the effect, not the motive.
Up next: Cultural Dimensions and How Groups Behave — Asch’s task was run in seventeen countries, and the results were not the same everywhere.
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