IB Psychology HLTopic 2 — Development of the SelfPaper 1 & 2Sociocultural approach~11 min read
Peers, Social Identity and Who You Become
Ask someone who they are and listen to the answer. Most of it is groups: their family, their country, their team, their year group. Social identity theory takes that seriously — a large part of your sense of self is borrowed from the groups you belong to, and defended the same way you would defend yourself.
📘 What you need to know
Social identity theory (SIT) says a person’s sense of self is shaped by their group memberships.
Groups you belong to are ingroups; groups you do not are outgroups.
Some ingroups are chosen (a team, a class), others you have no control over (nationality, ethnicity, age group).
Three key processes: social categorisation, social comparison, positive distinctiveness.
These lead to ingroup favouritism and outgroup derogation, and can feed prejudice and discrimination.
Adolescents are especially open to peer influence, because peers replace parents as the main source of influence.
Graupensperger et al. (2018) tested this with 379 NCAA student athletes.
The three processes
SIT is really a three-step chain, and each step feeds the next. Learn it as a sequence and you can reproduce the whole theory from one diagram.
Categorisation is cheap — it needs very little cognitive energy, which is exactly why stereotypes form so easily from it.
Social comparison in two directions
Downward comparison — the ingroup is seen as superior, for example an employed person looking down on someone unemployed.
Upward comparison — the outgroup is seen as superior, for example a small business owner admiring a billionaire entrepreneur.
The “they’re all the same” effect
Once the comparison starts, perception bends to help. People see their own group as full of distinct individuals, and the other group as a single block with one personality. This is the step where prejudice gets its raw material — for example asylum seekers being labelled as “criminals” or a “threat”, which makes them easier to dismiss.
The technical terms are outgroup homogeneity and ingroup differentiation. Use the picture to remember which way round they go.
Why adolescents are especially open to this
Social identity can push people to conform to the norms of their ingroup — including risky norms such as drinking and driving. Adolescents are particularly vulnerable, for three reasons:
peers replace parents as the main source of influence
the adolescent brain is highly sensitive to social rewards like approval and acceptance, which often come attached to risky behaviour
a strong need for peer approval motivates conformity
Adolescents also tend to imitate or amplify the behaviour of high-status individuals in their group, as a way of strengthening their own place in it.
Link this back to page one of the topic. The prefrontal cortex is the last part to mature, and the reward system is already running at full volume. Add a group whose approval you badly want, and the behaviour stops being mysterious.
Key study: Graupensperger et al. (2018)
🧩 The study in four steps
Aim — to investigate whether college-age athletes who strongly identify with their team are at increased risk of conforming to teammates’ risky behaviours.
Participants — 379 student athletes from the National Collegiate Athletic Association (NCAA), mean age 19, representing 23 sports including baseball, soccer, lacrosse and field hockey. Most were in their first year of college.
Procedure — participants responded to hypothetical risky-behaviour scenarios, such as being offered marijuana. They were then shown fictional teammate responses suggesting high agreement with those behaviours, and were later given the chance to change their original answers. A focus group interview was also held with seven recently graduated athletes from different sports.
Findings and conclusion — participants with higher levels of social identity were more willing to conform to risky behaviours, including binge drinking, smoking marijuana and drink driving. Athletes on teams with higher social identity were also more willing to conceal a concussion so they could keep playing. A strong social identity built on team membership makes conformity more likely.
The concussion finding is the one to quote. It shows conformity beating self-protection — these athletes were willing to hide a head injury to stay part of the group. That is a much stronger example than “they drank more”.
Evaluating SIT and peer influence
Strengths
A robust theory. SIT has been supported by a large body of research over several decades, standing up to both quantitative statistical testing and inductive qualitative work.
Strong application. It can inform anti-bullying programmes in schools by building a positive, prosocial picture of what it means to belong to the student body.
Mixed methods. Graupensperger combined scenario data with a focus group, so the numbers come with lived experience attached.
Limitations
Too simple. People do not always show ingroup preference — they may actively dislike or reject one of their own groups — so SIT’s claim that people identify with the groups they belong to is overly simplistic.
Unrepresentative sample. US college athletes are competitive and have unusually strong group loyalty by definition, so the results cannot be generalised to young people who are neither athletes nor American.
Hypothetical scenarios. Saying you would take a risk on a questionnaire is not the same as taking it, which limits ecological validity.
Link to concepts
Perspective — a strong social identity does not have to lead anywhere bad. In this same study, social identity also predicted conformity to teammates’ prosocial behaviours, such as being helpful. That means the effect can be harnessed to promote desirable behaviour, particularly in sport where group identities are already strong.
Causality — social identity is difficult to measure and group identities are unpredictable and changing. Someone can be a passionate Manchester United supporter while living in London and never having visited Manchester. It is also hard to say exactly when a group membership, such as being a psychology student, turns into a felt sense of belonging.
Exam practice
WORKED EXAMPLE
Explain one effect of peer influence on the development of self. [3 marks]
1. State the effect
Adolescents conform to the norms of their ingroup to gain peer approval.
2. Explain why it happensPeers replace parents as the main influence, and the adolescent brain is highly sensitive to social rewards.
3. Evidence
Graupensperger et al. found athletes with higher social identity were more willing to conform to risky behaviours, including concealing a concussion.
Effect + reason + evidenceGive the concussion detail. It is memorable and it proves you know the study.
WORKED EXAMPLE
Evaluate social identity theory. [ERQ paragraph]
Strength
SIT is supported by decades of both statistical and qualitative research, so it is a robust framework.
LimitationHowever it is simplistic: people sometimes reject groups they belong to rather than favouring them.
Sample point
Graupensperger’s athletes were competitive and loyal by definition, so the effect may be exaggerated in that group.
Judgement
SIT explains group behaviour well but overstates how consistently people identify with their own groups.
Robust, but not universalBalance means limiting the claim, not rejecting the theory.
💡 Exam tip
Learn the three processes as a chain. If you can name them in order you can write the theory from scratch.
Use one chosen and one unchosen ingroup as examples — it shows you understand that identity is not all voluntary.
Keep upward and downward comparison straight with the examples, not the words alone.
The prosocial finding is your best evaluation point, because it shows the theory is not just about bad behaviour.
This page connects to brain maturation. Cross-topic links score well in ERQs.
Say “hypothetical scenarios” when describing the method — it hands you an ecological validity criticism for free.
⚠️ Common mix-up
Ingroup favouritism is not the same as hating the outgroup. Favouring your own comes first; derogation is a further step.
Outgroup homogeneity is a perception, not a fact. The other group really is varied.
Do not call this conformity research from social psychology. Here it is used to explain the development of self.
379 athletes is the questionnaire sample. The focus group was seven recent graduates — different part of the study.
Social identity is not personality. It is the part of self that comes from group membership.
Do not claim SIT explains all prejudice. It explains a mechanism that contributes to it.
Up next: How Childhood Poverty Shapes Development — from the groups a child belongs to, to the material conditions they grow up in.
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