Thoughts, emotions and behaviour of people become more similar if they interact with each other. A social norm is a generally accepted way of thinking, feeling or behaving that most people in a group agree on. There are two types of social norms. Descriptive social norms are norms that serve the connectedness motive and refers to what people feel, think and do. Injunctive social norms serve the mastery motive and refer to what people should feel, think and do. Group conformity occurs if there is an ambiguous stimulus, but also if there is an objective stimulus (e.g: Asch’s experiment).

Conformity refers to the convergence of individual’s thoughts, feelings, or behaviour toward a social norm. There are two types of conformity. Private conformity occurs when people are truly persuaded that the group is right and willingly and privately accept group norms as their own beliefs. Public conformity occurs when people respond to real or imagined pressure and behave consistently with the norms that they do not privately accept as correct. People publicly conform because they fear ridicule and rejection. Social influence impacts early unconscious visual perceptual processing and thus changes what an individual sees.

People conform because they expect everyone to see the world the same way and they expect to see the world the same way as others do. The false consensus effect is the tendency to overestimate other’s agreement with one’s own opinions, characteristics and behaviour. The more important the connection to others, the stronger the false consensus effect.

Norms fulfil mastery motives. Norms help us understand the world and predict it better. Consensus tells us something about reality. Descriptive norms are powerful guides to reality. Norms have an informational influence. This is the process by which group norms are privately accepted to achieve or maintain mastery of reality. The amount of influence the group exerted increased as the size of the group increased, but only up to a point. The presence of someone that deviates from the norm decreases conformity.

Norms fulfil connectedness motives. Norms have a normative influence. This is the process by which group norms are privately accepted to achieve or maintain connectedness and valued social identity. Normative influences satisfy our need for connectedness because consensus provides and expresses our identity and values. People tend to accept group norms whenever they are reminded of their membership in a group that’s important to them.

Norms fulfil me and mine motives. People tend to conform to the in-group rather than the out-group. In-group messages receive more systematic processing than out-group messages. People want to see themselves in a positive light and thus see their in-group as right and conform to them and see the out-group as wrong and don’t conform to them. People adopt the group consensus to feel positive about the self and the valued in-group.

A reference group refers to those people accepted as an appropriate source of information for judgement because they share the attributes relevant for making that judgement. The reference group you turn to depends on the type of judgement or evaluation you’re making. People use almost everyone as a reference group when they have to make a judgement about a basic skill or facts. People use similar people as a reference group when they have to make a judgement about complex skills, value-laden or opinion-based judgements. People use peers when they have to make a judgement about social and personal judgements.

Group polarization is the process by which a group’s initial average position becomes more extreme following group interaction. It is possible that in a group there will be a compromise, but only if the group is divided, but balanced, otherwise polarization will occur. Group polarization can occur when people are processing superficially and when people are processing systematically.

If people superficially process the information, they can use the group position as a guide to what their own position should be. Consensus is used as a heuristic. Superficial acceptance of group descriptive norms can move the group toward the extreme. It can also lead to the extreme because people want to be the best group member and thus they present their opinion as more extreme.

Systematic processing makes group polarization even more likely. If the group has an initial preference and the group uses systematic processing, the following factors play a part in group polarization:

1. Majority arguments are more numerous
   The greater the number of people who hold a particular viewpoint, the more numerous the arguments favouring that position are likely to be. Initial preferences bias the arguments discussed.
2. Majority arguments are discussed more
   Information and evidence endorsed by more than one group member are more likely to be raised and discusses than ideas endorsed by only a single person.
3. Majority arguments seem more compelling
   Majority arguments seem more compelling because they are repeated by different individuals and which is more persuasive than a single individual and triggers the mere exposure effect.
4. Majority arguments are presented more compellingly
   Majority views are expressed faster, people who hold the view of the majority are more confident in expressing their view and majority arguments are seen as common ground which makes them more persuasive.

Consensus implies that opinions are valid, but this inference is true only when consensus is achieved in the right way. A consensus doesn’t reflect the right opinion if it is consensus without consideration. A consensus is less strong if the consensus is contaminated if the people reaching the consensus might have influences one another’s view. People view the in-group as more diverse and the consensus thus as more persuasive, because the chance of contamination is lower and the out-group as more homogeneous and the consensus thus less persuasive because the chance of contamination is higher.

Those who don’t agree with popular positions are often criticized and disparaged. Group members who are bullied or threatened with exclusion from the group often change their behaviour and comply to regain the group’s favour. Public conformity does not reflect true conformity. Group members whose deviant views trigger anger from others are more likely to publicly confirm unless they have an alternative group to go to. Pluralistic ignorance occurs when everyone publicly conforms to an apparent norm that no one privately accepts. Conformity to a consensus only fulfils mastery and connectedness motives when the consensus reflects careful consideration, is free from contamination and is privately accepted.

Groupthink refers to group decision making that is impaired by the drive to reach consensus regardless of how the consensus is formed. In these situations, the desire to reach consensus impairs effective decision-making. Groupthink occurs when groups feel overwhelming pressure for agreement to maintain a positive view of the group in the face of threat. Groups whose members are very similar and who are very focused on “who we are and what we stand for” are likely to use groupthink. Similar group members often use the same biases. Groupthink produces an illusion of unanimity rather than at true consensus.

In order to avoid consensus without consideration, groups need to engage in open inquiry and encourage dissenting perspectives and points of view. In order to avoid consensus that is contaminated, group membership can be initially selected for diversity. In order to avoid public conformity rather than private conformity, public votes shouldn’t be used.

Group members expect to agree, so a minority can exert influence by undermining the confidence in the correctness of the majority consensus or majority norm. In order for a minority to have influence, they should offer an alternative consensus. Minorities are also the most influential when they are consistent. Consistency is important because it conveys commitment to the viability of an alternative position. People who were recently exposed to dissent are more likely to dissent themselves.

Minorities have more influence if they are part of the in-group. Confirming one’s in-group credentials by first agreeing with the majority before dissenting is a particularly effective way to promote minority influence. Seeing a minority’s in-group credentials makes most in-group majority members wonder why the in-group minority thinks the way it does and this promotes systematic processing. Minorities often produce more private than public change in majority members’ opinions and behaviours. Minority influence might help against groupthink. Systematic processing leads people to think more creatively about the topic and this may allow them to see novel connections and to look at things from a fresh perspective. Minority dissent can be a facilitator of creativity and innovation.

Both the majority and minority can provide positive connectedness. The best way to promote effective group norm formation and consensus-seeking is to make group members more critical and systematic thinkers as a group rather than as individuals.