1.Categorisation serves an informative purpose. It tells you where somebody belongs etc...

2.It is a normative process- It allows you to group a new individual into an existing group without having to create a new category for the person.

3. It minimises effort- See point 2- easier to just place somebody into an exisiting group who share similar characteristics.

It may lead to stereotyping (the setting of expectations of another social group). Stereotypes may lead people to infer negative expectations of others.

Example: Negative stereotype that African American are violent.

When white participants witnessed an African-American pushing a white person, 75% deem the act as violent. When a white person pushes an African Americam, only 17% say it was violent, 42% say it was playful.

(Duncan, 1976)

When we group ourselves in to a group:

1. We depersonalise ourselves- shift from each members as unique individuals to all member being one entity/group. Shifting from "me and you" to "us vs them".

2. We assimilate into the ingroup norms.

3. We stereotype ourselves (self-stereotyping). We define ourselves based on the general charactereistics of the group.

How easy do we group ourselves and show intergroup bias?

Tajfel et al. (1971) had school children participants. It was found that even if the categorisation was based on arbitrary guidelines, participants still developed in group favouritism and intergroup bias.

Social Identity Theory states that we like to have a positive concept of self to maintain a positive self-esteem.

Our self indentities are derived from personal and group identities.

Therefore, we are motivated to increase the positive perception of our group in contrast to outgroups. This results in ingroup favouritism and intergroup bias.

It is that one see other outgroup members as being all the same. The groupness/homogeneity is amplified during intergroup differentiation- See Category differentiation model.

See also the Texas store clerk study- Platz and Hosch (1988)- Store clerks were better at identifying customers that were of the same race as them. Outgroups (other races) seemingly homogenous- less able to tell the difference between people of other races.

For ingroup:

Positive acts- We tend to use dispositional explanations- Just inherently good

Negative acts- We tend to use situation reasons- The situation force us to act the way we did.

For outgroup:

Postive act- Situational reasons- They were just being kind because it was convenient for them to do so in the situation.

Negative acts- Dispositional reasons- They are just inherently evil/bad people.

See Ultimate Attribution Error, Actor-Observer Bias

1. Competition for resources- Economic, health, education etc- See realistic conflict theory.

2. Individual differences- People high in Right Wing Authoritarianism (RWA) and Social Dominance Orientation (SDO) tend to be more motivated to maintain the stats of ingroup over outgroups- Thus create potential for intergroup conflicts.

3. Threat:

• Realistic threat- Threats to material well being of ingroup- (ie.threats to ingroup economic, political and health status)
• Symbolic threat- Threats to the ingroup's value systems

4. Intergroup anxiety- anxiety from negative interactions experiences with outgroups.

See Intergrated Threat Theory

1. Individual differences:

• People high in Respect for persons (Rfp)
• People high in empathy and perspective taking [of others]

These two traits motivate individuals to want to co-operate with outgroups more. This is because people high in these traits are willing to listen and accept other outgroups' opinions. They are also more willing to see things from outgroups' perspective. Hence the willingness to co-operate reduce risks of intergroup bias and conflicts

See Northen Irish study on Catholics and Protestants (Laham et al, 2010).  Another example is the Indian Muslims and Indian Christian study.

2. Physical contact- The more physical contact with outgroup- the lower the intergroup bias=lower risk of conflict. See East and West German attitudes towards foreigners study

3. Equal standing during contact between outgroups.

4. Authority sanctioned/monitored outgroups interactions.

5. Superordinate goals- shared goals- See Sherif et al. 1961- Robber's cave study- The summer camp with the Eagles and Rattlers.

6. Absence of competition between outgroups.

7.Extended contact- If an ingroup member has outgroup friends- less likely to prejudiced towards outgroups= lower intergroup bias= lower risk of conflict.

8. Reorganising the concepts of groups- Changing categorisation concepts:

• Recategorisation into 1 single superordinate group= change perspective of  'Us and them ' to 'we'= reduce intergroup bias= reduce conflict risk.
• Decategorisation- see outgroups members as individuals- not everyone is the same- reduce stereotyping prejudice= reduce intergroup bias= reduce conflict risk

See Gaertner et al. (1989) study on the ABAB as one group (recatgorisation) and as individuals (decategorisation)