Festinger, L., A Theory of Social Comparison Processes. Human Relations, 1954, 114-140.

This paper further's Festinger's views on group influences of opinions and applies it to abilities as well.

His first hypothesis is that in humans there exists a drive to evaluate his opinions and abilities by comparison with the opinions and abilities of others. Both opinions and abilities have a strong impact on his behavior. People want to know how their abilities stack up against others. Some abilities have clear criteria (e.g., running times), others are actually an opinion themselves (when there are non-social means of comparison available).

"In the absence of both a physical and a social comparison, subjective evaluations of opinions and abilities are unstable". Previous studies have shown that people's "level of aspiration" varies widely as performance varies.

On the contrary, when objective, non-social means of evaluation of abilities are readily available, people won't evaluate their abilities or opinions against others.

People also don't tend to evaluate themselves against others that are too different than themself. In fact, given a range of people they will choose people most like themselves for comparison.

Regarding stability of opinions, available comparisons to "like" people is stable, while available comparisons to "unlike" people can cause a person to change their evaluations of abilities and opinions.

Also, people are less attracted to situations where others are divergent from them compared to situations where others are more like them in opinions and abilities.

Also, a discrepancy in a group with respect to opinions or abilities will lead to action by members to reduce that discrepancy.

There is a unidirectional drive upward in abilities that isn't present for opinions. But there are non-social constraints that oftent make it difficult or impossible to change one's ability (unlike opinions). The above ideas imply that with respect to evaluation of abilities, a state of social equilibrium is never reached.

When there are differences of opinions or abilities, there will be a tendency to change oneself to move closer to others, or try to change others to be more like oneself. This is of course much more difficult and slower with abilities.

When a discrepancy exists with respect to opinions or abilities, there will be tendencies to cease comparing oneself to those who are very different in the group.

With opinions, cessation of comparison with others is accompanied by hostility or derogation such that continue comparions implies unpleasant consequences. This is very true with opinions (which subjectively could be right or wrong) but less so with abilities (which have a range of performance). In abilities there can be a status stratification.

With abilities, people tend to compete with those similar to themselves, and not with those much higher or lower than themself.

As an ability gains importance, the drive to reduce group differences will increase. But once people realize that some people have become incomparable (either much better or much worse) comparisons and competition between those groups will cease.

Groups of high attraction with each other will tend to be more competitive and will want to drive toward similarity of opinion, especially when the topic is of high relevance to the group.

Implications for Group Formation and Societal Structures
People tend to move into groups of similar opinions and abilities, and they move out of groups that fail to satisfy their drive for self-evaluation. Possibly this effect allows society to harbor and sustain groups of very different opinions and abilities.

These tendencies create a status structure, held in place by both higher and lower groups because it allows everyone to evaluate themselves within their own group. In lower groups, there might be greater pressures to conform because they would seek stronger support within themselves. This could explain how minority groups split into smaller and smaller groups when feeling pressute from majority groups. c