Editing Leon Festinger (section)

===Informal social communication===
In his 1950 paper, Festinger postulated that one of the major pressures to communicate arises from uniformity within a group, which in turn arises from two sources: social reality and group locomotion.<ref>Festinger, 1950</ref> Festinger argued that people depend on social reality to determine the subjective validity of their attitudes and opinions, and that they look to their reference group to establish social reality; an opinion or attitude is therefore valid to the extent that it is similar to that of the reference group. He further argued that pressures to communicate arise when discrepancies in opinions or attitudes exist among members of a group, and laid out a series of hypotheses regarding determinants of when group members communicate, with whom they communicate, and how recipients of communication react, citing existing experimental evidence to support his arguments.

Festinger labeled communications arising from such pressures toward uniformity as "instrumental communication" in that the communication is not an end in itself but a means to reduce discrepancies between the communicator and others in the group. Instrumental communication is contrasted with "consummatory communication" where communication is the end, such as emotional expression.<ref>Festinger, 1950, p. 281</ref>