Groups are an important fact of life., Almost every decision that you make involves other people, whether at home, at work or in social groups. Whether we think of juries coming to a verdict or Cabinet meetings that decide on war or peace, groups are important vehicles for decisions. Thus, the ways in which people influence one another in groups becomes paramount in our understanding of why some decisions are reached.
In this chapter, we will be covering a myriad of influence processes that occur when we are in the presence of, or interacting with, other people. We will be taking a particular perspective on the research literature (for others, see especially, Davis, 1973 ; McGrath, 1984 Brown, 2000). We will start with the simple situation where people are expressing viewpoints n groups. We will then move to situations where people are interacting and trying to persuade one another. Repeatedly, we will confront a basic tenet that runs throughout this chapter. People in groups tend towards agreement. We are not content to have positions that differ; there is always a strain to find which position is correct or appropriate. From this perspective, the different influence processes that we will consider differ mainly in where the consensus is found. Sometimes it is the position favored by the majority, termed conformity. Sometimes, it is the position favored by the minority, termed minority influence. Sometimes we will find that it is more extreme than the average of the individuals; this is termed polarization. We will then explore when these processes are assets versus liabilities when we consider the quality of performance and decision making, the likelihood that “truth will prevail”.