What affects decision-making in Groups?

Are two heads better than one?

       It has been said that two heads are better than one, but is this true? Do people make better choices when they are surrounded by peers or are they better left alone? 



 What is a group?

       Let us start with the most basic question. What is a group? A group is two or more people who share an evaluation of themselves and behave accordingly to said definition (Hogg & Vaughan, 2005). Unfortunately, it seems that working in groups has many negative effects. For example, when working in groups people tend to concentrate on things that they already knew, instead of exploring new ideas on a topic (Stasser et al., 1989; Stasser & Stewart, 1992). This effect gets worse when the teammates do not really know each other (Gruenfeld et al., 1996). Moreover, diversity on a team can also bring conflict (Mannix & Neale, 2005). This means that it may be better to work in a group in which you know everybody and they are similar to you.

(If you are interested in learning more about judgment and decision making, check out "Judgment and Decision Making" by David Hardman by clicking the picture or this link .)                                                                                                                                                                                                                     

What can affect decision-making in a group?

       There will be four factors covered that affect how groups make a decision. The first one is conformity. Asch (1956) demonstrated that people chose what the majority preferred if they were under pressure to conform. However, conformity is present even if team members are not pressured (Coultas, 2004), or physically present (Crutchfield, 1955). This type of behavior has even been observed in animals (Whiten et al., 2005). 

       The second factor is obedience to authority. And we all know who the authority is in this area of research: Stanley Milgram. Milgram (1963, 1974) demonstrated that people were capable of inducing lethal shocks just because someone with authority told them to do so. If someone in a position of authority can make you capable of killing someone, imagine the power of persuasion this type of people have over team members. 

       The third factor is minority influence. This is funny because we just talked about how people conform to the majority. The minority is more likely to influence a team if it is perceived as an expert on the topic (Thomas-Hunt et al., 2004), unless the minority is made up of only one team member (Mugny & Papastamou, 1980). The last factor covered is group polarisation. This refers to the concept that groups tend to choose extreme decisions, they either decide to take big risks (Wallach et al., 1962) or select safer options (Moscovici & Zavalloni, 1969). 


Asch, S. (1956). Studies of independence and conformity: A minority of one against a unanimous majority. Psychological Monograph, 70(9); whole of issue 416.

Coultas, J. C. (2004). When in Rome... An evolutionary perspective on conformity. Group Processes & Intergroup Relations, 70(4), 317-331.

Crutchfield, R. (1955). Conformity and character. American Psychologist, 10, 191-198. 

Gruenfeld, D. H., Mannix, E. A., Williams, K. Y. & Neale, M. A. (1996). Group composition and decision making: How member familiarity and information distribution affect process and performance. Organizational Behavior and Human Decision Process, 67, 1-15.

Hogg, M. A. & Vaughan, G. M. (2005). Social Psychology (4th edn). London: Pearson-Prentice Hall.

Mannix, E., & Neale, M. A. (2005). What differences make a difference? The promise and reality of diverse teams in organizations. Psychological Science in the Public Interest, 6(2), 31-55.

Milgram, S. (1963). Behavioral study of obedience. Journal of Abnormal and Social Psychology, 67, 371-378.

Milgram, S. (1974). Obedience to authority. London: Tavistock.

Moscovice, S. & Zavalloni, M. (1969). The group as a polarizer of attitudes. Journal of Personality and Social Psychology, 12, 125-135.

Mugny, G. & Papastamou, S. (1980). Minority influence and psycho-social identity. European Journal of Social Psychology, 12, 379-394

Stasser, G. & Stewart, D. D. (1992). Discovery of hidden profiles by decision-making groups: Solving a problem vs. making a judgment. Journal of Personality and Social Psychology, 63, 426-434.

Stasser, G., Taylor, L. A. & Hanna, C. (1989). Information sampling in structured and unstructured discussions of three- and six-person groups. Journal of Personality and Social Psychology, 57, 67-68.

Thomas-Hunt, M., Ogden, T. & Neale, M. (2003). Who's really sharing: Effects of social and expert status on knowledge exchange within groups. Management Science, 49, 464-477.

Wallach, M. A., Kogan, N. & Bem, D. J. (1962). Group influence on individual risk taking. Journal of Abnormal and Social Psychology, 65, 75-86

Whitem, A., Horner, V. & de Waal, F. B. M. (2005). Conformity to cultural norms of tool use in chimpanzees. Nature, 437(September), 737-740.