Group polarization


To polarize (tr.v) has two interesting meanings of relevance to social psychology. On the one hand, it can mean "3: to break up into opposing factions or groupings"; on the other hand, it can also mean "4: to concentrate", as in "1a: to bring or direct toward a common center or objective (Merriam-Webster Online Dictionary, 2005 8).

Kalat (2008) states that if nearly all the people who compose a group lean in the same direction on a particular issue, then a group discussion will move the group as a whole even further in that direction (p.523)[7].

Theoretical frame

It is the second meaning above the one that is used in social psychology when referring to group polarization. Indeed, group polarization is a phenomenon that occurs when people engage in group discussion of a topic. Such group discussion tends to bring all members of the group towards a common view. However, the group does not necessarily ends up with an average opinion made up from the contribution of its members. Instead, because of factors such as the relative social weight of some members or, simply, the tendency of the majority, the discussion becomes biased by the influence of those factors, thus limiting the independence of each member's contribution (e.g. not all members voice their opinion, or these are not equally considered by the remaining members). In time, as the discussion progresses, each member's attitudes become more alike that of the group, while the average group's attitude become more shifted towards the favored position because of the lack of independence. The result is a group average position that is more extreme than the original group average (e.g. the group's position is more extreme or more cautious than it would have been had each member remained independent of group influence).

This effect mainly describes groups/teams leaning towards the riskier side known as risky shift by James Stoner (1961) or leaning towards the more cautious side [Moscovici & Zavalloni (1969 9)]. If individual in the groups/teams tendency to take risk, this will result in group/team decisions to be more extreme in risk. If individuals are more cautious in groups/teams then the result made would be vice versa. While through discussions, views of particular topics/decisions are strength, with everyone in the group/team characterized to either risk-taker or cautious-taker, decisions made will then follow that direction and becomes extreme [Bray & Noble (1978 2)]. Group Polarisation occurs for two main reasons either by persuasive arguments interpretation and the other by social comparison interpretation.

Two main theories explain group polarization: informational influence and normative influence (Myers, 1983 10):

Informational influence

This theory explains that group sharing of ideas naturally shows the dominant viewpoint in the group, while some of this ideas may be more persuasive than others or elicit more arguments. Furthermore, active participation in sharing arguments also helps in strengthening attitudes and adopting a more extreme position, which explains the attitudinal shifting occurring after group discussions.

Normative influence

This theory explains group polarization as due to a social comparison of our ideas with those held by the group, while, at the same time, people may expressed stronger views in order to be perceived favorably by the (majority of) the group.


An extreme from of group polarization is also known as groupthink and it occurs when the members of a group suppress their doubts about a group's decision for fear of making bad impression or disrupting group harmony. (Kalat, 2008, p.524, cited from Janis, 1972 & 1985) [7].

Supporting evidence

Air Accident Example of Group Polarization

On 1st June 1999, American Airlines Flight 1420 crashed after the plane overran the runway 4R during landing at Little Rock National Airport, Arkansas [NTSB Aircraft Accident Report No. N215AA(13)]. The captain (chief pilot for the company) of the MD-80 was the flying-pilot. The weather conditions were bad and the plane was heading into severe thunderstorms with wind-shears. Investigation reports stated that the flight crew made the decision to continue its approach increasing the risk involved. This was a key-factor in the accident.

This example demonstrated that both pilots maybe risk-takers. Thus the decision is towards the risky shift as they felt that it is safe to land in such weather conditions. These individuals may have a tendency to be more risky, therefore such poor decisions was made. The power of Group Polarisation must be reduced at its minimum. If the co-pilot were on a cautious side, the outcome may not result in an accident.

Strategies such as polices, rule-handbooks and procedure manuals must be implemented to avoid Group Polarisation. Civil Aviation Authority (CAA) provided such defences by setting up the regulations for all personnel involved. Publications such as Manual of Air Traffic Services (to provide checklist and procedure for NZ ATC) (MATS), Aeronautical Information Publication (to ensure standards and flight issues in NZ) (AIP) and Civil Aviation Safety Order (CASO) are to provide proper procedures and standards to prevent operational staff from making extreme decisions. With a Benchmark with regards to safety, better judgement and decisions could be made to prevent any mishaps. Airlines industries also provide proper checklist and procedures at different situations to minimise extreme decision. This can be observed through the cockpit whereby they have a shelf of procedure/checklist to even small failures.

Refuting evidence

Way forward (to do list)

1. 12 MANAGE: THE EXTCUTIVE FAST TRACK (2008). Retrieved from on 2 September, 2008.
2. Bray, R. M., & Noble, A. M. (1978). Authoritarianism and decisions of mock juries: Evidence of jury bias and group polarization. Journal of Personality and Social Psychology, 36, 1424-1430.
3. Hart Paul’t (1990). GROUPTHINK IN GOVERNMENT. A Study of Small Groups and Policy Failure. Johns Hopkins University Press; Baltimore.
4. JANIS Irving L (1972). Victims of groupthink: a psychological study of foreign-policy decisions and fiascoes. Houghton Mifflin Company (Boston, USA), 1972. ISBN: 0395140021.
5. JANIS Irving L (1982). Groupthink: psychological studies of policy decisions and fiascoes. Houghton Mifflin Company (Boston, USA), 1982. ISBN: 0395317045.
6. JANIS Irving L, Leon MANN (1977). Decision making: a psychological analysis of conflict, choice, and commitment. Free Press (New York, USA), 1977. ISBN: 0029161606.
7. Kalat, J.W. (2008). Introduction to psychology (8th ed.). Thomson Wadsworth: Belmont.
8. MERRIAM-WEBSTER ONLINE DICTIONARY (2005). Retrieved from on 30 June, 2008.
9. Moscovici, S., & Zavalloni, M. (1969). The group as a polarizer of attitudes. Journal of Personality and Social Psychology 12, 125-135
10. MYERS David G (1983). Social psychology. McGraw-Hill Publishing (New York, USA), 1990 (3rd ed). ISBN 9780070442832.
11. NASA History Office. Report of the PRESIDENTIAL COMMISSION on the Space Shuttle Challenger Accident. Information Retrieved on 20th August 2006 from NASA official Website:
12. NASA Space link (1993). Challenger Press Release Turban, Efraim, Decision Support and Expert Systems. Macmillan Publishing Company, N.Y.
13. National Transport Safety Board. Aircraft Accident Report No. N215AA (publication)
14. Travel and History (n.d.). Bay of Pigs Invasion: Wars and Battles, April 14-19, 1961. Retrieved from Bay of Pigs Invasion on 11 December, 2008.
15. WALKER Rechel M (1994). The impact of cohesion on groupthink: a thesis submitted in partial fulfillment of the requirements for the degree of Master of Arts in Psychology at the University of Canterbury. University of Canterbury (Christchurch, New Zealand), 1994.

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