Before explaining why groups are difficult to manage and changes to their membership can reduce group performance, the definition and types of groups is important. Two types of groups can be differentiated: an aggregate of individuals and psychological groups. An aggregate is a considerable number of people who meet in a certain place for a specific period of time. For example students who are living in a hall of residence they act independently and not as a group. According to the definition, there are some characteristics which define psychological groups. First of all, the members have to interact with each other, they have to share ideas and not act independently. Furthermore, every individual has to participate in group activities in order to fulfil their tasks. Also each member has to have a specific role such as secretary or computer programmer; so everyone knows what has to be done. Moreover, groups are led by a leader who sets norms and rules. Psychological groups can be a band of boys,
Bibliography: Aubé, C. and Rousseau,V., (2005) “Team Goal Commitment and Team Effectiveness: The Role of Task Interdependence and Supportive Behaviors.” , Educational Publishing Foundation, New York, 2005 Sep Vol 9(3) 189-204 , Available at: http://0-psycnet.apa.org.unicat.bangor.ac.uk/index.cfm?fa=search.searchResults, (Accessed:12 November 2007 ) Douglas, T. (1976) , “Groupwork practice”, Tavistock Publications, London Huczynzki A.A. and Buchanan A.D, (2007) “Organisational Behaviour”, 6th Ed., Prentice Hall, England Kyle L. et al., (2007), “Organizational Behaviour and Human Decision Processes”, Department of Management, USA , Volume 103, Issue 2, July 2007, Pages 159-178, Available at: www.sciencedirect.com, (Accessed:12 November 2007 ) Wilson, A. et. al, (ed.) (1998), “Handbook of science communication”, Chapter: Working in groups and team , pp. 141 – 157, Institute of Physics Publishing, London http://www.managementhelp.org/grp_skll/theory/theory.htm#anchor387149, (1999-2007) “Group Dynamics: Basic Nature of Groups and How They Develop”, (Accessed:12 November 2007)