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Social Psychology Lecture 11

Social Psychology Lecture 11. Group Performance Jane Clarbour Room PS/B007 Email jc129@york.ac.uk. Eureka Task (Lorge et al, 1958). Jealous husbands 3 married couples have to cross the river but there is only 1 boat…. Rules of the task: Only men can row the boat

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Social Psychology Lecture 11

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  1. Social PsychologyLecture 11 Group Performance Jane Clarbour Room PS/B007 Email jc129@york.ac.uk

  2. Eureka Task (Lorge et al, 1958) Jealous husbands • 3 married couples have to cross the river but there is only 1 boat…. • Rules of the task: • Only men can row the boat • Wives can’t cross with another man unless the husband is present

  3. Lorge et al’s findings… • Individuals • only 3/21 solved problem • Groups • 3/5 solved problem Why????

  4. Overview • Group processes • Steiner’s typology of task • Brainstorming • Processes involved in productivity Additive tasks Disjunctive tasks

  5. Objectives • Give an account of Steiner’s typology of tasks • Specify the effects of group size on additive tasks • Specify the effects of group size on disjunctive tasks • Review evidence on the effectiveness of ‘brainstorming’ as a technique for maximising group performance.

  6. Theory of group performanceTheoretical framework(Steiner, 1972) • Performance is dependant upon 3 classes of variables: • Task demands • Resources • Process

  7. Task demands • The procedures necessary to perform a task. • Task demands as ‘building plans’ • house being built • materials needed • tools to use • order of work • Management of total process

  8. Resources • Relevant possessions of people in group • knowledge • abilities • skills • tools

  9. Group Processes • What the group does • ‘Process’ refers to the actual steps taken when confronted with a task • The extent that the total sequence of behaviours corresponds to the pattern demanded by the task Formula:- Actual productivity = potential productivity (minus losses due to faulty processes)

  10. Faulty Processes What aspects of group behaviour result in loss of production due to faulty processes? • Either poor supply of resources? • (low potential productivity) • Or processes fail to meet demands of task? • Or both!

  11. Two forms of faulty processes (Steiner, 1972) Steiner identified 2 forms of faulty process: • Coordination loss • Lack of synchronisation • Motivation loss • Lack of recognition • Lack of benefit

  12. Performance and group size • “What is the effect of group size on the task performance?” • Are groups more productive than an individual? • Are individuals more productive than a group? • Are large groups more productive than small groups? • What are the task demands? • How do the task demands relate to the available resources?

  13. Effect of group size on performance • Task demands are initial determinants of both potential and actual production. • Differences in faulty processes may vary: • Groups may be more productive than individuals, or.. • Individuals may be more productive than a group • So, necessary to have some kind of typology of task.

  14. Task dimensions Tasks can be distinguished along 3 main dimensions: • Divisible vs. unitary tasks • Maximising vs. mimimizing tasks • Combinability of the tasks

  15. Divisible vs. unitary tasks Some tasks are readily divided into sub-tasks • each of which may be performed by a different individual • Building a house • Playing football • Creating a garden • Other tasks make no sense if subdivided • Reading a page • Doing a maths sum

  16. Maximising vs. minimizing tasks • Maximizing/optimizing • Maximizing: (quantity) • Doing task as much as possible • Doing task as quickly as possible • Generating many ideas • Scoring the most runs • Optimizing: (quality) • Accuracy of bookkeeping • Weather forecasting • Writing your essays!!! • Minimising • doing as little as possible

  17. How combinable are the tasks for group members? • Additive tasks • Group product = sum of the members • Conjunctive tasks • A task which everyone must perform • Disjunctive tasks • The group selects from individual member’s judgments, requires a choice of answer among several possible alternatives • Discretionarytasks • Conditions sometimes may allow different members to contribute more or less (varied weightings) by assigning: • Total weight to single member • Equal weight to everybody • Or granting each person a different weight

  18. Individual products of group members • “What is the effect of group size on task performance?” • Meaningless question without a satisfactory taxonomy of tasks(Steiner, 1972, 1976).

  19. Additive tasks Earlyexperimental evidence RINGLEMANN (1913) A French agricultural engineer who conducted most of his research in late 1880’s. 1, 2, 3, or 8 people pulling on rope • Device measured the exact mount of forced exerted on the rope • 63 kilo (1 person) • 118 kilo (2 people) • 160 kilo (3 people) • 248 kilo (8 people)

  20. Group efficiency • Results showed an INVERSE relationship between the number of people in the group and individual performance • As more people pulled, they used less effort! • Found that a large group needed only half the effort per person than a small group • Attributed to co-ordination losses (pulling at different times) • Additive tasks – group performance is better than individual’s performance when on own, although relative efficiency per person may decrease with increasing group size.

  21. Conjunctive Tasks • A task that every group member must perform • Performance of group dependant upon weakest group member (i.e relay race, or group accent up the Tor) • Performance depends on the relative abilities of the individuals concerned • With increasing group size performance would be expected to decrease due to increased possibility of weak group member.

  22. Disjunctive Task • A task that requires a choice amongst several possible alternatives • Potential productivity of group is determined by the most competent member • If one member of the group can perform the task, the group can, possibly, still perform it • With increasing group size, you expect better performance Conjunctive Disjunctive more people = more people = lower performancebetter performance

  23. Disjunctive task: early experimental evidence TAYLOR & FAUST (1952) Game of ’20 questions’ (disjunctive as have to make a choice between several alternatives) • Ss divided into categories • Working alone (x 15) • Working in pairs (x 15) • Working in groups of 4 (x 15) • Ss given 4 problems a day for 4 consecutive days and allowed to ask 30 questions • Experimenter can only reply: • Yes / No / Partly / Sometimes / Not in the normal sense of the word. • DVs = no. of questions, failures, & time taken to solve problem

  24. ResultsTAYLOR & FAUST (1952) • Superiority of groups over individuals in terms of • Fewer questions asked • Fewer wrong answers given • Less time taken per problem • Groups superior to pairs: • Fewer wrong answers given • Individuals superior to groups and pairs: • For ‘man-minutes’ (e.g. time x no of people in group)Individuals were quicker than pairs, who were quicker than groups (in terms of man-minutes to reach a solution, rather than actual time) • So, cheaper to pay individuals by the hour than groups by the job

  25. Early conclusions (Taylor & Faust, (1952) • Disjunctive tasks • superior performance with groups (well established finding) • But this effect is inversely proportional to group size • Individuals are more effective (in terms of man-minutes) • Steiner suggests that superior performance of groups is due to the greater resources which they possess.

  26. BrainstormingOsborn (1957) • Special kind of group process • This is creative • Increased numbers of people disproportionately increase number of ideas generated • Rules of brainstorming • Free the individual from self-criticism and criticism of others • The more ideas the better • Can adapt others ideas • Can combine ideas • Should not be critical…

  27. Empirical evidence(MULLEN et al. 1991) Meta-analysis of 20 studies of brainstorming • Compared face-to-face groups operating under brainstorming conditions against ‘nominal groups’ • Nominal groups were individuals who were working alone but their ideas were subsequently pooled. • Productivity was measured in two different ways • Quantity: the number of non-redundant ideas • Quality: involved rating of the ideas

  28. Results(MULLEN et al. 1991) Meta-analysis of 20 studies of brainstorming • Individuals generated more ideas than face-to-face groups • Productivity LOSSES increase with the size of the group • Both individuals and groups work best without an ‘expert’ giving guidance • Most ideas were generated when responses were written down and not publicly shared

  29. Why production losses in brainstorming occur • Free-loading (social loafing) • Motivation loss • Individual members expect that all ideas will be pooled (group credit) • Group allocation?

  30. Effects of group allocation(Diehl & Stroebe, 1987) • Allocation of group affects productivity • Design: 2 x 2 • Results: • Only 8% of variance explained by credit given • Most of the effect explained by group allocation • Conclusion: • BRAINSTORMING GROUPS LESS PRODUCTIVE

  31. SummaryTask dependent performance(Steiner) • Additive & disjunctive tasks • Performance increases with increased group size • But relative efficiency declines • Conjunctive tasks • Performance decreases with increased groups size in conjunctive tasks

  32. Mullen et al. 1991 • don’t need to invoke any special group process for brainstorming • Group superiority over individuals can be explained by interpreting brainstorming as a conjunctive task But all this depends upon equal status…

  33. Group structure • Structure of group is independent of the people who occupy the various positions • Each person plays a ROLE within the group • Roles are determined by social norms, rules of conduct • Each role is evaluated differently by others • Each role has differing status • But how does status emerge?

  34. Interaction process analysis (IPA) • Problem solving groups of unacquainted persons • Observational analysis of behavioural categories (4 categories) • Interpersonal style of leadership • Positive socio-emotional behaviour • Negative socio-emotional behaviour • Task directed style of leadership • Task behaviours • Behaviours relating to exchanges of information

  35. Expectation-states theory • Emergence of group leaders • Higher status roles exert more influence over production than lower status roles(Torrance, 1954) • Assertive people are more influential than non-assertive people (Ofshe & Lee, 1981) • Males are more influential than females, blacks, and younger people (DeGilder & Wilke, 1994)

  36. Matching of leaders with resources • By matching people with subtasks most qualified to perform. • Some resources give rise to higher expectations of task completion than others (but not always!) • Hemphill (1961) suggests need to consider both the nature of the task and the availability of a group member with the required resources: • Groups must feel that task success is possible • Groups must attach value to task success • The task must require co-ordination and communication

  37. Supplementary reading for group performance • Wilke & Arjaan Wit (2001) Group Performance (pp. 445 – 478) In Hewstone, & Stroebe, ‘Introduction to Social Psychology’ (3rd edn). Blackwell Press

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