1. Social Psychology Lecture 11
Group Performance
Jane Clarbour
Room PS/B007

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????
A Eureka Task = when the correct answer becomes blindly obvious when you know the correct answer

4. Overview Group processes Brainstorming
Steiner’s typology of task
Brainstorming
Processes involved in productivity
Additive tasks
Disjunctive tasks
Shift in focus now to group processes
A central theme to the lecture is Steiner’s typology of task
Consider additive tasks – Does a bigger group do better?
We will look at a technique called brainstorming and consider group processes involved in productivity

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 performance Theoretical framework (Steiner, 1972)
Performance is dependant upon 3 classes of variables:
Task demands
Resources
Process
The relationship between group process and performance in the workplace
The questions that we will be looking at seem rather obvious…
“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?
In that perhaps it depends upon the nature of the task! But maybe it is not quite so simple as all that…

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
Likens task demands to ‘building plans’
Describes the house being built
Describes the materials needed
The tools to use
The order of work
The manner in which the total process is to be managed
Task demands specify what's needed

8. Resources Relevant possessions of people in group knowledge abilities
skills
tools
Resources include all the relevant possessions of all the people in the group who are attempting to perform the task:
Resources specify what’s got

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!
NEED EXAMPLES>>>(see next slide)

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
Coordination loss
Lack of synchronisation to take maximum advantage of one another’s efforts
(e.g. tug-of-war: ineffective unless all pull together)
Motivation loss
When individuals feel either unrecognised for their effort
When they feel they won’t benefit from it

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?
So, returning to our original question, Steiner suggests that types of tasks need to be further broken down and re-examined.

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
Steiner has proposed that tasks can be distinguished along 3 main dimensions:

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
Discretionary tasks
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 Early experimental 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 performance better 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. Results TAYLOR & 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:
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. Brainstorming Osborn (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. Meta-analysis of 20 studies of brainstorming
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?
But could motivation loss be affected by 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
Group type
Credit type
Nominal
Brainstorming
Group credit
Individual credit
Comparison of nominal groups and natural brainstorming groups when told either get individual or group credit (Diehl & Stroebe, 1987)
Only 8% of variance explained by credit given
Most of the effect explained by group allocation
BRAINSTORMING GROUPS PRODUCED LESS PRODUCTIVE
2 Conditions:
Group 1 = individual credit
Group 2 = group credit

31. Summary Task 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