social psychology lecture 11
Skip this Video
Download Presentation
Social Psychology Lecture 11

Loading in 2 Seconds...

play fullscreen
1 / 37

Social Psychology Lecture 11 - PowerPoint PPT Presentation

  • Uploaded on

Social Psychology Lecture 11. Group Performance Jane Clarbour Room PS/B007 Email [email protected] 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

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'Social Psychology Lecture 11' - christian

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
social psychology lecture 11

Social PsychologyLecture 11

Group Performance

Jane Clarbour

Room PS/B007 Email [email protected]

eureka task lorge et al 1958
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
lorge et al s findings
Lorge et al’s findings…
  • Individuals
    • only 3/21 solved problem
  • Groups
    • 3/5 solved problem


  • Group processes
    • Steiner’s typology of task
  • Brainstorming
  • Processes involved in productivity

Additive tasks

Disjunctive tasks

  • 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.
theory of group performance t heoretical framework steiner 1972
Theory of group performanceTheoretical framework(Steiner, 1972)
  • Performance is dependant upon 3 classes of variables:
      • Task demands
      • Resources
      • Process
task demands
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
  • Relevant possessions of people in group
    • knowledge
    • abilities
    • skills
    • tools
group processes
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


Actual productivity = potential productivity

(minus losses due to faulty processes)

faulty processes
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!
two forms of faulty processes steiner 1972
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
performance and group size
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?
effect of group size on performance
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.
task dimensions
Task dimensions

Tasks can be distinguished along 3 main dimensions:

  • Divisible vs. unitary tasks
  • Maximising vs. mimimizing tasks
  • Combinability of the tasks
divisible vs unitary tasks
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
maximising vs minimizing tasks
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
how combinable are the tasks for group members
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
individual products of group members
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).
additive tasks
Additive tasks

Earlyexperimental evidence


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)
group efficiency
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.
conjunctive task s
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.
disjunctive task
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

disjunctive task early experimental evidence
Disjunctive task: early experimental evidence


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
r esults taylor faust 1952
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
early co nclusion s taylor faust 1952
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.
brainstorming osborn 1957
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…
empirical evidence mullen et al 1991
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
results mullen et al 1991
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
why production losses in brainstorming occur
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?
effects of group allocation diehl stroebe 1987
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:
summary task dependent performance steiner
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
mullen et al 1991
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…

group structure
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?
interaction process analysis ipa
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
expectation states theory
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)
matching of leaders with resources
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
supplementary reading for group performance
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