social aspects of decision-making2015/10/7 1 resilience informatics for innovation ¾ social...
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2015/10/7
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Resilience Informatics for Innovation Social psychology and group performance
RERC/TMIKazuo FURUTA
Social aspects of decision-making
Social (Collective) decision-makingn decision-making by a group as consensusn Actual style of most decision-makingsn Important for organizational operations
Social influence on individual actionsn Significant for individual decisionsn Significant for organizational operations
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Group processes
Individual Factors(member ability, personality,biographical features, etc.)
Individual Factors(member ability, personality,biographical features, etc.)
Group Factors(group size, structure, group
cohesiveness, etc.)
Group Factors(group size, structure, group
cohesiveness, etc.)
Environmental Factors(task demands, role system,available information, etc.)
Environmental Factors(task demands, role system,available information, etc.)
Group ProcessGroup Process
Social Influence
Individual Performance
Social Decision Scheme
Group PerformanceGroup Performance
Social influence
Taxonomy by Deutsch & Gerald (1955)
Informational influencen An influence to accept information
obtained from another as evidence about reality
Normative influencen An influence to conform with the positive
expectations of another
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Social psychology and group performance
Group characteristicsn Conformity, authority gradient, social loafing,
social facilitation, risky shift, group polarization, groupthink
Leadership theoryn Two functions, PM theory, contingency theory
Communication network
Steiner’s group productivity theory
Group reliability
Conformity pressure
Asch experiment (1951)n One subject and seven confederatesn Line segment selection (obvious correct answer)n Common wrong answer by confederatesn 37% of subjects conformed to wrong answers
Even though the correct answer is apparent, the conformity pressure from a group to an individual is enormous.
Which one is of the same length?
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Authority gradient
Milgram experiment (1963)n The participants were asked to impose electric
shock to the answers (confederates) if they made mistakes in answering questions.
n The experiment was finished when the participants refused to raise the voltage.
n No less than 65% of participants raised the voltage to the upper limit.
Many people obey the authority, though they know they must refuse an order.
Social loafing
Ringelmann effectn 2, 3, 8 people pulled a rope and they showed an
effort of 93%, 85%, 49% of an individual.Latanet experiment (1979)n Participants were asked to make a loud voice in a
sound proof chamber. As participants increased, the loudness of an individual decreased.
Decrease of individual efforts under the participation of othersn Diffusion responsibilityn Murder of Kitty Genovese, Toyota Corp.
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Social facilitation an depression
Social facilitationn Racehorses run faster with others than individuallyn Increase of performance in the presence of others
Social suppressionn Decrease of performance in the presence of others
Zajonc experiment (1965)n Recall of meaningless sequence of words under
different training levelsn Facilitation in highly trained casesn Suppression in poorly trained cases
Risky shift
Kogan & Wallach experiment (1964)n Choice of an action for 12 imaginary situations
from high-risk / high-return or low-risk / low-return options
n Individual choice → group discussion → individual choice
n Group discussion facilitates preference of high-risk / high-return option.
n Why does risky shift occur?w Diffusion of responsibilityw Leadership (Aggressive opinions are likely to dominate)w Group wisdom (Anxiety is suppressed with many eyes)
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Group polarization
Group discussion sometimes enhances a risk averse conclusion.
Group discussion is likely to result in an extreme conclusion in general.
Group polarization seems a specific case of the amplifying effect of collective decision-making explained later.
Groupthinking
A highly qualified and cohesive group sometimes makes a serious decision failure.Janis (1971)n Analyses of historical fiascoes such as the Bay of
Pigs invasion by Kennedy administration
Symptomsn Overestimations of the group: power and moralityn Closed-mindedness: rationalizing warnings and
stereotyping opponentsn Pressure toward uniformity: self-censorship,
illusion of unanimity, direct pressure, mind-guards
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How to prevent groupthink
Silent leader at the beginningAssignment of “Devil’s advocate”Atmosphere that is easy to challengeConsideration of effective alternativesParallel discussion by independent subgroupsInvitation of outside opinions
Leadership style
What is leadership?n Functions and actions of facilitating a group of
people to act towards achieving a common goal
Taxonomy by Cartwright & Zander (1960)n Achievement of goals (Task-oriented, P-function)
n Maintenance of group (Relations-oriented, M-function)
PM theory (1966)n Motivated group PM > M > P > pmn Unmotivated group P > PM > M > pm
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Fiedler’s contingency modelLPC score: high LPC score ⇒ relations-oriented
low LPC score ⇒ task-oriented
1 2 3 4 5 6 7 8Leader-member G G G G P P P PTask structure H H L L H H L LPosition power S W S W S W S W
Corr
elat
ion
betw
een
prod
uctiv
ity a
nd
LPC
scor
e
0
+
−
Steiner‘s group productivity theory (1)
Task demandsn Requirements imposed on the individual or group
by the task (Relevant resources, information, procedure, etc.)
Resourcesn Knowledge, abilities, skills, or tools possessed by
the individuals attempting to perform a task
Group processesn Intrapersonal and interpersonal actions by which
people transform resources into a product
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Steiner’s group productivity theory (2)
[Actual productivity] =[Potential productivity] −[Losses due to faulty processes]
[Potential productivity] = f (Task demands, resources)
Steiner’s typology of tasks
Unitary taskn Disjunctive taskn Conjunctive taskn Additive taskn Discretionary task
Divisible (Complementary) task
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Task type and productivity (1)
Disjunctive taskn If at least one member can successfully complete
the task, the group can also complete it. Pg = 1 - (1 - P)N (Eureka type)
Conjunctive taskn Only if every member can successfully complete
the task, the group can also complete it. Pg = PN
Task type and productivity (2)
Additive taskn The group product is a summative
combination of the outputs of all members.
Discretionary taskn The group can chose an arbitrary scheme
of aggregating its product as a weighted combination of members’ outputs.
∑= iig RwR
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Task type and productivity (3)
Divisible taskn The group can decompose the task into
subtasks, each of which can be performed by a different individual.
n Achievement of the task requires achievement of all subtasks (conjunctive).w Fixed decomposition, fixed allocation.w Fixed decomposition, free allocation.w Free decomposition, free allocation.
Leavitt experiment (1951)
Groups of five people solved simple puzzles by passing hand-written memos.
chain circle
Y wheel
white red
brown
yellow
blue
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Communication network
Centralized networks are advantageous for solving simple problems (Leavitt)n Time required for solutionn Number of messages exchangedn Number of errors
Decentralized networks are advantageous for solving complex problems (Shaw & Mulder)
Group reliability analysis
For assessing general features of group performance, but not for evaluating human error probability of a particular scenario.n Probabilistic modeling of group processesn Group as an information processing network
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Model of group process
hj
i
wijwji
wiσi
Information worthSucc
ess
prob
abilit
y
1
0
)](exp[11
iki
ki
iiij
kjij
ki
p
wSw
βφ
σφ
+−+=
+= ∑≠
=success1
fail0kiS
State transition matrix
If state k and l are neighboring in terms of Si
Otherwise
)](exp[1 iki
ki
ikl S
Gβφ
λ++
=
∑ ∑= ≠=
−=
≠=N
i
N
klklikk
kl
GG
lkG
1 )(1
)(0
λ
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Group dynamics
Kolmogorov’s forward equation
Probability of group success
∑=
−=M
klklk
l tGtdt
td1
)()()( λπππ
schemedecision Social:
)()()(1
s
M
llsls
T
ttTtP ∑=
= π
Symmetric group
Consensus function
Asymptotic probability of group success
++= ∑∑
< i
kiiii
ji
kj
kiijk SwSSwC )(2
1 βσ
∑=
∞→
=Θ
Θ=
M
kk
kkt
C
Ct
1)exp(
)exp(1)(limπ
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Effect of cohesiveness
0.0 1.0 2.0 3.0Group cohesiveness
1.0
0.9
0.8
0.7Pro
babi
lity
of s
ucce
ss
β4 = –5
β4 = 2
β4 = –2
β4 = –4
β4 = –3
Leadership style
0.0 1.0 2.0Group cohesiveness
1.0
0.9
Pro
babi
lity
of s
ucce
ss
Standard leaderTop-downBottom-up
Competent leaderTop-downBottom-up
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Response to emergency
0 50 100Times of decision
0.990
0.985
0.980
0.975
Pro
babi
lity
of s
ucce
ss
w = 1.0
0.995
w = 1.5
w = 2.0