Rational Decision Making
Harrison, Ch. 3
Fred Wenstøp
Emotion and decision making
Case: Phineas Gage
Experiment 1:
A group of people, some normal and some suffering
from prefrontal deficiency was
Exposed to a fire alarm
Shown value laden pictures
Experiment 2:
Choice of card decks
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Damasio’s theory
Neocortex
Prefrontal
lobes
Amygdala
Stimulus
Feelings
Emotional response
from the body
Primary emotions trigger
Secondary emotions
trigger
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Rationality
Føllesdal 1992
Four dimensions of rationality
rationality as logical consistency
• pertains both to values and beliefs
rationality as well-foundedness of beliefs
• beliefs are well supported by available evidence
rationality of action
• application of decision theory
rationality as well-foundedness of values
• reflective equilibrium that gives a stable set of convictions that
are relevant for the decision situation
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The rational decision model
 Frame
 A set of mutually exclusive decision alternatives has been
identified
 A set of relevant objectives has been identified by which to
evaluate the alternatives
 Well-founded scores (x) have been established
 Predicted consequences of the altenatives, beliefs
 Well-founded weights (w) have been established
 Importance of the objectives, represent values
 Decision Table
 Contains all the information above
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Rational choice
An evaluating function that is in accordance with
the decision maker’s preferences has been
identified
U(x1,x2,..) = f(w1,w2,…,x1,x2,..)
The alternative with the highest expected value is
chosen
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Common evaluating functions
Linear model
U(x1,x2,x3) = w1u1(x1) + w2u2(x2) + w3u3(x3)
Multiplicative model
U(x1,x2,x3) = w1u1(x1) + w2u2(x2) + w3u3(x3) +
kw1u1(x1)w2u2(x2) + kw1u1(x1)w3u3(x3) + kw2u2(x2)w3u3(x3)
+ k2w1u1(x1)w2u2(x2)w3u3(x3)
These models ensures consistency of preference
Assumptions
• Value and preference independence
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HIV Case: The Decision panel
The Panel
Governmental advisor on AIDS matters
• Svein-Erik Ekeid
Deputy minister, Ministry of Social Affairs
• Emil Hansen
Director of National Institute of Public Health
• Bodolf Hareide
Decision context
Identification of viable program target groups
Value focusing
Essential values were identified without discussing
consequences of alternatives
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HIV Case: Value structure
Minimize social economic costs of the HIV epidemic
Minimize consequences
for the individual and
the society
Minimize future
cases of HIV
Minimize economic
costs of program
and morbidity
Right to privacy
Health care of AIDS patients
Anxiety in the society
Costs of program
Anxiety in exposed persons
Loss of income
Life quality of HIV+'s
Personal stigma
Group stigma
Early treatment
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HIV Case: Framing the problem
Decision Criterion
Cases prevented
Rights invasion
Anxiety creation
Anxiety reduction
Life quality reduction
Personal stigma
Group stigma
Economic costs
Early treatment
Unit
Worst value Best value
persons
0
4800
1000 persons
12000
0
1000 persons
12000
0
1000 persons
0
1200
person-years
7200
0
persons
120
0
1000 persons
80
0
mill. NOK
5000
-9000
persons
0
2400
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HIV Case: Weights
Costs Early
 Weight elicitation
Computer interactive
Discussions
Emotional responses
Unanimous result
G.stigma
P.stigma
Quality
Anx. red
Cases
Anx. cre
Rights
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Viability study
Target group according to HIV prevalence in home country
Decision Criterion
No action Low Medium High
Cases prevented
0
665
510
100
Rights invasion
0
67
38
4
Anxiety creation
0
67
38
4
Anxiety reduction
0
7
4
0
Life quality reduction
0
141
5700 2370
Personal stigma
0
2
95
40
Group stigma
0
67
38
4
Economic costs
0 -1332
-1027 -203
Early treatment
0
47
1900
790
Utility
0.285 0.285
0.285 0.285
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
Infections  N 1  (1  prev  trans)5intercourses

Infection potential
N
Europeans
American &
Oriental
Sub-Sahara
Size of sexual
contact group
15500
3700
480
Annual no. of
intercourses
25
34
30
HIV transmission prob.
0.001
0.01
0.05
HIV prevalence
0.01
0.05
0.2
Expected no. of
infections, 5 yrs
20
266
376
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HIV Case: Conclusion
The viability study showed that
in order to be efficient, any program directed against an
immigrant group must prevent new HIV cases at least:
• Europeans
665
• Americans & orientals 510
• Sub-Sahara Africans
100
A simulation study showed that
if left to themselves they would at the maximum infect
• Europeans
20
• Americans & orientals 266
• Sub-Sahara Africans
376
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