1The Evolutionary Origins of Morality and the Sense of JusticeKurz Ban
-
Upload
paolo-devia -
Category
Documents
-
view
5 -
download
0
description
Transcript of 1The Evolutionary Origins of Morality and the Sense of JusticeKurz Ban
1
The Evolutionary Origins of Morality and the Sense of Justice
Robert Kurzban
Evolution Seminar Series
27 July 2009
Santiago, Chile
2
Take-home Messages
• Narrow: Human minds contain subroutines designed for morality and altruism, but these are different
• Broad: The evolutionary approach sharpens the conceptual focus in psychology by asking what the subroutines of the mind are for.
3
Claims
1. Morality is not Altruism
2. The mechanisms underlying moral judgment aren’t designed for altruism.
3. Moral mechanisms are designed to benefit individuals, allowing them to avoid being on losing sides of conflicts.
4
Evolutionary Psychology
rotates the old axis of debate…
Innate
Genetic
Fixed
Learned
Cultural
Plastic
X
5
Evolutionary Approaches
To:
function-specific
General purpose
Evolutionary analysis:
Brain mechanisms are likely to be functionally specialized.
(Like the beaks of Darwin’s finches.)
6
Evolutionary Approaches
function-specific
General purpose
The systems that underlie “morality” could be general learning. Or they might have more narrow functions. (Either way, they are evolved systems.)
7
1. Morality is Not Altruism
8
Moral = Altruistic?
People are selfish, yet morally motivated.- Haidt, J. (2007), Science, p. 998.
Moral systems are interlocking sets of values, practices, institutions, and evolved psychological mechanisms that work together to suppress or regulate selfishness...
- Haidt, J. (2008). “Morality.” PoPS
Haidt, 2007, 2008
9
Morality is not Altruism
Larry sold a pint of blood to buy medication for his sister.
Jane worked as a temp so her husband could go back to college.
John Powers risked death to save five potential victims.
10
Morality is not Altruism
Tommy sold his kidney to buy medication for his sister.
Anne worked as a prostitute so her husband could go back to college.
Jack Bauer tortured a man to save five potential victims.
11
Morality & Altruism
Summary: To say something is (im)moral is not the same as saying that it is beneficial (harmful).
12
2. Moral judgment does not look designed for altruism.
13
Moral = Altruistic?
Starting with Darwin, explaining “morality” has generally focused on explaining why people benefit others.
14
MoralityBUT, there are two differentphenomena to explain:
Conforming to moral rules.
Moral condemnation.
(DeScioli & Kurzban, 2009)
15
Imagine a Population of People with Jiminy Cricket on Board
In a world of people with conscience, what function does moral condemnation serve?
16
Imagine a Population of People with Abigail Williams on Board
In such a population, what function does Jiminy Cricket serve?
(Conscience is defensive, not altruistic)
17
Theories of Morality Explain Conscience
• Adaptive Challenges
“Protect and care for young, vulnerable, or injured kin”
“Reap benefits of dyadic cooperation”
“Reap benefits of group cooperation”
“Avoid microbes, negotiate hierarchy…”
(Haidt & Joseph, 2007)
18
Perpetrator
Design: Compute costs/benefits
Victim
costs
benefits
Design: Impose costs to deter.
Problem: minimize costs.
Problem: ???
Design: Judge others & desire their punishment
Moralizer
What is the function of
Condemnation?
Problem: Extract benefits, avoid punishment
…conscience …revenge.
(DeScioli & Kurzban, 2009)
19
SummaryModern accounts of the evolution of morality identify selection pressures associated with guiding one’s own behavior. This gives rise to conscience, not condemnation.
The putative function of these mechanisms is (among other things) delivering benefits.
The central prediction of such models is that moral psychology should be well designed to bring about welfare gains
and minimize welfare losses.
20
Is Morality for Altruism?
• If moral cognition were designed to deliver benefits, what would the system look like?
This is the key methodological contribution of adaptationist/evolutionary approaches.
21
What is Moral Judgment For?
Suppose moral (third party) judgment were designed for generating aggregate benefits (altruism). What design features would it have?
To benefit others, condemn (disincentivize) acts that intend aggregate harm.
Do people look like J S Mill-bots?
22
The Famous Trolley Problem
Credit: SJ Kurzban
23
The Famous Trolley Problem
Credit: SJ Kurzban
24
Trolley Results
• Footbridge: ~90% wrong to push
Hauser et al., 2008
25
Hamilton vs. Kant
• Kin selected mechanisms are designed to deliver benefits. So, if morality is alsofor altruism, they should pull in the same direction.
26
Kin Trolley Problems
• Footbridge Version
• Independent Variable
Kin, Friends, Strangers
• Between subjects
• 100 subjects per cell
• Web-based sample.
27
Kin Trolley Problems
• Would you push?
• Is it wrong to push?
• Is it wrong not to push?
28
“Morality is for Altruism” Prediction
0
10
20
30
40
50
60
70
80
90
100
Would You
Push?
Is Pushing
Wrong?
Is Not Pushing
Wrong?
Stranger
Friend
Kin
29
The Famous Trolley Problem –Burying Beetle
Credit: SJ Kurzban
30
Results
0
10
20
30
40
50
60
70
80
90
100
Would You
Push?
Is Pushing
Wrong?
Is Not Pushing
Wrong?
Stranger
Friend
Kin
31
Results
Welfare benefits
Moral cognition undermines kin selected systems
Pushing kin not less wrong.
0
10
20
30
40
50
60
70
80
90
100
Would You Push? Is Pushing
Wrong?
Is Not Pushing
Wrong?
Stranger
Friend
Kin
32
Further data
• Only 56% say they would push a stranger to save 5 brothers
33
Results
• 50% don’t push one sibling. Morality (conscience) strongly undermines kin selected mechanisms.
• Also, kin selected mechanisms undermine conscience, increasing p(pushing), which is seen as “wrong.”
• 70% would not push strangers. Morality undermines altruism.
34
If Morality is NOT for altruism, what is it for…?
35
Morality & “Dynamic Bandwagoning”
• Humans form alliances.
• Conflicts arise
• Adaptive problem: Avoid being on the losing side of multi-party conflicts
36
Avoiding Losing
• Solution 1.
Always side with allies (chimps)
Problem
• Entrapment – if allies know you will take their side, they seek more conflicts.
• Leads to many conflicts
37
Avoiding Losing
• Solution 2.
Side with the biggest person (hyenas).
Problems
• If everyone does this, then you get a dictator.
• Once strategy is common, other strategies do poorly.
38
Avoiding Losing• Solution 3 (correlated equilibrium) Dynamic bandwagoning
• Side with the same person everyone else will, using some signal
Advantages• No dictators
• Limits frequency of conflicts.
Disadvantages• Any signal can come to be used
• We call these “moral norms”
39
Dynamic Bandwagoning
• Explains:
Impartiality
Nonconsequentialism, moral waste.
Variability in moral rules
Consensus about rule contents
Trial by Ordeal, arbitrary moral rules.
Act/Omission distinction
…
40
Perpetrator
Design: Compute costs/benefits
Victim
costs
benefits
Design: Impose costs to deter.
Problem: minimize costs.
Problem: Conflict Management!
Design: Judge others & desire their punishment
Moralizer
What is the function of Condemnation?
Problem: Extract benefits, avoid punishment
…conscience …revenge.
(DeScioli & Kurzban, in prep)
41
Claims
1. Morality is not Altruism
2. The mechanisms underlying moral judgment aren’t designed for altruism.
3. Morality is designed to benefit individuals, allowing them to avoid being on losing sides of conflicts.
42
Acknowledgements
Collaborator: Peter DeScioli
Special Thanks to
Rebecca Bruening
Danny Fein
John Christner
Kelly Asao
Alex Shaw
43
Thank You