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The Evolutionary Origins of Morality and the Sense of Justice

Robert Kurzban

Evolution Seminar Series

27 July 2009

Santiago, Chile

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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.

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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.

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Evolutionary Psychology

rotates the old axis of debate…

Innate

Genetic

Fixed

Learned

Cultural

Plastic

X

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Evolutionary Approaches

To:

function-specific

General purpose

Evolutionary analysis:

Brain mechanisms are likely to be functionally specialized.

(Like the beaks of Darwin’s finches.)

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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.)

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1. Morality is Not Altruism

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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

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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.

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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.

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Morality & Altruism

Summary: To say something is (im)moral is not the same as saying that it is beneficial (harmful).

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2. Moral judgment does not look designed for altruism.

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Moral = Altruistic?

Starting with Darwin, explaining “morality” has generally focused on explaining why people benefit others.

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MoralityBUT, there are two differentphenomena to explain:

Conforming to moral rules.

Moral condemnation.

(DeScioli & Kurzban, 2009)

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Imagine a Population of People with Jiminy Cricket on Board

In a world of people with conscience, what function does moral condemnation serve?

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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)

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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)

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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)

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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.

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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.

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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?

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The Famous Trolley Problem

Credit: SJ Kurzban

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The Famous Trolley Problem

Credit: SJ Kurzban

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Trolley Results

• Footbridge: ~90% wrong to push

Hauser et al., 2008

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Hamilton vs. Kant

• Kin selected mechanisms are designed to deliver benefits. So, if morality is alsofor altruism, they should pull in the same direction.

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Kin Trolley Problems

• Footbridge Version

• Independent Variable

Kin, Friends, Strangers

• Between subjects

• 100 subjects per cell

• Web-based sample.

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Kin Trolley Problems

• Would you push?

• Is it wrong to push?

• Is it wrong not to push?

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“Morality is for Altruism” Prediction

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10

20

30

40

50

60

70

80

90

100

Would You

Push?

Is Pushing

Wrong?

Is Not Pushing

Wrong?

Stranger

Friend

Kin

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The Famous Trolley Problem –Burying Beetle

Credit: SJ Kurzban

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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

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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

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Further data

• Only 56% say they would push a stranger to save 5 brothers

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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.

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If Morality is NOT for altruism, what is it for…?

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Morality & “Dynamic Bandwagoning”

• Humans form alliances.

• Conflicts arise

• Adaptive problem: Avoid being on the losing side of multi-party conflicts

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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

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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.

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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”

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Dynamic Bandwagoning

• Explains:

Impartiality

Nonconsequentialism, moral waste.

Variability in moral rules

Consensus about rule contents

Trial by Ordeal, arbitrary moral rules.

Act/Omission distinction

…

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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)

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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.

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Acknowledgements

Collaborator: Peter DeScioli

Special Thanks to

Rebecca Bruening

Danny Fein

John Christner

Kelly Asao

Alex Shaw

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Thank You