TH EDITION
EVOLUTIONARY
PSYCHOLOGY,
5
Chapter x
David Buss
Chapter 9
Cooperative Alliances
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What about Nonrelatives?
• How could altruism among nonrelatives
possibly evolve?
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Reciprocal Altruism
• Attempt to explain altruistic behavior
toward nonrelatives
• Under what conditions would such
behavior evolve?
• Altruism could evolve if the delivery of
benefits to recipient is reciprocated at
some point in the future
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Reciprocal Altruism
• Altruism could evolve if the delivery of
benefits to recipient is reciprocated at
some point in the future
– Both parties benefit
• Those who engage in reciprocal altruism will
outreproduce those who act selfishly
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© 2015 Pearson Education, Inc. All rights reserved.
Prisoner’s Dilemma
• If the game is played once (as in the
actual prisoner’s dilemma) the only
sensible solution is to defect
• However, if the game is played a repeated
number of times (as often happens in real
life) the strategy changes
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Tit for Tat
• The Prisoner’s Dilemma
– Tit for tat (solution to the prisoner’s dilemma)
• Cooperate on the first move
• Reciprocate on every move thereafter
– Three keys to its success
• Never be the first to defect
• Retaliate only after the other has defected
• Be forgiving
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The Problem of Cheating
• An individual could pretend to be a
reciprocal altruist, but then take benefits
without responding later in kind
• We would expect adaptation(s) to solve
the problem(s) of detecting cheaters
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Social Contract Theory
• Capacity 1
– The ability to recognize many different
individual humans
• Capacity 2
– The ability to remember the histories of
interactions with different individuals
• Capacity 3
– The ability to communicate one’s value to
others
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Social Contract Theory
• Capacity 4
– The ability to model the values of others
• Capacity 5
– The ability to represent costs and benefits
independent of the particular items
exchanged
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Our Problems with Abstract Logic
•
•
•
•
•
•
Archeologists
Biologists
Chess players
None of the archeologists are biologists
All biologists are chess players
What follows from this knowledge?
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Our Ability to Solve Problems
• Evolved ability to respond to problems
structured as social exchanges when they
are presented as costs and benefits
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Do People Remember Cheaters?
• What specific actions do people take when
one detects a cheater and how do those
actions differ depending on contexts such
as status discrepancies and genetic
relatedness?
– Some ground has been broken on the output
side by the proposal that a simple “walk away”
rule can evolve, whereby people leave in
response to groups or individuals providing
low cooperative returns
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Distinct Adaptations
• The Detection of Cheaters
– Those who take benefits without paying the
costs
• The Detection of Altruists
– Those whose motivation is genuine
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Becoming Irreplaceable
• How might a person act to increase the
odds of becoming irreplaceable? Tooby
and Cosmides (1996) outline several
strategies:
– 1. Promote a reputation that highlights one’s
unique or exceptional attributes;
– 2. Be motivated to recognize personal
attributes that others value but that they have
difficulty getting from other people;
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Becoming Irreplaceable
– 3. Cultivate specialized skills that increase
irreplaceability;
– 4. Preferentially seek out people or groups
that value what you have to offer and what
others in the group tend to lack—groups in
which one’s assets will be most appreciated;
– 5. Avoid social groups in which one’s unique
attributes are not valued or in which one’s
unique attributes are easily provided by
others; or
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Becoming Irreplaceable
– 6. Drive off rivals who offer benefits that you
alone formerly provided; people seem to be
especially sensitive to “newcomers” who may
duplicate your skill set, interfere with your
existing alliances, or threaten to impose costs
on your well-functioning group (Cimino &
Delton, 2010)
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Costs and Benefits of Friendship
• Benefits
– Sexual access
– Resources and protection
– Information about members of the opposite
sex
• Costs
– Intrasexual rivalry
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Costs and Benefits of Friendship
• Men and women both reported intrasexual
rivalry over mates in their same-sex
friendships, although not at high rates
– Friends are even perceived as potential mate
poachers
– Sexual rivalry is not restricted to interactions
between same-sex strangers and enemies
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Cooperative Coalitions
• Cooperative Coalitions
– Alliances of more than two individuals for the
purpose of collective action to achieve a
particular goal
• Problems
– Defection
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Cooperative Coalitions
– Free-Riding
» Sometimes enacts raids to seize the cattle of others.
Some Turkana raiders display cowardice by
deserting the group prior to a raid
» These defections jeopardize the success of the
coalition, of course, and men who use such excuses
too often get branded as cowards
• Solution
– Punishment of defectors and free-riders
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Competitive Altruism
• Status serves as a “magnet” for other
benefits such as enhanced desirability as
an alliance partner and as a potential mate
• People engage in “competitive altruism,”
competing to be seen by others as great
contributors to the group (Roberts, 1998)
and competing for reputations as being
highly generous to others in the group
© 2015 Pearson Education, Inc. All rights reserved.
© 2015 Pearson Education, Inc. All rights reserved.