On modeling cooperation:
Linking the laboratory to the real world
Richard Schuster
Department of Psychology
University of Haifa (Israel)
University of Haifa’s Forum on Research Methods – 4 April, 2006
On
modeling cooperation:
On explaining
cooperation:
Linking
Biology
Linking thePsychology
laboratory to and
the real
world
Richard Schuster
Department of Psychology
University of Haifa (Israel)
University of Haifa’s Forum on Research Methods – 4 April, 2006
The focus of this series is on interdisciplinary research
My talk is on cooperation. And how I use an
“Interdisciplinary approach”
This can means many things…...
Today I mean explanation: how do we answer the question
“why cooperate?
I will talk about the advantages from distinguishing between
two kinds of explanation……. Psychological and Evolutionary
….and then combining them within an integrated psycho-biological
framework…
A Behavioral/Psychological explanation looks at the influences on
the behavior of cooperating by individuals at the time that
the behavior is performed.
Behavioral / psychological explanation: this offers a proximate
explanation in answer to the question “Why cooperate?”
Aristotle called this an efficient cause whose action produces a
change of state: the kinds of causes that explain who behaves,
when, how often, in what form …………
Individual causes: stimuli; learning history (memories); current states of
motivation emotion and physiology; outcomes: rewards, etc
Social causes: presence of others: which others, ranks, past interactions…
What kinds of things are explained?
/who cooperates and who does not (individual differences)
/how often a given individual will engage in cooperation
/how is cooperation performed – the behavior, coordinated, cues…
/whether a given individual would choose cooperation when
non-cooperation is also available as an option
One Behavioral /Psychological factor I will emphasize today is
engaging in the behavior of cooperating:
By “behaving cooperatively,” I will refer to dimensions of behavior
associated with cooperating that are not associated with
not-cooperating.
For example, cooperation includes non-random choosing of partners
that use each other to work together for shared outcomes
based on coordination, complementary roles, social cues,
etc etc………….
I will ask whether “behaving cooperatively” is associated with
intrinsic states (emotions and the like) that are also part of the answer
to the proximate question “Why cooperate?”
Is cooperating intrinsically pleasurable? rewarding? motivating?
An Economic/Evolutionary explanation:
this looks mainly at outcomes that are linked to
behaving cooperatively with the potential to
benefit individuals (economic outcomes).
Such benefits may not follow as direct outcomes
from cooperating, they can occur at any time
during an individual’s lifetime and they have the
potential to influence natural selection.
Evolutionary / economic explanation:
this provides what is often called an ultimate explanation
The link to evolution offers an ultimate explanation because it
offers an answer to the “why question” that is framed as
“why the behavior might have come to exist as an
adaptation molded by evolution.”
It asks not what influences individuals when they cooperate – but
how much cooperation “pays” or is beneficial/profitable to the
individual at any time during its lifetime 
how outcomes can contribute to evolutionary fitness by increasing
individual success and ultimately reproductive success.
In animals, “outcome” in this context usually refers to cooperation
that pays off economically in things like more food from hunting
cooperatively, or a victory from fighting cooperatively that leads to
larger territory and/or more mating partners.
This economic evolutionary approach also uses economic
outcomes to distinguish between cooperation and other social
behaviors….
e.g., Robert Trivers, The Evolution of Social Behavior
(1985):
“…social acts” are classified by individual outcomes:
• both parties gain (cooperative)…..
•
•
the actor confers a benefit but suffers a cost (altruistic),
the actor gains while inflicting a cost (selfish)
Unlike a proximate or efficient cause, evolution does not explain
what triggers cooperation in any individual during its lifetime.
Instead, before an individual is born, natural selection has already
weeded out genes that reduced the fitness of ancestors, and the
selected genes explain a potential to cooperate that is only
expressed when the favorable conditions arise.
A proximate explanation is still needed to explain what makes a
given individual behave, how, how often, with whom……..
Another way to look at the difference between proximate and
ultimate explanations is to look only at outcomes and to
distinguish between short- and long-term outcomes following
an act of cooperation.
Assume a cooperative (or any) behavior is performed:
The short-term outcomes are the outcomes linked to the psychology of
cooperation by operating in the “here-and now” to determine the
likelihood of that an individual will engage in the behavior via processes
underlying perceptions, motivations, incentives, emotional states,
reinforcements …….at the time of engaging in the behavior.
The long term-outcomes are the profitable, economic and fitnessdetermining consequences at any time during the life of an individual
or its kin that are linked to cooperation and determine its evolution via
natural selection. These can emerge months or years later.
The link between them: short-term outcomes can activate proximate
mechanisms that function to evoke behaviors that are ultimately
beneficial by leading eventually to long-term profitable outcomes.
There are four points to know about the differences between short- and
long-term outcomes ….
1) Short- and long-term outcomes can be different – in different
currencies.
Two examples: play and illness.
Consider the widespread behavior of play in animals and humans.
We can speak of a behavioral “bias to play” because individuals –
usually young ones but not only - expend time and energy when
engaging in play that is not immediately compensated by any
economic outcomes such as food.
Why do this? Many will say that play leads to improving skills
that will eventually increase success over the life span:
ex. play hunting and play fighting.
This is the ultimate evolutionary explanation.
But how do they know? The likely answer is that they don’t.
So why do they do it? They are having a good time.
This then is the proximate / behavioral explanation: processes of
motivation, emotion and reward that evolved to make the behavior
happen in the first place and thereby lead to the ultimate payoffs.
Another example of the difference between proximate and
ultimate: illness
Proximate dimensions: Disease symptoms such as fever, pain,
sweating, loss of appetite, psychological states, misery are evoked
by reactions in the body to pathogens and their effects on
systems…..
Ultimate dimensions: Symptoms are signs of evolved
mechanisms that indicate the operation of defenses against
invading pathogens…….the symptoms are in fact linked to
advantages that increase survival.
As with play, the operation of proximate and ultimate processes
are both explanatory – and complementary – for explaining
disease ………..
2) Time –lag: There can be a substantial time lag between the outcomes
that influence behavior and the outcomes that influence evolution.
Long-term outcomes can guide evolution, but they often cannot be used
as an explanation of behavior when it occurs. The reason: discounting..
Discounting function: rapid decrease in the
value of delayed outcomes
Value of
outcome
0………………....x
Time
3. Some kinds of outcomes can only influence cooperation via
proximate processes…….
Events like intrinsic emotional states (pleasure, empathy….) can
be linked to engaging in cooperation with others for shared
outcomes: “helping another costs me but it feels good”
Such outcomes provide proximate explanations when they function
as incentives or goals that motivate and reinforce cooperation when
it is performed.
But such outcomes do not in and of themselves provide a
contribution to fitness unless they also lead later to beneficial
economic outcomes – but this is not always guaranteed.
4) The same beneficial economic outcomes can sometimes
operate as both proximate and ultimate outcomes…….
Some kinds of outcomes - like food, money, mating partners etc –
are both economically valuable and can be immediately gained
following cooperation.
Such outcomes provide a proximate explanation when they function
as hedonic incentives or goals that motivate and reinforce
cooperate when it is emitted: the Law of Effect of learning theories.
Economists speak of “utility” or “expected utility” as a
psychological quantity that represents the value of an outcome for
an individual – an incentive to behave
…and value as we know can be a relative thing……….
But the same outcomes also provide an ultimate explanation if they
are the kinds of beneficial outcomes that influence natural selection.
Which kind of explanation is preferable?
It would not matter if proximate outcomes mapped onto long-term
beneficial consequences that elevate fitness.
Immediate and long-term benefits would then offer different
measures of the same cause. Either could be measured.
But the type of explanation does matter when cooperation occurs at
levels that exceed predictions from the economic outcomes available
at the time of cooperating: there is too much cooperation which we
call a “bias to cooperate”
But first…..
I want to suggest that our understanding of cooperation is incomplete
and even distorted when explanation and methodology are
dominated by an economic perspective.
I take advantage of a historical tilt or bias towards the
economic/evolutionary type of explanation as capable of offering the
more powerful or fundamental way to answer the question “why
cooperate?” I will refer to three variants of this perspective:
the Evolutionary
the Behaviorist
and the Game-theoretical
The historical bias towards
economic/evolutionary explanations:
1. Explanation.
Here is an example of the Behaviorist perspective, anchored in
the Law of Effect that explains how the likelihood of
cooperation is determined by its reinforcing
consequences following the behavior of individuals…
B.F. Skinner (Science and Human Behavior, 1953, pp. 297298):
“.... a 'social law' must be generated by the behavior of
individuals. It is always an individual who behaves, ….and
he behaves with the same body and according to the same
processes as in a non-social situation."
Note that “social behavior” as a distinct category of
action has been defined into non-existence
Here is an example of the Evolutionary perspective from
behavioral ecologists who use game theory models to
focus on cooperation whose evolution is determined by
beneficial outcomes that elevate fitness





Since 1981, game theoretical models have been a large part of the literature
of animal cooperation. ….The game matrix focuses not on the nature of the
behaviours involved but on their economic consequences. Game theory's
significance as a tool for modeling cooperation hinges on the idea that one
can determine which combinations of actions are cooperative by examining
the game matrix. Hence, students of game theory prefer a view of
cooperation that de-emphasizes the behavioural properties of an
interaction, and focuses on the economic consequences of an interaction.
We argue that the economic definition of cooperation is the best option
because it can be objectively applied, and it offers us the powerful tools of
game theory.
Students of social behaviour should recognize as an economically defined
interaction that may or may not involve coordination. …we argue that
cooperation is an outcome, not a mechanism.
(and then go on to show cooperation without coordination or awareness……
in ants)
D.W. Stephens & J.P Anderson, Animal Behaviour, 1997
…and here is the same game-theory bias from
economic theorists…
Karl Sigmund, Ernst Fehr & Martin A. Nowak,
Scientific American, January 2002:
“It may seem callous to reduce altruism to considerations of
costs and benefits, especially if these originate in biological
needs. Many of us prefer to explain our generous actions
simply by invoking our good character. We feel better if we
help others and share with them. But where does this inner
glow come from? It has a biological function. We eat and
make love because we enjoy it, but behind the pleasure
stands the evolutionary program commanding us to survive
and procreate. In a similar way, social emotions such as
friendship, shame, generosity and guilt prod us toward
achieving biological success in complex social networks.”
Game theory treats outcomes as both a proximate cause
influencing individual motivation and behavior
and
as surrogates for fitness that determine evolution
Analogous economic processes are assumed to operate,
maximizing economically-important outcomes that determine
the emergence of cooperation as a consequence of both
proximate psychological processes (learning, etc)
and
ultimate processes of natural selection.
The historical bias towards
economic/evolutionary
explanations:
2. Methodology
The issue of methodology arises because the different kinds of
explanations – proximate vs. ultimate - have been associated with
different ways of modeling and analyzing cooperation in the
laboratory.
The domination of evolutionary / economic explanations is associated
with 50+ years of experimental models that de-emphasize the
influence of behavior by exaggerating the role of payoffs. The
influence of behavior is dismissed in both method and theory.
This was achieved by minimizing or totally removing the social
properties of behaving cooperatively that are intrinsic to many kinds
of cooperation performed by humans and animals in the natural
world.
The Psychologist/ Behaviorist B.F. Skinner:
cooperation is defined as an inter-dependent
contingency between the behavior of two or
more individuals and the outcomes achieved by
each whether or not there is social interaction.
B.F. Skinner (1953, p. 311):
Cooperation: when the reinforcement of two or more
individuals depends on the behavior of both or all of them

1) The explanation of cooperation resides in the contingency between
the behaviors of 2 or more individuals and outcomes. This is a pure
economic explanation.

2) The behaviors used when cooperating only address the secondary
question of what individuals actually do when they cooperate but not
why they do it. The why is selfish profit.

3) In the natural world, cooperating individuals might coordinate
actions in complex ways or interact and communicate.

4) But from an economic perspective, cooperation can still be
claimed in the complete absence of social interaction as long as an
individual's outcomes also depend on the behaviors of others and
benefits are obtained by all.

5) The neglect of cooperation as a social behavior is reflected in a
long history of experimental models that eliminate the differences
between the performance of cooperation and non-cooperation: both
are simple behaviors performed by anonymous and physically
isolated subjects.
Skinnerian laboratory models: as simple as individual
reinforcements for two animals that synchronize two simple,
brief acts such as pressing a bar…..
Non-social cooperation: Models with no social interaction
whatsoever are still called cooperative
Note the close similarity with the ecological / evolutionary
perspective quoted before………


“Hence, students of game theory prefer a view
of cooperation that de-emphasizes the
behavioural properties of an interaction, and
focuses on the economic consequences of an
interaction.”
“Students of social behaviour should recognize
cooperation as an economically defined
interaction that may or may not involve
coordination. …we argue that cooperation is an
outcome, not a mechanism.”
(D.W. Stephens & J.P Anderson, Animal Behaviour, 1997)
Game-theory models: more complex inter-dependent contingencies
specified in game theory payoff matrices that offer choice
Prisoners’
dilemma
Coop
Player 1
NonCoop
Player 2
Coop
NonCoop
RE
3
SE
Player 2
0
Coop
TE
5
Player 1
PE
NonCoop
RE
5
SE
TE
PE
3
1
Coop1
NonCoop
Mutualism
3
But Game-theory models retain all the impoverished social
dimensions of the earlier Skinnerian models…
3. Cooperation
and noncooperation are
defined entirely
by outcomes
1. Subjects
are
anonymous
and isolated
2. The behaviors of
“cooperation” and
“non-cooperation”
are arbitrary,
identical and
individual acts
I suggest that this bias toward the economic/evolutionary in method
and theory represents a historical error that has delayed efforts to
answer the question “Why cooperate?” by confounding psychology
and biology: everything has been linked to outcome and benefit
To me, this emphasis on economic decision-making – whether in
Economics, Evolutionary Biology or Psychology - represents an
unnecessary denigration of the psychological / proximate kind of
explanation as being somehow soft, imprecise or impossible to
confirm – a “soft science” how it is done (psychology) but not why (economics/evolution)
….whereas the economic approach offers the security of counting
and measuring explicit events in a hard and mathematical science.
This is an updating of the old “Behaviorist” issue of avoiding the
kinds of events that allegedly cannot be specified or confirmed.
…..the “hijacking” of psychology by economics
But economics alone cannot be used to explain cooperation that is
based on irreducible social dimensions…………..
The study of cooperation in the
natural world:
cooperation as a social behavior.
Question: Do models of isolation and anonymity have
relevance to cooperation in the natural world?
The validity of anonymous/isolation games seems relevant to those
situations in which behaviors are performed individually– and
potentially have impact on other anonymous individuals or on
society as a whole:
where to throw trash;
whether to make noise in a movie theater;
whether to drive a car with consideration for other drivers or
pedestrians;
whether to wait in line or jump the queue;
whether to give money anonymously;
whether to conserve natural resources or rare wildlife;
whether to work for peace…
There is a social context but it is anonymous, lacks personal social
interaction and reduces cooperation to an individual event.
If there is a social relevance, it is limited in humans to things like:
reputation, impression on others…
Another kind of cooperation that is also widespread in humans
and animals in the natural world consists of actions by individuals
that work together by using each other to act cohesively for
jointly-obtained outcomes, as in team sports, warfare or group
hunting. …….
The irreducible social dimensions associated with this kind of natural
cooperation include:

- cooperating individuals are familiar

- they work together by using each other’s
behaviors and locations to coordinate actions,
sometimes with complementary roles

- outcomes are jointly-obtained successes or failures

- outcomes may lead to competition and dominance over
allocation

- adjunct social interactions

(Schuster, Human Nature, 2002;
Schuster & Perelberg, Behavioral Processes, 2004;
Schuster & Berger, in press)
To understand this kind of cooperation, I will try to show that…
Levels of cooperation – and preference for cooperation – can exceed
predictions from economic outcomes at the time of performance.
This bias is caused by proximate processes linked to the behavior of
cooperating, especially its social dimensions. This can make
cooperation excessive and uneconomic in the short term.
The social dimensions of cooperation can be incorporated into
laboratory models that will then evoke the same kinds of behaviors and the bias to cooperate - as in the natural world
Cooperation – even when “excessive” or uneconomic in the short-term
– can still be economic but only in evolutionary terms when longrange consequences can be traced to such behaviors that influence the
natural selection of cooperation via ultimate processes.
These issues will be addressed in four parts:
1 - Behavior: How do animals and humans cooperate in their
natural world?
2 – Influence of Behavior: Is there a bias to cooperate that is
influenced by the social dimensions of cooperating?
3 - Models: How can cooperation be represented by laboratory
models that incorporate the behavioral dimensions of
cooperation in the natural world- and the bias?
4 - Explanation: How can a proximate and ultimate processes
be incorporated within an integrated explanatory framework?

1. Behavior: How do animals and
humans cooperate in their natural world?
In the natural world, when cooperation is expressed as
joint actions for shared outcomes, this kind of behavior
is associated with irreducible social dimensions that are
absent when not cooperating.
This is widespread in many species and in different
contexts….
hunting, aggression, defense, reproduction...
Three animal examples: dolphins, lions and chimpanzees
dolphins
Cooperative
hunting of
bottlenose dolphins
mms://vod4.haifa.ac.il/L/CRI/RM200604/do
lphins2.wmv
Cooperative hunting of lions
Zibalianja, Botswana
Intentional, planned and coordinated hunt
water
Lioness C
Lioness A
Prey: antelope
Lioness B
mms://vod4.haifa.
ac.il/L/CRI/RM20
0604/lions linyanti
short film.wmv
Cooperative hunting by the common chimpanzee,
Tai Forest, Ivory Coast
Intentional, planned and coordinated hunt
mms://vod4.haifa.ac.il/L/CRI/RM200604/chi
mp hunt Tai Oct 05.wmv
Analogous examples of human behaviors.......
Teamwork with complementary roles
“Distributed cognition:”
group performance divided among team members.
While cooperating, each individual performs a role so
specialized that it would be ineffectual if the individual was
forced to perform the entire task alone. This kind of organization
“..permits individuals to combine their efforts in ways that
produce results that could not be produced by any individual...
working alone.”
(E. Hutchins, Cognition in the Wild, 1995)
1. In all these cases, cooperating becomes an extended action based
on individuals acting cohesively
2. The only cues available during coordination are social:
from locations and behaviors of partners
3. While cooperating, there is unrestricted social interaction
4. Outcomes are also a social event: they are jointly achieved and
potentially shared, with the possibility of competition
5. Strategies develop within groups for working together
Pairs and groups therefore vary in:
cues * coordination * roles * dominance *
allocation of outcomes *
social behaviors ….

2. Is there a bias to cooperate that is
influenced by the social dimensions of
cooperating?
The bias is known from observing human behavior in the “natural
world” of group decision-making and joint action by groups
Robert Frank, Passion Within Reason, 1988
Sober & Wilson, Doing Unto Others, 1998
In Anthropology: hunter/gatherers (pygmies, Bushmen, Ache):
work of Colin Turnbull….
But Human subjects also cooperate more than expected in the
impoverished conditions of game-theory experiments……..
Fehr et al, 1999-2005;
Haselhuhn and Mellers, 2005
Reviews: Dawes, 1986
Palameta & Brown, 1999;
Colman, 2003 and commentaries (in Behavioral
and Brain Sciences – BBS)
Humans apparently play the games as if they have social
dimensions……..

If inform subjects about the participation of others
their behavior can be modified
(e.g., Baker & Rachlin, 2002).

Brain imaging: Rilling et al 2002, 2004

Social factors: Suleiman et al, Ido Erev et al,
Ilan Fischer…….

Emotions: Haselhuhn and Mellers, 2005
To explain the human bias towards cooperating, it is suggested that
humans are influenced by mediating psychological states that are
products of culture/religion/moral systems:
“social orientation,” group thinking, reputation, …
or merely the desire to avoid sanctions or embarrassment when
caught acting selfishly.
Another proposal (by Fehr et al) is centered on a strong motivation
in cooperating humans to punish selfish non-cooperators as a
means to “encourage” them to be more altruistic
But there are problems with this human cultural learning model….
One problem: there is usually little direct evidence for such states
apart from the bias towards cooperation.
Such explanations risk the danger of circularity.
A second problem: the same bias can also characterize animal
cooperation when it includes the kinds of social dimensions that
characterize cooperation in the natural world that is based on joint
actions for shared outcomes
Animals do not show the bias when cooperation occurs in the absence
of social interaction,
as in the isolated conditions of game theoretical experiments 
the preference is now NOT to cooperate
e.g., In prisoner’s dilemma games, animals prefer to defect
towards non-cooperation and the the larger potential outcome
Prisoners’
dilemma
Player 2
Coop
Player 1
NonCoop
Coop
NonCoop
RE
3
SE
TE
5
PE
0
1



Rats: Flood, M, Lendenmann, K., and Rapoport, A., 1983.
A 2 x 2 game played by rats: different delays of
reinforcement as payoffs. Behavioral Science, 28: 65-78.
Pigeons: Baker, F. and Rachlin, H., 2002b. Self-control by
pigeons in the prisoner's dilemma. Psychonomic Bulletin &
Review, 9: 482-488.
Blue jays: Clements, K.C. and Stephens, D.W., 1995.
Testing models of non-kin cooperation: mutualism and the
Prisoner’s Dilemma. Animal Behavior, 50: 527-535.
Animals are acting as if they are behaving alone and
either do not detect the inter-dependency of the
reinforcement contingency or are unaffected by
it……..
But animals reveal the bias when the social dimensions of
cooperation become explicit………..
and this can be shown in their natural world
Again, dolphins, lions and chimpanzees…….
Cooperation bias in dolphins


Alliances among male adolescents no obvious outcome
at the time and for many years
The Same animals as adults mate guard adult females for mating
that is NOT always shared equally (Connor et al, 2000)

The PhD work of Amir Perelberg on free-swimming
dolphins that spontaneously approach trainers to receive
petting at the Dolphin Reef tourist site in Eilat…..

The dolphins approach trainers singly or by coordinating
their approach in pairs

Petting can therefore be treated as a desired resource:
Is this what motivates the dolphins to approach?
Is it costlier to be petted together?
Coordination level of each dolphin with petter
Petting together
3.05±0.19 [mean±SE] separations/min
Petting alone
2.54±0.14 [mean±SE] separations/min
Wilcoxon Signed Ranks Test, N=13, Z=-2.27, P=0.023
Allocation of petting
Is there any preference for petting alone or
together?
Wilcoxon Signed Ranks:
Proportions of petting bouts count
1 hand
dolphin pair to dolphin
alone
Z=-0.22, P=0.823
2 hands
dolphin pair to dolphin
alone
Z=-3.29, P=0.001
Proportions of petting bouts count
A
B
N.S
***
1 hand
2 hands
Alone
0.52
0.21
Pair
0.48
0.79
1
0.75
0.5
0.25
0
Dolphins prefer to be petted together even though they
pay a price in reduced physical contact
Cooperation bias in lions:

Learning: Slow learning by cubs with almost NO material
reinforcement from hunting together
before about 2 years of age (Scheel & Packer, 1991),
coordination is poor, the targets often wrong, and the
probability of a kill minimal.
 if cooperation learning in lions is based on reinforcing
outcomes, nutritional gain does not seem to be the exclusive
or even the primary motive.

Preference for cooperation in experienced hunters
More food can be obtained by adults that hunt alone:
even though the likelihood of making a kill increases, lions
that hunt together must then share the prey
(Packer, Scheel & Pusey, 1990) 
Lions in the
Serengeti…
Cooperation bias in chimpanzees
Even slower learning than in lions
minimal success (little food reinforcement) for c. 10 years
(Boesch, 2002; Nishida, film)
No evidence for food as primary motive 
not related to hunger or absence of other food
(Mitani & Watts, 2001)
Sharing outcomes with non-hunters for political purposes…
Unequal allocation of outcomes 
Unequal allocation of outcomes
dominants get more; meat is shared with females; and some
cooperators get little or nothing
(Boesch & Boesch, 1989)
Size of prey
Small
(infant or
juvenile)
Large
(adult)
Keep all
(‘respect’)
Theft
Transfer
Division
22
3
1
2
3
1
4
25
Question: Is this still cooperation?

Not from an economic “rational” perspective limited to outcomes:

Immediate beneficial outcomes may be minimal or absent

Outcomes may not be allocated equally

Behavior is effectively altruistic

But from a behavioral perspective, the behavior is phenomenologically
cooperative because it is a social and coordinated joint action
and because it captures the altruistic dimension of cooperating (doing
for others):
animals are using each other’s behaviors and locations for obtaining
shared outcomes when more could be obtained by operating alone, or
when the immediate economic outcome is not the primary goal

If we assume that there is immediate reinforcement, I will suggest later
that this behavior can be explained by additional immediate
reinforcement that is not economic in the accepted sense because it arises
from motives and emotions associated with the behavior of cooperating
itself.
This also changes the way we characterize the process of
decision-making about whether or not to cooperate
From an economic perspective:
the choice is framed as a decision governed by outcomes and their
expected utility; the form of the behavior is irrelevant
From a behavioral perspective:
The choice is framed not only as a choice between different
material outcomes such as food, money, etc.
• but also as a choice between different kinds of behaviors:
•
cooperation associated with irreducible social
dimensions
•
non-cooperation associated with the absence of
those social dimensions.
This is consistent with a link to more basic behavioral/
psychological processes in animals linked to behaving
cooperatively……..
and the possibility that these are shared with humans.

3. Models: How can cooperation be
modeled in the laboratory to incorporate
the dimensions of cooperation in the
natural world – and the cooperation bias?
Our goal was to incorporate more of the social dimensions
associated with cooperation into our models in order to study the
influences of behaving cooperatively on performance and choice.
Cooperation: pairs of laboratory rats that are reinforced for
working together, using each other to coordinate behaviors
The behavior: to coordinate movements within a shared space
with unlimited social interaction
Incorporates features of cooperative behaviors such as group
hunting and aggression as they occur in the natural world
The economic reinforcement: water sweetened with saccharine
“Zugia” (Heb"pair”) – a model of social cooperation
Behavior  outcome contingency
Sacch
reinf
(1 or 2
cups)
2 cups
1.
Together
on Floor D
for 0.5 sec
2.
Together
on Floor N
for 0.5 sec
Floor N
Floor M
Floor D
94 cm
mms://vod4.haifa.ac.il/L/CRI/RM200604/rats.wmv
Contingency and control…..




Unlike isolation models with greater prediction
and control over individual behaviors…
The behavioroutcome contingency in this kind
of model is defined at the level of a dyad
Within the limits set by the contingency, pairs are
free to develop strategies with differences in
dominance, control, roles, etc. – each pair
develops its own way of coordinating
There are also differences across pairs in levels
of coordination and social interaction
Non-cooperation: single reinforcement for individual performance of
the same back-and-forth shuttling, even if others are present
Behavior  outcome contingency
Sacch
reinf
(1 cup)
1 cup
1.
Alone on
Floor D
for 0.5 sec
2.
Alone on
Floor N for
0.5 sec
Floor N
Floor M
94 cm
Floor D
1. Cooperating pairs learn to work together
Stage 1:
Group 1
Group 2
Matched reinf:
Stage 1:
Group 1
Then every
subject given
a new, naïve
partner for
cooperating
Stage 2:
N
Group 2
N
N
Stage 2:
former
cooperators
learned faster
with new naïve
partners than
former
non-cooperators
2. Pairs only learn to coordinate when reinforced
specifically for cooperating
Stage 1: Cooperative
contingency
Stage 1: Individual independent
contingencies with
matched reinforcement
But pairs coordinated only when reinforced for cooperating….
Sharing the
same space is
not enough to
coordinate:
cooperation is
controlled by
the
requirement
to cooperate
Pairs: Cooperative
Pairs: Independent
Non-coop
What happens
when choosing
between these
behaviors
and
outcomes are
matched?
Cooperation
???
Economic
perspective….?
Behavioral
perspective….?
Stage 1
First learned the
two tasks:
Non-coop
each task in a
separate chamber
10 sessions
Cooperation
Stage 2
Then learned the
locations
of the chambers
Non-coop
6 sessions/12 trials
Different
floors
Insert
guillotine
doors
Cooperation
Stage 3
Free choice
Non-coop
4 sessions/ 8 trials
Cooperation
Two experiments: cooperation was not more profitable
in terms of reinforcement (28 subjects)
Relative rate of reinforcement
(coop / indiv + coop)
0.6
0.53
0.46
0.5
Learning
Forced choice
Free choice
0.35
0.4
0.3
0.2
0.1
0.0
Stage
The 2nd experiment (n=22 subjects)
Relative rate of reinforcement
(coop / indiv + coop)
0.6
0.50
0.5
0.50
0.43
Learning
0.4
Forced choice
0.3
Free choice
0.2
0.1
0.0
Stage
Yet cooperation in Exp. 1 was strongly preferred (n=28)
0.9
Choices*
Subjects**
0.8
Proportion
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
coop
non-coop
coop
non-coop
Option
* Wilcoxon Signed Ranks Test. Experiment 1: Z=-3.26, p=0.001 **
Chi-Square Test. Experiment 1: χ2=11.57, df=1, p=0.001
And cooperation was again strongly preferred in Exp. 2…
Choices*
0.8
Subjects**
0.7
Proportion
0.6
0.5
0.4
0.3
0.2
0.1
0.0
Coop
Non-coop
Coop
Non-coop
Option
* Wilcoxon Signed Ranks Test. Experiment 1: Z=-3.39, p=0.001
** Chi-Square Test. Experiment 1: χ2=4.54, df=1, p=0.033
Choice was not linked to relative reinforcement:
Relationship between choices for cooperation (Stage 3) and relative
reinforcement during Learning Stage 1 (sessions 6-10)
Number of choices for
cooperation in 8 trials
8
7
6
5
4
y = 6.77x + 3.07
3
R2 = 0.14
2
1
0
0.00
0.10
0.20
0.30
0.40
0.50
0.60
Relative rate of reinforcement: cooperation
0.70
Number of choices by pair for
cooperation
Choice was linked to a pair’s level of coordination…….
16
14
y = -17.16x + 20.13
R2 = 0.66
12
10
8
6
4
2
0
High coordination -> Low coordination
0.3
0.4
0.5
0.6
0.7
0.8
0.9
Proportion of coordination errors to Floor D
1.0
The bias to cooperate was also shown by
allocation of outcomes that did not strongly
influence learning and performance…….
Experiment on competition over outcomes
100% double outcomes
left cup right cup
Completed coordination
or
Completed coordination
Intermittent double and
single outcomes
or
One partner?
Measuring competition and dominance:
when a single cup is presented, is it accessed by
the “owner” or “invader”
Cup presentations
or
Invader?
or
Invader?
Dominance within pairs was expressed as the degree of “invasion” of
the partner’s cup by the non-owner when presented alone
Dominance
First to arrive
score of invader
Final access
0
Owner
Owner unchallenged
1
Owner
Owner displaces invader
2
Invader
Owner displaces invader
3
Owner
Neither withdraws
4
Invader
Neither withdraws
5
Owner
Invader displaces owner
6
Invader
Invader displaces owner
7
Invader
Invader unchallenged
Majority of pairs eventually competed with cup dominance
level 5 (Scale 07) over Sessions 7-12
7
Dominance index
6
5
4
Mean
Mean
Mean
3
2
Mean
1
0
C25
C50
C-75
Group
C-100
Effect of outcome dominance on cooperation? None
Z-score of coordination rate sessions 7-12
(n = 48 pairs in 4 sub-groups; Sessions 7-12)
2.0
y = 0.02x - 0.29
1.5
2
R = 0.0015
1.0
“Good” cooperators
0.5
0.0
-0.5
“Bad” cooperators
-1.0
-1.5
-2.0
0
1
2
3
4
Index of cup
dominance
Increasing
dominance

5
6
Summary: levels of cooperation and the decision
about whether or not to cooperate are also
influenced by the behavior of cooperating that
can lead to a bias……..


In animals and humans, this is present in the field
In laboratory models with animals, this can be
evoked when cooperation incorporates social
dimensions analogous to those in the field
(the issue of external validity)

Question 4 - Explanation: How can proximate
behavioral processes and ultimate evolutionary
processes be incorporated within an integrated
explanatory framework?
Proximate Explanation if you are a psychologist:
What proximate processes operating at the time of
behaving could explain the bias towards cooperating?
1) Cooperation is reinforced by two kinds of immediate
outcomes:
A) Material economic gains (if any)
(food, mates, money…)
B) Intrinsic reinforcement from the act of
cooperating with others
• from coordinating actions?
• from affiliative social behaviors?
• from relationships that develop while
cooperating?
Economic outcomes:
surrogates for fitness
(food, money, etc)
Immediate outcomes
from cooperating
“Intrinsic” outcomes:
from states associated with
cooperating
(emotions, etc.)
One behavioral function of intrinsic reinforcement would be to provide
an immediate incentive when “economic outcomes” are absent,
insufficient or delayed at the time of cooperating
Act of cooperation
Immediate
economic
outcomes
Immediate economic
outcomes



Immediate
intrinsic
outcomes
when learning to cooperate is difficult
when non-cooperation is more profitable
when there is dominance and some cooperators receive less
Consistent with the rat, lion,
chimpanzee and dolphin data….
And
also
in
humans….
Emotions linked to coordinated and ritualized
behaviors:
ceremonial behaviors in groups evoking
excitement, affiliation, and power
(McNeill, 1995)
Praying mms://vod4.haifa.ac.il/L/CRI/RM200604/choir.wmv
Sports
mms://vod4.haifa.ac.il/L/CRI/RM200604/nfl.wmv
2) There are two kinds of decision-making:
A) Explicit rational thinking based on analysis of economic
data and estimations of likelihood
B) Implicit (unconscious?) decision making based on
influence of cues and contexts associated with cooperation
•
from explicit social interaction
•
from information about the involvement of others
(Rilling et al, Baker & Rachlin…)
Analogous to Tversky and Kahneman’s System I
(intuitive) and System II (deliberate, conscious,
rational) decision-making based on explicit
outcomes
Ex of implicit decision-making: Humans in Dictator gameEffects of eye-spots (“being observed”)…
$10: keep or divide:
single trial
Silent (ear-covers)
or no
Eye spots or no
Mean allocation:
No eyes + non-silent:
mean $2.45; 55% allocated
Eyes + non-silent:
mean $3.79; 88% allocated
Eyes only:
mean $3.14; 79% allocated
(Haley & Fessler, 2005, Evolution and Human Behavior)
Can we call this a behavioral economics
the influence of psychological dimensions associated with
cooperating on the likelihood of cooperation biases, etc?
From work of Frans de Waal, Schuster and others on animals:
Do individuals prefer cooperation when non-cooperation provides the
same or less in economic outcomes?
Yes in rats, lions, dolphins……….
Do individuals tend to share more if another has helped in gaining the
outcome?
Yes in capuchin monkeys, chimpanzees.
Do individuals cooperate more with other individuals who have
previously provided a benefit (“score-keeping”)?
Yes in a variety of animals from vampire bats to chimpanzees
Do individuals react to unfairness by monopolizing outcomes without
sharing?
Yes again in capuchin monkeys and chimpanzees
Ultimate explanation if you are a Biologist:


But bias invites the question:
How can cooperation evolve if it leads to uneconomic,
seemingly “irrational” behavior that is costly in time
and energy?
Needed is an evolutionary economics that is adaptive
and “rational” for a mindless ultimate process of
natural selection …………
even though the behaving individual may be incapable
of knowing or intending the ultimate purpose of his
action that influenced evolution
A short-acting immediate incentive can be adaptive if it also leads to
long-term adaptive outcomes that elevate fitness
Act of cooperation
Immediate
intrinsic
outcomes
Immediate
economic
outcomes
Immediate economic
outcomes
Long-term
ultimate
outcomes: fitness
This glue or bridge between the short- and long-term outcomes can be
the development of social bonds between individuals that engage
in joint actions for shared outcomes
…and these bonds are what lead eventually to the beneficial
consequences that guide the evolution
Two filmed examples……………..lion and chimpanzee
Lions: Lion cooperative hunting by males and/or females may not pay
in food gained per individual…..

But cooperative hunting can eventually pay off when 
- adult females cooperatively defend their cubs against
-infanticidal males (Packer, Scheel & Pusey, 1990),
-members of other prides (McComb, Packer & Pusey, 1994)
-hyenas (films).

-adult males cooperatively fight together when
taking over a pride of females

mms://vod4.haifa.ac.il/L/CRI/RM200604/lions2.wmv
Chimpanzees: Food and sex do not seem to be the primary
motivations for cooperative hunting (Mitani & Watts, 2001);
Male-male associations and social behaviors were the best
predictors

But cooperative hunting eventually can pay off
when adult males later engage in inter-group “warfare”
with direct consequences for mating success and fitness
(Watts & Mitani, 2001).
mms://vod4.haifa.ac.il/L/CRI/RM200604/chimp
warfare Gombe.wmv
Summary:
The links between behaviors and outcomes – and between
proximate and ultimate explanations - are complex:

(1) the immediate consequencess for cooperating include intrinsic social
emotions and social relationships that are problematical for explanations
anchored in rationality

(2) fitness is linked to material consequences that may be realized only in
the long-term and they are also far from certain;

(3) the fitness-enhancing consequences can also be indirect,
occurring in a different context and in a different currency from the
original cooperation.
(Schuster, 2002; Schuster & Perelberg, 2004; Perelberg & Schuster, in prep)
Do we want the term “rational” to apply when only longterm adaptive outcomes are maximized?
Implications for game theory matrices:
combining economic gains (E) with
intrinsic (psychological) reinforcement (P)
e.g., a Prisoner’s dilemma game
Player 2
C
Player 1
NC
C
NC
RE R+E RP
3+
3?
SE S+E SP
TE T+E TP
PE P+E PP
5 5+ ?
1 1+ ?
0 +
0 ?
Take-home messages:
In nature:
Cooperation is a class of behaviors incorporating irreducible
social dimensions
that are absent when engaging in nonLaboratory
Models:
cooperation
Models should have external validity, incorporating tasks
influenced
by theOutcomes:
irreducible social
dimensions
cooperation.
Immediate
Cooperation
is notofalways
economic at the time of cooperating:
-explicitImplications
material reinforcement
for evolutionary explanations:
-intrinsic
emotions
linked to behaving
Fitness
is reinforcement
determined by from
beneficial
(“economic”)
outcomes
that cooperatively
may only be realized long after the cooperative behavior
Explanation:
by incorporating
proximate
is performed.Only
The bridge
between the outcomes
is the
psychological
with ultimate
evolutionary
developmentprocesses
of social relationships
among
cooperating
individuals
the intrinsic
reinforcements
processes
can that
we experience
explain both
the behavior
and its
linkassociated
to fitnesswith engaging in joint actions for shared outcomes.
Anatol Rapoport (BBS, 2003) quoting David Hume (1739)
“Reason is, and ought to be, the slave of passions, and can
never pretend to any other office than to serve and obey
them.”

Rapoport adds:
“In other words, effective means to reach specific goals
can be prescribed, but not the goals.”

Herbert Simon: Rationality in Human Affairs
“The neocortex is the hired gun of the paleocortex.”
Recent summaries
R. Schuster & B.D. Berger, An animal model for studying the behavior of
cooperating. In: M. Anderson (ed.), Tasks and Techniques: A Sampling
of Methodologies for the Investigation of Animal Learning, Behavior
and Cognition. In press.
R. Schuster & A. Perelberg
Behavioural Processes, 2004, 66, 261-277
R. Schuster
Human Nature, 2002, 13, 47-83
R. Schuster
Proceedings of 6th Annual Symposium on the Science of Behavior:
Social Behavior.
University of Guadalajara, Mexico
Revista mexicana de análisis de la conducta
(Mexican Journal of Behavior Analysis), 2001, 27,
165-200)
Collaborators
Barry D. Berger, University of
Haifa
Moussa B.M. Youdim,
Technion- Israel Institute of
Technology, Faculty of Medicine,
Director of the Eve Topf and USA
National Parkinson Foundation
Centers of Excellence for Neurodegenerative Diseases
Peter R. Killeen, Arizona State
University
Howard Rachlin, State University
of NY at Stony Brook
Heidi Swanson, Netherlands Institute
for Brain Research
Shlomo Hareli, University of Haifa
Gadi Katzir, University of Haifa, Biology
Dietmar Tödt, Free University of Berlin,
Zoology
Shai Shoham
Students
Michael Tsoory
Amir Perlberg
Sonia del Canho
Steve Arnautof
Edna Cohen
Tamar Borovitch
Corina Dollingher
Shai Sela
Keren Gavish
Yona Rubin