CEFOM/21 Third International Symposium“Trust in Groups from Cross-Societal Perspectives”

Hokkaido University, September 26-28, 2003

An Institutional An Institutional ApproachApproach

to Groupsto GroupsGroups are important because people think that

groups are important,

but, one person alone cannot change her beliefs but, one person alone cannot change her beliefs about the about the importance of the group of the group.

Toshio YamagishiToshio YamagishiHokkaido University

We intuitively think that groups play an important, indispensable role in our social life.

Why are groups so important?

Our intuitive answer to this question is that groups are where cooperation takes place. We are better off as a member of a group than by living independently.

We do not have an answer to this question!

Most answers provided by psychologists are too intuitive and weak in logic. Game theorists have not come up with a satisfactory model of ingroup cooperation.

Why does cooperation take place mostly within groups?

Why does the group promote cooperation?Why does the group promote cooperation?A psychological mechanism that makes us behave cooperatively toward ingroup members is notnot acceptable as an answer to this question, since it immediately prompts another question:

Why do we have a psychological mechanism that makes us behave cooperatively toward ingroup members?

Psychologists’ approach to this question is to analyze the mechanism itself – This approach answers the question of howhow, but does not answer the question of whywhy.

The game theoretic approachThe game theoretic approach answers the question of whywhy, though it does not provide clues to the question of how.

We need to combine the two approaches to come up We need to combine the two approaches to come up with an acceptable answer to this question!with an acceptable answer to this question!

Why does the group promote cooperation?Why does the group promote cooperation?

What do we know about why we cooperate?What do we know about why we cooperate?Cooperation: Behavior that promotes another person’s (or other persons’) welfare with a non-zero cost to the cooperator him/herself (where C < B).Altruism: no constraint of C < B

kin-selection in evolutionary biologykin-selection in evolutionary biologyis relevant to our question only to the extent that groups consist of kin members. Since our question is about the group in general, and not limited to kin-based groups, kin-selection doeskin-selection does not not provide an adequate answer to our questionprovide an adequate answer to our question, unless our psychology confuses cues for the group with the cues for the kin.

Adaptive advantage of helping kin members quickly diminishes Adaptive advantage of helping kin members quickly diminishes beyond cousins. The psychological mechanism that confuses nbeyond cousins. The psychological mechanism that confuses non-kin group members with kin members is fitness reducing unlon-kin group members with kin members is fitness reducing unless groups consist mostly of close kin members.ess groups consist mostly of close kin members.

Why does the group promote cooperation?What do we know about why we cooperate?

②② Reciprocal altruism (evolutionary biology); tit-for-Reciprocal altruism (evolutionary biology); tit-for-tat strategy (game theory)tat strategy (game theory)

TFT-based mutual cooperation in iterated PD involves direct exchanges between particular partners. There There is no logical (game theoretic) reason that groups is no logical (game theoretic) reason that groups mattermatter.

Even if empirical research shows that PD players cooperate more with ingroup members than outgroup members, TFT-based cooperation cannot explain the fact.

Reciprocal altruism or TFT does Reciprocal altruism or TFT does notnot provide an provide an adequate answer to our question.adequate answer to our question.

Why does the group promote cooperation?What do we know about why we cooperate?

③③ Reputation-based generalized exchanges (giving Reputation-based generalized exchanges (giving game)game)

Each actor decides whether to give resources or not to another actor. (C < B)Actors who give earn a good reputation.A strategy to give only to others who have a good reputation can evolve –several game theoretic models are currently competing.

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Why does the group promote cooperation?What do we know about why we cooperate?Reputation-based generalized exchanges (giving game)Reputation-based generalized exchanges (giving game)

Each actor decides whether to give resources or not to another actor. (C < B)Actors who give earn a good reputation.A strategy to give only to others who have a good reputation can evolve –several game theoretic models are currently competing.

Unlike TFT, this strategy—image scoring, standing, etc.—does not require “shadow of the future” (high probability of future interactions with a particular other).

Insofar as the reputation information is transparent to everyone, and all actors regard an actor who gives her resources to someone else (regardless of which group the target belongs) as good, then the group plays no role in the promotion of cooperation.

Insofar as the reputation information is transparent to everyone, and all actors regard an actor who gives her resources to someone else (regardless of which group the target belongs) as good, then the group plays no role in the promotion of cooperation.

Reputation-based cooperation is hard to maintain when some of those who may potentially give resources to an actor does not have an access to the actor’s reputation (i.e., when only a fraction of people who potentially give to an actor knows her reputation).

RBC is viable when

Most of the potential givers to an actor share the actor’s reputationCooperation is maintained only within groups if we defined the group as a collection of people in which they share each others’ reputation and have a chance to give to everyone else.

We thus can explain cooperation within groups, based on the RBC model, if we define the group as a “community” in which everyone’s reputation is shared by all and all have a potential to help the others. What matters is whether a particular group one finds herself in is a community in this sense.

Group identity or a shared “marker” does not play any role in this explanation. What matters is the existence of the community – a marker is not needed to define such a community.

Does the shared marker play any role in the maintenance of cooperation among those who share the marker?

Does the shared marker play any role in the maintenance of cooperation among those who share the marker?

To answer this question, let us think of a population in which all can potentially help all others and all actors’ reputations are shared by all.

Furthermore, the whole population is divided into “groups” by a marker – in this example, a color.

Does the marker affect RBC in this population?

No!No!

unless,unless,actors believe that markers are important.

A marker matters when and only when actors believe that others use markers in defining who have a good reputation.

Beliefs aboutBeliefs about

how a good reputation is generated.

If actors believe that giving to their own kind (who share the same marker) is considered “good” by their own kind (and those who don’t share the marker are indifferent to the behavior), then the marker plays a critical role in the actor’s decision of to whom to give.

Does the shared marker play any role in the maintenance of cooperation among those who share the marker?

But, where does the belief come from?

The belief-based ingroup cooperation is a tautology unless we can answer this question.

The answer should be sought in the adaptive advantage of having such a belief (and adjusting behavior according to the belief).

A belief is self-sustaining when having that belief is adaptively advantageous.

A self-sustaining system of shared beliefs = institution (Aoki, 2003)

TThe belief-based ingroup cooperation he belief-based ingroup cooperation exists only as an institution!exists only as an institution!

Does the shared marker play any role in the maintenance of cooperation among those who share the marker?

Social RealityAn incentive structure in which having a particular set of beliefs and behaving according to the beliefs is adaptive

BeliefsActors acquire the set of beliefs and behaving according to the beliefs, since doing so is adaptive.

Beliefs are not necessarily reflections of the social reality!

What matters is the adaptive advantage of having the belief.

An institution as a self-sustaining system of shared beliefsAn institution as a self-sustaining system of shared beliefs

Beliefs

Shared system of meanings

Beliefs

Beliefs

Beliefs

Cultural Psychological Conception of Self-Cultural Psychological Conception of Self-perpetuating system of beliefs is similar to the perpetuating system of beliefs is similar to the conception of an institution, but it lacks the logical conception of an institution, but it lacks the logical foundations.foundations.

This may be true, but it is useless in the logical analysis of the role of the group in promoting cooperation.

An institution as a self-sustaining system of shared beliefsAn institution as a self-sustaining system of shared beliefs

Social RealityThose who ignore group boundaries and treat both ingroup and outgroup members in the same manner acquire a bad reputation (the ones who don’t help us) and fail to be treated favorably with either ingroup or outgroup members

BeliefsThe naïve theory of groups: Groups are where people help each other (including generalized exchange)

Those who share the beliefs engage in ingroup-favoring behavior

Adaptive advantage of sharing the beliefs: Having the naïve theory of groups protects one from making an error of disregarding group boundaries.

An institution as a self-sustaining system of shared beliefsAn institution as a self-sustaining system of shared beliefs

The Naïve Theory of Groups

Insofar as the majority of people in a society share the naïve theory of groups (collectivistic theory), it is advantageous to believe in the theory. It protects people from committing costly errors.

The naïve theory sustains itself in a self-fulfilling manner.Insofar as people share the belief that most people treat cooperation with or altruism toward ingroup members as good, it is better to behave in ingroup-favoring manners.

That behavior reconfirms the belief in a self-fulfilling manner.

What matters is the expectation about other people’s beliefs meta belief = belief about other people’s beliefs

Our experiments have demonstrated that the belief that others behave in an ingroup-favoring manner is behind high cooperation with ingroup members, ingroup-favoring reward allocations, and trust in ingroup members.

An institution as a self-sustaining system of shared beliefsAn institution as a self-sustaining system of shared beliefs

Experimental evidences that the belief that others behave in an ingroup-favoring manner is behind the high cooperation with ingroup members, ingroup-favoring reward allocations, and trust in ingroup members.

Example 1: Ingroup-favoring reward allocation in the minimal group experiment (Tajfel et al., 1972)

Minimal Group ExperimentMinimal Group Experiment (Tajfel et al., 1971)(Tajfel et al., 1971)

・ Ss are divided into two group on a trivial criterion. Preference of Klee and Kandinsky, estimation of the number of dots on a slide, etc.

・ There is no interaction within group members, and there is no conflict of interest between the groups.

・ Each S allocates rewards (money) between one “in-group” member and one “out-group” member.

・ Ss in such minimal group experiments often allocated more money to an in-group member than to an out-group member.

Social categorization alone produces in-group Social categorization alone produces in-group favoring behavior.favoring behavior.

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Money allocated to an ingroup and an outgroup member (out of 500 yen) by Ss who were also a target by other subjects' allocations (Target Condition) and those who were paid a fixed amount (Not a Target Condition)

The belief that others behave in an ingroup-favoring manner is behind the ingroup-favoring reward allocation in the minimal group experimentminimal group experiment (Karp et al., 1993)

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The same result was replicated by Jin,Jin, Yamagishi & Yamagishi & Kiyonari (1996)Kiyonari (1996)

The belief that others behave in an ingroup-favoring manner is behind the ingroup-favoring reward allocation in the minimal group experiment minimal group experiment (Karp et al., 1993)

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Furthermore, only those who expected their favors to the ingroup member to be reciprocated practiced ingroup favoritism.

The belief that others behave in an ingroup-favoring manner is behind the ingroup-favoring reward allocation in the minimal group experiment minimal group experiment (Karp et al., 1993)

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Cooperation in one-shot PD Cooperation in one-shot PD with an in-group partner and with an in-group partner and an out-group partner an out-group partner (Cooperation rate: proportion (Cooperation rate: proportion of the endowment of 100 yen of the endowment of 100 yen given to the PD partner).given to the PD partner).

The belief that others behave in an ingroup-favoring manner is behind the high level of cooperation with ingroup members (minimal groupsminimal groups) (Jin & Yamagishi, 1997)

Ingroup favoring cooperation typically observed in earlier experiments was replicated in this experiment; Ss were more cooperative when they played with an ingroup member than with an outgroup member.

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However, ingroup favoring behavior did not exist when the ingroup partner did not know that the subject was in the same group.

The belief that others behave in an ingroup-favoring manner is behind the high level of cooperation with ingroup members (minimal groupsminimal groups) (Jin & Yamagishi, 1997)

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The same pattern was obtained by Kiyonari (2000)Kiyonari (2000) more clearly.

Whether the partner was Whether the partner was an ingroup or an an ingroup or an outgroup member did outgroup member did not matter not matter unless unless the the player could expect player could expect ingroup-favoring ingroup-favoring behavior from otherbehavior from other in- in-group members.group members.

The belief that others behave in an ingroup-favoring manner is behind the high level of cooperation with ingroup members (minimal groupsminimal groups) (Jin & Yamagishi, 1997)

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Nationality (Japanese versus Australian), not the minimal group

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Japanese Data Ingroup=Japanese

Outgroup=Australian

Australian Data Ingroup=Australian Outgroup=Japanese

The belief that others behave in an ingroup-favoring manner is behind the high level of cooperation with ingroup members

The belief that others behave in an ingroup-favoring manner is behind the group-based trust (Foddy, Platow & Yamagishi)

Ss (students of La Trobe University) had a choice between two “dictators,” one from the same school and the other from Melbourne University.

Each “dictator” was given AUD16.00 to divide freely between him/herself and a “recipient.”

In the unilateral knowledge condition, Ss (recipients) knew the group membership of the “dictator” but the “dictator” did not know the recipient’s group identity.

In the mutual knowledge condition, both the “dictator” and the recipient (subject) knew their group identities.

The belief that others behave in an ingroup-favoring manner is behind the group-based trust (Foddy, Platow & Yamagishi)

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Trust in the ingroup member is based on the belief that ingroup members’ behavior is guided by the naïve theory of groups!

Do people ever behave in ingroup-favoring manner without the expectation that other members of the group behave in a similar manner?

The game theoretic analysis predicts that it is not likely.

Identification with the group alone—i.e., the cognition that one shares a marker with the other members of the group—cannot make people sacrifice their self-interest for the group.

How about the possibility that the maker works as a surrogate of something that makes people unconditionally cooperate?

Remaining IssuesRemaining Issues

Surrogate of a kin group?Not likelyThe adaptive advantage of using “group-ness” as a surrogate of a

kin group depends on the balance between two types of errors.

Type 1 Error: To mistake a kin member as a non-kin.

Type 2 Error: To mistake a non-kin as a kin.

The use of the surrogate reduces the Type 1 error with the cost of increased Type 2 error.

The need for the surrogate is strong when the kin members are remotely related. The benefit of reducing Type 1 error quickly diminishes as the kin-relatedness becomes weak.

The advantage of reducing Type 1 error is the minimum when the need for the surrogate is the strongest.

Remaining IssuesRemaining Issues

The marker as a surrogate of what?The marker as a surrogate of what?

Surrogate of a community?Not likelyUnconditional altruism for the community is fitness-reducing.

Remaining IssuesRemaining Issues

The marker as a surrogate of what?The marker as a surrogate of what?

How about when the community is the unit of group selection?Intergroup competition and the war

The incentive structure of intergroup competition, in particular, war, is the Assurance Game rather than a PD. It is basically a coalition formation to win. If the coalition is likely to win, joining is a better choice. If not, not joining is a better choice.

Unconditional cooperation is fitness-reducing

The logical analysis tells us that unconditional altruism toward others who share the same marker is fitness-reducing.

And yet, we seem to have unconditional “fondness” toward people who share a marker.

From the logical analysis, it is not likely that the fondness of ingroup members is a part of the psychological mechanism that promote unconditional cooperation (or altruism) toward ingroup members (i.e., those who share a marker).

It may be a mechanism that make people choose ingroup members as their interaction partners attachment

Remaining IssuesRemaining Issues

Cooperation versus Attachment?Cooperation versus Attachment?

We need to conduct a logical analysis specifying how attachment to the group (a collection of people who share a marker) promotes fitness.

Selective game paradigm is more appropriate device than the forced game paradigm to analyze the advantage of ingroup-attachment.

Remaining IssuesRemaining Issues

Cooperation versus Attachment?Cooperation versus Attachment?

Thank you for your attention!