Norms and Development: Interdisciplinary Approach

Week 3

Explaining Social Norms II:

Cultural-Evolutionary Approach

Meme: A Culturally Transmitted Trait

Used by Richard Dawkins in his first book, The Selfish Gene (1976).

Culture is not the specialty of social scientists anymore. It is an important research topic among biological scientists, too…

Yeah, But Is There Anything New?

Socialization and social learning are quite big issues in both social and psychological science, and have been investigated for a long time.

The term such as meme is just the different word meaning the same thing social scientists have discussed so far.

Is there anything new we can learn from biological scientists about culture?

Can you keep the same opinion

even after attending

the current and the next seminars?

If you have/had such an opinion, let me challenge to you.

What's the Problem We Faced?Step 1. Norm-compliance vs. violationStep 2. Punishment vs. free-riding

Except for some cases (i.e., communal sharing, small closed groups), evolutionary-perspective cannot explain the punishment of norm-violations.

As long as we consider the problem of social norms under the evolutionary framework, there may be no way to solve the problem…

Should We Retreat to Where We Escaped?

We discussed the importance of non-selfish psychological mechanisms such as shame, guilt, and (a propensity of) internalization of norms.

In evolutionary-perspective, these mechanisms may be defined as "norm-compliance where no punishment exists." However, norm-compliance per se cannot survive without punishment…

If we permit the existence of non-selfish psychological mechanisms a priori, we will close the way escaping from the disorder we found in the readings…

Cultural-Evolutionary Perspective

Let's change our focus from social norms to psychological mechanisms that enables us to acquire social norms in general; shame, guilt and a propensity to internalize norms are now separately defined from norms.

Instead of just assuming their existence a priori, we ask where these psychological mechanisms come from they are assumed to be the product of genetic evolution.

Evolutionary-Perspective:First-Order Approximation

Ti Ti+1

Evolutionary processes

Ti+2

Evolutionary processes

Trait at the time i (Ti) is selected by evolutionary processes. Adaptive traits spread in a population over generations.

Cultural-Evolutionary Perspective:Second-Order Approximation

Pi

Psychological mechanisms (Pi) determines which trait is culturally acquired by individuals. Evolutionary processes works on psychological mechanisms but not on traits.

Ti+1

Pi+2Pi+1

Evolutionary processes

TiCultural

transmissionTi+2

First-order approximation is often very useful as it is simple and parsimonious principle.

However, we have to shift to more precise second-order approximation if necessary.

For the researchers with life-span perspective, furthermore, cultural-evolutionary perspective provides much more intriguing ideas. Wait for the next week…

The Logic of Cultural-Evolutionary Perspective on Social Norms

Psychological mechanisms that make people acquire even fitness-reducing behaviors have evolved as they are adaptive. Such mechanisms may help social norms spread in a society.

At the moment, it is open questions why such mechanisms have evolved and how they help cultural transmission of social norms. For investigating the above logic, let’s move to the report on Gintis (2003).

Henrich & Boyd (2001; JTB):Another Cul-Evo Model of Social Norms

Boyd & Richerson (1985) and Henrich & Boyd (1996) showed conformity transmission bias is an evolutionarily adaptive trait.

They implemented this bias in the game of social norms. They assumed that individuals culturally acquire either norm-compliance or violation.

With the probability of α(<0.5), individuals acquire majority’s behavior (conformity-bias). With the probability of (1- α), individuals acquire beneficial behavior (payoff-bias).

Henrich & Boyd (2001, cont’d)

If no punishment exists, norm-violation is more individually beneficial and spreads by payoff-biased social learning even though majority comply with the social norm (as α < 0.5)…

If no punishment exists, both payoff-bias and conformity-bias in social learning suppress punishers being spread in a society. Thus, social norms cannot be sustained…

What will happen if punishment is common?

Henrich & Boyd (2001, cont’d)

1. If majority of people have punitive sentiment driving them to punishment of norm-violators, it is individually rational to comply with social norms.

2. Individuals with punitive sentiment don’t need to pay actual cost of punishment just because almost everyone comply with social norms!

3. As the actual cost of punishment gets smaller, the force of payoff-bias in social learning also gets weaker. This helps conformity-bias maintain majority’s behavior (i.e., punishment) in a population.

Henrich & Boyd (2001, cont’d)

4. Remember that, so far, we discussed only the influence of social learning. Once social norms are common in a society, Henrich & Boyd further found that genetic evolution may cause genes (!) for a particular social norm (i.e., norm of cooperation) proliferate.

Even though the force of conformity-bias is weaker than payoff-bias in social learning, it can sustain (individually costly) social norms.

Why Socially Harmful Norms are Rare?

The principle of multi-level selection: As within-group variance gets smaller relative to

between-group variance, selection pressure starts to work between groups (Sober & Wilson, 1998).

Conformity bias creates such a situation.

Before the conformity bias works.

B

BB

BB

B

B

BH

H

H

H

H

HH

H

HH

B BH

B

BB

BB

H

H

HB

H

H

H

H

HH

H

HH

H HB

After the conformity bias worked:

B (internalizing beneficial norm) enjoys higher benefit than H (internalizing harmful norm).

Group Selection Eliminates Harmful Norms

If the above situation emerges, members in groups with socially harmful norms may escape from their groups, or they may be disadvantageous in reproduction.

Once conformity bias in social learning reduced within-group variance, evolutionary pressure reduces the meme (or, phenotype in terms of Gintis, 2003) of socially harmful norms.

Finally, we arrived at the first destination of the three-week journey.

The hidden goal of this journey was to convey the idea of gene-culture coevolution taking social norms as an example.

What G-C Coevolution Teaches Us

Some cultural psychologists (and some mainstream social scientists) argue that culture separates us from other animals as it is autonomous transmission process that emancipates us from genetic influence…

If we focus only on a few generations, this argument is perfectly true. If we take much longer time horizon, however, this argument should be modified.

An idea that capacity of (social) learning is evolutionarily adaptive may not be new. It is obvious that ontogenetic plasticity is adaptive. Especially, social learning is effective as it can avoid the cost of trial and error..

Remember that we have already discussed on the first week that social norms are culturally transmitted from family members, peers, etc.

When we discussed about social learning, however, didn’t we implicitly assume that individuals are kind of the blank slate?

As we reviewed the last week, social learning is catch-all word.

What we have learned today is the importance of asking how, when, from whom, and what we (culturally) acquire individuals are not passive blank slates but active imitators.

This seems to be minor question at an individual level. However, it changes societal-level consequences and, subsequently, determines the fitness value of psychological mechanisms themselves.

An idea of gene-culture coevolution requires us, psychological scientists, to investigate the core psychological mechanisms underlying cultural transmission. Just repeating “we have the capacity of social learning/imitation” is not sufficient.

The topic of the next seminar

Summary of G-C Coevolution

Genetic selection is strong but very slow.

Cultural selection is weak but very fast.

Cultural transmission is like a fast runner. He runs and runs and evolutionary process cannot catch him. Though evolutionary process is quite slow, her force is very strong. She influences cultural transmission by changing the road where he will run in future. Mutual influences between genetic and cultural transmission is the key for understanding human beings as social animals.

Further Readings I

Further Readings II

Further Readings III

Li, S.-C., (2003).

Biocultural orchestration of developmental plasticity across level: The interplay of biology and culture in shaping the mind and behavior across the life span.

Psychological Bulletin, 129, 171-194.