EEB 122: Principles of Evolution, Ecology and Behavior?

Lecture?22. The Impact of Evolutionary Thought on the Social Sciences

https://oyc.yale.edu/ecology-and-evolutionary-biology/eeb-122/lecture-22

I?read?widely in how evolutionary thought had impacted psychology, anthropology, political science, economics; all of these cognate fields that have something to do with human behavior, and that bear on the issue of whether or not we have been selected to behave in certain ways in social contexts.?

This is the central claim: That we're stuck in a major evolutionary transition. We're feeling the pain. The pain is caused by the fact that there is a conflict between individual interest and group interest, and that conflict has not been resolved, and the selection mechanisms that have been pushing us in that direction are starting to break down.?This has to do with the impact of evolutionary thought on the social sciences, and its implications for understanding what we are.?

• Now, we are susceptible to lots of other social emotions besides patriotism. We express love, empathy, compassion, guilt, shame, embarrassment, duty and honor; and we do it by the age of three.?It looks like the susceptibility to moral emotions is innate. People who lack moral emotions we call psychopaths, or sociopaths. They commit crimes and end up in prison. We will trust strangers enough to engage in economic transactions; we'll even do it on the web, with our credit cards. That's pretty amazing too.

• It is not clear under what circumstances people can trust each other enough to engage in an economic transaction.?We?are willing to pay taxes to the government, in return for services that benefit the entire country; not just ourselves, not just our relatives.

• If?you look at the major religions of the world, you'll find that their central moral messages are mostly about stabilizing social behavior.?The idea behind this is that things like nationalism and religion are culturally transmitted value systems, and biology is providing handles on which those value systems can pull. And the way it does it is very probably by genetic influence on hormones and their receptors.

• If I want to stabilize trust, I can give people lots of oxytocin, and they'll cooperate and trust each other a lot more than they will if I give them an overdose of something like testosterone.?So testosterone is more or less more aggression, and oxytocin is more trust and cooperation.?We contain within ourselves physiological mechanisms that if genes want to, they can dial up and down like rheostats, and that will have some kind of indirect influence on the general level of either aggression or trust?in a group.?

So my questions about these kinds of problems are, are we in fact stuck in a major transition between individual and group? Has it gotten stuck because the selection mechanisms have broken down? Has the breakdown left us in a state of tension, caused by conflicts between individual and group? And do these individual group conflicts define a significant part of the human condition??

You can ask yourself, well what would happen if we really went right through the major transition??

• Eusocial insect colonies have gone through this transition; and they are defined by reproductive suppression. So if you were living in a state in which the opportunity to reproduce was in fact determined by the group and not by the individual, that would probably be a pretty strong signal that you had completed the transition. We're nowhere near that at the moment.

• However, we are certainly in a circumstance in which some of that happens. The Chinese One-Child Policy is an indication of that. The sort of political correctness of the environmental movement that encourages people towards zero-population growth and only having two children is that kind of thing.

In a major transition, things that were previously independent fuse into a larger whole and lose their independence. Then units in that larger whole specialize on different functions; they achieve a division of labor. That division of labor has to be stabilized, and it then integrates the new unit and improves performance, in competition with like units. And the cohesive integration, that's needed within the group, requires suppression of intra-group conflict, among previously independent units, so that you can be effective at competing with other similar groups. Often during this process a new system of information transmission will emerge.?

• This is something that's happened four or five times in evolution: prokaryotes to eukaryotes; single-celled eukaryotes to multi-cellular organisms; multi-cellular organisms into family groups; family groups into insect societies; and in mammals into naked African mole rats and dwarf mongooses, things like that.

• And in humans the new system of information transmission is cultural transmission, with language. So we now have a parallel genetic and language transmission of information, and they can be in conflict with each other.?

So to see if these ideas make any sense, we need to evaluate hierarchical selection. That sets up conflict between individual and group. We need to see what kind of cultural group selection might be going on, to select for cohesion, promoting group performance. We need to see how conflicts are generated and resolved, in a selective hierarchy; so the origins of group cohesion.?That brings us to the contentious subject of whether there are tribal social instincts and how they might originate.?

• Here are the basic issues in hierarchical selection. The thing you need to focus on is the distribution of variation within and among units.

• So if most of the variation in the population is within each group, and the groups don't differ too much from each other--they're all kind of motley, but they're all similarly motley--then you won't really have very much opportunity for group selection.

• But if the variation in the population is homogenous within groups, and different between groups, you have a much bigger opportunity for group selection.

The strength of selection?is going to be determined by the rate at which units are born and die. So if the little units, inside the groups, do things very rapidly, and the big units, the groups, do things very slowly, then that's going to prejudice things towards the individual and away from the group; and vice-versa. Then you need to look at the correlation of reproductive success?with trait variation at each level.?

• So if, within a group, a new social norm arises, it can spread through that group and homogenize that group pretty rapidly, simply because we are creatures that learn rapidly, and we imitate others, and we respond to social pressure, and to things like political correctness. This is essentially a description of the spread of political correctness.

• You can accelerate that spread with moralistic?or?altruistic punishment. That's benefited everybody in the group, at my cost. If there is any selection for people who behave that way, who go around and point fingers to?accelerate the spread of social norms, and rapidly make them uniform, within groups.

• Now part of the process of cultural group selection would be the extinction of a group, or the reproduction of a group. And the extinction of a group culturally doesn't require biological group extinction.?

Now the genetic differences between early human groups probably were long enough- large enough for lethal inter-group competition to account for the evolution of altruism and cooperation within the groups. In other words, we all have to band together, because if we don't cooperate with each other, those guys next door are going to wipe us out.?

And the necessary condition for that, in the theoretical models, is reproductive leveling within groups, that's generated by food sharing beyond the immediate family, that's generated by monogamy and generated by other cooperative means.?

Whether or not there were conditions that would tend to take the selfish Darwinian model of short-term selfishness--homo economicus;?strictly short-term, selfish, rational--and tend to convert that into a person who is more socially empathetic and more cooperative, at least within the immediate group.?

Well we would very much like to know, if this is going on, how a social norm, like food sharing or monogamy, gets fixed in a group. Culture is very real. Cultural transmission is there, and it's important, and it's different from biological genetic transmission.?So that one of the things that happened is--language and cultural transmission emerged in the human lineage, and became important probably between about 100 and 50,000 years ago--is that this process could start.?

• How does a norm spread through a group? How does something like that propaganda spread through a group? Well we have--and this is one of the places where perhaps biology is providing a handle for culture--we have a number of learning mechanisms. One of them is to copy the successful, the dominant, the frequent.

• The whole point of education is to try to keep you from having to learn everything by trial and error, so that you don't have to repeat all the mistakes of all of the previous generations of all the humans who ever lived, in order to get to a certain state of enlightenment.?But that won't explain the spread of an individually costly norm, like me trying to punish somebody for violating a social norm.?

One can punish defectors from group norms, even if it costs you. That's a very powerful force, and it's powerful enough to overcome inherited biological tendencies. So it's powerful enough to explain why we get celibate nuns and priests, why we get to declining birthrates, why we get other things that reduce lifetime reproductive success.?

How do we get it? Well it's not clear how altruistic punishment might evolve, and under what conditions it would be stable. You need to have pretty strong inter-group conflict for it to work. And why would that happen? Why would we get altruism??

So how can you resolve that kind of conflict? Well there are actually a lot of ways to do it. I've mentioned some of them already, in the course. You can convert individual stakes into common stakes, so that whatever an individual is going to get, out of living its life, is going to be identified with whatever a group can get out of performing better.?

Ecological constraint can be imposed on the group; the threat of outside risk will stabilize interactions within a group. One can cooperate with and sacrifice for kin; that's?kin selection. You all now know how that works. You can punish defectors; that's the punishment of violators of social norms, altruistic punishment.

You can stabilize the division of labor; that will certainly reduce conflict, by making sure that say all the people who are making shoes are not in conflict with all of the people who are making shirts. They're actually cooperating with each other; they're each making something that the other one needs. It's win-win, for them.

You can promote reciprocity. There could be cultural norms to promote reciprocity, and that is the basis of trust; and trust is the basis of cooperation.?

How to?convert separate stakes into common stakes? You randomize success. That's meiosis in the parliament of the genes. Once you set up a mechanism that means that every single gene in the genome has the same probability of getting into the next generation, then that is a structure that imposes homogeneity of success, on all of those genes. Meiotic drivers violate it, meiosis stabilizes it.?

• At the cultural level you can homogenize success with monogamy. So we have the Chinese One-Child Law. You can share food with non-kin. And if competition within a group is not an option, then the only path to better performance is the performance of the whole group. So that's the rising tide lifts all boats part of it.?

• You can cooperate with and sacrifice for kin. So multi-cellular organisms integrate very easily, because they are clones that originate in a single cell. So they're all 100% related to each other. And you can see the division of labor here, between the chlorophyll producing cell, cells that are producing carbohydrates and cells that are going to be actually reproducing that group.?

• It's well known, from anthropological work, that many hunter-gatherer groups consist mostly of close kin. There are interesting analyses of asymmetries in that, and there's big controversy over some of it. But it is nevertheless?a pretty safe broad generalization that many human groups consist of close kin, and therefore we can expect that kin selection has been operative, and that it has been promoting cooperation, altruism and sacrifice.

• You can punish defectors, and in a multi-cellular body one can, for example, eliminate the defecting cancer cells through apoptosis. So there certainly are ways that the immune system does attack, and partially succeeds in controlling cancer cells. And in social groups one can punish those who break social norms.

• You can stabilize the division of labor. In biology that's done with epigenetic mechanisms; epigenetic information is what stabilizes development and makes sure that brain cells stay brain cells, and liver cells stay liver cells. And in culture we've got things over history, like guilds, classes, castes, professions, job descriptions. There are all kinds of ways that the division of labor gets stabilized culturally.

• You can promote reciprocity. In evolutionary biology it's much easier to promote reciprocity in a two-dimensional surface where people are playing against their neighbors, than in a very well mixed kind of liquid. That's the basic take-home message of Martin Nowak's work on the evolution of cooperation. And a way to stabilize reciprocity culturally is through win-win economic exchange. So transactions in which both sides profit; that's the basis of business.?

So lots of ways to resolve or suppress conflict, but there are some problems. If you're going to stabilize conflict within a group, you very probably need a leader. You need the leader both to direct the collective within the group, and you need the leader to basically take over foreign policy to deal with extra group relationships. And in the multi-cellular body, that's been done by the central nervous system, and in the emerging social group, that's done by something like a president.?

• Well this guy wasn't selected at random, and there are some issues. Groups need leaders. A psychological predisposition to defer to authority is what would permit a strong, unrelated leader to emerge. You might trust your dad or your uncle, but the issue here is why is it that in groups humans actually will trust somebody unrelated to lead them? That's, in other words, going beyond the kin selection model.

• Deference, which may have evolved--this may be one of the human social instincts that's kind of a handle on which culture can pull--deference to leadership will let a selfish leader exploit the public. And selfish leaders invade. They've got to be controlled, while they're leading.

• A group that constrains its leaders to pursue public interest will have a competitive advantage, because they will be internally cohesive. If you have a long series of defecting leaders who are corrupt and who subvert the public interest, you will have the breakdown in social reciprocity and trust. The?defection is a recipe for the creation of a failed state. Nevertheless, leaders are motivated to defect, if they're selfish.?

So there's a problem with defecting leadership. And when you think about that, you think about deference, patriotism, empathy, trust; where do those emotions come from? Where did guilt come from? Why do we get embarrassed?

Now outrage at defection, where does that come from? Why do we want to punish defectors? We're very sensitive to defectors. We're very, very sensitive to people who deceive us. Why do we have a desire for revenge? Often that is a spiteful, self-defeating kind of a thing. Why do we have an impulse to conform? There's been lots of good psychological studies on this one; we have a frightening impulse to conform.?

Well the tribal social instincts hypothesis, that Richardson and Boyd have advanced, attempts to explain this kind of thing. They claim basically that gene culture co-evolution built social imperatives into our genes; that genes use hormones that create emotions?that manipulate our phenotypes; and that those emotions then are the biological handles on which culture pulls.?

That would be an assertion that our minds are not blank slates, and that we entered the world partially pre-programmed, and that some of the programming is for social interactions. That's a big claim. There's some evidence.?It seems that for social emotions, biology is important, culture does make a difference. Biology is providing a principle; culture's setting the parameters. That's kind of like language, the way that Chomsky thought of it.?

And it looks like we display a lot of symptoms of group adaptations. The mechanisms that might have selected them are plausible; they're not yet strongly supported. So are we going to fuse into a group identity, or are we going to remain torn between private interests and those of the group to which we belong, which is our current state??

• When we went from transition- when we transitioned from hunger-gatherers into agricultural settlements, the relationships among group members decreased, group size increased, and the average encounter was no longer with a relative but with a non-relative. That's a big city.

• Now we then started getting engaged in large-scale economic exchange, and it both reinforces and erodes cultural group selection. So exchange within groups promotes group cohesion; exchange among groups erodes group boundaries. This is a diagram of global trade a few years ago; the width of the arrows is how much is flowing. It shows, as the current economic crisis just shows so clearly, that we are now globally integrated by economics. So group boundaries are being strongly eroded by globalization.

Our group identity is now multi-dimensional. So it used to be, if you were in a hunter-gatherer band, or even if you were in a medieval guild, that your ethnicity, your religion and your politics pretty much overlap. But it's now possible for people to belong to different dimensions of identity, all at the same time.?

And that didn't used to be possible. Those things are now breaking apart. So the power of cultural group selection is decreasing, because these things are not adding up to push all in the same direction; they're pushing in different directions.?

In the evolutionary social sciences, by which I mean basically economic psychology and political science, we're stuck in the major transition between individual and group. There's quite a bit of support for that. The transition stalled, and the breakdown has left us in a state of tension.?

But, these conclusions are supported by plausibility arguments, and these plausibility arguments basically only achieve the level of consistency with the evidence. Consistency is a weak logical criterion. There's a lot of stuff that's consistent, but not necessarily true. It is much more difficult to demonstrate necessity and sufficiency. Basically to do that, you have to take the Social Sciences and transform them into the Natural Sciences, with the same standards of experimental demonstration and admission of evidence.?

Well that is a long-term, big project. That's not easy. So I say that, at the end, because I don't want to leave you with the impression that this idea, that we're stuck in a major transition, is well established. I think that it is consistent with the evidence that I know of, but I don't think the evidence is strong. And of course, down in my gut, when I take off my scientist hat, and my teacher hat, and I am sitting there alone quietly at 2:00 in the morning, in my house, thinking about this, I think it's probably true.