Kin Selection as Group Selection Updated

In the paper I presented in Vancouver, there were three new ideas.  They were new at least to me!  One is that kin selection is in fact group selection: the target of selection in cases of inclusive fitness (I risk my life to save three brothers) is clearly not me.  It is instead the genetic inheritance of my family. 

The second is that in primate groups and especially in our hunter-gather ancestral groups a very sophisticated form of reciprocal altruism is presenting itself.  When the group policies the behavior of the individual members, a social contract is in force.  The parties in this case are not two individuals, as in one animal doing a favor for another when it is likely that the other will return the favor.  A group that protects its members by sanctioning bullies and free riders is enforcing a social contract between the individual and the group itself. 

The third idea is that the once the group protects each individual within it, one of the things that can be protected is the access of each individual male to his mate.  This is, effectively, the social construction of marriage.  It seems likely that the nuclear family as we understand it is a product of the emergent social contract.  This is vital because, once it happens, the group can recognize not only the bonds between couples within the group, but bonds that extend beyond the group to the wife’s family. 

Here I discuss the first idea.  Early in Human Evolutionary Psychology (Louise Barrett, Robin Dunbar, & John Lycett) group selection is briefly considered and summarily rejected.  It is only the fitness of individuals that counts in natural selection.  Almost immediately the text complicates the matter by considering the selfish gene argument.  I will argue that it is complicated in the other direction as well. 

These are the basic models for the evolution of cooperation.  Kin selection (or inclusive fitness) indicates cooperative behavior that is selected for because it benefits closely related individuals.  In the paradigmatic example, if I call out because I see a tiger and so save the lives of five brothers, I may get more of the genes that code for my familial sacrifice into the next generation than if I survive and sire children of my own. 

Reciprocal altruism indicates a tradeoff: one individual pays a cost in order to benefit another because it is likely that the cost will be returned.  When one vampire bat shares blood with another because the other be expected to reciprocate later, that benefits both parties. 

Group selection indicates cooperation on the part of a member of the group that benefits the group but not necessarily the altruist.  Consider a group of organisms bound together and living in a pond.  When they run out of oxygen, the group must rise to the surface.  Producing the substance that allows them to rise requires energy and thus involves a sacrifice.  The sacrifice only pays off if enough individuals make the sacrifice to get the group where it needs to go. 

What occurred to me as I was writing this paper is that in all these cases, the target of selection was more than one individual.  The term “target of selection” indicates the actor whose behavior or trait was selected for.  If a well-camouflaged insect avoids predators and so successfully mates and reproduces, we can say that individual was the target of selection. 

In cases of group selection, the group is by definition the target of selection.  It is the fitness of the group that is favored by natural selection; individual members benefit only in so far as they are along for the ride. 

The same is true, however, for reciprocal altruism.  Consider the case of cleaner fish and their predatory clients.  The former consumes parasites off the skin and jaws of the latter.  Each must give up something: the cleaners eat only the parasites and not the healthy tissue; the predators refrain from eating the cleaners.  What is the target of selection in this case? I submit that it is the alliance.  Together they are selected for; divided they are selected against. 

In the case of kin selection, the target is not the individual who calls out the warning, for she is more likely than the others to attract the predator’s gaze.  Nor is the target of selection any individual sibling or cousin.  According to Hamilton’s rule, cooperation among kin can be selected for when c < rb.  Here c is the cost of the cooperative act, measured in the probability of successful reproduction on the part of the cooperator.  If a certain action is likely to result in reproductive failure one out of four times you do it, then c = .25.  If reproductive failure is almost certain (I charge the lion to save my brothers and sisters) c = close to one.  How closely I am related to the individuals I am taking a risk for is r.  Siblings are .5.  How many siblings I am saving is the benefit, or b. 

This explains the paradigmatic example deployed above.  If I sacrifice my life to save three brothers, then 1 < .5 x 3.  What is key here is that the target of selection, the T whose reproductive success is being selected for, is not any individual.  The target of selection is the family. 

Two things stand out for me.  One is that kin selection seems to provide a very limited selection pressure in organisms like ourselves (as opposed to social wasps, bees, and ants).  For siblings, r = .5; but for cousins it is only 12.5.  Only if the clan were a very strong institution, so that such a sacrificial act could reliably benefit a large number of relatives, would it be able to work. 

The other is that it runs into some of the same problems that group selection models face.  In the latter, the altruists in the group enable the group to grow larger due to their sacrifices; however, non-altruists in the group benefit more since they are making no sacrifices.  Eventually, the cheaters will outnumber the altruists and the system will collapse.  This is why many theorists suppose that group selection cannot work.  To make it work, you need mechanisms that enable altruists to find each other and to exclude cheaters. 

Kin selection is supposed to be more reliable because I can be more certain who my real siblings are and so my sacrifice will promote the genes that code for my behavior.  How reliable is this?  Only once the family is institutionalized can I have a good idea who my brothers and sisters are.  If the nuclear family emerged first in the course of human social evolution, and human beings were more rather than less monogamous before they joined together in larger units, then kin selection might have been the original driving force in that social evolution. 

If, however, the family is the product rather than the cause of our evolutionary trajectory towards political animals, then kin selection is a much less significant (which is to say, not insignificant) factor in that trajectory.  Aristotle was surely correct to say that human beings are more a coupling than a political animal, since that is true of all sexually reproducing vertebrates.  Coupling, however, does not mean “familial”.  Kin selection presupposes and therefore cannot explain the emergence of a coherent family unit.  

Aristophanes on the Family

Here’s a chicken and egg problem: what comes first, the family or the political community? This is one of the questions I have been working on.  I presented a paper on the subject in Vancouver and I will present a more elaborate version of the same this fall in San Francisco. 

Aristotle supposed that the family is more natural than the polis, for human beings are more a coupling animal than a political animal.  An alternative view is presented by Socrates’ greatest critic, Aristophanes.  In his best play (by my judgment and his) the Clouds, Strepsiades has gone into debt because of his son’s love of horse racing.  The father comes up with a desperate solution: send his son, Pheidippides, to study with Socrates.  The philosophers, he hears, can win any argument and someone with that power can defend him in court against his creditors.

He wants his son to go learn this art but Pheidippides refuses.  Strepsiades goes himself.  Socrates’ curriculum consists of two parts.  One is the rejection of the traditional Athenian gods.  The second is a rigorously scientific account of language and nature.  Strepsiades flunks out because he cannot grasp the second part but he leaves having learned well the first part.  More desperate than ever, he forces his son to enter Socrates’ school.  Pheidippides is the better learner. 

After his son graduates, Strepsiades thinks he has a get out of jail free card.  When his creditors show up for their money, he abuses them and sends them packing.  The moment of triumph is short lived.  When father and son quarrel over an obscene bit of poetry (involving incest between a brother and sister) Pheidippides physically assaults his father.  Strepsiades runs out of the house screaming for his kinsmen and neighbors to defend him, but no one comes.  His contempt of the gods and of the laws has effectively broken the social contract. 

Pheidippides offers to demonstrate to his father than his actions are just.  If a father can spank his son it is because the father is wiser, right?  So, if the son becomes wiser can he not return the favor?  Strepsiades is stopped short by this.  As distressing as his situation is, he can see the reason in his son’s words.  Then Pheidippides goes too far.  He says he can beat his mother too. 

At that point, Strepsiades explodes.  For the first time, he gets to the point before anyone else.  If a son can take liberties with his father because wisdom is the only basis of authority, that is one thing.  If he can take liberties with his mother…  the horror, the horror.  Strepsiades calls the gods to his side and goes to burn down Socrates’ house. 

I submit that the Clouds is a profound reflection on both philosophy and the family.  Human communities, both the familial and the larger political one, are grounded in cherished opinions about the gods and morality.  Philosophy is the attempt to replace opinions about the most important things with knowledge.  There is no guarantee that the knowledge that the philosopher seeks will support, rather than undermine, the familial and political bonds.  Thus, philosophy is potentially subversive of everything the father and citizen holds dear. 

Aristophanes’ genius here was to recognize that the family depended on the polis.  The authority of the parent may make sense on the grounds that adults know better than children what is good for the latter; however, the authority of the parent relies heavily on the fact that the parent is larger and stronger than the child.  As the son grows bigger and stronger, the father will have to rely on the community to preserve his authority should the son challenge it. 

In Aristophanes’ account, the political community is more fundamental than the family.  The latter can exist only so long as the community supports and enforces its taboos.  I think that this is correct.  Human beings are, as Aristotle said, coupling creatures.  The natural instinct of the male is to come together with the female.  It is not that, however, that makes a family.  For the familial community to be sound, the father must have some reason to believe that these children are his children.  For that, he must have some exclusive claim on his mate.  To understand the family, one must understand the political community that enforces these claims. 

Causation, Consciousness, & Free Will

One of my earliest memories is standing next to my childhood home, in a gap between shrubs where a garden hose was connected to the faucet.  I was staring at the reddish brick that covered three corners of our house and I seemed to go into a trance.  All I remember is that the experience was very pleasant and I wanted it to go on.  It didn’t.  My father came up behind me and barked out some order.  I was ripped out of the state and I turned and stuck out my tongue at him.  Those were the days when such a gesture stirred the familial gods into action. 

Dad grabbed me by the collar and swatted me two good times on the butt.  I remember thinking that I could not explain to him what had happened.  I also remember him saying “next time you better stop and think!” 

There is a lot to chew on in that memory.  Here, I will only focus on my father’s understanding of responsibility.  It lies in the ability to disengaged from the chain of causation.  One state of mind leads naturally to an action.  I am enraged, so I swing the club.  I am responsible for the action because I am capable of stopping and thinking.  I can step back from the momentum that includes all the psychological forces and the context that is funneling them toward the action and decide to act or not. 

I have for a long time believed that free will is rooted precisely in that ability and that consciousness is precisely the power that allows us to exercise it.  All the automatic processes that make up our biological activity‑e.g., intracellular mechanics and the response of heart rate to physical activity‑are flexible only within built-in parameters.  Consciousness is something different.  It can respond in creative ways to both familiar and novel situations. 

I am tempted to do something (eat this, cuddle with her, etc.).  How is it that I decide not to do it?  One explanation is that contrary inclinations arise from my social conditioning, which works on my evolved inclinations.  Just as a stool supports my butt because its four legs push towards its center, so I keep to my diet and avoid adultery because the balance of forces pushes in that direction.  It is easy enough to model consciousness as only a sophisticated system of monitoring.  My becoming aware of food is analogous to my thermostat responding to a change in the room’s temperature. 

The problem with that explanation is that, if it were true, there would be no need for appetites and emotions.  An autonomous biological machine could balance inputs to produce outputs (actions) without any need for pain and pleasure, fear and love.  Such a machine would, however, be much less flexible than one that was genuinely free.  An organism that is free is unpredictable and not limited to previous responses and strategies.  It can do whatever the Hell it pleases. 

A conscious animal might do anything within the limits physical capabilities, including range of motion and spectrum of perception.  That freedom, however, needs to be harnessed by the forces of natural selection.  The animal exists because its ancestors existed.  It can do anything it wants but it has to want to do what will promote the successful reproduction of its kind if its kind is to be communicated across time.  Since it is conscious and therefore free to do or not do, it had to be bribed with appetites and passions to do what promoted its successful reproduction. 

This is, in my view, the only plausible explanation for genuine consciousness.  All organisms, conscious or not, are constantly trying to do something.  The vine climbing the wall is trying to reach the sunlit stones.  The spider crawling across the table is up to something.  We cannot understand organic activities without a dimension of value.  The plant will flourish and flower or wither.  The spider will feed and mate, or not.  Only conscious animals will have good and bad days, satisfying or wretched lives. 

The only alternative to this explanation is epiphenomenalism.  According to this view, consciousness is only an accidental product of neurological processes.  All the effective causation is going on below the level of consciousness.  We become aware of our decisions only after they have been made by our subconscious brains.  There are two reasons why I find this very implausible.  One is that involves an effect with not consequences.  It would be very odd that this amazing phenomenon, consciousness, is a result of causation but produces not consequences of its own. 

The bigger problem is that it seems to recapitulate Cartesian dualism.  On the one side, you have all the effective mechanisms that operate in the physical brain.  On the other, the mind that is fooled into thinking that it plays a causal role.  Causation flows only one way, so there is no interaction problem and I am not sure that this is logically incoherent.  Still, it is very weird.  It would be analogous to trying to explain the movie industry while resolutely insisting that what shows up on the screen has no part in the explanation. 

We can be reasonably certain, I submit, that the elements of our consciousness‑sensation, emotion, and deliberation‑have a causal role in our behavior.  Free will and moral responsibility are emergent products of our mammalian evolutionary inheritance.  I don’t think that this necessarily requires a metaphysically robust doctrine of free will.  One might well wind all of this back into a deterministic physics.  But then I regard deterministic physics as conceit of the early moderns. 

Free will is analogous to the clutch on a standard transmission.  It allows us to disengaged and make a decision.  We can stop and think before we plow ahead.