Section III: Group Selection, Fitness, and Cooperation
Group Selection
In the long term, we are all dead - Lord Keynes
It is an article of religious faith among biologists that individual selection is more important than group selection. There are a lot of ways of evaluating the truth of such an article of faith. We have looked at some of them already. If we start by assuming a species with continuity through endless time, one such as... well any good biologist, I am sure, can find a host of species that has existed forever - take one such species and individual selection can be said to completely account for the properties of this species' individuals. There simply is no other way to look at it.
But suppose we relax the condition of temporal continuity for a species. What if occasionally a species were to go extinct. Imagine an extinct species such as the dodo. Once it is extinct, certainly, it is impossible to posit that individual selection is at work. There are no individuals, there is no selection.
Now, imagine two species inhabiting the same biological niche. By definition they compete. It is axiomatic that either the groups will diverge and exploit subtly different strengths, these differences magnified over time in ways that would not generally make sense in the absence of such competition, or one of the species will go extinct. The very long list of extinct species suggests that sometimes species do go extinct. A person standing outside the field will find it very puzzling logic indeed, if extinction of a species does not count as a kind of selection process. Nor is it meaningful to think of such a process of competition between species as individual selection. Individual selection is - or properly ought to be - thought of as occurring between members of the same species.
Let us assume that sometimes whole groups of individuals - families, clans, tribes, subspecies, or species - die out for some reason. Perhaps they are destroyed by predators or parasites. Perhaps they have specialized to exploit one particular food source and that food source becomes unavailable. Perhaps a species that is better adapted for some reason occupies their ecological niche and pushes them out of existence. Perhaps they multiply too fast for their ecological niche, exhaust the resources, and perish.
It is tempting to believe that all the reasoning about group selection takes on a bias that could only arise in a frontier culture in an overly successful species. Suppose one were a prominent evolutionary biologist, but one just happened also to belong to an endagered species; the gorilla, for instance. As an evolutionary biologist, one would see the dwindling number of one's own species, and one might reason by extension of one's own condition that all species go extinct; therefore, group selection was a powerful force in evolution. From the gorilla's point of view, there really is not much hope. Natural habitat is shrinking, food is becoming more scarce, and predation is becoming a significant problem. When the gorilla is extinct, it will be incumbent upon biologists to explain the phenomenon in terms of natural selection. If one might be able to do so in terms of individual selection, it seems that any such explanation would seem contrived compared to one that involved group selection.
To help us think about group selection propose an axiom.
Axiom - Given enough time, all species go extinct.
We present this as an axiom because there is no way to prove it so. Some species are remarkably durable, even highly advanced ones. Crocodiles and allegators might be one example. Certain ferns or evergreen trees might also be good examples. So, too, might certain sea sponges. But history is not over. Nor does the strict truth of the axiom matter much. What actually matters is that we consiously assent to the idea that all species are subject to the forces that cause extinction, and that, in any given time period there is a finite chance that a species will, in fact, go extinct.
Theorem- Given any (sufficiently long) finite time period, t and any species S, with a population n, there exists a finite probability that species S will go extinct, P(n=0)>0.
Proof: suppose that there were some species for which this were not true. It would be equivalent to saying the species could not go extinct. But all that is required for a species to go extinct is that all of its individuals fail to reproduce before they die. For each individual, there is some finite chance that this might occur; therefore, for the whole population there is some finite chance that this might occur. The idea of natural selection is meaningless if this were not true.
We know that some species do go extinct without leaving any descendents. But the continual pressures of adaptation tend to drive change in all species. Thus, if we believe Darwin's argument and if evolutionary science has meaning, some species give rise to other species and go extinct in some definitional or technical sense. So long as there exists life on planet earth, each individual will have descended from some predecessor. At some point in history an individual's predecessor probably can be identified as being a member of an extinct species.
Theorem - Some extinct species leave no survivors.
Proof: The dodo, the sabretooth tiger, and the mastadon are three examples of species that perished without leaving survivors.
Fossil history is full of extinct species. It is impossible to prove exactly in every case which had descendents and which did not. What we do know is that in our own lifetimes, species have become extinct. and they did not leave survivors. It is likely that many, perhaps most extinct species went extinct without producing survivors.
Theorem - Some extinct species leave survivors.
Proof: Imagine that this did not happen. It would require a process of speciation in which one group diverges from a parent group, succeeds in an evolutionary sense, but never has any net competetive effect on the parent group. If they did have some competitive effect, they would drive change in the parent species. And if the competition persisted long enough, the parent species must evolve to the point at which its set of characteristics were sufficiently different from its ancestors that it no longer can be considered the same species. Evolutionary biology assumes this must be the case, else the fossil record is not relevant to understanding evolution.
All that is required for the theorem to be true is that we can identify one extinct species that has living survivors. It is probable that there are thousands or tens of thousands of highly likely candidates. Almost every trait observed in living organisms today can be found in organisms in fossil records. This suggests the heritablility of traits from one species to a descendent species. This strongly suggests that some extinct species have left survivors.
Thus, there are two kinds of extinct species: those that leave living descendents, and those that do not. It seems difficult not to see this as being analogous to what happens to individuals within a species. Just as all species go extince, all individuals die. Just as some individuals leave descendents and others do not, some species leave descendents and others do not. If species are shaped by individual selection, then the set of organisms alive on earth is shaped by group selection.
In an age in which more species have gone extinct due to competition between species than has happened since the end of the age of dinosaurs, it seems fatuous to claim either implicitly or explicitly that the extinction of whole species is not an evolutionary force. Sometimes competition between species plays a bigger role in determining which individuals will inhabit the earth and what their characteristics will be than does competition within a species. Which gorilla succeeds in copulating with a female and passing on his genes to a new individual will prove of little evolutionary importance once gorillas are extinct.
The process at work must be considered a group selection process; because what is going on with groups in this sense, is precisely the same thing as what is going on with individuals within a population of a species. Some groups leave descendents; some groups leave no descendents.
In the time frames humans occupy, there appears to be a great deal of continuity within species. In geological time, however, species come and go much as individuals do within species in shorter time frames. Just as some individuals prove well adapted and others poorly adapted, some species prove well adapted to the environment, others prove less well adapted. It seems that selection between groups is qualitatively indistinguishable from selection between individuals. Nor is it very different from selection between bits of genetic material.
In all three cases, at all three levels there exist two fundamental forces, two framing ideas against which all biological processes can be measured: Competition, and Cooperation. That this is so is is clearly suggested by the fact that almost all kinds of behavior and natural phenomena observed in the process of evolution are so well described by game theory, a mathematical modelling language that quantifies the benefits of cooperative and competitive behaviors and strategies.
In particle motion problems, we find that sometimes the analysis proceeds most naturally by using kinematic descriptions. In other cases we find that analysis is simplest if we use energy methods. Sometimes momentum analysis is most productive. These are different analytical techniques one brings to bear on a common type of problem. Similarly, in evolutionary biology, it is sometimes useful to think in terms of individuals. It is sometimes useful to think in terms of genes or groups of genes. It is sometimes useful to think in terms of populations. Religious points of view that focus on one to the exclusion of others are counterproductive.
The Question of Fitness
It is impossible to talk about Williams’ thought experiment
without discussing the conception of fitness. Williams’ thought experiment is consistent with a point of
view that
a)
one might conceive of a singular measure of fitness, and
b)
that singular measure of fitness might be expressed fully in a
single individual.
If either a or b is false, then Williams’ view of the world
crumbles, because while it may be individuals who are the vectors of population
fitness, a rather large number of individuals taken together is required to
embody this fitness. Bear in mind
that it is assumed that roughly 10,000 individuals are required to embody all
the genes in the human population. That is very tiny compared to the whole population, but is very huge
compared to the genetic impact an individual has.
When the environment challenges an organism repetitively in the same or in very similar ways, there may be particular competencies that are good proxies of fitness. And one might imagine some individuals as representing differential levels of fitness with respect to some such fixed challenge. When this is the case, one might be able to create a functional definition fitness in terms of a very small number of characteristics. Darwin's thesis is developed in terms of such situations. But the reason for making this choice is not because there is a single measure of fitness, but because it is logically far more difficult to carry Darwin's argument on the basis of a wide variety of physical traits that predispose an individual for success.
But in a world where one might conceive a large number of
challenges, there must be a large number of competencies. One must then also
imagine a large number of measures of fitness. The issue of what might be meant by the term ‘fitness’
requires some exploration.
Darwin painstakingly described special features of hundreds
of animals across a wide range of classes. He observed how their specific and notable features related
to observable functions. He noted
how those specific functions aided in survivability. And he observed how certain features were inherited. He
invented the idea of evolution as the process of speciation. Then he used these observations to pose
the theory that sexual selection was primarily responsible for the path that
evolution took in local populations.
Darwin observed that striped caterpillars and asked, “Of
what possible use are those stripes?” The answer turned out to be, “Striped caterpillars taste bad to
predators.” Thus, predators learned quickly to avoid them as a source of food. He observed long, tubular flowers and he asked “Why not short
flowers with easy access? ” The
answer turned out to be “Special moths (or birds) pollinate those
flowers.” And this make polination more effective. He asked a long series
of questions about odd or special features and he discovered that he was able
to track down special functions that accounted for those features. He did this a large number of
times with a large number of species. He found special features that gave particular advantages. He posited that all species that
displayed such features did so in subtly varying degrees. And he reasoned that the sexual
selection process was a critical step in passing on special heritable features
or traits.
Now, before we go any further, we must take a brief look at
the culture in which Darwin lived. First, we wish to point out that there has been a habit among western
man to rank things. “My favorite
color is…” “My favorite flavor is
…” Along these lines there has been a habit of thought assuming that some
people are simply better than others. It had been assumed in England and much of Europe for quite some time
that there were two types of people; aristocrats, and riff-raff. It was assumed that one could rank
people according to some objective measure from best to worst according to
intelligence, for instance . (See Spearman.) And it was assumed that the aristocrats would all be at the
head of the line. Similarly, it
was assumed that one could rank people from best to worst in a more general
sense. So when Herbert
Spencer coined the term “survival of the fittest” he was exploiting a mental
habit that had widespread currency among Europeans in general and the British
aristocracy in particular. That
mental habit was a tradition that ran backwards in history a millennium or two,
or more.
Furthermore, when Spencer used the term “survival” he was
probably thinking of the substantial section of Darwin’s work where Darwin
showed how native populations in Tasmania and New Zealand diminished to
extinction after the British colonized the areas. To Spencer and to all British aristocrats who knew Darwin’s
work, the phrase “survival of the fittest” simply explained that the British
were a superior race. It explained
why the British colonists succeeded in wiping out the indigenous people. Brits were the fittest because they
survived. And they survived
because they were the fittest. Or,
a little more ominously: Brits survived and the people they displaced did not
and this proved that Brits were simply more fit. And this, by implication, would justify any acts that helped
the natural phenomenon along a bit. Extermination of non-Europeans could simply
be seen as a sort of proof of a convenient scientific theory.
Spencer’s term “fitness” we interpret to be an allusion to a
prejudice that people can be ranked from best to worst, and that, as a general
rule, the aristocrats will be the first in rank. But, in fact, when we look at
our world we see that one person excels at tennis, another at golf. One person excels at crossword puzzles,
another is a whiz at Boggle. One person
grasps all the subtle nuances of higher mathematics, and another is blessed
with remarkable financial abilities. Some people are remarkably skilled at making friends and allies. Some people are good at making
grammatically perfect sentences. The world is full of very different problems and it is full of people
with markedly different capacities in all of them. It is even true that one will occasionally find individuals
who lack a wide spectrum of rather common talents but display a remarkable ability
in some esoteric talent.
It is frequently true, then, that how one scores “fitness”
is highly subjective. No matter
how one goes about it, if one wishes to define “fitness” as a singular quality
and one wishes to judge it in some objective manner one has to relate it to
survival in either a real or a hypothetical sense. Fitness is a hypothetical construct whose value lies in
its ability to predict survival.
One might approach the problem in a different way. Assume there are thousands, of heritable
traits. Assume we don’t know
what many of them are. Assume that
many of the macroscopic qualities we understand to be heritable may be
expressions of a large number of heritable qualities. Assume that the world is
a complex place and that sometimes extraordinarily low competencies prove much
more harmful than lack of any special competencies. In such a case there are lots of measures of “fitness.” In fact, for each unique female zygote
one might be able to imagine a unique male zygote that would represent the
optimum “fitness” in a
hypothetical individual created by their union.
To draw a mathematical analogue: There are times when one
wishes to multiply together two matrices in order to obtain the identity
matrix. In order to be successful, the values in the second matrix depend in a
very specific way on the values of the first. Change one value in the first
matrix, and some large number of values in the second matrix may have to change
for the matrix multiplication to successfully produce the identity matrix. In this analogy perhaps the values in
the squares of the matrix correspond to various genetic predispositions to
various traits. Maybe they are
genes or groups of genes, or other bits of genetic code. In some cases it is definitely
preferable to be heterozygous for a trait, as in the case of sickle-cell anemia
(or not to have the gene at all if one is living where malaria is absent). So if one parent has the gene, it is
best if the other does not. Fitness with respect to malaria is defined in a very specific way. And there must be a rather
large set of cases in which specific competencies are accentuated and
weaknesses attenuated by some ideal set of genes in a mate. And, in fact where
fitness is conditional upon the environment.
What we are arguing here is that if one can properly argue
for ‘fitness’ as a technical term that describes any sort of sexual
relationship of anything to anything else, the most useful idea would be to
define it in a way that brought together complementary and synergistic
qualities. And one that produced
an individual that was conditionally fit – fit for the conditions he was
to encounter in his environment.
This is a rather hand-wavy description, but if the purpose
of every base on every string of DNA were known precisely and one could
calculate precisely what the outcome would be of every combination, then if it
is not possible to calculate one ideal complementary zygote for any given
zygote, it might at least be possible to calculate a finite set of ‘pretty
good’ ones or to choose good and better choices from among several options. We
are not proposing this as a technology for making human beings to some
specification; we are only proposing it as a hypothetical model for “fitness.”
What we notice about this model is that fitness defined in
this way has only a rather hypothetical connection to reality. And this is where we mean to point the
discussion. Fitness is not a
single thing. It is not a quality
that can be defined in a fixed and non-contingent way. It can only be viewed in a more or less
of in a hypothetical and contingent way. Alternatively, one can think about it
in a highly specific way as Darwin did, as relating to a single, particular,
and necessary heritable trait.
Thinking of Spencer’s notion of general fitness, when we get
done with all this modeling and calculating, we have to assess the quality of
the outcome. We have to make a
judgment. What will be the
criteria? We might imagine that
there is a single ideal. But, in
fact, a premise of evolutionary thought is that genotypic variety potentiates
phenotypic variety. And phenotypic
variety potentiates adaptation to varying environmental conditions. So one could not define fitness for a
single individual, one would have to do it for a whole population.
For example: imagine that the population of humans is to
exist with clothing in Iceland and without it on the Kenyan steppes. A very dark-skinned person living in
Ireland would be at a disadvantage with respect to turning sunlight into vitamin
D. On the other hand, a very
pale-skinned person living in Kenya without clothes would not be able to go
outside during the day without getting seriously burned and blistered. If
humans are to occupy these two niches, it is impossible to conceive of a single
valued function of fitness with respect to skin pigment. So when we talk of either skin pigment
or sickle-cell anemia, there is no single measure of fitness.
In a different sensse, a society needs doctors, lawyers,
teachers, accountants, storytellers, engineers, administrators, and a host of
other people with competencies in a widely varying number of skills. And each of these sorts of competencies
depends differently on human skills and propensities. If we were to accidentally imagine that the only good design
for a human male were a tall, dark, and handsome doctor, we might find that
certain other material needs are less optimally met. When the roof blows off your house in a storm, who do you
call? And, by the way, how do you
get food?
So, again, fitness of one individual is contingent on all
the other capacities within the population. If there is a shortage of one capacity, then the society is
incrementally rewarded when it produces individuals with that capacity. If there is a surfeit of one capacity,
then that capacity will grow to be undervalued for some time.
Fitness is not a single thing. It is not a single heritable trait. Nor is it a set of traits heritable by
a single individual. It is a
characteristic of a population. And it is so by virtue of its making individuals of a population capable
of surviving under a variety of subtly different circumstances. General fitness is a hypothetical
quality that relates to how well a population fills its niche, to how adaptive
it is in terms of exploiting opportunities presented by the environment, and to how successful it is in limiting
the damage caused by challenges presented by the environment – including
the assumed incentive to overpopulate.
Specific fitness may be defined in a way consistent with
Darwin’s usage, in relation to a specific trait that provides a specific and
known advantage. We might suggest,
then, the idea that these two fitness ideas are rather different. One is general and it applies to all
heritable traits in the population. And one is specific to a particular trait. We might refer, then, to particular fitness or to general
fitness.
When we re-examine Spencer’s language we see that it is
nonsense. Fitness is a
hypothetical quality presumed to potentiate survival. It is not a real quality of any individual. Certainly at the level of
a specific individual, survival does not prove fitness. Nor is it useful to assume that in any
strict sense “only the fittest” survive. One Greek philosopher observed, “The Gods take first whom they love most.” This suggests that one rather important ancient Greek author
actually imagined that the least fit survive, at least in some sense.
Certainly evolution creates new individuals with new
qualities. Certainly it is true that
to the extent that these new qualities either do not materially handicap
individuals who inherit them the qualities tend to continue in currency in the
population. Certainly it is true
that to the extent that these new qualities confer some advantage in some area
of endeavor they marginally increase the likelihood that they will be passed
on. Certainly this marginally increased likelihood of expression in a given
generation causes the gene to be expressed in an ever larger portion of the
population in each subsequent generation for so long as it confers a
competitive advantage. In this sense, we can buy the idea that in a statistical
(stochastic) sense heritable traits survive preferentially because of the
benefits they confer.
We are left with the question of what connection we might
make between fitness and survival. If one were to say “fitness potentiates survival” one would not be wrong
by much. That is the relationship
between the two. Fitness exists as
a hypothetical construct to explain a real phenomenon, survival. This is a natural and illuminating way
of using the words in a single sentence in a meaningful way. When, however, one
speaks of “survival of the fittest” the language is repugnant because of its
intended connotation, because of its persistent connotation, and because it is
literally a tautology. “Survival
of the fittest” carries approximately the same cultural baggage as the ‘n’
word. And it deserves to be made
extinct.
Choice or Cooperation
The question of choice, and the question of altruism are both unanswerable questions given our current understanding of behavior and how it is regulated. Can humans exercise rational choice? It is assumed that we can; but some people who look at history are skeptical. On the other hand, it is possible to define cooperative behaviors and evaluate behaviors objectively for their cooperative components.
So long as a population exists at a level below its optimal level the simple act of existence is a cooperative behavior. And it is arguably one of the more profound. Similarly, any act of commerce is a cooperative act provided that each party fully understands the consequences of the act and enters into it freely and willingly without constraint. There is a sense in which copulation is a cooperative act. Again, so long as the result does not push a population toward ruin, it benefits all parties. All societies are built up from a huge set of interconnected relationships that are a result of a long history of cooperative acts and they are disposed to generate a long list of them into the future.
If one reads almost any work by E.O. Wilson it becomes impossible to view ants and bees as being anything less than the models of cooperative society on earth. In some aspects the vision is ominous, especially to people who value individual freedom over all other qualities. In the case of ants here is a kind of Hegelian inevitability to history that pervades the culture of the ant colony. It is really is a little dark and a little scary. But if humans are fundamentally cooperative, social creatures, and if we value our individual autonomy, it is incumbent upon us to think about ways of crafting societies that naturally preserve the qualities of freedom that we value while embracing the cooperative principles that make ants successful.
Williams’ argument might be construed to go to the notion of choice. It denies that evolutionary subjects have or can excercise choice. It is ridiculous to imagine that yeast could choose to behave differently than it does. Still, when we observe yeast cells in a bottle we see that their rate of reproduction changes with population level and environmental conditions. When we look at mid-twentieth century whalers and fishermen of today, or when we look at western man’s consumption of fossil fuels, we see approximately the same behavior as that of yeast in a bottle. It is reasonable to wonder what role choice has been playing, and what role it might play. It is reasonable to assume that perhaps Williams is correct. But it is not reasonable to accept his doctrine with a sort of blind faith.
Wynn-Edwards believed that whalers might have been able choose to behave differently. He believed that populations that succeeded in regulation succeeded in not going extinct. So, too, does Diamond. It is with the hope that man might be able to choose to succeed in choosing that Collapse is written.
Williams implicitly denies intelligent choice. Most populations lie in between the yeast-in-a-bottle model and the model of whalers in terms of how much we believe choice might play in the final outcome. If we believe that choice is not relevant in the case of whalers, then we might as well forget about all measures of good government. In fact, we ought to dismiss the idea that good government is theoretically possible. For Williams trumps that notion with inviolable evolutionary laws. When viewing political history in the last three decades there is lots of reason to believe that Williams might be correct. But it remains possible that to the extent he is correct it is because we have failed to believe that Wynn-Edward’s view of the world is possible. And it remains possible that this was a kind of general infection of the mind that has pervaded political thought since the mid 1970's.
Good choices are frequently costly. They frequently trade certain short term goods for very uncertain longer term goods. And this is not a practice that Americans since Wynn-Edwards have been especially good at doing. We imagine there might have been times in history when particular populations were better at it. But we have no shred of evidence to support that conjecture.
The Evolution of Cooperation
In the mid-1980’s there appeared a popular book called The Evolution of Cooperation. It was essentially a report about a series of computer simulations of a game like the prisoner’s dilemma. The prisoner’s dilemma is about two people who are arrested for a crime. What we know as omniscient observers is that if neither prisoner confesses, both will get charged and convicted of petty offences. If A informs on B or vice versa the charges against the informant will be dropped, but the other prisoner will be punished severely. Similarly, if each informs on the other, both will be punished severely. Thus, the behavior of one prisoner under investigation is powerfully informed by his belief about the behavior of the other. If one considers their joint utility function, they are better off cooperating. But if either fails to expect cooperation from the other, he will confess.
In general, the game is defined in such a way that reciprocal cooperation has small benefits to both parties. Cheating of one party is associated with large gain by one party and one loss by another party. Cheating of both parties is associated by a loss by both parties.
The computer game used for the simulation was closely allied to this. Two simulated parties engaged in an exchange. We assume that the exchange might be compared to any market trade of the sort people engage in to get food or durable goods. At the execution of the trade each party could either honor the terms of the exchange or they could cheat. If neither party cheated, both enjoyed a tiny incremental benefit. If one party cheated, the incremental benefit was much larger, and the other party paid a penalty. And if both cheated, both parties paid a penalty.
The simulation proceeded like this: The game created a number of species that behaved according to some set of simple rules. One rule, for instance, might be “always cooperate” Another rule might be “cooperate until the other guy cheats, then never cooperate.” Another might be called tit-for-tat “Start by cooperating, then behave as the other guy did on the last interaction.” Points would be awarded at the end of each exchange. When a species accumulated enough points, it would replicate. The species would then gain an additional individual. The success of a species would be assessed on the basis of how many individuals existed and by how many individuals survived to the end of the simulation. If an individual lost too many points, he would die. And a population that had no more individuals was extinct.
Near the beginning of the simulation things happened that would not have surprised evolutionary biologists. The species that were ‘cheating-’ behaving as Williams predicted - were reproducing very quickly and it was quite clear that they would soon take over the entire ecosystem. Then, when the economic importance of more cooperative players had diminished to the point of hardly being noticeable, and most of this simulated world was dominated by non-cooperative species, those non-cooperative species just about wiped each other out. And voila, the cooperative species remained. They never did reach the population levels of the non-cooperative species. But they survived a lot longer. The species, by the way, that survived best was ‘tit-for-tat’ and subtle variants of that species. It cooperated so long as its trade partner did, but it punished non-cooperative behavior with non-cooperative behavior. When cooperative behavior recurred, it cooperated once again.
Each game was played until some equilibrium condition was met, perhaps thousands or even tens of thousands of times. And the reward system was varied to make cheating more or less valuable. Changes in the reward system changed the system dynamics, but they did not change the final, stable outcomes. In short, cooperation won out.
The simulation is an almost perfect metaphor for Williams’ thought experiment. And, in the short term, it behaves rather closely to Williams’ prediction. Ultimately, however, the ‘cheating’ behaviors become too costly. And the cheaters lose out. It is useful to note here that in this case cooperation is conditional. Unconditional cooperation never did fare well. It was only in a general environment where cheating was punished that cheaters perished. So long as cheating was rewarded it flourished. But cheating, under any circumstances is a less productive behavior than cooperation. And that makes it, by definition, less sustainable. Cheaters perish. If it is not by acts of more cooperative entities, it is by acts of other cheaters.
The game in question is an example of game theory. Since the popularity of Evolution of Cooperation, it has been realized that game theory describes a host of interactions within the fields of biology and economics that involve choices between cooperative and non-cooperative behavior. Interestingly, the subtle power of repeated, habitual cooperation seems to easily and naturally overwhelm the power of non-cooperative behavior, so long as cooperative groups erect modestly effective barriers against the harms of non-cooperative behaviors. As one might have guessed from the prisoners’ dilemma, it is the expectation of cooperation in a particular act that motivates good behavior, or, at least a kind of behavior consistent with such an expectation. And it is good behavior that creates that expectation. This has profound implications for how humans choose to shape their culture; but we will not talk about them here.
The competitive world is a brutal one. It is a ruthless one. But it is one composed of cooperative units. And competition succeeds against a background of cooperation. To proclaim that the only games in evolution are competitive ones is to declare a rather narrow view of the world. It is to impose a rather brittle and unhelpful orthodoxy on the study of biological systems. Cooperation exists. To deny its existence may be the most promising way to prove incontrovertibly that, in fact, it does exist.
Proof by Contrapositon
Williams’ argument is part of a framework of evolutionary theory that implicitly posits that cooperation does not exist because it is theoretically impossible. If Williams did not intend it this way, then certainly Alcock has argued for this sense. The argument he poses is just an example of this kind of reasoning. Sociobiology, according to Alcock, follows in this tradition. We find such an asocial point of view to be both puzzling and disturbing because we believe that social animals exist as social animals because of the evolutionary advantages they accrue in cooperative interactions. Why would a person studying physical chemistry posit that no physical laws apply to the field? Why would a person studying sociobiology deny the existence of cooperative social principals? In either case the only sane reason we can think of is to construct a proof by contraposition.
Yet curiously, when a socio-biologist finds examples of cooperation, instead of using them to prove that, in fact, cooperation exists, he explains the cooperation in terms of how the behavior provides a competitive advantage. And then socio-biologists use the fact that the competitive advantage exists to argue that the discovered cooperative behavior supports the standard theory that cooperative behavior does not exist. Only competitive behavior. In other words, cooperation is not cooperative if it might possibly convey a competitive advantage! We find this to be a conception of cooperation we are not prepared to grasp.
We understand that competitive behavior is important. And we understand how the emphasis on competitive behavior arises out of Williams conception of the adaptive process. Nor do we deny that competitive forces play a profound role regarding which individuals survive or perish. Whether it is competition between populations or competition between individuals, competition is the evolutionary force that shapes nature.
Where we disagree with the current practice of socio-biologists is in the total dismissal of cooperation and of the importance of competition between groups. Individuals go extinct all the time. Populations go extinct rather less frequently. But surely the measure of fitness of a population is whether it is extinct: an extinct population does not survive. What portion of the species created on this planet survives intact? What portion has given rise to new species? What portion has disappeared without leaving a living legacy? Is it not true that the populations that have propagated themselves continuously through time have a greater fitness than those that disappeared? This is the ultimate test of success or failure of a population and of its members. And if we look at the trend we see that cooperation within a population generally confers a competitive advantage. The does not prove that cooperation does not exist: it proves the opposite.
We believe it might be more useful to admit that certain kinds of cooperative behavior do, in fact exist. Then one could create useful distinctions between the kinds of cooperative behavior we are talking about. In one typical category of cooperative behavior one can identify three or more separate groups. There are two or more parties who actively cooperate, and there is everyone else. At one level one might divide such a category into two subcategories: One kind of cooperation causes the active and the passive parties to be better off. Another causes the active parties to be better off but the passive parties to be worse off. There are lots of other potential ways of categorizing cooperation. And each way will provide different insights into behavioral strategies. But the point is that each time two organisms or two groups of organisms interact cooperatively they generally gain a tiny incremental advantage. And almost every act can be judged a competitive act in one light and a cooperative act in another.
It is a general practice in the field of mathematics to prove a thing by assuming its opposite. Imagine we wish to prove proposition A – “The moon is not made of cheese.” We would proceed by proposing not A “The moon is made of cheese” then we use what we know to demonstrate that assuming not A leads to a contradiction. “All things made of cheese are quickly consumed by mice or by men or by mold.” But we know that the moon is hundreds of years old, at least, and it has not been consumed by mice or by men. Therefore it is not made of cheese. This is called a proof by contraposition. It assumes the opposite, shows that’s ridiculous, and that’s that. (We understand that this proof is full of holes, but it is, after all, a proof about cheese, and all proofs about cheese are full of holes.)
In mathematics, proof by contraposition is a very common means of proving quite a number of propositions. So, if one were to set out to prove that cooperation were a force in nature, a productive means would be to posit, along the lines of socio-biologists who follow in the tradition of Williams, that cooperation does not exist. Then one would go out and find counterexamples.
Definition: if an act of one agent (i.e. individuals or groups) produces benefits for another individual or group it is said to be cooperative.
We will admit that this is not a very high hurdle to clear. We also imagine that there must be quite a lot of cases where we wish to define cooperative acts more completely. Finally, any cooperative act that applie benefits differentially within a population is, by a definition of competition, also a competitive act. Still, we believe that this captures the most essential quality of a cooperative act, namely that someone else benefits from the act of an actor. By the way. When we speak of act, we may consider refraining to act in the same light. Certain kinds of non-action might be considered cooperative behaviors as well, although quantifying such might be more difficult.
Axiom: parents derive evolutionary benefit from the existence of their offspring.
We assume this proposition is true. In an evolutionary sense, offspring and their own reproductive success is the very definition of success. Thus, the production of offspring is, in an evolutionary sense, the greatest benefit that can accrue from an act. If this axiom is false, we might as well give up both the study of evolutionary biology and the whole business of reproduction.
Theorem 1: there exist cooperative acts in nature.
Proof: Assume that there exist no cooperative acts. Now, consider sexual reproduction. Parents derive benefit from that act by virtue of existence of offspring. So, either we must admit that acts causing (and support the long term effects of) sexual reproduction are either cooperative or, we reject that parents derive benefit from the existence of offspring. Therefore, we are forced to admit that sexual reproduction is a cooperative act. BTW, we need not always believe that every act of reproduction is cooperative in the sense that some other party derives benefit, only that it is sometimes cooperative. Or it was at least once.
Theorem 2: there exist cooperative acts in nature besides copulation.
Proof: Assume that reproduction is the singular cooperative act. No other act could cause individuals or groups to derive joint benefits. Now, consider the act of a mother nursing her offspring. If this is not a cooperative act then one of the two actors must not benefit from the act. Clearly the offspring benefits, because without food it would perish. (We implicitly assume that existence is preferable to extinction, at least in an evolutionary sense.) If the offspring perishes from lack of nutrition, then its mother no longer can derive from the benefit of bearing offspring. The mother, therefore derives benefit from feeding her offspring. Breast-feeding of offspring is an example of a cooperative act, therefore, there exist cooperative acts in nature over and above copulation.
So, we have proven that cooperation can exist and that it does exist. Any act that confers a benefit on another individual or upon a group, is, by definition a cooperative act. From one side of the line, even war - a profoundly competitive and destructive act - can be viewed as a kind of a cooperative act. It is a cooperative effort of individuals of one group to seize territory or assets held by another group. The individuals act together to gain advantages for their group. It is correct to view it as a competitive actt; and it is correct to view it as a cooperative act. The same act takes on different qualities from different points of view.
Societies of humans and of animals alike are built up of quite a series of tiny cooperative acts. Anthills and cities will testify to this fact. Go might be a beehive or an anthill. Or one might travel to New York City. A person looking for cooperation or its fruits really need not look far to find it.
Consider the mean time between cooperative acts in a large ant colony. In colony with ten thousand members one might find thousands of cooperative acts either completed or in-process in any second. It boggles the mind. Only a good statistical treatment of these processes might succeed in uncovering how profound the effects might be.
Certain socio-biologists when they look at an anthill and see all the cooperation dismiss it. “These worker ants are all so closely related as to be – in a genetic sense - the same individual. They work, therefore, in their own self-interest. How can you call that cooperation?” How, indeed? Think of the two prisoners. For each prisoner there exist two ways of working in his self-interest. One way, if he has good reason to believe his buddy will stay mum, is not to confess. The other way, is to rat on his pal. In both cases one could explain the motive as self-interested behavior. But this does not help us understand the behavior at all. If we want to understand the behavior, not just dismiss it, we need to grasp its fundamentally cooperative nature. We must assent that cooperation exists and we must understand more about how it might work.
Cooperation exists in every species that nurtures or protects its young. That is, by definition all mammals. It also includes all social animals. It includes all animals that share food. It is even impossible to define sexual reproduction in a way that completely avoids some cooperative components. Thus the very focus of evolutionary biology as it exists today is a focus on perhaps the most profoundly important cooperative act in nature. Of course there is competition between members of the same gender, but there is also a certain amount of cooperation. And there is cooperation among members of opposite genders; but there exists a certain amount of competition, too.
Sexual reproduction accrues benefits for all the parties involved. The fact that it accrues benefits does not prove that an act is not cooperative. The fact that it accrues benefits, rather, proves that it is cooperative. That is how we define cooperative acts. So, socio-biologists have spent forty years finding acts that appear to be cooperative on the surface, but in reality are competitive. And this proves that they are not, in fact cooperative? It’s like arguing with someone who appears to be eating ice cream at an ice cream shop: “Ice cream is something I eat. Therefore what you are not eating ice cream.” (Note that how the first proposition reads depends on what we are thinking when we say I: ‘I’ or ‘only I’) Both arguments appear to depend on a rather profound denial fact in order to conform to a quirky view of reality.
In the mathematical world, a single example of cooperation would suffice to disprove Alcock's ’ implicit assumption that cooperative acts are impossible or that they are irrelevant to natural selection. But the most casual review of the facts suggests that cooperation is quite widespread. There exist but tiny number of examples in nature where cooperation is not part of the picture. In fact, if one views copulation as a cooperative act – which it is by definition – then evolutionary biology simply does not amount to very much after all cooperative acts are stripped from its purview.
The View from Here
To the extent that evolutionary biology has been founded on the assumptions in Williams’ pivotal thought experiment, it risks defining a number of the most important processes that shape populations and the individuals that make up those populations as being irrelevant. This strikes a person who has studied physical sciences to be like asserting that chemistry is about single atoms and it has nothing to do with collections of them. Such a view would deny that the really interesting parts of chemistry arise when one combines these atoms in particular ways to create compounds. These have new physical and chemical properties. And these new compounds have an incredibly huge array of uses that would be impossible to anticipate if one studied individual atoms. It is hard to derive all of the behavior of a complex protein from nothing but its chemical formula.
Similarly, anyone who has studied thermodynamics or physical
chemistry understands that a population of identical things can behave in ways
that may be quite strongly influenced by the qualities of its components, but
that behavior may not be understood without defining qualities that belong to
the collection. It is one thing to know what an atom is. But it is another
thing altogether to understand what the ideal gas law says. And it is quite helpful to be able to
mathematically connect the one point of view with the other. Thus, the study of
populations and their qualities as they relate to the qualities of their
individuals is an essential study. And it is highly reliant on the understanding of the individual, an
understanding that must be reached using Williams’ assumption. But it is not the whole picture.
In evolutionary biology it is quite important to assume as
Williams did that copulation plays a vital role in natural selection. But all enquiries along these lines are
destined to tell us just a little about individuals and how they are shaped by
some tiny element of the final selection process itself. It will tell us nothing about how
interactions between members of a society contribute to the qualities of
individuals in that society or how those qualities are expressed in the
survival of the population. E.O.
Wilson in Consilience makes a powerful
argument that evolutionary biology needs to include work that ties together
population models with ideas about natural selection, its products, and its processes.
To the extent that it is appropriate to make a distinction
between evolutionary biology and socio-biology,
we would propose admitting to the latter some notion of studying interactions
between individuals over and above the act of copulation. And, in fact, expending effort in
studying how groups interact. It
is likely that Williams is correct in asserting that adaptation within a
population is driven by selective processes that work at the level of the
individual. But we expect
that the exclusion of the study of populations and of the interrelationships
between individuals excludes from consideration a majority of the factors that
account for the long-term success of cooperative populations. Some of individual interactions are
cooperative; some are competitive in nature. Many are both. Ignoring all cases of cooperative behavior may not matter in the case of
certain minor frontier insects, but it probably does matter for almost every
economically important organism.
Perhaps it is unrealistic to expect such a profound change
of views about biological processes among researchers who have been so closely
focused exclusively on copulation. Perhaps it is a really fanciful notion that socio-biology might ever have any social component. Perhaps the whole field of study
requires a new breed of specialists with a new name. Perhaps they will rightly
be named bio-economists. Regardless of what the field is named, the world needs
an organized study of the whole range of biological processes that take place
in social contexts.
We hope it might help us better understand our relationships
with each other and our relationships with other organisms, especially those on
which humans depend so heavily. We hope it might help us understand how to
preserve a rich natural environment that rewards us profoundly for the hard
days we spend cooperating and competing with each other. We hope that it might
help us understand interconnections between individuals, groups, and species in
ways that make our societies more fair, robust, sustainable, and prosperous.
Section I - Different Perspectives on Sociobiology
Section II - Negative Returns of Marginal Fertility
Several months have elapsed since writing this piece. I have read most of Williams' Adaptation and Natural Selection and most of it seems quite level-headed. In fact, very little of the kind of religious fervor that infuses Alcock's Triumph of Sociobiology can be found in Williams. Williams seems to have no problem admitting cooperative behavior, he simply goes out and finds what benefit cooperative behavior might bring to an individual or a species. The impression one gets in reading Alcock is that the idea of proving that altruism cannot exist is more important than the idea of understanding biology. This makes Alcock's book resemble a theological argument more than Williams' would seem to do.
The fundamental problem, I believe, lies in the terminology 'altruism.' As argued above, it is very easy to define cooperation. And it is easy to make more highly refined and nuanced definitions for kinds of cooperation, specifying conditions and parties, and benefits in each. Thus, it is easy to make cooperation a highly functional term of art. Altruism, on the other hand, has such a profoundly loaded sense to it that it is almost impossible to use it in a technical sense. Nor does the term 'reciprocal altruism' make any sense. Get rid of the term 'altruism' and the baggage it carries, learn about how cooperation works, and the problem Williams and Alcock are trying to describe will resolve itself naturally without resorting to theology and dogma.
I have also read Trivers' piece describing when cooperation can occur in populations. Trivers demonstrates that once a population admits some cooperation, the practice tends to spread because of the advantages that accrue from cooperation.
I have viewed Robert Sapolsky's Biology and Human Behavior: The Neurological Origins of Individuality, a course offered by the Learning Company. Sapolsky suggests that the work by Trivers (not mentioned) and by Axelrod has established among evolutionary biologists that, in fact, cooperation does exist. He discusses an experiment in which people play the Prisoner's Dilemma game while their brains are being scanned using an MRI. Experiments show that when both members cooperate, the brain releases dopamine. This release of dopamine causes a sense of pleasure or well-being. But if either party cheats this dopamine release does not occur. In other words, humans are hard-wired to cooperate.
Other workers have found 'empathy' centers in other primates that associate acts done to other individuals with oneself - a system that would cause an individual to become agitated or upset by ill-treatment of another. There are multiple senses in which humans derive pleasure not just from being treated fairly, but also from treating others fairly. And they derive displeasure, ennui, or anger from ill treatment of others. This goes a long way toward explaining why religious faiths that work to establish cultures of fairness have such lasting endurance. Cooperation matters.
Copyright: Stephen R. Brubaker, 2006. All Rights Reserved