Cyber Sapiens

October 26, 2006 by Chip Walter
Original link:  http://www.kurzweilai.net/cyber-sapiens
Excerpted from Thumbs, Toes, and Tears, Walker & Co. 2006. Published on KurzweilAI.net October 25, 2006.

…We will no longer be Homo sapiens, but Cyber sapiens–a creature part digital and part biological that will have placed more distance between its DNA and the destinies they force upon us than any other animal … a creature capable of steering our own evolution….

Today nature has slipped, perhaps finally, beyond our field of vision.

-O. B. Hardison Jr.

Now after six million years of evolution, where do we go next? How will evolution, our newly arrived intellect, our primal drives and the powerful technologies we continually create, change us?
Our current situation is unlike anything nature has seen before because we are not simply a by-product of evolution, we are ourselves now an agent of evolution. We are this animal, filled with ancient emotions and needs, amplified by our intellects and a conscious mind, embarking on a new century where we are creating fresh tools and technologies so rapidly that we are struggling to keep pace with the very changes we are bringing to the table.

Where will this lead? Will we develop new brain modules, new appendages, revamped capabilities just as we have over the past six million years? Absolutely, but probably not in the way we suspect. It appears, if we look closely, that the DNA that has been such a perfect ally in the evolution of life, may itself be in for a revamping. Evolution may be prowling for a new partner. And the partner may be us, or at least the technologies we make possible.

The irony is that it takes a being like us, a human being, to bring about change this fundamental. The job requires an amalgamation of high intelligence and emotion, conscious intent, primal drives and great quantities of knowledge made possible by minds that can communicate in highly complex ways. If you pulled any one of these out, the future, at least one involving intelligent, conscious creatures like us, would fall apart. It takes not just cleverness, but passion, sometimes fear, fired by focused intention, to create and invent. Without this combination there would be no technologies, no wheels or steam engines or nuclear bombs or computers. And there would be nothing like the world we live in today. At best we would still be huddled in the black African night, eking out whatever existence the predators waiting in the darkness around us would allow. Not even fire would be our friend.

But the traits that have shaped us into the human beings we are have endowed us with strange abilities, and they are hurtling us into a future radically unlike the past out of which we have emerged. And that future will be profoundly different from anything most of us can imagine.

Take the thinking of Hans Moravec as an object lesson. Moravec is a highly respected robotics scientist at Carnegie Mellon University. In the late 1980s, he quietly passed his spare time writing a book that predicted the end of the human race. The book, entitled Mind Children, didn’t predict that we would destroy ourselves with nuclear weapons or rampant, self-inflicted diseases, or undo the species with self-replicating nanotechnology. Instead, Moravec, who had an abiding and life-long fascination with intelligent machines, predicted we would invent ourselves out of existence, and robots would be the technology of choice.

In a subsequent book (Robot, Mere Machine to Transcendent Mind) Moravec explained that this transformation would unfold one technological generation at a time, and, because of the blistering rate of change today, would pretty much run its course by the middle of the 21^st century. We would manage this by boosting robots up the evolutionary ladder, roughly in decade-long increments, making them smarter, more mobile, more like us. First they would be as intelligent as insects or a simple guppy (we are about there right now), then lab rats, then monkeys and chimps until, finally one day, the machines would become more adept and adaptive than their makers. That, of course, would quickly raise the question: “Now who is in charge?” Would Homo sapiens, after some 200,000 years living on top of the planet’s food chain, no longer rule the roost? Would we, in the cramped space of this evolutionary ellipsis, find ourselves playing Neanderthal to technologies that had become, like us, self-aware—the first conscious tools built by a conscious toolmaking creature?

The unavoidable answer would be, yes. Evolution will have found through us a new way to make a new creature; one that could forsake its ladders of DNA and the fragile, carbon-based biology that nature had been using for nearly four million millennia to manage the job.

The “end” would not come in the form of a Terminator style invasion, it would simply unfold in the natural course of evolutionary events where one species, better adapted to its environment replaces another that is no longer very fit to continue. Except the new species wouldn’t be cobbled out of DNA, it would be fashioned from silicon, alloy, and who knows what else, invented by us. But once successfully invented, we wouldn’t be necessary any more.

Whether events will play out like this or not remains to be seen. But Moravec’s scenario makes a point—the world and the life upon it changes, and simply because we are the agents of change, doesn’t mean we won’t be affected by it.

***

It is strange to think of the invention of machines, even robotic ones, as having anything to do with Darwin’s natural selection. We usually regard evolution as biological—a world of cells, DNA and “living” creatures. And we think of our machines as unalive, unintelligent and shifted by economic forces more than natural ones. But it isn’t written anywhere that evolution has to be constrained by what we traditionally think of as biology. In fact each day the lines between biology and technology, humans and the machines we create are blurring. We are already part and parcel of our technology.

Since the day Homo habilis whacked his first flint knife out of flakes of flint, it has been difficult to know whether we invented our tools or our tools invented us. The world economy would crash if its computer systems failed. We can’t live without laptops, palmtops, cell phones or iPods, which grow continually smaller and more powerful. We regularly engineer genes, despite the raging debates over stem cell therapy. A human being will very likely be cloned within the next five years. We now have computer processors working at the nano (molecular) level and microelectromechanical machines (MEMS) that operate at cellular dimensions. Already electronic prosthetics make direct connections with human nerves, and electronic brain implants for Parkinson’s disease and weak hearts are common place. Scientists are even experimenting with electronic, implantable eyes. New clothing weaves digital technologies into their fiber and brings them a step closer to being a part of us. The military are working on “battlesuits” that will fit like gloves, a kind of second skin and amplify a soldier’s senses, strength and ability to communicate, even triangulate the direction of a bullet headed his or her way.

What next? Speech, writing and art enabled us to share inner feelings in new and powerful ways. But it takes months or years to learn a new language or how to play the piano or master the art of engineering bridges and buildings. Will new technologies that accelerate communication (virtual reality, telepresence, digital implants, nanotechnology) create new ways to communicate that can by-pass speech? Will we someday communicate by a kind of digital telepathy, downloading information, experiences, skills, even emotions the way we download a file from the Internet to our laptop? Will we become machines, or will machines become more powerful versions of us? And if any of this comes to pass, what ethical issues do we face? At what point to do we stop being human?

Lynn Margulis, probably the world’s leading microbiologist, has argued that this blurring of technology and biology isn’t really all that new. She has observed¹ that the shells of clams and snails are a kind of technology dressed in biological clothing. Is there really that much difference between the vast skyscrapers we build or the malls in which we shop, even the cars we drive around, and the hull of a seed? Seeds and clam shells, which are not alive, hold in them a little bit of water and carbon and DNA, ready to replicate when the time is right, yet we don’t distinguish them from the life they hold. Why should it be any different with office buildings, hospitals and space shuttles?

Put another way, we may make a distinction between living things and the tools those things happen to create, but nature does not. The processes of evolution simply witness new adaptations and preserve those that perform better than others. That would make Homo habilis’s first flint knife a form of biology as sure as a clamshell, one that set our ancestors on a fresh evolutionary path just as if their DNA had been tweaked to create a new, physical mutation, say an opposable thumb or a big toe.

Even if these technological adaptations were outside what we might consider normal biological bounds, the effect was just as profound, and far more rapid. In an evolutionary snap, that first flint knife changed what we ate and how we interacted with the world and one another. It enhanced our chances of survival. It accelerated our brain growth which in turn allowed us to create still more tools which led to yet bigger brains. And on we went, continually and with increasing speed and sophistication, fashioning progressively more complex technologies right up to the genetic techniques that enable us to fiddle with the self-same ribbons of our chromosomes that made the brains that conceived tools in the first place. If this is true, all of our technologies are an extension of us, and each human invention is really another expression of biological evolution.

Moravec and Margulis aren’t alone in asking questions that force us to bend our traditional thinking about evolution. Scientist and inventor Ray Kurzweil has, like Moravec, pointed out that the rate of technological change is increasing at an exponential rate. Also like Moravec, he foresees machines as intelligent as we are evolving by mid century. Unlike Moravec he doesn’t necessarily believe they will arrive in the form of robots.

Initially Kurzweil sees us reengineering ourselves genetically so that we will live longer and healthier lives than the DNA we were born with might normally allow. We will first rejigger genes to reduce disease, grow replacement organs, and generally postpone many of the ravages of old age. This, he says, will get us to a time late in the 2020s when we can create molecule-sized nanomachines that we will program to tackle jobs our DNA never evolved naturally to undertake.

Once these advances are in place we will not simply slow aging, but reverse it, cleaning up and rebuilding our bodies molecule by molecule. We will also use them to amplify our intelligence; nestling them among the billions of neurons that already exist inside our brains. Our memories will improve; we will create entirely new, virtual experiences, on command, and take human imagination to levels our currently unenhanced brains can’t begin to conceive.² In time (but pretty quickly) we will reverse engineer the human brain into a vastly more powerful, digital version.

This view of the futures isn’t fundamentally different from Moravec’s brain-to-robot download, except it is more gradual. Either way we will have melded with our technology if, in fact, those barriers ever really existed in the first place, and in the end, erase the lines between bits, bytes, neurons and atoms.

Or looked at another way, we will have evolved into another species. We will no longer be Homo sapiens, but Cyber sapiens—a creature part digital and part biological that will have placed more distance between its DNA and the destinies they force upon us than any other animal. And we will have become a creature capable of steering its own evolution (“cyber” derives from the Greek word for a ship’s steersman or navigator—kybernetes). The world will face an entirely new state of affairs.

Why would we allow ourselves to be displaced? Because in the end, we won’t really have a choice. Our own inventiveness has already unhinged our environment so thoroughly that we are struggling to keep up. In a supreme irony we have created a world fundamentally different from the one into which we originally emerged. A planet with six and a half billion creatures on it, traveling in flying machines every day by the millions, their minds roped together by satellites and fiber optic cable, rearranging molecules on the one hand and leveling continents of rain forest on the other, growing food and shipping it overnight by the trillions of tons—all of this is a far cry from the hunter-gatherer, nomadic life for which evolution had fashioned us 200,000 years ago.

So it seems the long habit of our inventiveness has placed us in a pickle. In the one-upmanship of evolution, our tools have rendered the world more complex and that complexity requires the invention of still more complex tools to help us keep it all under control. Our new tools enable us to adapt more rapidly, but one advance begs the creation of another, and each increasingly powerful suite of inventions shifts the world around us so powerfully that still more adaptation is required.

The only way to survive is to move faster, get smarter, change with the changes, and the best way to do that is to amplify ourselves eventually right out of our own DNA so we can survive the new environments—physical, emotional and mental—that we keep recreating.

Is all of this too implausible to consider? Will Homo sapiens really give way to Cyber sapiens that seamlessly integrate the molecular and digital worlds just as our ancestors merged the technological and biological worlds two million years ago? Evolution has presided over stranger things. It took billions of years before the switching and swapping of genes brought us into existence. Our particular brain then took 200,000 years to get us from running around in skins with stone weapons to the world we live in today. Evolution is all about the implausible. And the drive to survive is a relentless shaper of the seemingly impossible. We ourselves are the best proof.

If all of this should happen; if DNA itself goes the way of the dinosaur, what sort of creature will Cyber sapiens be? In some ways we can’t know the answer anymore than Homo erectus could imagine how his successors would someday create movies, invent computers and write symphonies. Our progeny, our “mind children,” will certainly be more intelligent with brains that are both massively parallel, like the current version we have, and unimaginably fast. But what of those primal drives that we carry inside our skulls, and those non-verbal, unconscious ways of communicating? What of laughter and crying and kissing? Will Cyber sapiens know a good joke when he hears one, or smile appreciatively at a fine line of poetry? Will he tousle the machine made hair of his offspring, hold the hand of the one he loves, kiss soulfully, wantonly and uncontrollably? Will there be a difference between the “brains” and behaviors of he and she? Will there even be a he and a she? And what of pheromones and body language and nervous giggles? Maybe they will have served their purpose and gone away. Will Cyber sapiens sleep, and if they do, will they dream? Will they connive and gossip, grow mad with jealousy, plot and murder? Will they carry with them a deep, if machine made, unconscious that is the dark matter of the human mind, or will all of those primeval secrets be revealed in the bright light cast by their newly minted brains?

We may face these questions sooner than we imagine. The future gathers speed every day.

I’d like to think the evolutionary innovations and legacies that have combined to make us so remarkable, and so human, won’t be left entirely behind as we march ahead. Perhaps they can’t be. After all, evolution does have a way of working with what is already there, and even after six million years of wrenching change, we still carry with us the echoes of our animal ancestors. Maybe the best of those echoes will remain. After all, as heavy as some baggage can be, preserving a few select pieces might be a good thing, even if we are freaks of nature.

---

1. This was during a conversation with Professor Margulis at her home in western Massachusetts.

2. Note: the current version of a creature can never comprehend the exerience of the creature that will follow because it does not yet have the evolved capacity (whatever it is) that will make that experience possible. We cannot accurately imagine what a digitally enhanced brain will conceive any more than Homo erectus could imagine our experience of the world.

© 2006 Chip Walter. Reprinted with permission.

Footnotes

Kin selection

From Wikipedia, the free encyclopedia

 

The co-operative behaviour of social insects like the honey bee can be explained by kin selection.

Kin selection is the evolutionary strategy that favours the reproductive success of an organism's relatives, even at a cost to the organism's own survival and reproduction. Kin altruism can look like altruistic behaviour whose evolution is driven by kin selection. Kin selection is an instance of inclusive fitness, which combines the number of offspring produced with the number an individual can ensure the production of by supporting others, such as siblings.

Charles Darwin discussed the concept of kin selection in his 1859 book, The Origin of Species, where he reflected on the puzzle of sterile social insects, such as honey bees, which leave reproduction to their mothers, arguing that a selection benefit to related organisms (the same "stock") would allow the evolution of a trait that confers the benefit but destroys an individual at the same time. R.A. Fisher in 1930 and J.B.S. Haldane in 1932 set out the mathematics of kin selection, with Haldane famously joking that he would willingly die for two brothers or eight cousins. In 1964, W.D. Hamilton popularised the concept and the major advance in the mathematical treatment of the phenomenon by George R. Price which has become known as Hamilton's rule. In the same year John Maynard Smith used the actual term kin selection for the first time.

According to Hamilton's rule, kin selection causes genes to increase in frequency when the genetic relatedness of a recipient to an actor multiplied by the benefit to the recipient is greater than the reproductive cost to the actor.^[1][2] Hamilton proposed two mechanisms for kin selection. First, kin recognition allows individuals to be able to identify their relatives. Second, in viscous populations, populations in which the movement of organisms from their place of birth is relatively slow, local interactions tend to be among relatives by default. The viscous population mechanism makes kin selection and social cooperation possible in the absence of kin recognition. In this case, nurture kinship, the treatment of individuals as kin as a result of living together, is sufficient for kin selection, given reasonable assumptions about population dispersal rates. Note that kin selection is not the same thing as group selection, where it instead is proposed that natural selection acts on the group as a whole.

In humans, altruism is both more likely and on a larger scale with kin than with unrelated individuals; for example, humans give presents according to how closely related they are to the recipient. In other species, vervet monkeys use allomothering, where related females such as older sisters or grandmothers often care for young, according to their relatedness. The social shrimp Synalpheus regalis protects juveniles within highly related colonies.

Historical overview

Charles Darwin was the first to discuss the concept of kin selection. In The Origin of Species, he wrote clearly about the conundrum represented by altruistic sterile social insects that

This difficulty, though appearing insuperable, is lessened, or, as I believe, disappears, when it is remembered that selection may be applied to the family, as well as to the individual, and may thus gain the desired end. Breeders of cattle wish the flesh and fat to be well marbled together. An animal thus characterised has been slaughtered, but the breeder has gone with confidence to the same stock and has succeeded.

— Darwin^[3]

In this passage "the family" and "stock" stand for a kin group. These passages and others by Darwin about "kin selection" are highlighted in D.J. Futuyma's textbook of reference Evolutionary Biology^[4] and in E. O. Wilson's Sociobiology.^[5]

The earliest mathematically formal treatments of kin selection were by R.A. Fisher in 1930^[6] and J.B.S. Haldane in 1932^[7] and 1955.^[8] J.B.S. Haldane fully grasped the basic quantities and considerations in kin selection, famously writing "I would lay down my life for two brothers or eight cousins".^[9] Haldane's remark alluded to the fact that if an individual loses its life to save two siblings, four nephews, or eight cousins, it is a "fair deal" in evolutionary terms, as siblings are on average 50% identical by descent, nephews 25%, and cousins 12.5% (in a diploid population that is randomly mating and previously outbred). But Haldane also joked that he would truly die only to save more than a single identical twin of his or more than two full siblings.^[10][11] In 1955 he clarified:

Let us suppose that you carry a rare gene that affects your behaviour so that you jump into a flooded river and save a child, but you have one chance in ten of being drowned, while I do not possess the gene, and stand on the bank and watch the child drown. If the child's your own child or your brother or sister, there is an even chance that this child will also have this gene, so five genes will be saved in children for one lost in an adult. If you save a grandchild or a nephew, the advantage is only two and a half to one. If you only save a first cousin, the effect is very slight. If you try to save your first cousin once removed the population is more likely to lose this valuable gene than to gain it. … It is clear that genes making for conduct of this kind would only have a chance of spreading in rather small populations when most of the children were fairly near relatives of the man who risked his life.^[12]

W. D. Hamilton, in 1963^[13] and especially in 1964^[1][2] popularised the concept and the more thorough mathematical treatment given to it by George Price.^[1][2]

John Maynard Smith may have coined the actual term "kin selection" in 1964:

These processes I will call kin selection and group selection respectively. Kin selection has been discussed by Haldane and by Hamilton. … By kin selection I mean the evolution of characteristics which favour the survival of close relatives of the affected individual, by processes which do not require any discontinuities in the population breeding structure.^[14]

Kin selection causes changes in gene frequency across generations, driven by interactions between related individuals. This dynamic forms the conceptual basis of the theory of social evolution. Some cases of evolution by natural selection can only be understood by considering how biological relatives influence each other's fitness. Under natural selection, a gene encoding a trait that enhances the fitness of each individual carrying it should increase in frequency within the population; and conversely, a gene that lowers the individual fitness of its carriers should be eliminated. However, a hypothetical gene that prompts behaviour which enhances the fitness of relatives but lowers that of the individual displaying the behaviour, may nonetheless increase in frequency, because relatives often carry the same gene. According to this principle, the enhanced fitness of relatives can at times more than compensate for the fitness loss incurred by the individuals displaying the behaviour, making kin selection possible. This is a special case of a more general model, "inclusive fitness".^[15] This analysis has been challenged,^[16] Wilson writing that "the foundations of the general theory of inclusive fitness based on the theory of kin selection have crumbled"^[17] and that he now relies instead on the theory of eusociality and "gene-culture co-evolution" for the underlying mechanics of sociobiology.

"Kin selection" should not be confused with "group selection" according to which a genetic trait can become prevalent within a group because it benefits the group as a whole, regardless of any benefit to individual organisms. All known forms of group selection conform to the principle that an individual behaviour can be evolutionarily successful only if the genes responsible for this behaviour conform to Hamilton's Rule, and hence, on balance and in the aggregate, benefit from the behaviour.^[18][19][20]

Hamilton's rule

Formally, genes should increase in frequency when

${\displaystyle rB>C}$

where

r=the genetic relatedness of the recipient to the actor, often defined as the probability that a gene picked randomly from each at the same locus is identical by descent.

B=the additional reproductive benefit gained by the recipient of the altruistic act,

C=the reproductive cost to the individual performing the act.

This inequality is known as Hamilton's rule after W. D. Hamilton who in 1964 published the first formal quantitative treatment of kin selection.

The relatedness parameter (r) in Hamilton's rule was introduced in 1922 by Sewall Wright as a coefficient of relationship that gives the probability that at a random locus, the alleles there will be identical by descent.^[21] Subsequent authors, including Hamilton, sometimes reformulate this with a regression, which, unlike probabilities, can be negative. A regression analysis producing statistically significant negative relationships indicates that two individuals are less genetically alike than two random ones (Hamilton 1970, Nature & Grafen 1985 Oxford Surveys in Evolutionary Biology). This has been invoked to explain the evolution of spiteful behaviour consisting of acts that result in harm, or loss of fitness, to both the actor and the recipient.

Several scientific studies have found that the kin selection model can be applied to nature. For example, in 2010 researchers used a wild population of red squirrels in Yukon, Canada to study kin selection in nature. The researchers found that surrogate mothers would adopt related orphaned squirrel pups but not unrelated orphans. The researchers calculated the cost of adoption by measuring a decrease in the survival probability of the entire litter after increasing the litter by one pup, while benefit was measured as the increased chance of survival of the orphan. The degree of relatedness of the orphan and surrogate mother for adoption to occur depended on the number of pups the surrogate mother already had in her nest, as this affected the cost of adoption. The study showed that females always adopted orphans when rB > C, but never adopted when rB < C, providing strong support for Hamilton's rule.^[22]

Mechanisms

Altruism occurs where the instigating individual suffers a fitness loss while the receiving individual experiences a fitness gain. The sacrifice of one individual to help another is an example.^[23]

Hamilton (1964) outlined two ways in which kin selection altruism could be favoured:

The selective advantage which makes behaviour conditional in the right sense on the discrimination of factors which correlate with the relationship of the individual concerned is therefore obvious. It may be, for instance, that in respect of a certain social action performed towards neighbours indiscriminately, an individual is only just breaking even in terms of inclusive fitness. If he could learn to recognise those of his neighbours who really were close relatives and could devote his beneficial actions to them alone an advantage to inclusive fitness would at once appear. Thus a mutation causing such discriminatory behaviour itself benefits inclusive fitness and would be selected. In fact, the individual may not need to perform any discrimination so sophisticated as we suggest here; a difference in the generosity of his behaviour according to whether the situations evoking it were encountered near to, or far from, his own home might occasion an advantage of a similar kind." (1996 [1964], 51)^[1]

Kin recognition: theory predicts that bearers of a trait (like the fictitious 'green beard') will behave altruistically towards others with the same trait.

Kin recognition: First, if individuals have the capacity to recognise kin and to discriminate (positively) on the basis of kinship, then the average relatedness of the recipients of altruism could be high enough for kin selection. Because of the facultative nature of this mechanism, kin recognition and discrimination are expected to be unimportant except among 'higher' forms of life such as the fish Neolamprologus pulcher (although there is some evidence for it among protozoa). Note also that kin recognition may be selected for inbreeding avoidance, and little evidence indicates that 'innate' kin recognition plays a role in mediating altruism. A thought experiment on the kin recognition/discrimination distinction is the hypothetical 'green beard', where a gene for social behaviour is imagined also to cause a distinctive phenotype that can be recognised by other carriers of the gene. Due to conflicting genetic similarity in the rest of the genome, there would be selection pressure for green-beard altruistic sacrifices to be suppressed, making common ancestry the most likely form of inclusive fitness.

Viscous populations: Secondly, even indiscriminate altruism may be favoured in "viscous" populations with low rates or short ranges of dispersal. Here, social partners are typically genealogically close kin, and so altruism can flourish even in the absence of kin recognition and kin discrimination faculties—spatial proximity and circumstantial cues serving as a rudimentary form of discrimination. This suggests a rather general explanation for altruism. Directional selection always favours those with higher rates of fecundity within a certain population. Social individuals can often enhance the survival of their own kin by participating in and following the rules of their own group.

Hamilton later modified his thinking to suggest that an innate ability to recognise actual genetic relatedness was unlikely to be the dominant mediating mechanism for kin altruism:

But once again, we do not expect anything describable as an innate kin recognition adaptation, used for social behaviour other than mating, for the reasons already given in the hypothetical case of the trees. (Hamilton 1987, 425)^[24]

Hamilton's later clarifications often go unnoticed, and because of the long-standing assumption that kin selection requires innate powers of kin recognition, some theorists have tried to clarify the position in recent work:

In his original papers on inclusive fitness theory, Hamilton pointed out a sufficiently high relatedness to favour altruistic behaviours could accrue in two ways — kin discrimination or limited dispersal (Hamilton, 1964, 1971,1972, 1975). There is a huge theoretical literature on the possible role of limited dispersal reviewed by Platt & Bever (2009) and West et al. (2002a), as well as experimental evolution tests of these models (Diggle et al., 2007; Griffin et al., 2004; Kümmerli et al., 2009). However, despite this, it is still sometimes claimed that kin selection requires kin discrimination (Oates & Wilson, 2001; Silk, 2002 ). Furthermore, a large number of authors appear to have implicitly or explicitly assumed that kin discrimination is the only mechanism by which altruistic behaviours can be directed towards relatives... [T]here is a huge industry of papers reinventing limited dispersal as an explanation for cooperation. The mistakes in these areas seem to stem from the incorrect assumption that kin selection or indirect fitness benefits require kin discrimination (misconception 5), despite the fact that Hamilton pointed out the potential role of limited dispersal in his earliest papers on inclusive fitness theory (Hamilton, 1964; Hamilton, 1971; Hamilton, 1972; Hamilton, 1975). (West et al. 2010, p.243 and supplement)^[25]

The assumption that kin recognition must be innate, and that cue-based mediation of social cooperation based on limited dispersal and shared developmental context are not sufficient, has obscured significant progress made in applying kin selection and inclusive fitness theory to a wide variety of species, including humans,^[26][27] on the basis of cue-based mediation of social bonding and social behaviours.

Kin selection and human social patterns

Families are important in human behaviour, but kin selection may be based on closeness and other cues.

Evolutionary psychologists, following early human sociobiologists' interpretation^[28] of kin selection theory initially attempted to explain human altruistic behaviour through kin selection by stating that "behaviors that help a genetic relative are favored by natural selection." However, most Evolutionary psychologists recognise that this common shorthand formulation is inaccurate;

[M]any misunderstandings persist. In many cases, they result from conflating "coefficient of relatedness" and "proportion of shared genes," which is a short step from the intuitively appealing—but incorrect—interpretation that "animals tend to be altruistic toward those with whom they share a lot of genes." These misunderstandings don’t just crop up occasionally; they are repeated in many writings, including undergraduate psychology textbooks—most of them in the field of social psychology, within sections describing evolutionary approaches to altruism. (Park 2007, p860)^[29]

As with the earlier sociobiological forays into the cross-cultural data, typical approaches are not able to find explanatory fit with the findings of ethnographers insofar that human kinship patterns are not necessarily built upon blood-ties. However, as Hamilton's later refinements of his theory make clear, it does not simply predict that genetically related individuals will inevitably recognise and engage in positive social behaviours with genetic relatives: rather, indirect context-based mechanisms may have evolved, which in historical environments have met the inclusive fitness criterion (see above section). Consideration of the demographics of the typical evolutionary environment of any species is crucial to understanding the evolution of social behaviours. As Hamilton himself puts it, "Altruistic or selfish acts are only possible when a suitable social object is available. In this sense behaviours are conditional from the start." (Hamilton 1987, 420).^[24]

Under this perspective, and noting the necessity of a reliable context of interaction being available, the data on how altruism is mediated in social mammals is readily made sense of. In social mammals, primates and humans, altruistic acts that meet the kin selection criterion are typically mediated by circumstantial cues such as shared developmental environment, familiarity and social bonding.^[30] That is, it is the context that mediates the development of the bonding process and the expression of the altruistic behaviours, not genetic relatedness per se. This interpretation thus is compatible with the cross-cultural ethnographic data^[27] and has been called nurture kinship.

Examples

Eusociality (true sociality) is used to describe social systems with three characteristics: an overlap in generations between parents and their offspring, cooperative brood care, and specialised castes of non-reproductive individuals.^[31] The social insects provide good examples of organisms with what appear to be kin selected traits. The workers of some species are sterile, a trait that would not occur if individual selection was the only process at work. The relatedness coefficient r is abnormally high between the worker sisters in a colony of Hymenoptera due to haplodiploidy. Hamilton's rule is presumed to be satisfied because the benefits in fitness for the workers are believed to exceed the costs in terms of lost reproductive opportunity, though this has never been demonstrated empirically. There are competing hypotheses, as well, which may also explain the evolution of social behaviour in such organisms.^[16]
 

Sun-tailed monkeys favour their own maternal kin.

In sun-tailed monkey communities, maternal kin (kin related to by mothers) favour each other, but that with relatives more distant than half-siblings, this bias drops significantly.^[32]

Alarm calls in ground squirrels appear to confirm kin selection. While calls may alert others of the same species to danger, they draw attention to the caller and expose it to increased risk of predation. The calls occur most frequently when the caller had relatives nearby.^[33] Individual male prairie dogs followed through different stages of life modify their rate of calling when closer to kin. These behaviours show that self-sacrifice is directed towards close relatives, and that there is an indirect fitness gain.^[31] Surrogate mothers adopt orphaned red squirrels in the wild only when the conditions of Hamilton's rule were met.^[22]

Alan Krakauer of University of California, Berkeley has studied kin selection in the courtship behaviour of wild turkeys. Like a teenager helping her older sister prepare for a party, a subordinate turkey may help his dominant brother put on an impressive team display that is only of direct benefit to the dominant member.^[34]

Even certain plants can recognise and respond to kinship ties. Using sea rocket, Susan Dudley at McMaster University, Canada compared the growth patterns of unrelated plants sharing a pot to plants from the same clone. She found that unrelated plants competed for soil nutrients by aggressive root growth. This did not occur with sibling plants.^[35]

In the wood mouse (Apodemus sylvaticus), aggregates of spermatozoa form mobile trains, some of the spermatozoa undergo premature acrosome reactions that correlate to improved mobility of the mobile trains towards the female egg for fertilisation. This association is thought to proceed as a result of a "green beard effect" in which the spermatozoa perform a kin-selective altruistic act after identifying genetic similarity with the surrounding spermatozoa.^[36]

In humans

Whether or not Hamilton's rule always applies, relatedness is often important for human altruism, in that humans are inclined to behave more altruistically toward kin than toward unrelated individuals.^[37] Many people choose to live near relatives, exchange sizeable gifts with relatives, and favour relatives in wills in proportion to their relatedness.^[37]

Experimental studies, interviews, and surveys

Interviews of several hundred women in Los Angeles showed that while non-kin friends were willing to help one another, their assistance was far more likely to be reciprocal. The largest amounts of non-reciprocal help, however, were reportedly provided by kin. Additionally, more closely related kin were considered more likely sources of assistance than distant kin.^[38] Similarly, several surveys of American college students found that individuals were more likely to incur the cost of assisting kin when a high probability that relatedness and benefit would be greater than cost existed. Participants’ feelings of helpfulness were stronger toward family members than non-kin. Additionally, participants were found to be most willing to help those individuals most closely related to them. Interpersonal relationships between kin in general were more supportive and less Machiavellian than those between non-kin.^[39]

In one experiment, the longer participants (from both the UK and the South African Zulus) held a painful skiing position, the more money or food was presented to a given relative. Participants repeated the experiment for individuals of different relatedness (parents and siblings at r=.5, grandparents, nieces, and nephews at r=.25, etc.). The results showed that participants held the position for longer intervals the greater the degree of relatedness between themselves and those receiving the reward.^[40]

Observational studies

A study of food-sharing practices on the West Caroline islets of Ifaluk determined that food-sharing was more common among people from the same islet, possibly because the degree of relatedness between inhabitants of the same islet would be higher than relatedness between inhabitants of different islets. When food was shared between islets, the distance the sharer was required to travel correlated with the relatedness of the recipient—a greater distance meant that the recipient needed to be a closer relative. The relatedness of the individual and the potential inclusive fitness benefit needed to outweigh the energy cost of transporting the food over distance.^[41]

Humans may use the inheritance of material goods and wealth to maximise their inclusive fitness. By providing close kin with inherited wealth, an individual may improve his or her kin’s reproductive opportunities and thus increase his or her own inclusive fitness even after death. A study of a thousand wills found that the beneficiaries who received the most inheritance were generally those most closely related to the will’s writer. Distant kin received proportionally less inheritance, with the least amount of inheritance going to non-kin.^[42]

A study of childcare practices among Canadian women found that respondents with children provide childcare reciprocally with non-kin. The cost of caring for non-kin was balanced by the benefit a woman received—having her own offspring cared for in return. However, respondents without children were significantly more likely to offer childcare to kin. For individuals without their own offspring, the inclusive fitness benefits of providing care to closely related children might outweigh the time and energy costs of childcare.^[43]

Family investment in offspring among black South African households also appears consistent with an inclusive fitness model.^[44] A higher degree of relatedness between children and their caregivers frequently correlated with a higher degree of investment in the children, with more food, health care, and clothing being provided. Relatedness between the child and the rest of the household also positively associated with the regularity of a child’s visits to local medical practitioners and with the highest grade the child had completed in school. Additionally, relatedness negatively associated with a child’s being behind in school for his or her age.

Observation of the Dolgan hunter-gatherers of northern Russia suggested that, while reciprocal food-sharing occurs between both kin and non-kin, there are larger and more frequent asymmetrical transfers of food to kin. Kin are also more likely to be welcomed to non-reciprocal meals, while non-kin are discouraged from attending. Finally, even when reciprocal food-sharing occurs between families, these families are often very closely related, and the primary beneficiaries are the offspring.^[45]

Other research indicates that violence in families is more likely to occur when step-parents are present and that "genetic relationship is associated with a softening of conflict, and people's evident valuations of themselves and of others are systematically related to the parties' reproductive values".^[46]

Numerous other studies suggest how inclusive fitness may work amongst different peoples, such as the Ye’kwana of southern Venezuela, the Gypsies of Hungary, and the doomed Donner Party of the United States.^{[47][48][49][50][51]}

In non-human species

Vervet monkeys display kin selection between siblings, mothers and offspring, and grandparent-grandchild. These monkeys utilise allomothering, where the allomother is typically an older female sibling or a grandmother. Other studies have shown that individuals will act aggressively toward other individuals that were aggressive toward their relatives.^[52][53]

Synalpheus regalis is a eusocial shrimp that protects juveniles in the colony. By defending the young, the large defender shrimp can increase its inclusive fitness. Allozyme data revealed that relatedness within colonies is high, averaging 0.50, indicating that colonies in this species represent close kin groups.^[54]

Objections

The theory of kin selection has been criticised by Alonso in 1998^[55] and by Alonso and Schuck-Paim in 2002.^[56] Alonso and Schuck-Paim argue that the behaviours which kin selection attempts to explain are not altruistic (in pure Darwinian terms) because: (1) they may directly favour the performer as an individual aiming to maximise its progeny (so the behaviours can be explained as ordinary individual selection); (2) these behaviours benefit the group (so they can be explained as group selection); or (3) they are by-products of a developmental system of many "individuals" performing different tasks (like a colony of bees, or the cells of multicellular organisms, which are the focus of selection). They also argue that the genes involved in sex ratio conflicts could be treated as "parasites" of (already established) social colonies, not as their "promoters", and, therefore the sex ratio in colonies would be irrelevant to the transition to eusociality.^[55][56] Those ideas were mostly ignored until they were put forward again in a series of papers by E. O. Wilson, Bert Hölldobler, Martin Nowak and others.^[57][58][59] Nowak, Tarnita and Wilson argued that

Inclusive fitness theory is not a simplification over the standard approach. It is an alternative accounting method, but one that works only in a very limited domain. Whenever inclusive fitness does work, the results are identical to those of the standard approach. Inclusive fitness theory is an unnecessary detour, which does not provide additional insight or information.

— Nowak, Tarnita, and Wilson^[16]

They, like Alonso (1998) and Alonso and Schuck-Paim (2002) earlier, argue for a multi-level selection model instead.^[16] This aroused a strong response, including a rebuttal published in Nature from over a hundred researchers.

Darwinian anthropology

From Wikipedia, the free encyclopedia

Darwinian anthropology describes an approach to anthropological analysis which employs various theories from Darwinian evolutionary biology. Whilst there are a number of areas of research that can come under this broad description (Marks, 2004) some specific research projects have been closely associated with the label. A prominent example is the project that developed in the mid 1970s with the goal of applying sociobiological perspectives to explain patterns of human social relationships, particularly kinship patterns across human cultures.

This kinship-focused Darwinian anthropology was a significant intellectual forebear of evolutionary psychology, and both draw on biological theories of the evolution of social behavior (in particular inclusive fitness theory) upon which the field of sociobiology was founded.

Overview

In 1974 the biologist Richard D. Alexander published an article The Evolution of Social Behavior which drew upon W.D.Hamilton's work on inclusive fitness and kin selection and noted that:

Although ten years have passed since Hamilton's landmark papers, apparently only a single social scientist (Campbell, 31) has made a distinct effort to incorporate kin selection into theories of human altruism... But so have the biologists, for one reason or another, failed to consider the enormous literature on topics like kinship systems and reciprocity in human behavior. (Alexander 1974, 326)^[2]

Amongst other suggestions, Alexander suggested that certain patterns of social cooperation documented by ethnographers, in particular the avunculate ('mother's brother') relationship, could be explained in reference to individuals pursuing a strategy of individual inclusive fitness maximization under conditions of low certainty-of-paternity. This hypothesis was subsequently taken up and elaborated in a series of studies by other Darwinian anthropologists:

The hypothesis follows that matrilineal inheritance is a cultural trait that evolved in response to low probability of paternity. [...] The paternity hypothesis was rescued and made explicit in the context of modern evolutionary theory by Alexander in 1974. Over the next 10 years this provided the impetus leading to numerous theoretical refinements and scholarly and empirical investigations (Flinn 1981; Gaulin & Schlegel 1980; Greene 1978; Hartung 1981b; Kurland 1979).(Hartung 1985,661-663) ^[3]

Ultimately these analyses were considered unsuccessful, and were specifically criticized by other sociobiologists on a number of grounds. One problem was said to be that interpreting inclusive fitness theory to imply that individuals have evolved the characteristic of pursuing strategies to maximize their own 'inclusive fitness' is erroneous; the theory should instead be interpreted to describe selection pressures on genes:

Alexander’s argument... erred through looking at things from the point of view of an individual... I believe this kind of error is all too easy to make when we use the technical term ‘fitness’ [of individuals]. This is why I have avoided using the term in this book. There is really only one entity whose point of view matters in evolution, and that entity is the selfish gene.(Dawkins 1989 (1976), 137 emphasis in original) ^[4]

A related problem was that, in assuming that individuals simply operate as inclusive fitness maximizing agents, any investigation of the proximate psychological mechanisms that mediate social behaviors was ignored. Symons made this observation in his 1989 Critique of Darwinian Anthropology:

DA’s central hypothesis is that “evolved behavioral tendencies” cause human “behavior to assume the form that maximizes inclusive fitness”(Irons 1979b, 33). Turke and Betzig (1985) state this hypothesis as a formal prediction: “Modern Darwinian theory predicts that human behavior will be adaptive, that is, designed to promote maximum reproductive success through available descendant and nondescendant relatives.”(p 79)… [T]he key terms in [this] quotation are used in DA to bypass the question of phenotypic design in characterizations of adaptation.(Symons 1989, 131-132) ^[5]

Symons, along with Tooby and Cosmides, were amongst the founders of the emerging school of evolutionary psychology, whose aim has been to focus more on these hypothesized proximate psychological mechanisms.

Theoretical background

Darwinian anthropology was critiqued by Symonds for its agnosticism as to the psychological mechanisms governing how social behavior is actually expressed in the human species, and its reliance on interpreting inclusive fitness theory to simply imply that humans have evolved to be inclusive fitness maximizers. This section will review some of the relevant background discussion in inclusive fitness theory to clarify why this position was considered untenable.

Evolutionary versus proximate explanations

Inclusive Fitness theory has often been interpreted to mean that social behavior per se is a goal of evolution, and also that genes (or individual organisms) are selected to find ways of actively distinguishing the identity of close genetic relatives ‘in order to’ engage in social behaviors with them.

[M]any misunderstandings persist. In many cases, they result from conflating “coefficient of relatedness” and “proportion of shared genes,” which is a short step from the intuitively appealing—but incorrect—interpretation that “animals tend to be altruistic toward those with whom they share a lot of genes.” These misunderstandings don’t just crop up occasionally; they are repeated in many writings, including undergraduate psychology textbooks—most of them in the field of social psychology, within sections describing evolutionary approaches to altruism. (Park 2007, p860)^[6]

The apparent rationale for this common mis-interpretation is that organisms would thereby benefit the “Inclusive Fitness of the individuals (and genes) involved”. This approach overlooks the point that evolution is not a teleological process, but a passive, consequential and undirected biological process, where environmental variations and drift effects are present alongside random gene mutations and natural selection.

Inclusive fitness theory takes the form of an ultimate explanation, specifically a criterion (br>c), for the evolution of social behaviors, not a proximate mechanism governing the expression of social behaviors. What forms of social behavior might meet this criterion are cannot be a priori specified by the theory, nor can it shed light on whether the life history of a species provides opportunities for social interactions to occur. Thus, strictly speaking, the interpretation that organisms ‘have evolved to’ direct social behavior towards genetic relatives is not implied by the theory (see also inclusive fitness).

Investigating how inclusive fitness theory might apply to the potential emergence of social traits in any given species must begin with an analysis of the evolutionarily typical ecological niche, demographics, and patterns of interaction of that species. Where significant interaction between individuals is not present in the life history of a species, the theory is necessarily null regarding social behaviors between individuals. As Silk (2001) put it;

The role of kinship in the daily lives of animals depends on the demographic composition of the groups in which they live. Kin selection will only be an important force in the evolution of social behavior if animals find themselves in situations where they have an opportunity to fulfill the predictions of Hamilton’s rule. At a minimum, kin must be available. The number, availability, and degree of relatedness among kin will depend on how groups are constructed in nature.” (Silk 2001, 77)^[7]

Consideration must thus be given to whether the ecological niche leads to the clustering of individuals in groups or whether individuals are typically solitary. Socioecology research, for example, suggests that fundamental influences on demographic patterns are the distribution/fecundity of primary food sources as well as patterns of predation. When considering social behavior traits of a given species, consideration of these influences is in a sense, logically prior to analyses of inclusive fitness pressures on the species.

Selection pressure on genes or strategy of individuals

Darwinian anthropology, following R. D. Alexander, used the notion of the inclusive fitness of individuals rather than the inclusive fitness of genes. Dawkins (above) pointed to this as an error. The source of the confusion can be traced to discussions in Hamilton's early papers on inclusive fitness. In his 1963 paper Hamilton refers, unambiguously, to selection pressures on genes;

[T]he ultimate criterion which determines whether G [a gene] will spread is not whether the behaviour is to the benefit of the behaver but whether it is to the benefit of the gene G; and this will be the case if the average net result of the behaviour is to add to the gene pool a handful of genes containing G in higher concentration than does the gene pool itself.” (1996 [1963], 7)^[8]

However, in his paper published in 1964, actually written before the 1963 paper (Hamilton 1996), Hamilton had included a subsidiary discussion on what the genetic theory might imply for how we look at the fitness of individuals:

Actually, in the preceding mathematical account we were not concerned with the inclusive fitness of individuals as described here but rather with certain averages of them which we call the inclusive fitness of types. But the idea of the inclusive fitness of an individual is nevertheless a useful one. Just as in the sense of classical selection we may consider whether a given character expressed in an individual is adaptive in the sense of being in the interest of his personal fitness or not, so in the present sense of selection we may consider whether the character or trait of behaviour is or is not adaptive in the sense if being in the interest of his inclusive fitness.” (Hamilton 1996 [1964], 38)^[9]

It is clear here that the formal treatment is of the selection pressures on types (genes or traits), whilst the notion of individual inclusive fitness may serve as a guide to the adaptiveness of the trait; just as consideration of effects of a trait on an individual's fitness can be instructive when considering classical selection on traits. At the same time, it is understandable that Alexander took the inclusive fitness of individuals as a heuristic device.

Context-based or discrimination-based expression mechanisms

In his 1964 paper, Hamilton 'hazards' “the following unrigorous statement of the main principle that has emerged from the model”;

The Social behaviour of a species evolves in such a way that in each distinct behaviour-evoking situation the individual will seem to value his neighbours’ fitness against his own according to the coefficients of relationship appropriate to that situation.”(1964 [1996], 49)^[9]

He uses the terms 'hazards', 'unrigorous', and 'will seem' deliberately, since his formal analysis makes clear that the model specifies the evolutionary selection pressure, rather than specifying what mechanisms govern the proximate expression of social behaviors. He also clearly points to social behaviors being evoked in distinct situations, and that individuals may encounter potential social recipients of different degree of relationship in different situations. If one ignores the cautious qualifying words however, the passage might readily be interpreted to imply that individuals are indeed expected to make an active assessment of the degree of relatedness of others they interact with in different situations. Later in the paper, Hamilton again discusses the issue of whether the performance (or expression) of social behaviors might be conditional on; (a) discriminating factors which correlate with close relationship with the recipient, or (b) actually discriminating which individuals 'really are' in close relationship with the recipient:

The selective advantage which makes behaviour conditional in the right sense on the discrimination of factors which correlate with the relationship of the individual concerned is therefore obvious. It may be, for instance, that in respect of a certain social action performed towards neighbours indiscriminately, an individual is only just breaking even in terms of inclusive fitness. If he could learn to recognise those of his neighbours who really were close relatives and could devote his beneficial actions to them alone an advantage to inclusive fitness would at once appear. Thus a mutation causing such discriminatory behaviour itself benefits inclusive fitness and would be selected. In fact, the individual may not need to perform any discrimination so sophisticated as we suggest here; a difference in the generosity of his behaviour according to whether the situations evoking it were encountered near to, or far from, his own home might occasion an advantage of a similar kind.” (1996 [1964], 51)^[9]

For certain social behaviors, Hamilton suggests there may be selection pressure for more discerning discrimination of genetic relatedness, were the mutation to occur. But 'in fact' the same net result of accurately targeting social behaviors towards genetic relatives could be achieved via a simpler mechanism of being expressed in proximity to the actor's 'home'. Hamilton is thus agnostic as to whether evolved social behaviors might be expressed via straightforward proximate mechanisms such as location-based cues, or whether more specific discriminatory powers might govern their expression. He does suggest that the distinct social contexts within which various social behaviors are expressed are factors to consider. Other theorists have discussed these questions of whether proximity, context or more discriminatory expression may govern behaviors:

Animals cannot, of course, be expected to know, in a cognitive sense, who their relatives are, and in practice the behaviour that is favoured by natural selection will be equivalent to a rough rule of thumb such as ‘share food with anything that moves in the nest in which you are sitting.’ If families happen to go around in groups, this fact provides a useful rule of thumb for kin selection: ‘care for any individual you often see’.” (Dawkins 1979, 187)^[10]

If, for example, animals behave with an equal degree of altruism to all their “neighbours”… and if on average animals are related to their neighbours, then I would regard this as an example of kin selection. It is not a necessary feature of kin selection that an animal should distinguish different degrees of relationship among its neighbours, and behave with greater altruism to the more closely related…”(Maynard Smith 1976, 282 emphasis in original)^[11]

Dawkins believes social behaviors will in practice be governed by context-based expression. Maynard Smith is, like Hamilton, agnostic, but reiterates the point that context-based cues might well govern their expression and that actively distinguishing relatives is not necessarily expected for the expression of those social traits whose evolution is governed by inclusive fitness criteria. In sum, inclusive fitness theory does imply that; the evolutionary emergence of social behavior can occur where there is statistical association of genes between social actors and recipients; but that the expression of such evolved social behaviors is not necessarily governed by actual genetic relatedness between participants. The evolutionary criterion and the proximate mechanism must thus not be confused: the first does require genetic association (of the form br>c), the second does not.
Darwinian anthropology's central premise that human behavior has evolved to maximize the inclusive fitness of individuals is thus not a logical derivative of the theory. Also, the notion that humans will discriminate social behaviors towards genetic relatives is again not entailed by the theory.

Reception by anthropologists

Before the questions raised within anthropology about the study of ‘kinship’ by Schneider ^[12] and others from the 1960s onwards, anthropology itself had paid very little attention to the notion that social bonds were anything other than connected to consanguinal (or genetic) relatedness (or its local cultural conceptions). The social bonding associated with provision of and sharing of food was one important exception, particularly in the work of Richards,^[13] but this was largely ignored by descriptions of ‘kinship’ till more recently. Although questioning the means by which ‘kinship bonds’ form, few of these early accounts questioned the fundamental role of ‘procreative ties’ in social bonding (Schneider, 1984). From the 1950s onwards, reports on kinship patterns in the New Guinea Highlands added some momentum to what had until then been only occasional fleeting suggestions that living together (co-residence) might underlie social bonding, and eventually contributed to the general shift away from a genealogical approach. For example, on the basis of his observations, Barnes suggested:

[C]learly, genealogical connexion of some sort is one criterion for membership of many social groups. But it may not be the only criterion; birth, or residence, or a parent’s former residence, or utilization of garden land, or participation in exchange and feasting activities or in house-building or raiding, may be other relevant criteria for group membership.”(Barnes 1962,6)^[14]

Similarly, Langness' ethnography of the Bena Bena also emphasized a break with the genealogical perspective:

The sheer fact of residence in a Bena Bena group can and does determine kinship. People do not necessarily reside where they do because they are kinsmen: rather they become kinsmen because they reside there.” (Langness 1964, 172 emphasis in original)^[15]

By 1972, Schneider^[16][17] had raised deep problems with the notion that human social bonds and 'kinship' was a natural category built upon genealogical ties (for more information, see kinship), and especially in the wake of his 1984 critique^[12] this has become broadly accepted by most, if not all, anthropologists.^[18]

The darwinian anthropology (and other sociobiological) perspectives, arising in the early 1970s, had not unreasonably assumed that the genealogical conceptions of human kinship, in place since Morgan's early work^[19] in the 1870s, were still valid as a universal feature of humans. But they emerged at precisely the time that anthropology, being particularly sensitive about its own apparent 'ethnocentric' generalizations about kinship (from cultural particulars to human universals) was seeking to distance itself from these conceptions. The vehemence of Sahlins' rebuttal of sociobiology's genetic relatedness perspective in his 1976 The use and abuse of Biology, which underlined the non-genealogical nature of human kinship, can be understood as part of this 'distancing' trend.

Alternative approaches

The lack of success of darwinian anthropology created space for alternative approaches to analyzing human social behaviors from a biological perspective. Alexander's initial point (above) that the inclusive fitness framework had been scarcely applied to human kinship and social patterns has remained largely valid. But the move away from genealogical kinship in anthropology has continued to be a major barrier to any potential resolution. This section reviews a range of approaches to synthesizing ideas from evolutionary biology to observations and data about human social behaviour across contemporary human populations. Whilst some of these approaches include the inclusive fitness approach, others may seek to demonstrate fit to other theories from evolutionary biology, or to demonstrate that certain proximate mechanisms of social behaviour are both compatible with the inclusive fitness approach, and also with the broad variety of ethnographic data on human kinship patterns.

Criticism

Theories in evolutionary biology relevant to understanding social behavior may not be limited to frameworks such as inclusive fitness theory. The theory of reciprocal altruism may have equal or greater explanatory power for some forms of human social behavior, and perhaps kinship patterns. Other approaches may maintain that human behavior is less amenable to biological analysis due to the prominent influence of social learning and cultural transmission in the human species, and instead advance ideas based on the role of e.g. culture, historical contingencies or economic/environmental conditions. All or any of these may or may not contribute valuable insights to our understanding of social behavior and social patterns in humans.