For it to work, the group level selection story first requires a kind of systematic and organized “religion” that is historically rather recent. These are the kinds of religions which, through a variety of mechanisms such as intensified morality and supernatural surveillance, enable the formation of groups larger than prototypical hunter-gather bands.

Because these sorts of religions began appearing no more than 5,000 years ago in conjunction with the rise of the earliest city-states, it is reasonable to ask whether the dynamic being described has much to do with evolution, sensu stricto. Group level selectionists tend to conflate biological evolution with cultural change or what they call “cultural evolution.” Some simply jump from one to the other as if there were no differences between organisms and cultures, while others more subtly argue that biology and culture co-evolve.

These group level selection models assume a relatively homogenous and insular group of people who share the same religious beliefs, and that because of these beliefs (along with corollary institutions), the society is stable, competitive, and successful. It sounds good in abstract theory, even if it ignores the messy realities of the historical and human processes by which religions are constructed and contested.

On the surface, Saudi Arabia would appear to be perfect model for group level selectionists. It is an insular society that revolves around a single form of religion: Wahhabist Sunni Islam. The rulers champion religion, the clerics support the rulers, and the people believe. Saudi society, so the story goes, is bound tightly and ethically together by religion.

It’s a great story until one digs deeper and discovers some of the messy realities and variables which group level selectionists always ignore in their models. In this piece on the soon-to-be-without-head Saudi man who had the temerity to tweet about Muhammad, I was reminded of these realities:

While the most vituperative responses to the Hamza Kashgari affair are no doubt rooted in zealous conviction, the reality is that this episode, and particularly the government’s support for the case against him, has little to do with protecting the sanctity of Islam. Rather, the Saudi regime is playing a calculated political game, one that aims to oppress some critics, to outmaneuver others and to bolster its thin claims to religious legitimacy.

Kashgari was hardly a revolutionary, but his views most certainly were. The kingdom’s government is intolerant of free speech, especially anything that challenges political authority. Dissenting religious and political views, including those expressed by Kashgari, are widely shared inside the kingdom. Among the droves of death threats and the cries of angry critics, Kashgari also commands a sympathetic following. Thousands have rallied in his support. And the regime in Riyadh is well aware, particularly in an era of revolutionary upheaval, that a significant number of its subjects bristle against its authority.

The Saudi royal family has long leaned on the country’s senior clerics to stamp its temporal power with the imprimatur of religious legitimacy. But many in the kingdom see through the claim. Pious and agnostic alike consider the royal family corrupt and irreverent. It is commonly held that Riyadh’s assertion of Islamic authority is spurious, a fiction that the government peddles as an excuse to protect its personal fortunes and power. Whether genuine or not, the result has been the empowerment of a class of religious scholars who are committed to protecting their own authority.

It has long been my contention that when we talk about post-Neolithic religions and their effects on societies, evolutionary analyses aren’t very helpful or enlightening. Biocultural co-evolutionary models can neither capture nor describe things like economy, power, politics, cynicism, corruption, and dissent, all of which affect “religion.” Because religion is the key variable in group selection models, this is a problem.

When your primary variable is highly unstable, and can’t even be defined without making unrealistic assumptions about what religion is and how it works, chances are good that your model doesn’t describe anything real.

Post-Postscript

In this Nature article about Henry Markram’s controversial pitch for a $1 billion brain modeling project, he expresses concerns about modeling similar to those I have about the too tidy models favored by group level selectionists:

At the heart of that approach is Markram’s conviction that a good unifying model has to assimilate data from the bottom up. In his view, modellers should start at the most basic level — he focuses on ion channels because they determine when a neuron fires — and get everything working at one level before proceeding to the next. This requires a lot of educated guesses, but Markram argues that the admittedly huge gaps in knowledge about the brain can be filled with data as experiments are published — the Blue Brain model is updated once a week. The alternative approach, approximating and abstracting away the biological detail, leaves no way to be sure that the model’s behaviour has anything to do with how the brain works, said Markram.

These mistakes are the result of methodological ignorance or carelessness. In an ideal world, anyone who writes on the evolution of religion would be required to read Michael Ghiselin’s The Triumph of the Darwinian Method (1969). Many errors could thus be avoided.

“Good scientific investigations employ critical tests of hypotheses by serious attempts to refute them. They do not involve simply amassing data consistent with a particular interpretation, oblivious to whether or not the facts are equally consistent another hypothesis.” (239)

“It is easy to see how a psychologist, attempting to give evolutionary meaning to his data, would tend to use habits of thought quite different from those employed by Darwin. The natural inclination would be to impose an oversimplified evolutionary rationalization upon the observations. The evolutionary theorist, on the other hand, would look at the facts in order to confirm or refute the predictions of his hypothesis.” (210)

Those who do not follow this method (hypothesize, predict, confirm-refute) “completely miss the point of Darwin’s argument: behavioral properties may be mixtures of adaptations and historical accidents.” (211)

“Darwin thought that many behavioral phenomena have resulted through accidents of history comparable to the pleiotropic effects which he discoursed upon at such great length. He did not believe, as many have believed, that all behavior patterns have some adaptive significance, say, as directly serviceable or communicative.” (205)

“It is perfectly true that if a group of organisms had some property, the survival of that group would be favored once the property had been evolved; but this does not explain how that property might have originated.” (57)

The failure to take these ideas seriously has led to a great deal of unrestrained and imaginative storytelling about the “evolution of religion,” unencumbered by more compelling and parsimonious hypotheses that have non-speculative support in the historical record.

I was reminded of Horace’s enduring wisdom by two recent studies; the first on cooperation and second on punishment. Both are major contributions to our understanding of human altruism and collective action. Neither invokes the magic of gods.

In the “Evolution of Direct Reciprocity,” Andrew Delton and colleagues demonstrate that humans are naturally generous even to strangers and that such generosity is evolutionarily advantageous. A co-author of the July 25 PNAS study, Leda Cosmides, explains why humans can afford to be generous (i.e., incur costs) even when interaction might be a one-time affair:

There are two errors a cooperating animal can make, and one is more costly than the other. Believing that you will never meet this individual again, you might choose to benefit yourself at his expense –– only to find out later that the relationship could have been open-ended. If you make this error, you lose out on all the benefits you might have had from a long-term, perhaps life-long, cooperative relationship. This is an extraordinarily costly error to make.

The other error is to mistakenly assume that you will have additional interactions with the other individual and therefore cooperate with him, only to find out later that it wasn’t necessary. Although you were “unnecessarily” nice in that one interaction, the cost of this error is relatively small. Without knowing why, the mind is skewed to be generous to make sure we find and cement all those valuable, long-term relationships.

This is the restrained and mathematical kind of evolutionary psychology we can believe in.

In “Punishment Sustains Large-Scale Cooperation in Prestate Warfare,” Sarah Mathew and Robert Boyd find that profane punishment solves the free-rider problem that so exorcizes some evolutionary theorists of religion:

Understanding cooperation and punishment in small-scale societies is crucial for explaining the origins of human cooperation. We studied warfare among the Turkana, a politically uncentralized, egalitarian, nomadic pastoral society in East Africa.

Based on a representative sample of 88 recent raids, we show that the Turkana sustain costly cooperation in combat at a remarkably large scale, at least in part, through punishment of free-riders. Raiding parties comprised several hundred warriors and participants are not kin or day-to-day interactants. Warriors incur substantial risk of death and produce collective benefits. Cowardice and desertions occur, and are punished by community-imposed sanctions, including collective corporal punishment and fines. Furthermore, Turkana norms governing warfare benefit the ethnolinguistic group, a population of a half-million people, at the expense of smaller social groupings.

These results challenge current views that punishment is unimportant in small-scale societies and that human cooperation evolved in small groups of kin and familiar individuals. Instead, these results suggest that cooperation at the larger scale of ethnolinguistic units enforced by third-party sanctions could have a deep evolutionary history in the human species.

Large-scale cooperation, in other words, can revolve around something other than systematic religion or supernatural punishment. Shared language and ethnicity — along with earthly rewards (and beatings) — seem to work just fine.

We don’t need a group level or adaptive deus ex machina to explain the extraordinary success of ordinary humans. Parsimony to the rescue.

References:

Delton AW, Krasnow MM, Cosmides L, & Tooby J (2011). Evolution of direct reciprocity under uncertainty can explain human generosity in one-shot encounters. Proceedings of the National Academy of Sciences of the United States of America PMID: 21788489

Mathew S, & Boyd R (2011). Punishment sustains large-scale cooperation in prestate warfare. Proceedings of the National Academy of Sciences of the United States of America, 108 (28), 11375-80 PMID: 21670285

It is also a problem in science, which scorns postmodernism and savages it with satire. Science, and those who play in its fields, is chock full of highly intelligent people who adhere to irreconcilable schools of thought. We can only hope that the schoolmasters involved are, as Heller twice notes, thinking truthfully. Those who are not specialists in a particular field and who rely on experts are entitled, at a minimum, to intellectual honesty.

In this regard, it was refreshing to see an evolutionary psychologist recently make a public confession: resurrection apparently does not contradict science because it is beyond natural law. Death, in a special one-off some 2000 years ago, is not really death. This is on good authority of the pope and tradition.

Prior to this confession, I had long been at a loss to understand the stories this evolutionary psychologist has been telling about the “evolution of religion.” Matt Rossano, psychology professor at Southeastern Louisiana University, has been nothing if not prolific on the subject and recently published a book that purports to explain how religion evolved through “supernatural selection.” At least we now know what has been driving Rossano, and that his use of science and anthropology is not disinterested.

Anthropologists are in general agreement that between 80,000 and 60,000 years ago, one or several groups of humans living in Africa experienced some kind of breakthrough enabling them to increase their numbers, leave the continent, and colonize the world. Who these humans were and where they lived remains something of a mystery. What sorts of advantages these humans possessed also remains something of a mystery.

There is no shortage of plausible hypotheses. They could have been the first group(s) to possess fully fluent language or the capacity for symbolic thought. They may have been technological innovators, crafting better tools, weapons, shelters, and clothing than their predecessors. Some or all these things would have resulted in larger group sizes, which surely played a primary role in their success.

Or, as Rossano would have us believe, they were the first to get religion. This is of course possible. But is it probable? Is it parsimonious? Does the majority of the evidence point in this direction? The answers are no, no, and no.

The evidence is uncertain and equivocal, though you would never know this by reading Rossano’s work. As he selectively presents the evidence, you would think that science has the answers and it all points to the adaptive or supernatural, which for Rossano seem to be one and the same. Science does not yet have the answers, and the incredible story Rossano tells about the “evolution of religion” appears to be wishful (or Catholic) thinking.

In a series of foundational papers and books, George C. Williams, John Maynard Smith, William D. Hamilton, Robert Trivers, and Richard Dawkins explained how altruism and cooperation could have evolved through the combined operations of inclusive fitness and kin selection. The upshot of all this is that what looks like altruistic behavior is actually self interested behavior, when viewed from the perspective of an individual organism and its genes. There is, in other words, no such thing as “pure” altruism.

A small number of scholars have never been able to stomach the notion that what appears to be altruism is rooted in selfishness. Many, I suspect, are metaphysically troubled by the idea and simply cannot accept that “pure goodness” does not exist. In an effort to carve out conceptual space for unadulterated kindness, they have championed the idea of group level selection. They are the Kantians (or perhaps deists) of evolutionary biology. This group includes George R. Price, David Sloan Wilson, Elliot Sober, E.O. Wilson, and Oren Harman.

As some may know, Wilson recently co-authored an already notorious (and as Jerry Coyne explains, certainly dubious) paper in Nature asserting that kin selection is a chimera. Harman, for his part, recently published The Price of Altruism, which is part biography of George Price and part sermon extolling group level selection. Harman’s book was revealing in more ways than one: it exposed the metaphysics that I suspect motivates more than a few group level selectionists. George Price was an ecstatic (and eccentric) Christian.

This longish preface brings me to the point of this post: the “Trickster” figure who is found in the oral traditions of nearly all hunting and gathering peoples. Although this figure has been especially well documented among Native Americans, the trickster appears in nearly all world mythologies in one guise or another (e.g., Prometheus and Loki). After reading Paul Radin’s The Trickster: A Study in American Indian Mythology and Mac Linscott Ricketts’ “The North American Indian Trickster,” I came across this astonishing explanation of the ancient and archetypal Trickster myths:

It is [Franz] Boas’s contention that a sense of altruism is not likely to be very well developed in simpler societies, and so the members of such societies w0uld find it difficult to understand why a culture hero [i.e., the trickster] would want to benefit mankind.

The problem of motivation is solved, however, if the “benefits to mankind” are the accidental by-products of actions which the culture hero [or trickster] undertakes for purely selfish reasons. (Carroll 1984:110-111).

Boas offered this assessment in 1898 — long before anyone had considered the apparent contradiction of altruism in evolutionary terms. If Boas is correct, our ancestors had already considered the issue and resolved it without benefit of arcane equations or recourse to metaphysics: altruism is a byproduct of selfishness.

References:

Ricketts, M. (1966). The North American Indian Trickster. History of Religions, 5 (2) DOI: 10.1086/462529

Carroll, M. (1984). The Trickster as Selfish-Buffoon and Culture Hero. Ethos, 12 (2), 105-131 DOI: 10.1525/eth.1984.12.2.02a00020

Although there are several problems with this story (such as the lack of archaeological evidence for proto-religion and simpler explanations for what little evidence there is), the primary flaw in the argument is that it says nothing about the primary variable — group size — which drives the outcome of group competition. What makes one group more successful than another? In nearly all cases involving competing groups of social mammals, larger groups out-compete smaller ones.

The reasons are fairly obvious and supported by the evidence: larger groups have lower predation risk and have greater success in agonistic encounters. They have larger ranges or territories, and when resources are depleted or disappear, migration – usually a hazardous undertaking, is less hazardous. When a larger group of social mammals encounters a smaller one, the larger nearly always prevails. Larger groups also have a greater store of collective knowledge with respect to nearly everything that matters: water, food, shelter, and predators.

In a previous post, I examined the primary variables affecting group competition in an ancestral setting. Aside from group size, these included tools and language. The latter, in particular, would have had a galvanizing effect: “In addition to the planning and coordination it would have enabled, language at some point made possible notions of extended and fictive kinship, further strengthening this most powerful form of social glue.”

In an important study recently published in Science, Kim Hill and colleagues examined 32 present-day hunting and gathering societies to determine their group structure and residence patterns. They found “that hunter-gatherers display a unique social structure where (i) either sex may disperse or remain in their natal group, (ii) adult brothers and sisters often co-reside, and (iii) most individuals in residential groups are genetically unrelated. These patterns produce large interaction networks of unrelated adults and suggest that inclusive fitness cannot explain extensive cooperation in hunter-gatherer bands.” Surprisingly, most residential bands were not composed of primary genetic kin:

The data demonstrate that primary kin associations are typical, but that most adult band members are not close kin in any of the societies in our sample….[P]rimary and distant kin of a family unit make up only about 40% of the co-resident adult members of a band….[A]bout one-quarter of the individuals in a band are not linked directly to ego by any known genealogical or marriage tie.

Stated another way, 40% of the adult members of a typical foraging band are genetic kin and 75% of them are linked by genes and/or marriage. That is a high percentage of genetic and affinal relatedness. But what about the other 25% who are not related by blood or marriage? Are they considered to be non-kin? Hardly.

All known hunter-gatherer societies have elaborate kinship systems that extend kinship to large numbers of people who are not related by genes or marriage. Indeed, these systems are so extensive and complicated that a good number of anthropologists have devoted entire careers to studying them. These studies began with Lewis Henry Morgan in 1871 (Systems of Consanguinity and Affinity of the Human Family) and culminated with Claude Levi-Straus’ classic, The Elementary Structures of Kinship (1949).

What is the point of all this kinship, whether genetic, affinal, or fictive? The most compelling explanation is that it enables larger residential groups and creates networks of allied groups. Larger groups with more allies would have had an obvious advantage competing against groups lacking such ties. We do not need proto-religion to explain enhanced group cohesion and cooperation. Kinship will do just fine.

Reference:

Hill, K., Walker, R., Bozicevic, M., Eder, J., Headland, T., Hewlett, B., Hurtado, A., Marlowe, F., Wiessner, P., & Wood, B. (2011). Co-Residence Patterns in Hunter-Gatherer Societies Show Unique Human Social Structure. Science, 331 (6022), 1286-1289 DOI: 10.1126/science.1199071

First, it is extremely discouraging that 150 years after Darwin there appears to be a need to continue publishing books explaining evolution and debunking creationism. As Ronald Numbers’ shows in his masterful history The Creationists, wishful thinking has incredible staying power. Second, did Dawkins really need to publish another book of this kind? It seems as if you have read any of Dawkins’ recent books (excepting his three best, The Selfish Gene, The Extended Phenotype, and The Ancestor’s Tale), you have read them all. Given Dawkins’ considerable scientific skills and abilities as a writer, I wish he would cover some different ground.

I am not sure what it is about Spiegel reporters, but they are some of the best in the business. They seem always to know much about their topic and ask great questions. The interview with Dawkins is no exception. It touches on some key issues that deserve further comment.

Spiegel: The American geneticist Dean Hamer postulated the God Gene hypothesis, proposing that humans are genetically hardwired for religious faith.

Dawkins: I’d prefer to say that we have a lot of genetic predispositions for a lot of psychological attributes, which can under the right circumstances add up to religion. But I’m also thinking of things like a predisposition to be obedient towards authority, which might even be useful under certain circumstances. Or a predisposition to be afraid of death or, when frightened, to run to a parental figure. These are all separate psychological predispositions which under the right cultural circumstances end up pushing one into a religion, whichever the religion of one’s cultural upbringing. I wouldn’t call it a God Gene.

Dawkins is spot on with this answer. There are numerous attributes of the human brain-mind that, when combined in consciousness, inevitably give rise to belief in the supernatural. These attributes include, but are not limited to: causal attribution, pattern imposition, agency detection, theory of mind, and commonsense dualism. We have evolved a brain-mind that naturally and spontaneously constructs experience using these attributes, with the result being belief in the supernatural. When you add emotions such as fear, attachment, attraction, and sorrow to the mix, you have an organism that is perfectly primed and highly receptive to certain kinds of cultural patterning or inputs. All religions are built on this biological-neurological substrate.

The next question and answer are less auspicious:

Spiegel: Has religion not been very successful in an evolutionary sense?

Dawkins: The thought that human societies gained strength from religious memes in their competition with others is true to a certain extent. But it is more like an ecological struggle: It reminds me of the replacement of the red by the gray squirrel in Britain. That is not a natural selection process at all, it is an ecological succession. So when a tribe has a war-like god, when the young men are brought up with the thought that their destiny is to go out and fight as warriors and that a martyr’s death brings you straight to heaven, you see a set of powerful, mutually reinforcing memes at work. If the rival tribe has a peaceful god who believes in turning the other cheek, that might not prevail.

Dawkins loses his bearings with this answer. Societies and cultures are not organisms; thus, biological evolutionary processes cannot be used to explain their origins and development or histories — fundamentally different processes are at work. The whole meme thing needs to be junked; it was a bad analogy to begin with and has not gotten any better over time. Ideas are not the same as genes. Dawkins is not getting any closer to the mark by arguing that cultural history is akin to ecological succession.

It is this category mistake — conflating biological evolution with cultural history — that afflicts the large and growing literature purporting to explain the “evolution of religion” by appealing to group level selection. Because societies are not organisms, the transitive property does not apply and we should stop talking about “cultural evolution.” There is no such thing.

Because Dawkins erroneously conflates biological evolution with cultural history, the interviewers are justifiably skeptical:

Spiegel: But following a religion that does not promote the chances for survival seems to contradict evolutionary logic.

Dawkins: Oh yes, clearly there is a conflict between meme and gene survival. We are familiar with such conflicts. They sometimes work out one way, sometimes the other.

Terrible. Humans follow what we today call “religions” for reasons having little or nothing to do with ongoing biological evolution. There are more powerful processes at work and much simpler explanations. These processes and explanations are grounded in economy and politics, not in biology. Modern “religions” — i.e., those which appeared in conjunction with the Neolithic Revolution — have a logic all their own and this logic is not evolutionary.

Another way of stating this is that if there are two groups competing over resources essential to survival and reproduction (the sine qua non of evolutionary fitness), a group that is larger, has better technology, and/or can fluently converse will win out over groups that are more tightly knit because of shared supernatural beliefs and rituals but which lack these other advantages. An altruistic and cooperative group of 30 beseeching the aid of the animal spirits and willing to die for the group simply will not prevail in warfare against a “secular” group of 150. We can reverse these figures to see how technology and language could impact group competition.

Imagine (on the one hand) a group of 30 Paleolithic hunter-gatherers who lack shared conceptions of the supernatural and do not engage in group rituals. They are not in other words “proto-religious.” This group, however, has developed projectile weapons: bows, arrows, and atlatls (spear throwers). They also have fully developed language abilities, which means they are fully capable of planning and asking “what if” types of questions.

Imagine (on the other hand) a group of 150 Paleolithic hunter-gatherers who share conceptions of the supernatural and engage in group rituals. These rituals render them more cooperative and altruistic. They are in other words “proto-religious.” But this group lacks projectile weaponry; they are using sharpened spear-sticks and hafted points that require close-quarter combat. Moreover, this group does not have fully developed language abilities — their ability to plan and communicate during a group encounter is limited.

Now imagine these two groups encountering one another and warring over resources that enable survival and reproduction. Who wins? There is a better than even chance that the smaller non-supernatural group prevails over the larger supernatural group.

I was reminded of this last night while reading Richard Klein’s monumental book, The Human Career: Human Biological and Cultural Origins. In Chapter 7 (“Anatomically Modern Humans”), Klein discusses what might explain the all-important Upper Paleolithic transition approximately 50,000 years ago:

The most frequently cited “modern” behavioral markers are art and ornamentation, but new technologies that facilitated hunting and gathering were even more fundamental, for they enhanced human reproduction and survival and they promoted population growth. Most specialists would probably agree that that the subsequent growth propelled modern humans out of Africa and that their augmented ability to reproduce and survive explains the rapidity of their expansion across Eurasia.

While it is possible that more elaborate forms of supernaturalism and ritualism played a role in this transition, such forms do not appear in the archaeological record and must remain speculative. More importantly, other factors — such as advanced technologies — more parsimoniously explain this transition and actually appear in the record. There is no need to invoke “proto-religion” as an explanation for this transition. Proto-religion was not some talisman that magically resulted in group success and population growth.

Rowthorn’s study is a mathematical exercise – it models what would happen if his underlying premises and simplifying assumptions were true. If, in other words, the premises and assumptions exist in the real world, then Rowthorn’s conclusions follow. It is at this point that all students of critical thinking become wary. The conclusions, no matter how sophisticated the math used to reach them, stand or fall on the soundness of the premises and assumptions.

In this instance, Rowthorn’s premises are wrong and his assumptions are fictitious. There is no religion gene. Religion does not get passed to children via ova and sperm.

Over the coming week, I will be dissecting Rowthorn’s paper, but thought I would begin by repeating his argument, with one major difference that should highlight the absurdity of this entire approach: where Rowthorn uses the words “religion” and “secular” I have substituted the words “love” and “non-love.”  Without further ado, here is Rowthorn’s paean to religion love, genes, and babies:

Religion Love, Fertility and Genes: A Dual Inheritance Model

It is widely agreed that love has biological foundations – that belief in amour, obedience to passion or susceptibility to ardor and enchantment depend on genetically based features of the human brain. For love to influence genetic evolution it must convey some kind of selective advantage. Such an effect might come about through social bonding via ritual, formation of group identity through myth, honest signaling through participation in costly ceremonies and adherence to social norms through pair bonding and fear of loneliness.

In most cases, loving individuals gain advantage from their activities or beliefs. However, love may also induce behavior that has a fitness cost to the individual but is beneficial to the group. In the modern world, loving people, even controlling for income and education, have more children on average than people without love. The impact of differential fertility on the loving composition of society depends on the scale of switching between loving groups, and between them and the non-loving population.

To explore these issues we shall consider some simple mathematical models. The models are in the gene-culture tradition. The models are of the dual inheritance type, in which children inherit both their genes and their initial loving (or non-loving) allegiance from their parents. A child who is genetically predisposed towards love is more likely than other children to remain or become loving as an adult.

Throughout the analysis we shall assume that fertility is an entirely cultural phenomenon: genes affect the likelihood the particular individuals will become loving, but do not directly influence their reproductive behavior. All loving adults (“Romeos” or “Juliets”) have the same fertility irrespective of their genes; likewise non-lovers have the same fertility irrespective of their genes.

In all the models we consider, loving predisposition (“lovingness” for short) is determined by a single gene. This is unlikely to be true in practice, but without this simplification the analysis would be intractable.

This paper assumes that there exist genetic differences between individuals that affect their predisposition towards love. In the same cultural environment, some individuals are for genetic reasons more likely to become or remain loving than others. It also assumes the loving people have more children on average than non-loving people.

These scenarios have different implications for the genetic evolution of society. If loving people continue to have a higher birth rate on average than non-loving people, then any genes which predispose people towards love will spread.

Provided a core of high-fertility love groups continues to exist, they will transform the genetic composition of society either through internal growth or defection. This has been demonstrated in the present paper using a single gene for love.

In reality, a phenomenon as complex as love predisposition is likely to be influenced by many different genes. But this does not alter the main argument.

Comment

Does not alter the main argument? Please. The main argument does not even get off the ground. No argument can be taken seriously when it begins with mistaken premises and depends on fictitious assumptions. Accountants have a term for this: GIGO. Garbage in, garbage out.

Talking about a “religion gene” makes about as much sense as talking about a “love gene.” They have precisely the same analytical and explanatory power, which is to say they have none.

While this makes for a plausible story, there are a number of problems. The first is that we have little archaeological evidence of ritual behaviors, especially those that would have been group oriented. While some have argued that evidence of symbolic thinking – in the form of decoration-adornment and markings on material objects – indicates ritual behavior, this linkage is attenuated at best and imaginary at worst. While wearing perforated shell or decorating material objects is suggestive, such displays neither entail nor require ritual-religious behavior.

A simpler explanation is that people were using such items as social markers, to individuate themselves and perhaps signal to others identity or status. There remains a large gap between these artifacts and the kinds of group ritual activities, such as singing and dancing, that some have imagined. While such data do not rule out ritual or proto-religious behaviors, they constitute sparse evidence for ruling them in.

Bigger Groups Win

The second major problem – the one I wish to focus on here, concerns competition between groups. What makes one group more successful than another?  In nearly all cases involving competing groups of social mammals, larger groups out-compete smaller ones.  The reasons are fairly obvious and supported by the evidence: larger groups have lower predation risk and have greater success in agonistic encounters between groups. They have larger ranges or territories, and when resources are depleted or disappear, migration – usually a hazardous undertaking, is more feasible. When a larger group of social mammals encounters a smaller one, the larger nearly always prevails. Larger groups also have a greater store of collective knowledge with respect to nearly everything that matters – water, food, shelter, and predators.

While there are several factors that impact group size, ecological ones being foremost, it is safe to say that ritualistic or proto-religious behaviors are not among them.  Highly social mammals are for the most part bound together by that most powerful of evolutionary bonds: genetic kinship.  Extraneous factors need not be invoked to explain cooperative or even altruistic behavior.  Inclusive fitness is sufficient.

Talking about Tools

Focusing specifically on hominins, there are two factors that would have decisively impacted the size and ultimate success of Paleolithic groups: language and technology. One need not accept the “social grooming” hypothesis to realize that language (or advanced forms of proto-language) is a game changer when it comes to cooperation and cohesion.  In addition to the planning and coordination it would have enabled, language at some point made possible notions of extended and fictive kinship, further strengthening this most powerful form of social glue.

For at least 2.5 million years and probably longer, technology has been a defining characteristic of hominins. Although there are broad progressive technological trends in the lithic record, it is also clear there were long periods of stasis and even reversion. Few things would have had a greater impact on any given group’s odds of success than its technologies. Although apparently slight advances (such as material choice and flaking methods) were undoubtedly advantageous, other technologies were – like language – game changers. The control of fire is obviously one of these. The first groups to develop composite weapons, spear throwers, and bows-arrows would have had immense advantages over other groups, not only in hunting but also in warfare. For groups radiating toward northern latitudes, clothing would have provided similar benefits.

In sum and in rough order of importance to the success of any given hominin group, the factors that would have had the greatest impact intergroup competition are: (1) group size; (2) proto-language or language; and (3) technology. Any group having advantages in one or more of these areas would have been better able to compete against groups deficient in them, but which might have had the kind proto-religion or ritual that enhances group solidarity and commitment.  Such solidarity and commitment is, of course, determined in the first instance by kinship, which is not dependent on proto-religion or ritual for its efficacy.

It seems unlikely that proto-religion or ritual provided any groups with advantages with respect to language or technology. No one has ever suggested that language evolved or technology progressed because either was linked to the supernatural. Given this fact, and the paramount importance of group size to group success in ancestral environments, the critical question facing advocates of group level selection as the functional impetus for the evolution of religion is: Did proto-religion enable Paleolithic hominins to form larger groups? If group ritual oriented around supernatural beliefs somehow resulted in larger groups, then the “religion evolved as a group level adaptation” story may have legs.

Paleolithic Group Size – No Religion Necessary

Let us assume, for the sake of argument, that at some point during the middle or upper Paleolithic, certain groups developed proto-religious ideas that promoted ritual activities and resulted in increased cooperation or cohesion. Do we have any reason to think that such ideas or activities also resulted in larger groups, which the single best predictor of success when it comes to group competition? While we can speculate on the ways in which proto-religion might have affected group size, a better method is to look for evidence that hominin group sizes increased during the Paleolithic. If we can identify increases in group size among Paleolithic hunter-gatherers, we can then ask whether the larger groups were enabled or caused by proto-religion.

Because we do not have direct evidence of Paleolithic group size, we have to rely on proxies and analogies, however imperfect. As a proxy, we can examine primate group size. For an analogy, we can examine known hunter-gatherer groups. Although primates obviously do not have anything like proto-religion, it is reasonably safe to assume that the factors affecting primate group size are similar to those that would have affected hominin group size. As for known hunter-gatherers, they do have something akin to “religion,” although their loosely organized, non-systematic, and individualized shamanic practices bear few resemblances to the kinds of religions that humans systematically developed in conjunction with agriculture. If we can identify groups that grew over time or were larger than others, we can ask whether the observed size increase was connected to supernatural-religious beliefs, or whether other factors better explain the larger groups.

Because there are over 300 species of extant primates, it should come as no surprise that group size (and composition) varies considerably; the range is from a few family members to a few hundred. While several variables affect group size, the most important are predation risk, resource density, and neocortex size. The latter speaks to the tremendous load that intense sociality places on cognition and memory.

Chimpanzees and baboons are perhaps the most relevant models; the former because they are the most closely related to hominins and the latter because they are largely terrestrial and live in relatively stable multi-male and multi-female groups. Many researchers are of the opinion that this mode and composition most closely resembles the ancestral hominin condition. Chimp group size varies from 15 to 65 and the mean, other factors being equal, is approximately 30. Baboon group size varies from 25 to 250, with a mean near 100.

Remarkably, these numbers are quite similar to those of known hunter-gatherers. The basic foraging unit – which usually includes a few related families – consistently clusters around 30 people. This group typically maintains close ties to neighboring groups that are similarly sized and genetically related. The units occasionally aggregate into a group that averages 150 members, most of whom are related. This fairly tight knit group is primary, and is the one that can be counted immediately counted on in times of need. In most cases, these primary groups of 150 maintain kinship ties with surrounding groups of similar size, with the result being that a kinship group of approximately 500 constitutes the larger regional network that may come together only infrequently. This secondary group is typically the largest and hunter-gatherer groups rarely exceed this number. Beyond the regional network group of 500, relations are attenuated and conflict more likely. This pattern (basic = 30, primary = 150, secondary = 500) is fairly consistent across time and space.

This consistency in forager group size, when coupled with similar group sizes for chimps and baboons, leads to the conclusion that the upper limits of hominin group size remained relatively stable for much of human evolution. These limits and groupings were, of course, substantially altered by the dynamics of domestication; with agriculture and sedentism, human group size increased substantially. It is at this time, when groups become larger than 30-150-500, that kinship glue is no longer able to hold people together, and collective abstractions – such as polity or religion – are required to maintain larger groups. For most humans in the world, this fundamental transition (from foraging to agriculture) occurred no more than 7,500 years ago.

No Group Evolution of “Religion”

Where does this leave us? It means there is no need to invoke religion or ritual to explain group level success. Given the limited group sizes we are talking about for most of human evolution, other factors – such as language and technology – would have had far more profound effects on the success of one group versus another. Kinship, both real and fictive, is more than sufficient to bind such limited-size groups together and make them cohesive, cooperative, and altruistic. This is not to say that proto-religion and ritual would not have had an impact, but it is difficult to imagine the circumstances under which a “religious” 30 member group would prevail over a “non-religious” 150 member group. If group sizes were equal, and one group was proto-religious but the other was not, other factors would have been more decisive in determining the outcome of any conflict between them.

It is only when all primary variables are equal – group size, linguistic ability, and technological prowess – that a proto-religious group may have had some kind of advantage due to increased cohesion or cooperation. This places religion far down on the list of factors that explain group success during the Paleolithic. It also means that “religion” did not evolve because it made some groups more competitive than others.

Sources:

Aiello, Leslie and Dunbar, Robin. 1993. “Neocortex Size, Group Size, and the Evolution of Language.” Current Anthropology, 34(2):184-193.

Baer, Darius and McEachron, Donald. 1982. “A Review of Selected Sociobiological Principles: Application to Hominid Evolution — The Development of Group Social Structure.” J. Social Bio. Struct., 5:69-90.

Isbell, Lynne and Young, Truman. 1996. “The evolution of bipedalism in hominids and reduced group size in chimpanzees: alternative responses to decreasing resource availability.” Journal of Human Evolution, 30:389–397

Janson, Charles and Goldsmith, Michele. 1995. “Predicting Group Size in Primates: Foraging Costs and Predation Risks.” Behavioral Ecology, 6(3):: 326-336.

Kosse, Kristinza. 1989. “Group Size and Societal Complexity: Thresholds in Long Term Memory.” J. Anth. Arch., 9:275-303.

Marlowe, Frank. 2005. “Hunter Gatherers and Human Evolution.” Evolutionary Anthropology, 14:54 –67.

Wrangham, Richard, et al. 1993. “Constraints on Group Size in Primates and Carnivores: Population Density and Day-Range as Assays of Exploitation Competition.” Behavioral Ecology and Sociobiology, 32(3)199-209.