Group selection enthusiasm still rampant in the social sciences

Most evolutionary biologists got over group selection back in the 1970s. However, there's one area of biology where it is particularly prominent: the social social sciences. There's particular enthusiasm for cultural group selection - as though cultural evolution plays by different rules in this area.

Cultural kin selection represents an alternative perspective which makes little mention of selection acting on groups. Instead of humans being part of innumerable overlapping groups, their genes and memes are modeled as being related to the genes and memes of others. This perspective has been much more enlightening in the organic realm, and I think it will prove to be much more enlightening in the cultural realm as well. The largely-fictional groups of group selection are just a clumsy and awkward way of viewing the situation - most of the time. The perspective has a long history of producing dud science.

In most of evolutionary biology, 90% of scientists are using kin selection and 10% are using group selection. In the social sciences, it's the other way around. I think that this fairly clearly indicates the existence of a problem.

Why is group selection still so popular among social scientists? For a long time many of them held out hope that it would prove to be a new theory of social behaviour. These hopes now appear to have been crushed by the failure of the theory to make different predictions from the long-established orthodoxy of kin selection.

Social scientists have a long history of not understanding how evolutionary biology applied to their subject areas. As a result there's a large scientific lag afflicting the study of cultural evolution. Group selection enthusiasm seems to be clearly one aspect of that: the numerous social scientists involved are stuck back in the 1960s somewhere, where the virtues of the kin selection perspective were not yet widely appreciated.

Lastly, group selection in the social sciences seems to have found extensive funding from the John Templeton Foundation. In a surreal twist to the final battle between science and religion, group selection enthusiasm has been funded to the tune of millions of dollars. That kind of marketing budget can buy a considerable quantity of confusion.

Obvious types of kin selection

If you ask a student of kin selection about the most obvious aspects of the human phenotype that have been influenced by kin selection and are coded for in human DNA, I think you would generally get back a list looking something like this:

• Genitals;
• Breasts;
• Placenta;
• Umbilical cord;
• Female body fat;
• Maternal love;

If you ask a group selection proponent the corresponding question (what are the most obvious aspects of the human phenotype that have been influenced by group selection and are coded for in human DNA), I think you would get back a very different list. The group selection proponent might be more likely to mention multi-cellularity - but I think they would be highly likely to back a very different list.

What's up here? Kin selection and group selection are basically the same thing.

I don't pretend to have a complete explanation for this - but I think the group selection enthusiasts were led astray by the urge to distinguish themselves from kin selection enthusiasts. If discussing family groups, it was obvious that kin selection applied to it - and explained it. The group selection advocates therefore focused their attention elsewhere - where it seemed as though there was more chance to explain new phenomena that kin selection failed to cover. This hypothesis explains the migration of group selection enthusiasts to cultural evolution - since that is obviously not down to shared DNA.

Eventually, there was nowhere else to run, and the group selection advocates mostly gave up their claims that group selection was something new and different. Now the rhetoric in the area has mostly shifted to other issues.

Goodnight on kin selection rampage

Charles Goodnight has been explaining why he doesn't like kin selection recently, in a string of articles - most notably Why I Don’t like Kin Selection.

However, this article seems littered with misunderstandings to me. Goodnight claims kin selection can only focus on altruism. That is a mistake - kin selection has also been applied to spiteful behaviour. Goodnight claims that kin selection can't handle cultural relatedness. That's wrong - cultural kin selection handles cultural relatedness just fine. Goodnight claims that kin selection is ¨an optimality approach¨. In fact, evolution is a gigantic optimization process. All adaptations are the result of optimizations. The accusation that that kin selection is an optimality approach just seems totally confused to me. Goodnight claims that multi-level selection models in which selection on different levels acts in the same direction can't be studied using kin selection models. That seems ridiculous to me - of course they can. In fact, neither group-selection nor kin selection models spend much time on this case. For group selection, this is because proponents are still struggling to find evidence for their effects - and this case typically doesn't help do that.

Goodnight winds up publicly explaining where he doesn't understand kin selection. That's fine - but readers should not be persuaded by an article with so many mistakes.

The article closes with:

However, like optimal foraging theory, it appears to mainly be useful in making broad stroke qualitative predictions that can be used in the introduction, or in a laudatory paragraph about how wonderful Hamilton is at the end of a paper. If you want to make quantitative statements about selection in real world populations that will contribute to our understanding of social evolution multilevel selection might be a better choice.

Ironically, this is almost the exact reverse of what kin selection enthusiasts often say about group selection. Kin selection features the coefficient of relatedness - whereas group selection is rarely concerned with the level of relatedness within or between groups. So: kin selection is typically quantitative, while group selection is much more concerned about identifying the level at which a feature is adaptive - which is a more qualitative issue.

Inclusive fitness applies to genes too

Recently Martin Nowak - in one of his attacks on the concept of inclusive fitness claimed that:

On the level of genes there is no inclusive fitness

I think this is a fairly straightforwardly mistaken idea. The basic logic of Hamilton's 1964 paper applies to genes too. Hamilton claimed that organisms are not just be driven by self interest, and concern for their offspring, but can be expected be interested in the welfare of their other relatives too (brothers, cousins, parents, etc). Similarly, genes aren't just out for themselves. They also act as though they are concerned about their relatives.

With genes the situation is simpler to analyze. To a first approximation, most other genes are related to them by either being identical clones - or by being completely unrelated. These situations correspond to r=1 and r=0 - in the standard inclusive fitness mathematical formalism. If you plug these numbers into Hamilton's rule, you get sensible results. Genes often act as though they do care about the welfare of identical copies of themselves.

The inclusive fitness of a gene can be calculated in the same way as the inclusive fitness of an organism - by adding and subtracting fitness components due to self and relatives - as described by Hamilton.

West, Gardner and I are all in agreement on this issue. In 2013, they said:

Even at the level of the gene, we would still want to know what the maximand is, and the answer is ‘the inclusive fitness of the gene’

So: what was Martin Nowak thinking about? Perhaps he meant to write that inclusive fitness was not a necessary concept at the level of the gene. For example, if you think of genes as being informational, then it is conventional to refer to all the copies of a particular physical nucleotide sequence as representing the same "gene" (or "allele", as some people prefer to say). In which case, talk of "inclusive fitness" is unnecessary.

However, the concept of inclusive fitness is applicable on the level of the genes. I think to claim otherwise is just to invite confusion and misunderstanding.

Why the kin vs group selection arguments persist

There have been a few attempts to explain the persistence of the clash between kin selection and group selection enthusiasts, beyond the recognition of the broad equivalence of the approaches.

D. S. Wilson wrote Clash of Paradigms: Why Proponents of Multilevel Selection Theory and Inclusive Fitness Theory Sometimes (But Not Always) Misunderstand Each Other.

Recently Herbert Gintis has offered his perspective in a review of the book Evolutionary Restraints: The Contentious History of Group Selection.

It seems to me that much of the apparent disagreement comes from those on the outskirts of the debate, who don't properly understand it. The last couple of years has seen a number of confused articles - from Steven Pinker, Edward Wilson, Martin Nowak and others - who just don't know what they are talking about.

Part of the disagreement comes from inertia. People get taught one technique and then get attached to it - and are reluctant to use the other 'unnecessary' approach.

I also think this is partly a conservative vs revolutionary issue. Kin selection is the establishment, group selection is the rebel. Kin selection is tried and trusted, group selection is new and disruptive. Theories with these traits appear to different personality types.

There's also the issue of 'selfishness'. Group selection pictures groups that nurture cooperation flourishing at the expense of groups of selfish individuals. Kin selection seems to be promoting a picture of gene level selfishness. This picture is factually false (the reality doesn't change depending on how you look at it) but the connotations are there. Some like to publicly signal their unselfishness via their beliefs. To others, such cheap signalling seems more like tasteless self-promotion.

Lastly there's confusion over cultural evolution. Most of the group selection enthusiasts come from the social sciences. I've repeatedly heard them argue that kin selection only applies to genetic relatives, and that human cooperation extends beyond blood kin - so there must be something else going on. This argument ignores the important topic of cultural kin selection. The "something else" that is going on turns out to be kin selection after all.

Since kin vs group selection seems closely tied to political and moral issues, perhaps we won't see much more agreement on the topic anytime soon.

Kin selection's 50th birthday

There were prior murmurings, but 1964 marked kin selection's initial publication in a number of respects. Now it's 2014 - it's kin selection's 50th birthday.

Academics have noticed this and are celebrating. One of the celebrations is the Philosophical Transactions of The Royal Society B's theme issue:

‘Inclusive fitness: 50 years on’ compiled and edited by Andy Gardner and Stuart A. West

The introduction says:

In order to better assess the health of inclusive fitness theory on its 50th anniversary, here we showcase research showing the research programme in action, from the extremely pure, mathematical realm, through basic empirical science, to bold applications in a variety of disciplines.

I disapprove of the Claidière / Scott-Phillips / Sperber contribution. They doubt the applicability of kin selection to cultural variation, writing:

Darwinian selection leads to the maximization of inclusive fitness, and this explains the appearance of design in the natural world. Is there an analogous result for cultural attraction? As selection is a special case of attraction, design is possible and in some cases explicable in standard Darwinian terms. Having said that, such explanations will not apply generally, and may not even apply commonly.

From my perspective, this seems like ignorant nonsense. Kin selection is about as applicable and useful to cultural evolution as it is to understanding organic evolution.

Nowak nominates inclusive fitness for retirement

The 2014 annual question at The Edge is: What scientific idea is ready for retirement?

Martin Nowak nominated inclusive fitness. He writes:

Contrary to what is often claimed there exists no empirical test of inclusive fitness theory; nobody has ever performed an actual inclusive fitness calculation for a real population. Inclusive fitness was originally understood as a crude heuristic that can guide intuition in some cases, but not in general. It is only in recent years that inclusive fitness has been elevated—mostly by mediocre theoreticians — to a religious belief, which is universal, unconstrained and always true. Understanding the limitations of inclusive fitness gives us now the opportunity to develop mathematical descriptions of key phenomena in social evolution. It is time to abandon inclusive fitness and focus on a meaningful interaction between theory and experiment in sociobiology.

This seems like unsubstantiated scientific FUD to me.

Nowak claims that the:

dominant and unfortunate impact has been the suppression of meaningful mathematical theories in wide areas of sociobiology.

He means group selection? I think this is unreferenced and unsupported nonsense.

From the 1970s onwards we actually understood that evolution does not permit a single quantity that is always maximized. This fact still has to sink in with many in the inclusive fitness community.

I think that the first sentence here is technically mistaken. You can in fact, model the evolution of any dynamical system using the concept of maximisation of a utility function. Take, for example, the utility function that assigns world events that happen utility 1 and world events that do not happen utility 0. In this case, the evolution of the system can be modeled by "a single quantity that is always maximized". This is the fact of the matter. Nowak's proposed 'fact' is a simple falsehood. We didn't understand this 'from the 1970s onward' - it is simply not true in the first place.

Nowak writes:

On the level of genes there is no inclusive fitness.

Really? Most pairs of genes are either copies of each other (r=1) or not (r=0). Plug these numbers into Hamilton's rule and it works fine. This illustrates the meaning of "The Selfish Gene": genes only care about themselves - or copies of themselves. Nowak doesn't explain what the perceived problem is.

More relating to Nowak's article:

• Marczyk, Jesse (2014) Which Ideas Are Ready to Go to Florida?

• Reuell, Peter (2014) Harvard Gazette press release