Niche construction

Darwin 1.0: Is the EES playing catch-up?

5 November 2018

A consequence of the gene-centric view of evolution we call the Modern Synthesis (MS) is to foster a severe constriction in scientists’ understandings of Darwin. Despite Darwin’s original treatment of evolution being enormously rich, he becomes the purveyor of just one dangerous idea: evolution by natural selection – the idea which, when modified by the post-Darwinian discoveries of Mendelian and population genetics, underpins the MS. Hence we find Richard Dawkins catching the gist of a hundred biology textbooks by claiming both that ‘the selfish gene theory is Darwin’s theory expressed in a way that Darwin did not choose’ [1], and, that while Darwin believed in the ‘Lamarckian’ principle that acquired characters were heritable, this belief ‘was not a part of his theory of evolution’ [2]. Only in such an intellectual world, a world still sustained by MS assumptions, could the MS be said to capture the ‘central tenets’ of Darwin’s work [3].

If the MS take on Darwin is Version 2.0, what of Version 1.0? Could it be that the EES is, in large part, an unwitting ‘back to Darwin’ rediscovery of what was lost when the MS remade the history of evolution in its own image? Yes it could – though with the obvious caveat that Darwin knew nothing about the huge wealth of modern biological findings, most notably perhaps, the discoveries of Mendelian inheritance and DNA. How serious is this caveat? Not, perhaps, so serious as we might think. Because Darwin appreciated something that the MS did not. Witness his warning: ‘two distinct elements are included under the term “inheritance” – the transmission, and the development of characters; but as these generally go together, the distinction is often overlooked’ [4]. This distinction is finessed by the MS, of course, in its assumption that organisms develop according to the genetic blueprint they have been transmitted. Darwin did not subsume development under transmission in the MS way. See his explanations of secondary sexual characters for example: these were ‘transmitted through both sexes, though developed in one alone’ [5]. Most germane to the EES – the processes of reproduction and development were the main domain of what Darwin called an organism’s natural ‘plasticity of organisation’ [6].

Reemphasis on the importance of something beyond genetic transmission in making ‘grandchildren like grandfathers’ [7], namely constructive development, is one of the two hallmarks of today’s EES. The other is reciprocal causation, the idea that developing organisms are not solely products but are also causes of evolution. And here we come to the nub of my new book Darwin’s Psychology: The Theatre of Agency – shortly to go into production at OUP [8].

Reciprocal causation counters MS claims that the mutation and recombination of genes are what yields the new, stable variants upon which selection acts. The MS view that variation is produced by these two gene-level processes helps seed the myth that Darwin was ignorant of the source of organic variability [9].  I call this myth, because Darwin 1.0 said a great deal about the sources of selectable variation. The first three chapters of The Origin of Species all deal with the genesis of the variation which affords evolutionary novelty of the kind now defined as ‘discrete phenotypic traits new in composition or context of expression relative to established ancestral traits’ [10].

The central driver of variation for Darwin was the intricate interdependency of agencies – animate and inanimate – that make up what naturalists then called the economy of nature. Action, or what Darwin called ‘habit,’ led the way. ‘Ha! Lamarck!’ say modern synthesizers like Dawkins (see above). But when Darwin wrote ‘changed habits produce an inherited effect’ [11], he explicitly referred to what we nowadays call the Baldwin effect – a process which, as Baldwin himself reminded us, was discussed extensively in the Origin, under the heading ‘transitional habits’ [12].

Cue the flying squirrel. In explaining transitional habits, Darwin asked us to imagine that a squirrel has gained the habit of launching itself, not just from branch to branch, but from the tops of trees. This would create a new selection pressure that would advantage any squirrels aided by an anatomical or physiological character that helped them jump greater distances (stronger spring at take-off, better depth vision, lighter body-weight, more aerodynamic tail, broader flanges of skin between front and back legs). Tree-surfing would put a new premium on glide-friendly changes to the squirrel’s physique, such that any chance heritable variation that fitted it better to its new habit would likely increase its reproductive success compared to its unchanged aerial conspecifics. Hence, ‘it would be easy for natural selection to fit the animal, by some modification of its structure, for its changed habits’ [13]. Thus, while the production of what we now call genetic variations, which stabilized the bodily changes that make tree-surfing easier for squirrels, might be random – the direction of adaptation would conform to the non-random agentic innovations of the flying squirrel. These ideas are very much in accord with the EES’s emphases on ‘plasticity first evolution’ and ‘developmental bias’ resulting from facilitated variation.

Indeed, given the EES’s increasingly dynamic understanding of ecology [14], might we not say that, by leaping more ambitiously, the squirrel had ‘constructed’ a novel component of its ‘niche’? Here we find another rapprochement with Darwin. In contrast to the evolutionary psychology of his contemporary Herbert Spencer, Darwin’s theorizing never invokes ‘the environment’ as something that could stand independently of, and logically prior to, any given organism. Neither did Darwin ever use the word ‘behavior.’ His favored terms were habit, inhabitant, and habitat – or ‘conditions of life.’ A strong allusive chime obtains between habit and habitat: one’s habitat means the place one in-habits – the place one’s habits make one’s home. This chime well conveys Darwin’s vision of interdependency between an organism’s agency and its dwelling-place.  Likewise with ‘conditions of life,’ a phrase which posits no separation between organism and externalities. As with the ‘if → then’ of logical conditionality, any organism’s existence necessarily implies specific conditions. George Lewes underlined this in 1868. For Darwin, ‘conditions of life’ meant the specific relations which afford the existence of a given organism, relations which were ‘external and internal, physical, organic, and social’ [15]. Conversely, items in a population of organisms’ surroundings which ‘cause no reactions in them, are, for them, as if non-existent’ [16]. To misunderstand this, as did Spencer, was to render the organism ‘passive under the influence of external conditions,’ and so deny an organism as ‘agent in act’ [17].

Accordingly, Darwin’s account of nature had two axes. First came the ‘what,’ the so-called economy of nature, with a time-scale ranging from moments to a lifespan – a theatre of interdependent agents, animate and inanimate. Second and orthogonally, came the resultant of that theatre: common descent, something having an inordinately vaster time-scale, ranging from millennia to periods Darwin likened to eternity, ‘which the mind cannot grasp’ [18].

The phrase ‘economy of nature’ may today sound unfamiliar. Yet, it was the central focus of natural history in the 1700s and early 1800s, and so too for Darwin [19]. As the phrase implies, writers like Carl Linnaeus and Charles Lyell saw nature as a divinely-constructed economy in which the division of labor between the interdependent activities and stations of its various inhabitants were ‘fitted to produce general ends, and reciprocal uses,’ and thus ‘ensure the health and well-being of the natural world’ [20].

The interdependencies of agency which were key to the economy of nature, were what grounded the mill of evolution hypothesized by Darwin, both in plants – mistletoe and orchids were favorite examples – and animals (e.g. woodpeckers and earthworms). Darwin’s mill yielded both the wheat of variation, and winnowed the kernels of inter-generational success from the chaff of failure through what he called ‘the Struggle for Existence in a large and metaphorical sense’ – a process that included, not just combat, but relative reproductive success and, the ‘dependence of one being on another,’ often cooperative [21]. It was these two processes, of variation and the struggle for life, that Darwin held to produce as their combined effect what he called the ‘law’ of natural selection [22].

Agency or habit, and in particular transitional habits, were also at the heart of Darwin’s explanations for: co-adaptation and co-evolution (e.g. moth and orchid); divisions of labor within species (e.g. social insects); the diversification of species – Darwin’s ‘principle of divergence’ (e.g. taxonomic hierarchies); and the evolution of the human brain. Which brings us to the topic of culture.

One of the most unfortunate legacies of the MS – and its failure to see that phenotypic activity (or plasticity) is what leads evolution – is the conclusion that evolutionists need to seek separate explanations for gene-based ‘biological’ versus non-genetic ‘cultural’ evolution [23]. For, as Mary Jane West-Eberhard makes clear: while ‘non-genetic transmission of acquired phenotypes is most readily associated with culture and animal behaviour … it occurs even in the reproduction of single-celled organisms’ [24]. In keeping, The Descent of Man extrapolates from animals the central role played by sexual agency and moral culture (or its Victorian synonym, ‘civilization’) in specifying and so shaping human conduct – and thereby the struggle for existence which yields natural selection.

Descent’s most intense scrutiny of human culture is given to considering ways in which the mores of the most civilized societies could impede natural selection. Here, Darwin affirmed a remark by Chauncey Wright that ‘one useful power’ may be acquired through natural selection because it brings ‘many resulting advantages.’ However, once evolved, such a power may also bring ‘limiting disadvantages,’ with negative evolutionary ‘utility’ [25]. Darwin agreed, arguing in Descent that Wright’s point ‘has an important bearing on the acquisition by man of some of his mental characteristics’: a facet of human agency may have evolved due to certain advantageous effects, yet also collaterally produce other, maladaptive effects [26]. Descent lists the negative impact of adaptations to communal living in humans as including ‘abject’ conformity to maladaptive customs and superstitions, and mating on grounds of ‘mere wealth or rank’ [27]. Hence, in Darwin’s eyes, many aspects of contemporary human agency had traceable evolutionary ancestries, yet were maladaptive in the here-and-now by virtue of the specification given to them by contemporary culture. This meant that, while being just as ‘biological’ as any other type of action, they were more explicable in cultural than evolutionary terms.

Perhaps the most prevalent MS-inspired myth about Darwin’s psychology is that he didn’t have one. Typically, today’s evolutionary psychologists first celebrate the Origin’s brief valedictory statement that the law of evolution by natural selection has revolutionary implications for psychology [28] – then deplore that, a century and a half later, the social and behavioral sciences remain largely untouched by these implications. Which implies Darwin himself did nothing substantial to work out how his theory of evolution might bear on the complexities of human and animal (and vegetable) agency. Hence, its advocates say, the need for a new evolutionary psychology to fulfil Darwin’s vision. Meaning that it is only now, two centuries after his birth, that ‘the distant future that Darwin envisioned is upon us’ [29].

Witness for example how Kevin Laland justifies the title for his recent, prize-winning book Darwin’s Unfinished Symphony: How Culture Made the Human Mind.  Appropriating Darwin’s disingenuously modest description – as ‘imperfect and fragmentary’ – of just one of his own chapters in Descent [30], Laland reads this remark as applying to Darwin’s entire account of ‘the evolution of mind’ [31]. Most notably absent from Darwin’s psychological understanding, we hear, ‘was the central role played by culture in the origins of mind.’ Hence, ‘comprehending the evolution of the human mind is Darwin’s unfinished symphony’ [32].

In fact, Darwin’s intuitions and arguments are both richer and more critically aligned with Laland’s analysis than he appears to appreciate. Darwin’s Psychology marshals the extensive evidence in Darwin’s publications which shows that he did develop a profound understanding of psychological matters, in which – at least where humans were concerned – culture played a leading role. The above reflections considered, the EES starts to look like a ‘back to the future’ movement, with even some of today’s most radical evolutionary thinkers playing catch-up on the path blazed by Darwin’s visionary writings about evolution and agency [33].

Coming Soon

Darwin’s Psychology: The Theatre of Agency by Ben Bradley (Oxford University Press, in press)

[1] Dawkins R (2006). Selfish Gene (OUP), p.xv, my italics.

[2] Dawkins R (1991). Blind Watchmaker (Penguin), p.290.

[3] Garwood J (2017). Darwin Reloaded, Lab Times 3, pp.20-23.

[4] Darwin C (1874). Descent of Man (Murray), p.227, my italics.

[5] Loc.cit., my italics.

[6] E.g. Darwin C (1875). Variation of Animals and Plants under Domestication, Vol.2 (Murray), p.428.

[7] Darwin CR (1838-1839), Notebook E (link), p.58.

[8] Bradley B (in press). Darwin’s Psychology: The Theatre of Agency (OUP).

[9] Dobzhansky T (1951). Genetics and the Origin of Species (Columbia University Press), p.50.

[10] West-Eberhard MJ (2008). Toward a Modern Revival of Darwin’s Theory of Evolutionary Novelty, Philosophy of Science 75, p.899.

[11] Darwin C (1876). Origin of Species (Murray), p.8.

[12] Baldwin JM (1909). Darwin and the Humanities (Review Publishing), pp.19-20.

[13] Darwin C (1859). Origin of Species (Murray), pp.179-186, quote from p.183.

[14] See e.g. Odling-Smee FJ, Laland KN & Feldman M (2003). Niche Construction: The Neglected Process in Evolution (MPB-37) (Princeton), p.419, where ‘niche’ is defined as including organisms’ ‘niche-constructing acts, and selection from [the] sources’ available in their environment.

[15] Lewes GH (1868). Mr Darwin’s Hypotheses I, Fortnightly Review 3, p.367, my italics.

[16] Lewes GH (1868). Mr Darwin’s Hypotheses III, Fortnightly Review 4, p.63.

[17] Ibid, pp.66, 73.

[18] Darwin C (1859). Origin of Species (Murray), p.287.

[19] Pearce T (2010). “A Great Complication of Circumstances” – Darwin and the Economy of Nature, Journal of the History of Biology 43, pp.493–528.

[20] Ibid, p.498.

[21] Darwin C (1859). Origin of Species (Murray), p.62.

[22] E.g. Darwin C (1874). Descent of Man (Murray), p.48.

[23] See e.g. Lewens T (2015). Cultural Evolution: Conceptual Challenges (OUP). Here I leave aside (though Darwin’s Psychology does not) the question whether, because some human cultures/societies have become more complicated over time, we can invoke an evolutionary (MS-inspired: memes, population-thinking, etc.), or evolution-like, explanation for culture and cultural change, assuming a single natural-selection-like process of cultural change. Following Darwin, my book (Ch.10) argues that we cannot. Cultural change is more plausibly the consequence of a disparate assortment of almost too many processes to count: industrialisation; colonization; war and social conflict; demographic changes; resource distribution; economic diversification; reflexive modernization; energy sources; climate change; epidemics; migration; revolutions; sexual, class-based and racial oppression; etc.

[24] West-Eberhard MJ (2003). Developmental Plasticity and Evolution (OUP), p.115.

[25] Darwin C (1874). Descent of Man (Murray), p.571; Wright, C (1870). Review [of Contributions to the Theory of Natural Selection. A Series of Essays by Alfred Russell Wallace], North American Review 111, p.293.

[26] Note that Darwin recognized that sexually (and by extension, socially) selected traits do not fit with the idea of natural/survival-utility selection – which is what led him to treat sexual selection separately: see West-Eberhard MJ (2014). Darwin’s Forgotten Idea: The Social Essence of Sexual Selection, Neuroscience and Biobehavioural Reviews 46, pp.501-508. ‘Unintended’ consequences of the evolution of human consciousness were dubbed ‘non-adaptive sequelae’ by Gould SJ (1984). Challenges to Neo-Darwinism and Their Meaning for a Revised View of Human Consciousness (pdf), p.62.

[27] Darwin C (1874). Descent of Man, pp.118, 617.

[28] Darwin C (1859). Origin of Species (Murray), p.488: ‘In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation.’

[29] Buss D (2009). The Great Struggles of Life: Darwin and the Emergence of Evolutionary Psychology, American Psychologist 64, p.147.

[30] Ch.5 in Darwin C (1874). Descent of Man, p.127. Historians warn that Darwin’s comments about his own work should always be viewed skeptically (see Darwin’s Psychology, Ch.5).

[31] Laland KN (2017). Darwin’s Unfinished Symphony: How Culture Made the Human Mind (Princeton University Press), pp.13-14. Note that Darwin’s publications never discuss as such ‘the mind,’ and so never mention ‘the evolution of mind.’ Darwin was interested in explanations for, and the biological consequences of, purposive movement (i.e. agency), whether in plants or animals, simple or complex. In this, once again, he today appears ahead of the curve: e.g. Walsh DM (2018). Objectcy and Agency, in Nicholson D and Dupré J, eds., Everything Flows: Toward a Processual Philosophy of Biology (OUP), pp.167-185.

[32] Laland KN (2017). Darwin’s Unfinished Symphony (OUP), p.14.

[33] I would like to thank John Dupré, Katrina Falkenberg, Kevin Laland, Tobias Uller, and Mary Jane West-Eberhard for their helpful responses to earlier drafts of this blog. The views expressed in it remain entirely my own.