January 6, 2010

Niche Construction Revisited

Technology and Human Evolution

Why technology in the first place? The answer, anthropologically and philosophically, revolves around humans relating to their environment. –Don Ihde

We have modified our environment so radically that we must now modify ourselves in order to exist in this new environment. –Norbert Weiner

Many theorists have metaphorized the development of technology as a kind of evolution; thus, one talks about “the evolution of technology.” As far as I know, Karl Marx was the first to suggest a Darwinian reading of the history of technology (in Das Kapital [1867]), but one finds the idea in work by contemporary techno-theorists too, such as Kevin Kelly in his TED talk. While such analyses can be, at times, intriguing, I am much more interested in how technology has influenced the evolution of humans in the past 2.6 million years (dating back at least to Homo habilis). In other words, I would like to understand technology along the diachronic axis not as a separate phenomenon – one that may or may not undergo a process analogous to Darwinian selection – but rather as a phenomenon constitutive of human evolution itself.

For example, anthropologists hypothesize that the creation of early lithic technologies had an amplificatory effect on human intelligence: as our ancestors came to rely on such technologies for survival, those with greater cognitive powers (to fashion such lithics) were naturally selected for. This established a positive feedback loop such that intelligence begat intelligence. Thus, in this way, human-built artifacts actually mediated the evolutionary process of natural selection to bring about more “encephalized” (bigger-brained) phenotypes.

In the literature on evolution, a new school of thought has recently emerged that rejects the standard Darwinian (or neo-Darwinian) model – a model in which organisms are always molded to fit their environments, in which causation extends unidirectionally from the environment to the organism. In contrast to this understanding of adaptation, “niche constructionists” argue that organisms actually make the environments in which they live and to which they are adapted. At the most passive end of the constructionist spectrum, simply being a “negentropic” organism far from thermodynamic equilibrium changes various factors in the environment, while at the most active end one finds Homo sapiens, a unique species that has profoundly altered the environment in which it (and most other Holocene organisms) exist (or once did).

Thus, niche construction theory explicitly brings into its theoretical view the human creation of technology – specifically, those artifacts that have in some way helped “construct” the niches that we occupy. While this is a good theoretical start (although not all biologists, including Dawkins, have jumped on the niche constructionist bandwagon), niche construction theory seems to neglect a crucial phenomenon relating to technology – a phenomenon that might be called “cyborgization” or, more prosaically, “organism construction” (on the model of “niche construction”).

To motivate this point, let me back up for a moment. First, note that explanation in biology is paradigmatically causal (rather than non-causal, as in nomological explanations citing the second law of thermodynamics ). Thus, since the standard model of Darwinian evolution sees causation as unidirectional, from the environment to the organism, it follows that explanations of organismal adaptation entail specifying an environmental factor that has, over transgenerational time, brought about a change in the corresponding organismal feature. Some philosophers have typologized this kind of explanation as “externalist,” since it is the selective environment external to the organism that accounts for the organism’s adaptedness to that environment.

But niche constructionists think that there is another type of explanation for organismal adaptation – a “constructive” explanation. According to this view, organismal features could complement or match the relevant environmental factors not because of natural selection, but because the organism itself modified those factors. While in many cases this modification is inadvertent (see the example of the Kwa-speaking yam farmers), humans are unique in the radical extent to which we have intentionally modified the environment. Back to this in a moment.

So, the picture sketched thus far looks like this. Fact: organisms are generally well-adapted to their environments (the explanandum). But why? According to niche constructionists, and in contrast to traditional neo-Darwinians, either of the following two phenomena might have occurred (these are not mutually exclusive): (i) natural selection might have intervened to bring about an adaptive change in an organismal feature to match an environmental factor, or (ii) the organism might have “constructed” its niche to make the relevant environmental factors complement its own features. Since causation here is bidirectional, causal explanation of adaptation therefore swings both ways – from the environment to the organism (externalist) and from the organism to the environment (constructive).

But what seems to be missing from this picture, at least when focusing on Homo sapiens, is the use of technology to artificially extend, substitute and enhance features of the human organism itself, for the purpose of increasing our complementarity to the increasingly artificial milieu in which we live. That is to say, niche constructionists only explicitly recognize natural selection as bringing about changes in organismal features. On reflection, though, it seems transparently clear that we humans have largely usurped the role of natural selection by technologically modifying our own behaviors, morphology and physiology – i.e., our phenotypes. The pervasive artifactual metaphors of function, mechanism, design, etc. as well as the agential metaphor of natural selection, are all being gradually replaced by literal functions, by literal mechanisms, by a literal engineer.

While some examples of “organism construction” are highly intuitive, such as neural implants and prosthetic limbs, I would like to intrepidly venture beyond our pre-theoretical intuitions and suggest that entities like the automobile might, under certain conditions, actually count as part of the (technologically-modified) human organism itself. For example, I see the automobile as a case in which engineers intervened to “construct” the human organism for the purpose of adaptively modifying it to complement a very specific selective environment, namely the road. One might therefore say that the human-automobile system is adapted to the road rather like the earthworm is adapted to its environment, which also turns out to be thoroughly constructed.

If one thinks this is a giant conceptual leap to an implausible picture of human evolution, consider the following: since the late nineteenth century, theorists have repeatedly characterized technologies as “extensions of man” (in Marshall McLuhan’s words); in his 1877 book Grundlinien einer Philosophie der Technik, the first philosopher of technology, Ernst Kapp, termed this phenomenon “organ projection.” More recently, some philosophers of mind (most notably Andy Clark) have argued that the boundary of the mind – and indeed the self too – is not demarcated by “skin and skull,” as our pre-theoretical intuitions might suggest. Rather, these philosophers claim that when specific criteria relating to (e.g.) function and reliability are satisfied, technological entities like notepads and computers literally become part of the individual’s cognitive system – that is, they become components internal to the individual’s mind and self. In a similar spirit, the physiologist J. Scott Turner has defended the conceptual-metaphysical thesis that organisms are fuzzily bounded, and still other theorists have considered the possibility of “boundary shifting,” as in the peculiar case of water crickets.

This being said, a common objection to understanding artifactual entities like automobiles, clothes, glasses, and so on, as instances of “organism construction” – that is, as extended adaptations of a sort – is that many technological modifications involve transient and reversible changes to human behavior, morphology and physiology. Unlike the evolutionary acquisition of a bigger brain, for example, the “automobilic phenotype” is expressed only temporarily. Rather than take this as a problematic datum, though, I see it as suggesting a novel interpretation of what biologists have called phenotypic plasticity, or the ability of an organism to manifest particular phenotypic features in response to specific environmental factors on an ontogenetic timescale. As Darwin once wrote: “I speculated whether a species very liable to repeated and great changes of conditions might not assume a fluctuating condition ready to be adapted to either condition.”

This is, in fact, precisely what one finds in our highly composite, artificialized world – that is, modernity is a complex mosaic of interlocking and disparate environmental conditions, each of which contains its own peculiar factors that complement often times very different features of the (technologized) organism. The point here is twofold: (i) it seems undeniable that our contemporary environment is not homogeneous but highly heterogeneous in nature, and (ii) it also seems obvious that no single set of organismal features – whether technologically modified or not – is sufficiently adapted to all of these disparate conditions. Thus, being liable to repeated and great changes of conditions, the modern human assumes a fluctuating condition through the use of technology, and therefore becomes ready to be adapted to all of the many conditions that he or she may encounter.

In sum, we humans have increasingly become adapted to our environments through active human intervention – that is, through technological modifications targeting both ourselves and our surroundings. While niche construction theory explicitly recognizes the latter category of techno-modification, it seems to problematically neglect the former. This is not a trivial lacuna, in my opinion, especially with all the talk in bioethics and biopolitics today about the creation of “enhancement” technologies, i.e., technologies that aim to augment some feature of the human organism or add entirely new features or capacities to its phenotypic repertoire. Thus, for these reasons, it seems that the niche constructionist framework ought to be expanded into a dual constructionist account of human evolution, even if this requires us to rethink inveterate concepts like phenotypic plasticity.