“From hominins to humans: how sapiens became behaviourally modern”

K. Sterelny. 2011. Phil. Trans. R. Soc. B, vol. 366, pp. 809–822.
This paper contributes to a debate in the palaeoarchaeological community about the major time-lag between the origin of anatomically modern humans and the appearance of typically human cultural behaviour. Why did humans take so long—at least 100 000 years—to become ‘behaviourally modern’? The transition is often explained as a change in the intrinsic cognitive competence of modern humans: often in terms of a new capacity for symbolic thought, or the final perfection of language. These cognitive breakthrough models are not satisfactory, for they fail to explain the uneven palaeoanthropological record of human competence. Many supposed signature capacities appear (and then disappear) before the supposed cognitive breakthrough; many of the signature capacities disappear again after the breakthrough. So, instead of seeing behavioural modernity as a simple reflection of a new kind of mind, this paper presents a niche construction conceptual model of behavioural modernity. Humans became behaviourally modern when they could reliably transmit accumulated informational capital to the next generation, and transmit it with sufficient precision for innovations to be preserved and accumulated. In turn, the reliable accumulation of culture depends on the construction of learning environments, not just intrinsic cognitive machinery. I argue that the model is (i) evolutionarily plausible: the elements of the model can be assembled incrementally, without implausible selective scenarios; (ii) the model coheres with the broad palaeoarchaeological record; (iii) the model is anthropologically and ethnographically plausible; and (iv) the model is testable, though only in coarse, preliminary ways.


Last week Asa presented a paper by Kim Sterelny (2014)—an important source for the idea of sociocultural niche construction Ellis develops. Sterelny focuses on an apparent paradox, discussed in the present paper as well: although in a physiological sense the characteristics of homo sapiens (i.e. “anatomically modern humans”) were present 200 to 150 kya (thousand years ago), “those first humans do not seem to have been behaviourally modern” (p. 811, emph. added). Behavioral modernity only starts to appear 50-60 kya. What changed that led what seems to have been essentially the same creature to act in very different, and much more complex, and more recognizably human, ways?

As Asa notes, against the view that there must have been some sudden genetic change that allowed for emergence of behavioral modernity, Sterelny points to changes in the social conditions in which early humans lived. In the paper Asa examined, Sterelny points to the increased complexity of social interactions. In the paper I am considering, the changes are the result of niche construction.

The sort of niche construction Sterelny has in mind, to be precise, is very much related to what I discussed in my post on Pinker’s paper “The Cognitive Niche.”  That is, humans gain the resources they need from their surroundings not just in virtue of their physical abilities, but also their cognitive skills. The cognitive niche is constructed in two senses: it is the result of human activity, as people reinforced their mental capacities through their interactions, but also it is inherited by the next generation, for which it is the environment to which they must adapt.

But, as Sterelny emphasizes, a key function of the inherited niche is that it channels organisms’ development. This is a general characteristic of niche construction—as Sterelny observes, “termites develop in a world built by and for termites . . . hence the phenotypic effects of [termite] genes are more predictable” (p. 809). In the case of the cognitive niche, human beings create learning environments which, in various ways, activate the cognitive capacities—no doubt genetically based—of their young. Sterelny points to apprentice learning as an example: “It is learning by doing. But it is learning by doing in an environment seeded with informational resources. . . . [It] depends on individual cognitive adaptations for social learning but it depends as well on adaptively structured learning environments” (p. 810). That is, human beings’ cognitive capacities develop because humans enter into life in an environment (their culture) that has been constructed by previous generations to elicit their exercise. In Sterelny’s words, “the young come to explore and act in a world that supports and directs learning” (p. 816). This is how our species survives.

Sterelny argues that this developmental aspect of the cognitive niche plays a role in the ability of humans to, as he puts it, accumulate cognitive capital. For, the mechanisms he identifies allow for the body of information a social group uses to survive to be passed on reliably from one generation to the next. Reliable transmission is a condition of expansion of knowledge—comprising both the capacity to do additional things, and, particularly importantly, the gradual improvement in the capacity to do specific things. “Behavioural modernity,” Sterelny concludes, “probably depends both on an increase in the rate of innovation, as individual humans come to deliberately intervene on the world in ways guided by their increasing understanding, and by improved preservation and amplification of successful innovation” (p. 815).

This ability to accumulate cognitive capital is the underlying driver of the process Ellis points to to explain the long-term development of human beings’ capacities to transform the biosphere. In a sense, Sterelny explains how evolution produced the beings—behaviorally modern humans—who appear at the starting line of the process Ellis places toward the left of his Figure 3 (see p. 304). I have two pretty open-ended questions about the situation of the beings—us, broadly speaking—at the far right of that figure.

Figure 3, p. 305

The first I think picks up from Lynn’s comments on communication technology in her last post. Sterelny points to the dynamics of developmental influence of humans’ cognitive (more generally, sociocultural) niche. Assuming those dynamics continue to operate, what are the effects we should expect to see on the development of people raised in the cognitive environment of a global communications network in all its manifestations. What are the implications for the physical environment of the fact that “digital natives” inhabit a virtual environment—itself, of course, thoroughly constructed?

The second question has to do with what I take as one of Sterelny’s most important points: that the suite of traits associated with behavioral modernity is as much a product of social structure as (perhaps even more than) of genetic endowment (see p. 813). Again, assuming that that underlying dynamic remains in force—i.e. the possibilities for human behavior today may be constrained, but are not tightly determined by our genes—it seems to follow that broad patterns of behavior are at least somewhat plastic. At a moment when existing patterns of behavior have presented us with some frightening prospects (the scary Anthropocene), this is perhaps a hopeful thought. But it begs this question: is it possible to apply the understanding of the developmental power of the human niche to a kind of sociocultural niche re-construction, to foster more positive next steps in what Ellis calls the anthroecological succession?

Further Reading

Alex Mesoudi. 2016. Cultural evolution: integrating psychology, evolution and culture. Current Opinion in Psychology, vol. 7, pp. 17–22. This paper presents some psychological mechanisms that structure the kinds of learning that can take place in the developmental context of the cultural niche.
K. Sterelny. 2014. A Paleolithic Reciprocation Crisis: Symbols, Signals, and Norms. Biological Theory, vol. 9, pp 65-77. This is the paper Asa discusses, also cited by Ellis.

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