Evolution and the metaphor of agency
Professor Samir Okasha, University of Bristol, UK
It is striking that evolutionary biology often uses the language of intentional psychology to describe the behaviour of evolved organisms, their genes, and the process of natural selection that led to their evolution. Thus a cuckoo chick ‘deceives’ its host; a worker ant ‘prefers’ to tend the queen's eggs to those of other workers; a swallow ‘realises’ that winter is approaching and ‘wants’ to escape it; an imprinted gene ‘knows’ whether it was inherited paternally or maternally; and natural selection ‘chooses’ some phenotypes over others.
This intentional idiom is a symptom of a broader way of thinking about and modelling evolution, which I call ‘agential’. This involves treating evolved entities, paradigmatically individual organisms, as if they were agents trying to achieve a goal, namely maximisation of reproductive fitness (or some proxy). The use of rational choice models, originally intended to apply to deliberate human action, in an evolutionary context, is one symptom of agential thinking.
I offer a cautious defence of agential thinking in evolutionary biology. I argue that this mode of thinking does genuine intellectual work, and is not ‘idle metaphor’. The key point is that attributions of agency presuppose a ‘unity of purpose’. Therefore an evolved organism can only be treated as agent-like to the extent that its phenotypic traits have complementary rather than antagonistic functions, i.e. contribute to a single overall goal. Where this is not the case, e.g. because of unresolved intra-genomic conflict, the metaphor of agency ceases to be applicable.
Developmental niche construction
Dr Karola Stotz, Macquarie University, Australia
In the last decade niche construction has been heralded as the neglected process in evolution. But niche construction is just one way in which the organism’s interaction with, and construction of the environment, can have potential evolutionary significance. This constructed environment not just selects for, it also produces new variation. Nearly three decades ago, and in parallel with Odling-Smee’s book chapter ‘Niche-constructing phenotypes’, West and King introduced the ‘Ontogenetic Niche’ to give the phenomena of exogenetic inheritance a formal name. Since then a range of fields in the life sciences and medicine has amassed evidence that parents influence their offspring by means other than DNA (parental effects). Diverse scientists use different theoretical constructs for overlapping sets of processes, all of which show one way or another how heritable variation can be environmentally induced and developmentally regulated. Here I propose the concept of ‘developmental niche construction’ as a framework to integrate findings from fields ranging from molecular biology to developmental psychology. It elucidates how a diverse range of mechanisms contributes to the transgenerational transfer of developmental resources. This talk will explore the overall significance of these developments in the life sciences, and particularly how they advance the ongoing integration of development, heredity, ecology, and evolution.
Human nature, human culture: the case of cultural evolution
Professor Tim Lewens, University of Cambridge, UK
In recent years, far from arguing that evolutionary approaches to our own species permit us to describe the fundamental character of human nature, a prominent group of cultural evolutionary theorists has instead argued that the very idea of 'human nature' is one we should reject. It makes no sense, they argue, to speak of human nature in opposition to human culture. But the very same sceptical arguments have also led some thinkers – usually from social anthropology – to dismiss the related idea that we can talk of human culture in opposition to human nature.
How, then, are we supposed to understand the cultural evolutionary project itself, which seems to rely on a closely allied distinction between 'organic' and 'cultural' evolution? This talk defends the cultural evolutionary project against the charge that, in refusing to endorse the concept of human nature, it has inadvertently sabotaged itself.
Human niche, human behaviour, human nature
Professor Agustín Fuentes, University of Notre Dame, USA
Scholars from a diverse range of disciplines disagree on what human nature is, what it could be, or even if there is one. There is no single ‘best’ discourse on, or mode of approach to, human nature. However, in the context of what we know about the evolutionary history, anthropology, and biology of Homo sapiens sapiens it is clear that an evolutionary approach should be among the principal modes of inquiry. At present we are faced with a few different narratives as to exactly what such an evolutionary approach entails. However, one point is clear: we need a robust and dynamic theoretical toolkit in order to develop a richer, and more nuanced, understanding of the cognitively sophisticated genus Homo and the diverse sorts of niches humans constructed and occupied across the Pleistocene, Holocene, and into the Anthropocene. In this talk I review current evolutionary approaches to ‘human nature’ and argue that we benefit from re-framing our investigations via the concept of the human niche and in the context of the Extended Evolutionary Synthesis (EES). In providing an overview of human evolution and the human niche I illustrate the benefits of moving the discourse on human nature(s) to an integrated evolutionary approach incorporating processes of the Extended Evolutionary Synthesis. This is not a replacement of earlier evolutionary approaches but rather an expansion and enhancement, a broadening of our toolkit and the landscape of inquiry. I offer brief examples from human evolutionary histories in support of these assertions.