EHBEA NEW INVESTIGATORS
2013 AWARD WINNER: David Lawson
Plenary Title: Natural Selection on Wealth and Fertility in Humans
Abstract: Life history theory argues that all organisms have two main goals – 1) competitively extract resources from the ecological and social environment and then 2) selectively allocate these resources to reproduction in a way that maximizes inclusive fitness. In this talk, building on the work of a number of evolutionary anthropologists and demographers, I argue that natural selection has shaped humans to rely on largely distinct proximate pathways to address these two goals. Resource accumulation is a cognitively taxing and complex social process, requiring considerable context-dependent plasticity and conscious goal-directed strategizing. A review of studies of fertility and offspring success however suggests that automatic physiological mechanisms, which suppress reproduction only when maternal or child survival is at immediate risk, have been sufficient to ensure optimal reproductive behaviour throughout most of human history. Recognizing this distinction exposes our inherent vulnerability to maladaptive decision-making in novel environments where wealth accumulation is now in conflict with reproductive opportunities for both men and women – improving our understanding of why fertility rates plummet when populations undergo socioeconomic development (i.e. the demographic transition). I review empirical evidence that supports the hypothesis that modern low fertility rates can be understood as a response to increased status competition and returns to high parental investment, and that fertility limitation is ultimately maladaptive in terms of both short and long-term fitness. Finally, I critique recent studies concluding that natural selection continues to act positively on wealth even in contemporary low fertility populations, and argue that natural selection is now acting negatively on strategies of wealth accumulation and is for the first time strongly favouring individuals that desire early childbearing and large families regardless of the socioeconomic consequences.
- Lawson, D.W., Alvergne, A. & Gibson, M.A. (2012). The life-history trade-off between fertility and child survival. Proceedings of the Royal Society B: Biological Sciences 279: 4755-4764.
- Goodman, A., Koupil, I. & Lawson D.W. (2012). Low fertility increases descendant socioeconomic position but reduces long-term fitness in a modern post-industrial society. Proceedings of the Royal Society B: Biological Sciences 279: 4342-4351.
- Lawson, D.W. & Mace R. (2011). Parental investment and the optimization of human family size. Philosophical Transactions of the Royal Society B: Biological Sciences 366, 333-343.
2012 AWARD WINNER: Pontus Striming
Plenary Title: Sadly, general models can't predict the outcome of cultural evolution
Abstract: One goal of the study of cultural evolution is to predict how the outcome of cultural change is structured and what cultural traits are likely to be in it. Very much like population genetics is interested in the structure of the equlibria and what genes are likely to be in it. In fact researchers modeling cultural evolution have been hopeful that models from population genetics, with small alterations, would be sufficient to generate such predictions in cultural evolution. However, after extensive research this turned out not to be the case. In this talk, I bring more bad news to the table. Not only can we not adapt population genetics models; we will probably never create general models for cultural evolution that predict as well as general models do in population genetics. There, details that at first seemed essential, such as whether the species was haploid or diploid, turned out not to matter in many cases. This resulted in simple models with high predictive value. In cultural evolution, we are not so lucky.
In this talk I go through several specific factors, such as the number of cultural parents or the size of the initial population, each of which radically changes the predictions of the models. Creating a general model that accounts for all these factors is probably impossible. So in the case of cultural evolution, general models will either be too complex to study or run the risk of giving faulty predictions. I conclude by outlining strategies for escaping this dilemma by using specific models that rely heavily on empirical data.
- Strimling, P., Enquist, M. & Eriksson, K. (2009). Repeated learning makes cultural evolution unique. PNAS, 106(33): 13870-13874.
- Strimling, P., Sjöstrand, J., Enquist, M. & Eriksson, K. (2009). Accumulation of independent cultural traits. Theoretical Population Biology, 76(2): 77-83.
- Enquist, M., Strimling, P., Eriksson, K., Laland, K. & Sjöstrand, J. (2010). One cultural parent makes no culture. Animal Behaviour, 79: 1353-1362.
2011 AWARD WINNER: Thom Scott-Phillips
Plenary Title: Communication, cognition, and the evolution of language
Abstract: Speaking very broadly, we can identify two different approaches to communication: the code model, in which meaning is fully encoded in the signal, and inferential communication, in which speakers provide evidence for their intended meaning, and listeners use that evidence to infer the speaker's meaning. Probably most animal communication is of the former type, but human linguistic communication is of the latter type. There are several evolutionary questions we can ask about inferential communication. What are the cognitive foundations of inferential communication, and how did they evolve? How does inference affect the cultural evolution of communication systems? Do only humans have inferential communication? In my talk, I will describe the research I have conducted that begins to shed light on these questions.
- Scott-Phillips, T. C. (2010). Evolutionary psychology and the origins of language, Journal of Evolutionary Psychology 8(4), 289-307.
- Scott-Phillips, T. C. & Kirby, S. (2010). Language evolution in the laboratory, Trends in Cognitive Sciences 14(9), 411-417.
- Scott-Phillips, T. C., Kirby, S. & Ritchie, G. R. S. (2009). Signalling signalhood and the emergence of communication, Cognition 113(2), 226-233.
- Scott-Phillips, T. C. (2008). Defining biological communication, Journal of Evolutionary Biology 21(2), 387-395.
2010 AWARD WINNER: Dr Alex Alvergne
Plenary Title: Variation in human paternal care - ultimate and proximate factors
Abstract: During recent decades, an increase in paternal involvement in childcare in occidental societies has led many to question the role of fathers beyond traditionally prescribed functions of breadwinner, moral authority and masculine role model. Anthropological studies have also highlighted the considerable diversity in fatherhoods between and within human cultural groups. Taking an integrative evolutionary perspective, I address both ultimate and proximate factors underlying the expression of paternal care, and consider the impact of such variation on child development and later reproductive success. According to evolutionary theories of parental investment and kin selection, father investment is expected to vary depending on socio-ecological factors such as paternity uncertainty and mating opportunities. Drawing on data collected from France and Senegal, I argue that paternity uncertainty has constituted an important selective pressure on the use of paternity cues by men (i.e. odour and facial similarity), as well as a manipulation by women of men's perception. Furthermore, I show that the expression of paternal investment is traded-off with mating investment, and mediated through hormonal mechanisms. Finally, I found that the link between paternal investment and fitness-related traits in children depends on the studied population. Overall, this research increases our understanding of the socio-ecological and hormonal factors associated with paternal investment, and highlights the relevance of an evolutionary approach to the study of human behaviour. It also provides a general model to address currently challenging questions such as why father investment has recently experienced a dramatic increase in western societies.
- Alvergne, A., Faurie, C., Raymond, M. (2009). Father-offspring resemblance predicts paternal investment in humans. Animal Behaviour, 78: 61-69.
- Alvergne, A., Faurie, C. and Raymond, M. (2010). Are parents' perceptions of offspring facial resemblance consistent with actual resemblance? Effects on parental investment. Evolution and Human Behaviour, 31:7-15.
- Alvergne, A. & E. Huchard, et al. (2010). More than friends? Behavioural and genetic aspects of heterosexual associations in wild chacma baboons. Behavioural Ecology and Sociobiology, 64(5):769-781.
- Alvergne, A., Jokela, M., & Lummaa, V. (2010). Personality and reproductive success in a high fertility human population. Proceedings of the National Academy of Sciences, USA, 107(26):11745-11750.