Our work so far has focussed on four main areas.
a) Witchcraft accusation
Witchcraft beliefs are widespread and have the potential to cause great suffering. But it is a very hard topic to study. Postdoc Dr Sarah Peacey, with help from PhD student Olympia Campbell, have created a database of witchcraft accusation from 121 Bantu societies sub-Saharan Africa, which included 500 individual cases where a specific act of accusation of witchcraft was documented in the ethnographic literature where it was possible to identify the gender and other characteristics of the accuser and the accused. This dataset has enabled us to show that witchcraft accusations are gender specific and reflect competition for resources within families and communities (published in Scientific Reports).
b) Gender and honour-based violence.
Violence against women and girls, most of which is from their own partners or families, is a worldwide pandemic. PhD student Olympia Campbell has analysed various data sources, including demographic health survey (DHS) on Jordanian women, and a database of newspaper reports from Pakistan, including a focus on whether cousin marriage played any role in 'honour-based' violence, including 'honour' killing, usually (but not exclusively) of young women, often by members of their own family (published in Evolution, Medicine and Public Health and others in review).
c) Gender biases in workload
Using data from an in-depth cross-cultural field study in rural China, we used accelerometers to gain accurate measures of the work burden of males and females in a set of different kinship systems, in some of which females disperse at marriage (the most common) and some of which males, or neither, or both sexes disperse at marriage. PhD student Yuan Chen is using this dataset to examine the influence of sex inequality generated by dispersal, kinship and sex ratio on gender balance in workload. We find that both being female and dispersing at marriage are predictive of high workloads (published in Current Biology).
d) Culturally sanctioned celibate roles
Monastic celibacy is an evolutionary puzzle. PhD student Erhao Ge, with our Chinese collaborators from Lanzhou University, have analysed our demographic data from Tibetan villages which shows that both the brothers of monks benefit and the fathers of monks have more children or grandchildren. Postdoc Alberto Micheletti has modelled in what cases celibacy could be shaped by inclusive fitness interests, and his modes show that celibacy is rarely favoured if the decision is made by the boy himself, but it can be favoured by his parents if there is a benefit to brothers. Parent-offspring conflict appears to underpin the acceptance of sending young boys or sometimes girls to these hugely influential religious institutions (published in Behavioral Ecology and Proc. Royal Society B and EHB). EG is now examining social networks between community members to see if there are any reputational benefits associated with having a monk in the family. Overall, it appears that the practice is not costly to parents.
This work has also lead us to contribute to the wider debate on the role of inclusive fitness in how culture evolves. We have written two papers on how to think about and test the extent to which inclusive fitness interests do indeed shape human cultural behaviour (published in Behavioural Ecology (What is cultural evolution anyway?).
