The gender division of labour varies significantly across societies. In some cultures women actively participate in employment outside of the home, while in others there is a clear specialisation of tasks along gender lines with women tending to stay at home while their husbands go out to earn the money. These differences are most clearly illustrated by the vast differences in female labour force participation, which in 2000 ranged from 16.1% in Pakistan to 90.5% in Burundi.
Many determinants of these differences have been thoroughly studied, including per capita income and the specialisation of the economy in female-friendly industries. However, even controlling for these variables there remain important time-invariant differences in gender roles.
The root cause of gender work-role differences
A number of scholars have argued that these differences can be explained by cultural values. However this leaves the questions of where these values come from. Ester Boserup (1970) in her path-breaking book Women’s Role in Economic Development argues that gender role differences have their origins in different forms of agriculture practiced traditionally.
In particular, she identifies important differences between shifting and plough cultivation. The former, which uses hand-held tools like the hoe and the digging stick, is labour intensive and women actively participate in farm work. The latter, in contrast, is more capital intensive, using the plough to prepare the soil. Unlike the hoe or digging stick, the plough requires significant upper body strength, grip strength, and burst of power, which are needed to either pull the plough or control the animal that pulls it.
Because of these requirements, when plough agriculture is practiced, men have an advantage in farming relative to women. Also reinforcing this gender-bias in ability is the fact that when the plough is used, there is less need for weeding, a task typically undertaken by women and children. In addition, child-care, a task almost universally performed by women, is most compatible with activities that can be stopped and resumed easily and do not put children in danger. These are characteristics that are satisfied for hoe agriculture, but not for plough agriculture since large animals are typically used to pull the plough.
In a recent study (Alesina et al. 2011) we test Boserup’s hypothesis. The idea is that this division of labour then generated norms about the appropriate role of women in society. Societies characterised by plough agriculture, and a resulting gender-based division of labour, developed the belief that the natural place for women is within the home. These cultural beliefs tend to persist even if the economy moves out of agriculture, affecting the participation of women in activities performed outside of the home, such as market employment, entrepreneurship, and participation in politics.
Modern outcomes and ancient farming
We test Boserup's hypothesis by combining pre-industrial ethnographic data, reporting whether societies traditionally used plough agriculture, with contemporary measures of individuals' views about gender roles, as well as measures of female participation in activities outside of the home. Our analysis examines variation across countries, ethnic groups, and individuals. We find a strong and robust negative relationship between historical plough-use and unequal gender roles today. Traditional plough-use is positively correlated with attitudes reflecting gender inequality and negatively correlated with female labour force participation, female firm ownership, and female participation in politics.
One difficulty in interpreting these relationships is the fact that the adoption of the plough may have been the result of pre-existing cultural values, which may persist over time. To identify the causal impact of the plough on current gender norms, we exploit variation in the extent to which ancestral locations had geo-climatic characteristics that were favourable to the cultivation of specific cereals that benefitted most from the use of the plough, which are referred to as plough-positive crops.
Using data from the FAO, we identify the geo-climatic suitability of finely defined ancestral locations for growing plough-positive cereals (wheat, barley and rye) and plough-negative cereals (sorghum and millet). We then use the relative differences in ethnic groups' suitability for the two types of crops as instruments for ancestral plough use. The IV estimates continue to find that traditional plough use is associated with attitudes of gender inequality, as well as less female labour force participation, female firm-ownership, and female participation in politics.
Having identified the persistent impact of traditional plough-use on gender norms, we then turn to an analysis of the precise channels underlying the effects. It is possible that the persistence of culture explains the effects. But, it is also possible that culture impacts the formation of specific institutions and it is these that crystallise certain gender roles. To disentangle the impact of the plough working through institutions versus direct cultural persistence we examine second-generation immigrants living in the US. These are individuals who now live in identical institutional settings, but have different cultural backgrounds. Within this group, we continue to find that the use of the plough by their ancestors from their homeland is strongly correlated with female labour force participation.
Although our results highlight the persistence of cultural norms, they do not imply that culture does not evolve. There are many examples of very rapid change as a result of shocks. An example is change arising from large-scale warfare, when women were called to work in large numbers to fill the spaces left by men. However, our results show that there is still some persistence for certain cultural traits and that these can last for centuries.
Boserup, Ester (1970), Women’s Role in Economic Development, Allen & Unwin.
Alesina, Alberto, Paola Giuliano, Nathan Nunn (2011), “Fertility and the plough”, NBER Working Paper 16718.