Published on Let's Talk Development

Gender differences in social preferences: Lessons from a day care experiment in Rio de Janeiro

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The paper exploited the lottery system implemented in Rio de Janeiro to estimate the intent-to-treat effects of daycare attendance. Photo: Stephan Bachenheimer/ World Bank The paper exploited the lottery system implemented in Rio de Janeiro to estimate the intent-to-treat effects of daycare attendance. Photo: Stephan Bachenheimer/ World Bank

A study about gender norms in Brazil from 2014 reported that, among girls ages 6 to 14, 81% made their own bed, 77% washed dishes and 66% cleaned the house. In contrast, among these girls’ brothers, only 12% made their own bed, 12% washed the dishes and 11% cleaned the house. These statistics might not be surprising for those familiar with gender norms in Brazil. And they might not be very different elsewhere in the world. 

One obvious question is to what extent these differences in behaviors might be driven by preferences. Men and women often have different preferences, which could at least partly explain gender differences in choices and outcomes. Some would argue that, if gender gaps in outcomes are driven by gender differences in preferences, then there is no need to address them.  On the other hand, boys and girls may develop different preferences because they are raised differently from very early on. There is thus an increasing interest in understanding the origins of the gender differences in preferences. The origins of gender differences in social preferences are perhaps particularly interesting because of gender stereotypes that expect women to be more prosocial than men.  

Do girls more easily agree to be left behind? 

In a recent working paper, we investigated the role that early education plays in children’s economic preferences and decision-making abilities. In 2007, the local government of the city of Rio de Janeiro used a lottery system to determine admissions into oversubscribed public free-of-charge daycare centers. We exploited this exogenous variation in daycare enrollment to identify intent-to-treat effects of daycare attendance. Nine years after those who were admitted started attending daycare, we surveyed about 2,100 of the applicant-children. We administered four incentivized experiments to measure their economic preferences as well as the quality of their decision-making. 

Overall, we find that daycare attendance did not affect economic preferences and had no impact on decision-making abilities. However, there is one exception: daycare attendance seems to have changed children’s social preferences – particularly of girls 

How do we measure social preferences? 

Children played a sharing task using a tablet. In this task, the child had to choose between two different allocations; each allocation paid a number of tokens to the participant and a number of tokens to another anonymous child (the tokens could be exchanged for toys at the end of the survey). 

The children would for example have to choose between the allocation on the left and the one on the right in the screenshot of the tablet reproduced in Figure 1. In this case, the participant chose between the equitable allocation on the left in which the two children get the same (3 tokens for the participant and 3 for the other child) and the allocation on the right in which she received less than the other child (3 for the participant but 6 for the other child). 

Figure 1

Figure 1: Snapshot of sharing task with an example of disadvantageous inequality.  In blue (“Leandro”) are the tokens assigned to the participating child, while in red (“Outra Criança – Other Child”) are the tokens assigned to the other anonymous child. 

Note that both allocations give three tokens to the participant. They only differ in how many tokens are given to the other child. The allocation on the right in particular, represents a case of “disadvantageous inequality” where the participant gets three tokens less than the other child. We infer that a participant exhibits “aversion to disadvantageous inequality” if she chooses the allocation on the left, “taking away” three tokens from the other child to ensure that she is not left behind.  

The effects of daycare attendance on social preferences 

We exploited the lottery system implemented in Rio de Janeiro to estimate the intent-to-treat effects of daycare attendance.  The top panel of Figure 2 shows no effect on boys’ choices (in blue). In contrast, the bottom panel shows that daycare attendance increased girls’ (in pink) aversion to disadvantageous inequality. Treatment girls were substantially more likely than control girls to choose the equitable allocation, “taking away” the three tokens from the other child to ensure they were not left behind. Among control children, control boys exhibited a greater aversion to being behind than control girls did. The effects of daycare attendance are large enough to close this gap: treatment girls were as averse to disadvantageous inequality as control boys.  

Figure 2

Figure 2: Intent-to-treat effects of daycare attendance on preferences expressed in the sharing task illustrated in Figure 1. Boys on the top panel in blue, girls on the bottom panel in pink. The markers represent effect sizes. The brackets correspond to 95% confidence intervals. 

A natural question is why the daycare lottery changed girls’ preferences but not of boys. One possible explanation is that it changed girls’ perceptions of gender roles, including about how accommodating they are expected to be and how acceptable it is for girls to be more concerned with their own wellbeing and less concerned with the wellbeing of others. In any case, the evidence from the Rio de Janeiro daycare experiment suggests that gender differences in social preferences, such as attitude toward inequality, are malleable and can be influenced by the socialization process experienced by children  early in their lives. 



Joana Cardim Dias

Senior researcher at the Education Policy Institute

Pedro Carneiro

Professor of economics at the University College London

Leandro Carvalho

Economist at the University of Southern California’s Center for Economic and Social Research

Damien de Walque

Lead Economist, Development Research Group, World Bank

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