What is your dissertation about?

“I try to understand what makes people have different health and education outcomes, and in particular, what is the role of nature and nurture in generating those differences. Economists have long been interested in these questions, and they used natural experiments such as twins and adoptees to disentangle nature from nurture. In the last twenty years there has been a so-called genome revolution. Now we can decode someone’s DNA and construct individual predictors for health and education outcomes. The idea for this thesis is: let’s take these new measurements that are available from the social science genetics field and use them to answer questions about inequality that we couldn’t answer before.”

How did you do this?

“The first thing I did was looking at gene environment interactions. The idea is that perhaps not only genes and environment matter, but also how they combine with each other. It could be that you’re particularly susceptible to a certain environment, depending on your genes. So we’re trying to see if gene-environment interactions help us explain a larger share of inequality.

“Secondly, I focused on equality of opportunity and social mobility in education, and how genetics can contribute to our understanding of both notions. The theory of equality of opportunity states that inequality is not wrong or undesirable, rather there are fair and unfair sources of inequality. People usually consider effort and choice as fair sources of inequality and for instance early life social class as an unfair source of inequality. I wanted to know what happens to the estimates of equality of opportunity when we add the role of genetic advantage. Then, I investigated how the lack of social mobility in education between parents and children can be explained by genetic transmission.”

How does your research then fit in within the nature vs nurture debate?

“It’s both: genes, environment, and in some cases their interaction.”

What were your most important conclusions?

“I did find that genetics can explain some of the inequality, but what’s most surprising to me is that when you add genetics as a measure, you find more inequality than you thought existed before. For me the most interesting conclusion is that by using genes, you can explain a much bigger share in the variance in the differences in outcome.

“If you’re born in a low social class and you don’t have a high genetic advantage, you can see that these two factors will make it difficult to study longer. If you’re in a low social class, but you have a high genetic advantage, that compensates a bit. I found that after parental social class, the genetic component is the second biggest circumstance explaining educational differences. It really adds a new layer of inequality that we could not observe before.”

How does that translate to, for instance, social policy?

“Knowing that a large part of your educational attainment is explained by two factors over which you have no control, genes and environment, raises important questions on the fairness of large income differences based on educational attainment.”

On the ethical side: is there a danger in predicting ‘success’ with genes?

“That’s always an important question when you’re doing this kind of research. It’s already a reality that companies construct polygenic indexes for embryos, after which you can pick the one you want based on genetic predisposition. First of all: you are never going to predict an outcome based on your genes. Genes act through the environment and are moderated by the environment. You can have a high predisposition for being tall, but if you don’t eat enough growing up, you may end up being short. This is the same for many traits. So, the genetic effects we find are conditional on the society we have right now. We just don’t know how they would change if society changes.

“I also think that ignorance is never a solution. There is still ‘research’ claiming that there are genetic differences between races. But what scientists found is that there is no such a thing as human races; we are all genetically too similar to each other. So we need people doing proper research, so that we can have serious and unbiased discussions on genetics, how it contributes to inequality, and importantly, how it does not! And in this way research can actually help to lessen inequality, and contribute to a more informed world.”

How was the process of doing your PhD?

“I really liked it. I always had a very good work/life balance, my supervisors set a great example in this. It was possible for me to enjoy the great art and music scene Rotterdam has to offer, and I made so many close friends from all over the world here. The only thing I will not miss in this city when I go back to Portugal, is the weather.”

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