You’re at a birthday party; how would you describe your research?

“I do research on how people make decisions and referee how different disciplines have approached the study of decision-making. My thesis is a series of papers on philosophical questions on the intersection of economics, psychology and cognitive science. Basically, it’s about economic models of decision-making. Economists use mathematical models to represent how people reason and make decisions. These days, economics is interacting with psychology and cognitive science quite a bit to make their models more realistic. They try to understand why people often make irrational decisions, and study how different contexts can lead to good or bad decision-making.”

Could you give an example of one of these models?

“One modelling technique that is very popular is called a ‘dual-self’ model. It builds on important research in psychology: it takes a person and divides them into two separate decision agents. One agent is the ‘planner’, the other is the ‘doer’. The planner has long-term goals, whereas the doer consumes, spends and acts impulsively. Economists have taken this basic framework and formalised it with rigorous mathematical tools. There is an intuitive appeal to this because in the history of philosophy and psychology, going back as far as Plato, you’ve always had this idea of the divided self. It’s a metaphor that everyone can relate to. Over the last 25 years or so, research in psychology and neuroscience have helped to legitimize the idea of the dual-self by identifying dualistic processes and systems in the brain. Economists now say: ‘That’s what we meant all along, taking the intuitive model and adopting new evidence.’ But I’m sceptical about some of this evidence.”

Why are you sceptical?

“I think it’s a useful narrative or metaphor but I think it oversimplifies things dramatically. That is one of the most important conclusions of my thesis. There are both philosophical and scientific reasons to think that this metaphor may distort rather than illuminate what happens when people make decisions. For every argument in support of dualistic processes or systems, you could ask: ‘Why not call it one massive system composed of separate specialized mechanisms or modules?’ Or: ‘Why not propose a third system which deliberates between the two?’ There is much evidence to support both alternatives.

“Furthermore, new research into nudging – a technique to influence how people make decisions – relies heavily on the same psychological research as dual-self models. But if dual process and dual system research oversimplifies how people reason and decide, nudge policies could be wrong, or at least much improved. Simplicity may be good for lobbying policymakers, but it could lead to important problems in application.”

How is your thesis making the world a better place?

“There is all this ‘economics-made-fun-stuff’ coming out these days like Freakonomics, Thinking: Fast and Slow, and Predictably Irrational. Bestseller economics and psychology books for the general public that are well-written and fascinating, but I think there’s too much of a focus on simple metaphors, while this stuff is not easy. My hope is that philosophers, scientists and non-academics will think more carefully about these topics. Be sceptical and be careful.”

Have you become better at making decisions yourself?

“Being a philosopher and a total headcase in general, I’ve always been wrapped up by the question ‘how do I choose?’ That’s what has led to this thesis in a way. But I have no easier time making decisions, it’s only become more complex. The benefit is that while I still make bad decisions, I now know a bit more about why I make them. A lot of how I make decisions is based on what’s good for me at a certain point, but without a global plan. Moving from Los Angeles to Europe, for instance, was entirely unplanned. There’s a famous quote by Kierkegaard, the existentialist philosopher, saying: ‘We live forward, but we understand backward.’ I guess this encapsulates my experiences.”

What’s on the cover?

“I wanted something purposely abstract, because a lot of the thesis is conceptual analysis. One could see the image as a complex structure: as you get closer to the centre its shape and colour become homogenous, but as you move away it appears disordered. This is the case with a lot of concept analysis. Another explanation is that it just looks cool.”