Research Interests

  • Millionaires
  • Social Finance
  • Behavioral Finance
  • Experimental Economics
  • Happiness


Millionaires are more generous in dictator games than any other group studied in the literature. Yet, millionaires reduce their generosity in a bargaining context (ultimatum game). For fund raisers, it is therefore important to tap into the giving mindset of the wealthy and prevent an exchange focus like: "You give, you get". 
  • "Buying Time Promotes Happiness", Proceedings of the National Academy of Sciences (with Ashley Whillans, Elizabeth Dunn, Rene Bekkers and Michael Norton) 
How should individuals spend their money to maximize their life satisfaction? Across the United States, Canada, Denmark and the Netherlands, we find that spending money to buy time increases life satisfaction. Outsourcing tasks such as house cleaning, cooking and doing groceries reduce feelings of stress. Yet, surprisingly, almost half of the Dutch millionaires do not buy time.
  • “Time Use and Happiness of Millionaires” (with Ashley Whillans, Rene Bekkers and Michael Norton), submitted
Millionaires spend their time in a surprisingly similar way as the general population. For example, millionaires spend the same amount of time as the general population cooking, shopping, and eating – and even spend more time on household chores. Yet, the wealthy engage in more active leisure (e.g., exercising and volunteering) and less passive leisure (e.g., watching TV and relaxing), which contributes to their happiness.
  • "Preferences for Inequality: An Experiment with Millionaires" (with Alain Cohn, Lasse Jessen and Marko Klasjna)
Millionaires in the US are substantially more tolerant towards inequality than the general population in a large experiment in which participants redistribute real earnings of workers. In particular, we find that many millionaires refuse to redistribute at all, even when the source of inequality is pure luck as opposed to hard work. Preferences for inequality explain voting behavior and attitudes towards redistributive policies.

Sustainable Finance Social preferences are the most important driver for investors to hold socially responsible mutual funds. Many investors accept lower expected returns on socially responsible investments and are willing to pay higher management fees. Providers of socially responsible investments benefit from a focus on the societal impact of responsible investments rather than focusing too much on financial performance.
Covered by Harvard Law School Forum

The extent to which investors at socially responsible banks can identify with their socially responsible investments is an important driver for allocations to socially responsible banks. Return expectations and risk preferences also play a role, but are less important. Providers of socially responsible investments can benefit from creating strong social connections with their clients.

Financial Decision Making

Financial incentives increase retirement information search by 52%. Financial incentives are cost-effective: only $4.21 for informing one additional pension fund beneficiary. In contrast, all our social norms treatments are ineffective and sometimes significantly reduce the rate at which participants inform themselves. We develop an experimental method to estimate individuals’ time and risk preferences tailored to long-term decision making, like pension savings decisions. We directly compare our approach to low stakes incentivized experiments with short horizons, typically used in the literature. 
  • "Testosterone and Overconfidence of Investment Managers" (with Pim van Vliet) 
​We measured the testosterone levels of professional investment managers who manage about 100 billion euro of assets. Investment managers with a high level of testosterone are substantially more likely to believe they outperform their peers than justified by the actual performance data.
  • "Lets Invite the Women: Gender Diversity Reduces Overconfidence in Pairs" (with Tobias Ruof)
Gender composition of pairs matters for information processing. Pairs that include men suffer from asymmetric belief updating, by responding much stronger to positive feedback than to negative feedback. In contrast, female-only pairs and pairs with unknown gender update their beliefs in a symmetric way. The results inform the debate on gender diversity in companies and universities.

Philanthropy Reports

Joint projects with financial institutions

Robeco abn amro tridos bank asn bank deutsche bank loyalis

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