In a letter, Benjamin Franklin (1789) once famously remarked that in this world there is nothing certain

but death and taxes. Indeed, risk and uncertainty dominate decisions ranging from taking the subway

instead of a taxi, to undergoing surgery instead of chemotherapy, to investing in stocks instead of bonds.

Although we cannot help but navigate a world full of risk and uncertainty, not everyone responds to them

in the same way. In fact, people differ widely in how they deal with risk: Some people refrain from all

risky bets, whether in the stock market, in their profession (e.g., never change jobs) or, simply, in daily

habits (e.g., always carry an umbrella); others may thrive on the opportunities associated with risk, and

even actively seek out situations that would frighten others (e.g., running with the bulls in Pamplona or

experimenting with illegal drugs).

For a long time, psychologist and economists have been developing behavioral paradigms to measure how

people respond to risks and uncertainties. However, theoretical conceptions of risk taking differ across

disciplines. Economists typically define risk as the variability of outcomes and risk taking as a preference

for this variability. Clinicians and psychologists, on the other hand, often define risk taking as behavior

with potentially harmful and negative consequences. Grounded in these theoretical views, the behavioral

paradigms measuring risk taking differ substantially between the disciplines. Whereas economists use

rather simple but well-defined choices between monetary gambles to measure risk taking, clinicians use

more complex, but also more natural risk-taking paradigms. Both approaches have documented a large

inter-individual variability in people’s risk taking, but the determinants of this variability are still largely

unknown. Recent research, however, suggests that biological factors such as a person’s genetic make up

and hormone levels contribute to a person’s appetite or disdain for risk. To address this, we will elicit risk

taking using a wide array of behavioral paradigms and investigate risk taking, taking into account its

cognitive, genetic, and hormonal foundations.

Adopting a multi-disciplinary approach by linking decision science, cognitive psychology and cognitive

and molecular neuroscience enables us to pursue several important objectives: First, building upon but

also going beyond recent research, we will measure the psychological phenotype, risk taking (in a large

sample of healthy participants), by taking advantage of a plurality of measurement paradigms, ranging

from risky choices between well-defined alternatives in a stable environment to repeated choices between

alternatives with unknown consequences. Second, by rendering use of computational modeling techniques

(developed in cognitive science and psychology), we will identify the cognitive mechanisms and processes

underlying risk taking. Third, we then will relate overt behavior and cognitive processes (identified via

modeling) to variations in various genetic polymorphisms and hormonal states, respectively.

Consequently, we can comprehensively investigate to what extent differences in risk-taking behavior and

in associated cognitive processes can be mapped onto differences in biological properties. Our

multi-method and multi-disciplinary approach promises to substantially elucidate the molecular genetic

physiology and hormonal underpinnings of people’s risk-taking and inter-individual variations on this

important dimension of human behavior. This knowledge will be of crucial importance in developing

better diagnostic tools for measuring risk taking, and the identification and treatment of pathological risk

taking such as drug addiction or gambling.