“…First, we aim to investigate whether we observe a sex difference in cooperation using a more representative sample of participants in terms of age, sex, and occupation and involving a larger set of countries. This is an open question, since the cooperation relevant factors introduced above – risk aversion (Halek & Eisenhauer, ; Mata, Josef, & Hertwig, ), trust (Sutter & Kocher, ), and prosocial behaviour (Matsumoto, Yamagishi, Li, & Kiyonari, ) – are influenced by age and other demographic factors. Hence, studies with more diverse participant samples would allow for conclusions with higher external validity.…”