A large share of research on human behaviour assumes that everyone shares most fundamental cognitive and affective processes, and that findings from one population apply across a range of population. In this, the authors suggest that this in fact is not the case. Their claim is supported by a growing body of evidence. For example, experimental findings from several disciplines indicate considerable variations among human populations across a variety of domains, such as visual perception, analytic reasoning, cooperation, memory and intelligence. Moreover coincides with what anthropologists have long suggested: that people from Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies, and in particular American undergraduates, are some of the most psychologically unusual people on earth. Using participants from such an unusual population could have important practical consequences.
The authors offer four suggestions to help put theories of human behaviour and psychology on a firmer empirical footing:
- Editors and reviewers should push researchers to support any generalization with sustainable evidence.
- Granting agencies, reviewers, and editors should give researchers credit for comparing diverse and inconvenient subject pools.
- Granting agencies should prioritize cross-disciplinary, cross-cultural research.
- Researchers must strive to evaluate how their findings apply to other populations.
Finally, a key long-term goal is to establish a set of principles that researchers can use to distinguish variables from universal aspects of psychology. Recognizing that (populations of) people differ does not mean giving up on the quest to understand human nature. Instead, this recognition enables a journey into human nature that is more exciting, more complex, and ultimately more consequential than has previously been suspected.
