How to Find the Next Big Research Question
A few rules of thumb for aspiring researchers
Posted Jun 15, 2020
How do researchers come up with good scientific questions?
Several decades ago, I went to visit my friend David Funder, who was then an assistant professor at Harvard University, and had been sitting in on E.O. Wilson's "sociobiology" class. Wilson had made the claim, radical at the time, that we could better understand human nature if we considered our own species through the lens of evolutionary biology.
Funder found Wilson’s class interesting, but was not convinced that an evolutionary perspective did anything more than re-explain what we already knew. We already knew men were more inclined to want multiple sexual partners than women did, for example, and an evolutionary perspective simply provided a possible explanation – that particular sex difference stemmed from the fact that women made an intrinsically higher “obligatory parental investment” – that is, women carry the fetus inside their bodies and nurse the child afterwards, so they had more to lose from an ill-chosen sexual decision. But could an evolutionary perspective generate any new hypotheses, ideas that would not have just as easily been generated by a social learning theorist, or a sociocultural theorist? Funder was raising what I would call the First Big Question for evolutionary psychology. Indeed, it is the First Big Question for any new scientific theory: Can the perspective generate new hypotheses, rather than just re-explain what we already knew?
I am not sure how I responded at the time, but likely replied that a learning or cultural perspective would have led us to presume that such phenomena would vary with a person’s particular learning experiences or cultural background. So one hypothesis would be that certain phenomena, those based in mammalian differences in parental investment, for example, would be universal. Men in every society should, on average, value multiple sexual partners more than did women, for example. Later research by David Schmitt and a team of international collaborators did establish that to be the case.
Since then, however, evolutionary theorists have generated hypotheses that would not have been generated from other perspectives. One hypothesis stemming from an evolutionary life history perspective is that young men, guys in their teens, should be attracted not to younger women, but to women older than themselves. It should only be men over age 25 or 30 who showed a pronounced interest in younger women, and the relative gap between the man’s age and that of his partner should increase as the man got older. Working with Richard Keefe, I collected data showing that indeed, although women in societies around the world prefer older men, men’s preferences vary as the men age (see The Mind as a Coloring Book 2).
Unlike older men, teenage boys find college aged women more attractive than they find girls younger than them. Only older men show a strong preference for relatively younger women. Men in their early twenties, on the other hand, are attracted to women of their own age. Those findings were not consistent with earlier hypotheses -- that men prefer partners with less societal power, for example, or that men prefer women who are more likely to reward their interests (teenage boys are well aware that college aged women do not reciprocate their interests). But the findings do fit with the fact that women’s fertility peaks in the early twenties, explaining why both younger and older men are attracted to women of this age range.
Martin Daly and Margo Wilson (1988) also used an evolutionary perspective to predict universals and variations in homicide which did not follow from earlier sociocultural models (see Who are Psychology's Geniuses, Part 2 for some references to their work). For example, infanticide is not only likely to be committed more by women than by men, but is more likely to be committed by younger women than older women.
My assignment for a recent issue of Evolutionary Behavioral Science was to generate the next big question in evolutionary psychology. I wasn’t sure I could come up with the perfect answer, so I changed the question to: How might one go about generating such a question?
I offered several possible ways to answer that question, and with a little thought, a budding researcher could apply these suggestions even if he or she is not interested specifically in questions about evolution. Here are 4 of them:
1. Look for an interesting phenomenon that has been poorly explained from other perspectives. Before Keefe and I did our research, several researchers had observed that men are interested in younger women, and that women are interested in older men. They considered the explanation obvious: The differences were due to the sexist norms of American society, which specified that women should choose partners with more social power than they had (taller, more educated, and older), whereas men should choose the converse.
Keefe and I suspected instead that the sex difference was linked to differences in male and female life history. Females reach puberty before males, peak in fertility in the early 20s, and later go through menopause. Men contribute not their bodies, but indirect resources, and do not attain sufficient skill and status until they are older. If the life history theory was correct, the phenomenon should not only be universal, but it should, as just noted, not be found among teenagers. Although teenage males have very little social power and status to attract the most desirable mates, they ought still to find features of high fertility attractive in women.
If one looks through a textbook in social or developmental or clinical psychology, there are no doubt many phenomena that could be better understood in evolutionary perspective. The key is to find predictions that differentiate your new hypothesis from the traditional explanations.
2. Find a problem that would have mattered in the evolutionary past, but might be overlooked in the present. Mark Schaller and Damien Murray and their colleagues began investigating the links between disease and prejudice because modern people seemed unconcerned with such issues. In the last few months, that has suddenly changed, and it has become quite clear that we still have a lot to understand about our psychological mechanisms for dealing with infectious disease. (see The psychological immune system for a brief interview with Schaller about this work).
Our hunter-gatherer ancestors also faced problems such as finding shelter against the elements, and locating sufficient food and water to survive. How might these ancestral problems show up in the modern world? In many cases, our ancestral preferences and proclivities are out of touch with the modern world, a problem evolutionary psychologists call “mismatch.” In an article in Current Directions in Psychological Science, Norm Li and his colleagues Mark Van Vugt and Stephen Colarelli delve into the fascinating implications of mismatch for understanding some of our problems adjusting to life in the modern world.
3. Ask whether the phenomenon has been explained at all levels of analysis. This was a suggestion from my friend Mark Schaller. We know that there is a universal tendency for men to commit homicides. At the comparative level, this is linked to a tendency we share with other mammals – males compete more for relative status. The evolutionary explanation invokes the concept of differential parental investment I mentioned earlier – if females are more selective about choosing mates, males have to compete with one another to prove their relative worth. We also know that male intrasexual competitiveness is linked to developmental sex differences in testosterone production that get amplified around puberty, when humans begin seeking reproductive partners. And we know something about the cognitive triggers to intra-male aggression, including insults to one another’s relative social standing. But for many other phenomena, such as the sex differences in preferring younger or older mates, we know very little about the underlying hormones or brain mechanisms involved, or what developmental experiences and ecological factors lead to individual differences in such choices – are they different when there is a female-biased or male-biased sex ratio, for example?
4. Try to solve an important social problem. There are 3 general problems that seem increasingly likely to lead to the extinction our species: overpopulation, environmental destruction, and international conflict. Perhaps the Really Big Question is: How are our evolved mechanisms involved in escalating those problems, and how might we exploit those mismatched ancestral mechanisms to help solve these critical modern day problems? If you can answer that question, or even part of it, you’d not only have a productive scientific career ahead of you, you’d be saving the world.
William McGuire wrote a great article about how to generate research questions, well worth reading if you're a student or an already established researcher who missed his brilliant ideas. McGuire's article might also be interesting if you're not a researcher but want to know where all those ideas come from.
Who are psychology's geniuses, Part 2. Describes several researchers whose work was truly revolutionary.
Why are Hollywood actors paired with such young women? A discussion of the research on age preferences described above.
The mind as a Coloring Book 2: Why cultural diversity does not mean a Blank Slate mind. A discussion of a culture that seems, at first glance, to violate the rule about relationships between older men and younger women.
Kenrick, D.T. (2020). Discovering the next big question in evolutionary psychology: A few guidelines. Evolutionary Behavioral Sciences. Early online release. ttp://dx.doi.org/10.1037/ebs0000204
Kenrick, D.T., Gabrielidis, C., Keefe, R.C., & Cornelius, J. (1996). Adolescents' age preferences for dating partners: Support for an evolutionary model of life-history strategies. Child Development, 67, 1499-1511
Kenrick, D.T., & Keefe, R.C. (1992). Age preferences in mates reflect sex differences in mating strategies. (target article) Behavioral & Brain Sciences, 15, 75- 91
Schaller, M., & Murray, D. R. (2008). Pathogens, personality, and culture: Disease prevalence predicts worldwide variability in sociosexuality, extraversion, and openness to experience. Journal of Personality and Social Psychology, 95, 212–221
Schmitt, D. P. (2005). Sociosexuality from Argentina to Zimbabwe: A 48-nation study of sex, culture, and strategies of human mating. Behavior and Brain Science. 28, 247–275
McGuire, W. J. (1997). Creative hypothesis generating in psychology: Some useful heuristics. Annual Review of Psychology, 48, 1-30
Daly, M., & Wilson, M. (1988). Homicide. New York: Aldine deGruyter
Li, N. P., van Vugt, M., & Colarelli, S. M. (2018). The evolutionary mismatch hypothesis: Implications for psychological science. Current Directions in Psychological Science, 27(1), 38-44.