https://studiegids.vu.nl/en/courses/2025-2026/P_MCAUSGEYou will learn what is gene-environment interplay, and discuss its importance, ubiquity, nuances, and the pitfalls related to gene-environment research. You will learn about state-of-the-art methodology and see modern examples with psychological traits. You will also learn how certain study designs can inform about causality, as well as their inherent limitations. As part of the course, we will also cover the replication crisis and the candidate gene era. You will see what went wrong, and what we can do better now. You will practice an important way to ensure valid results: research pre-registration. Upon successful completion of the course, students should be able to:Develop a conceptual framework to reason about causation and gene-environment interplay.Critically appraise research on the topic.Critically appraise new strategies and approaches.Practice in communicating and discussing scientific findings.Hands-on experience with research pre-registration.In our complex world, where gene-environment interplay is widespread, it’s hard to find the causes behind psychological traits. In Psychology and Social Sciences, research on factors/causes has typically treated the “environment” as if it were pure, direct measures. As if it were disentangled from genetics. In Human Genetics and Behavior Genetics, on the other hand, genetics has been treated as independent of the environment – neither correlated (rGE) nor varying in magnitude conditional on the environment (GxE). For decades, those assumptions had been called into question. However, early attempts to study (and account for) gene-environment interplay were flawed. Nowadays, many researchers want to move beyond those early failures. It’s clearer now that genetics can massively confound environmental effects, and the environment can massively confound genetic effects. In the scientific journey toward causation, we must appreciate the ways genes and environments interplay. In this course, we will touch on a variety of topics – some briefly, others more in-depth. These topics include: the problem of causation, the challenges to build causal knowledge, reasons for the replication crisis, the failures of the candidate gene era, the importance and ubiquity of gene-environment interplay, pgs x environment design, stratified GWAS, direct vs indirect genetic effects, children-of-twins design, within-siblings design, geographical and social stratification, exposome, environment-WAS, intra-uterine environment, mendelian randomization, natural experiments, regression discontinuity design, etc.Lectures, discussions in class, and homework assignments.Weekly assignments, class participation, student presentation, and (mock)research pre-registration.On Canvas, you can find a list of the peer-reviewed papers for the course. The bolded papers are essential, and I expect you to read them during the course. The other papers there are a good complement, but less critical. There is no textbook.