How Representative are Neuroimaging Samples? Large-Scale Evidence for Trait Anxiety Differences Between fMRI and Behaviour-Only Research Participants

Caroline Charpentier, Paul Faulkner, Eva Pool, Verena Ly, Marieke Tollenaar, Lisa Kluen, Aniek Fransen, Yumeya Yamamori, Niall Lally, Anahit Mkrtchian, Vincent Valton, Quentin J M Huys, Ioannis Sarigiannidis, Kelly Morrow, Valentina Krenz, Felix Kalbe, Anna Cremer, Gundula Zerbes, Franziska Kausche, Nadine WankeAlessio Giarrizzo, Erdem Pulcu, Susanna Murphy, Alexander Kaltenboeck, Michael Browning, Lynn Paul, Roshan Cools, Karin Roelofs, Luiz Pessoa, Catherine Harmer, Henry Chase, Christine Grillon, Lars Schwabe, Jonathan Roiser, Oliver Robinson, John O'Doherty

Research output: Contribution to journalArticlepeer-review


Over the past three decades, functional MRI (fMRI) has become key to study how cognitive processes are implemented in the human brain. However, the question of whether participants recruited into fMRI studies differ from participants recruited into other study contexts has received little to no attention. This is particularly pertinent when effects fail to generalize across study contexts: for example, a behavioural effect discovered in a non-imaging context not replicating in a neuroimaging environment. Here, we tested the hypothesis, motivated by preliminary findings (n = 272), that fMRI participants differ from behaviour-only participants on one fundamental individual difference variable: trait anxiety. Analysing trait anxiety scores and possible confounding variables from healthy volunteers across multiple institutions (n = 3317), we found robust support for lower trait anxiety in fMRI study participants, consistent with a sampling or self-selection bias. The bias was larger in studies that relied on phone screening (compared to full in-person psychiatric screening), recruited at least partly from convenience samples (compared to community samples), and in pharmacology studies. Our findings highlight the need for surveying trait anxiety at recruitment and for appropriate screening procedures or sampling strategies to mitigate this bias.
Original languageEnglish
Publication statusPublished - 5 May 2021

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