Henry is a Professor of Legal Psychology at the Faculty of Psychology and Neuroscience, Maastricht University and a research professor (legal psychology) at the Faculty of Law and Criminology, KU Leuven.
His research focuses on developmental changes in memory relating to statements in eyewitnesses, victims, and perpetrators from childhood to adulthood. He is interested in factors (eg trauma) that relate to the development of memory illusions. He has a strong interest in biases and legal decision-making and how biases can affect expert witness work. He collaborates with research groups across the world including the UK, Europe, Canada, Australia, Chile, North America and Indonesia.
He has received many grants and prizes for his work and has disseminated his research extensively to psychologists, students, and practitioners. He has often cooperated in legal cases involving (child) witnesses which has attracted national and international media attention. He also works for the Maastricht Forensic Institute as an expert witness and is a member of the Landelijke Expertisegroep Bijzondere Zedenzaken and the College voor Toetsing en Advies of the Landelijke Deskundigheidsmakelaar. These committees fall under the National Police and in these committees, legal cases and expert witness work are discussed.