You are not currently logged in. Please create an account or log in to view the full course.

Forensic Psychology – Biological Explanations for Offending

6. XYY Syndrome

This is the course trailer. Please create an account or log in to view this lecture.

  • Description
  • Cite

About this Lecture


In this lecture, we think about XYY syndrome, focusing in particular on: (i) the role that a Y chromosome plays in deciding that a person is male; (ii) the speculated ability of an additional Y chromosome to ‘hypermasculate’ a man; (iii) the disproportionate commonality of XYY men in offender populations, but not the expected trend for them to have committed violent offences; (iv) how learning difficulties associated with XYY syndrome may act as a moderator for the relationship between the syndrome and criminal actions.


In this course, Professor Ciarán O’Keeffe (Buckinghamshire New University) explores biological explanations for offending. In the first lecture, we think about the concept of ‘making a criminal’ and the transition from philosophical to scientific methodologies. In the second lecture, we think about biological strategies for preventing criminal behaviour, including nutritional interventions and facial surgery for criminals. In the third lecture, we think about the Raine et al. (1997) study, which identified brain areas linked to violence and aggression. Next, we think about the Haney et al. (1973) study, also known as the Stanford Prison Experiment, run by Philip Zimbardo. In the fifth lecture, we think about how brain injury can influence violence and aggression, as well as the ability for brain injury research to inform our understanding of this field. In the sixth and final lecture, we think about XYY syndrome and the mixed results research on it have found regarding its impact on violence, aggression and criminal behaviour.


Professor Ciarán O’Keeffe is associate professor of education and research and head of the School of Human and Social Sciences at Buckinghamshire New University. Professor O’Keeffe’s research interests include investigative psychology and parapsychology, and has made numerous television and radio appearances alongside an array of celebrities. Some of Professor O’Keeffe’s recent publications include 'Things That Go Bump In The Literature: An Environmental Appraisal of 'Haunted Houses'' (2020) and 'Restorative Justice and Recidivism: Investigating the impact of victim-preference for level of engagement' (2014).

Cite this Lecture

APA style

O'Keeffe, C. (2022, April 01). Forensic Psychology – Biological Explanations for Offending - XYY Syndrome [Video]. MASSOLIT.

MLA style

O'Keeffe, C. "Forensic Psychology – Biological Explanations for Offending – XYY Syndrome." MASSOLIT, uploaded by MASSOLIT, 01 Apr 2022,

Image Credits

Get instant access to over 7,100 lectures