William George Iacono

William George Iacono is an American psychologist who serves as Distinguished McKnight University Professor in the Department of Psychology at the University of Minnesota, where he is also co-director, with Matt McGue, of the Minnesota Center for Twin and Family Research. He holds professorial appointments in Psychology, Law, and Neuroscience at the University of Minnesota and retired from the university in February 2023 after 40 years as a faculty member. Iacono served as Past-President of the Society for Psychophysiological Research (1996-97) and former Member of the Department of Defense Polygraph Institute's Curriculum and Research Guidance Committee.

Iacono is one of the most prominent scientific critics of polygraph testing in forensic applications. Inspired by David Lykken's 1974 critique of lie detection, Iacono and colleagues have conducted extensive analysis of polygraph methods and science. His work has systematically challenged the validity of the Comparison Question Test (CQT), the most widely used polygraph technique. His research concluded that the scientific basis of the CQT is weak, extant research is of low quality, the polygraph profession's claims for high accuracy are unfounded, and although the CQT has greater than chance accuracy, its error rate is unknown. Notable contributions include a 1991 field study that attempted to circumvent the confession-criterion methodological problem, pioneering surveys documenting scientific opinion on polygraph validity, and comprehensive critiques of field study methodology showing how sampling bias inflates accuracy estimates. His 2024 review article provided a fifty-year perspective on how the polygraph industry has remained largely unchanged despite scientific criticism.

In 2008, Iacono received the Society for Psychophysiological Research's highest honor, the Award for Distinguished Contributions to Psychophysiology, which the society reserves for the very best scholars in psychophysiology. He also received the Distinguished Scientific Award for an Early Career Contribution to Psychology from the American Psychological Association in 1987, and in 2009 received the Distinguished Scientist Award from the Society for the Science of Clinical Psychology. He testified before the U.S. Senate Judiciary Committee in 2001 on polygraph screening of federal employees. He has served as chair or member of numerous NIH study sections and has been a consultant on lie detection to a wide variety of government agencies. His collaboration with frequent co-authors including Christopher J. Patrick, David T. Lykken, and Gershon Ben-Shakhar has produced influential critiques published in leading journals and legal reference volumes.

While Iacono's polygraph research represents a major strand of his career, his broader work spans behavior genetics and psychophysiology. He uses family, adoptive, and twin study designs to investigate the development and etiology of common mental disorders, including substance use, antisocial, and major depressive disorders, work carried out through the Minnesota Center for Twin and Family Research which he co-directs. His contributions to behavioral genetics via twin and family study designs, specifically examining schizophrenia, common mental disorders and substance abuse, are immense. His polygraph work connects to this broader program through studies examining psychophysiological markers, including research on how psychopathy affects polygraph accuracy, the use of event-related potentials to detect concealed memories, and studies of countermeasures using antianxiety drugs.