Marcus Winbush

Marcus Winbush was affiliated with the Psychology Department at the University of North Dakota, Grand Forks, where his research was supported by the Minority Access to Research Careers (MARC) program as part of his honor thesis in 1996. While limited biographical information is available about his subsequent career path, his sole known contribution to polygraph science emerged from this undergraduate research collaboration with established deception detection researchers Charles R. Honts, Mary K. Devitt, and John C. Kircher.

Winbush's research contribution centered on the vulnerability of the Concealed Knowledge Test (CKT) to countermeasures. The study examined the effects of physical (pressing toes to the floor) and mental (counting backward by sevens) countermeasures on the concealed knowledge test in a mock crime experiment, finding that both countermeasures reduced the accuracy of the CKT. This research demonstrated that the CKT has no special immunity to the effects of countermeasures, challenging assumptions about the technique's resistance to deliberate manipulation.

The 1996 Psychophysiology study has been widely cited in the deception detection literature, appearing in major reviews including the National Research Council's comprehensive assessment of polygraph testing. Winbush's collaboration with Honts and Kircher—both prominent figures in psychophysiological deception detection research—placed this early-career work within an important research lineage examining the limitations and vulnerabilities of polygraph techniques.