User:Sxologist/sandbox/Dennis McFadden

Dennis McFadden (born October 2, 1940) is an American auditory scientist, experimental psychologist and an Emeritus Professor at The University of Texas at Austin. McFadden is best known for his research of the auditory system and inner ear, and found clear differences between men and women, and differences between heterosexuals and homosexuals. Since these differences are measurable at birth and constant over ones life, McFadden has concluded that his research provides a strong biological marker that sexual orientation is likely determined during prenatal development.

Education and career
McFadden received his doctoral degree in Sensory Psychology from Indiana University in 1967. That fall he began as an Assistant Professor at UT, and he stayed for his entire academic career. In 1984 he received a five-year Jacobs Javits Neuroscience Investigator Award from the National Institues of Health, in 1987 he was awarded a Piper Professorship for excellence in teaching, in 1998 UT made him an Ashbel Smith Professor in Experimental Psychology, and he became Professor Emeritus upon his retirement in 2012. Dr. McFadden was a founding member of the UT Institute for Neuroscience and served for many years on its Executive Committee. He served as Associate Editor for Psychological Acoustics for the Journal of the Acoustical Society of America, and his research was funded by the National Institutes of Health from 1969 to 2012.

Research
Dr. McFadden's research involved behavioral measurements on various aspects of human hearing--sound localization, binaural hearing, masking, pitch perception, the aftereffects of exposure to intense sound, and other topics.

In later years, his interests turned to more physiological measures of the auditory system, especially otoacoustic emissions (OAEs), which are sounds generated in the inner ear and monitored using a sensitive microphone system placed in the ear canal. Initially, Dr. McFadden measured the heritability of the individual differences observed in OAEs (they are highly heritable), and that led to an interest in the sex differences seen in OAEs (females have more and stronger OAEs than males). Because the sex differences in OAEs exist in newborns just as in young adults, the implication was that differential prenatal exposure to androgens was the reason for the OAE differences between the sexes. The effects of hormones on hearing became a primary research interest for Dr. McFadden, and his lab studied various special populations of humans (twins, users of oral contraceptives, children with attention-deficit, hyperactivity disorder, non-heterosexuals) as well as collections of animals treated with androgenic and anti-androgenic agents (hyenas, rhesus monkeys, sheep). Considerable evidence emerged in support of the idea that hormones can affect the auditory system, just as they affect other aspects of prenatal development and sexual differentiation. The final major study run in Dr. McFadden's lab involved measuring sex differences for a number of common auditory tasks and comparing the individual differences on those tasks with the individual differences present in OAEs and auditory evoked potentials (AEPs)

Sexual orientation and auditory system
McFadden's research found that both auditory differences play a role in ear structure.

In 2017, McFadden published a response to neuroscientist Marc Breedlove regarding androgen exposure in utero and it's relation to sexual orientation.