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Dennis McFadden, Ph.D.
Ashbel Smith Professor Emeritus of Psychology (Retired)
Email: mcfadden@psy.utexas.edu
Phone: 471-4324 Lab: 471-1704
Office: SEA 4.226 Lab: SEA 4.130(A-B)
Center for Perceptual Systems
See also Perceptual Systems
Dr. McFadden received his Ph.D. from Indiana University. His research Interests are sensation and perception, audition, sex differences in the auditory system, prenatal hormonal effects on the auditory system, and the effects of drugs on the auditory system.
Historically, I have been interested in various aspects of auditory performance--sound localization, masking, adaptation-like effects, and the effects of drugs and intense sound on the auditory system. In recent times, I have become interested in certain sex differences in audition and have been using the auditory system as a tool for studying hormonal effects during early development. One measure we have used is otoacoustic emissions (OAEs) which are sounds produced in the inner ear and recorded from the ear canal. OAEs are stronger and more numerous in females than in males, and this sex difference exists in newborns as well as in adults. We have been trying to understand the mechanisms underlying these sex differences. The evidence suggests that prenatal differences in exposure to androgens contribute to the sex difference in OAEs--just as it does for other sex differences in the body and the brain. Some of this evidence comes from work on special populations of humans such as females with male co-twins, homosexual and bisexual females, and children diagnosed with attention-deficit/hyperactivity disorder (ADHD). Also, we have recorded OAEs in spotted hyenas and rhesus monkeys that have been treated with androgenic or anti-androgenic agents during prenatal development and found them generally to be altered in the predicted direction--the greater the exposure to androgens, the weaker the OAEs. We believe that OAEs can act as a marker for the degree of androgen exposure a person receives during early development, and thus, they have the potential to serve as an noninvasive supplemental tool for scientists interested in a wide array of topics other than audition itself. My Macintosh-based lab is equipped to synthesize and generate simple and complex auditory waveforms, and to test up to eight human subjects simultaneously in a wide array of standard psychoacoustical tasks. We also have an advanced system for recording and analyzing otoacoustic emissions. We have the capability to obtain OAE measurements from distant locations over the internet. We use LabVIEW for generating waveforms, controlling experiments, and some data analysis.
Courses
Psychology 323S - Sex Differences in Cognition and Perception
Psychology 394U - Psychoacoustics
Recent Publications
McFadden, D. Masculinization effects in the auditory system. Archives of Sexual Behavior, 2002, 31, 93-105.
McFadden, D., and Bracht, M.S. The relative lengths and weights of metacarpals and metatarsals in baboons (Papio hamadryas). Hormones and Behavior, 2003, 43, 347-355.
McFadden, D. and Bracht, M.S. Sex differences in the relative lengths of metacarpals and metatarsals in gorillas and chimpanzees. Hormones and Behavior, 2005, 47, 99-111.
McFadden, D., Loehlin, J.C., Breedlove, S.M., Lippa, R.A., Manning, J.T. and Rahman, Q. A reanalysis of five studies on sexual orientation and the relative length of the 2nd and 4th fingers (the 2D:4D ratio). Archives of Sexual Behavior, 2005, 34, 341-356.
McFadden, D., Westhafer, J.G., Pasanen, E.G., Carlson, C.L., and Tucker, D.M. Physiological evidence of hypermasculinization in boys with the inattentive subtype of attention-deficit/hyperactivity disorder (ADHD). Clinical Neuroscience Research, 2005, 5, 233-245.
McFadden, D. Pasanen, E.G., Raper, J., Lange, H.S., and Wallen, K. Sex differences in otoacoustic emissions measured in rhesus monkeys (Macaca mulatta). Hormones and Behavior, 2006, 50, 274-284.
McFadden, D., Pasanen, E.G., Weldele, M.L., Glickman, S.E., and Place, N.J. Masculinized otoacoustic emissions in female spotted hyenas (Crocuta crocuta). Hormones and Behavior, 2006, 50, 285-292.
McFadden, D. What do sex, twins, spotted hyenas, ADHD, and sexual orientation have in common? Perspectives on Psychological Science, 2008, 3, 309-323.
Valero, M.D., Pasanen, E.G., McFadden, D., Ratnam, R. Distortion product otoacoustic emissions in the common marmoset (Callithrix jacchus): Parameter optimization. Hearing Research, 2008, 243, 57-68.
McFadden, D., Pasanen, E., Valero, M.D., Roberts, E.K., and Lee, T.M. Effect of prenatal androgens on click-evoked otoacoustic emissions in male and female sheep (Ovis aries). Hormones and Behavior, 2009, 55, 98-105.
McFadden, D. and Bracht, M.S. Sex and race differences in the relative lengths of metacarpals and metatarsals in human skeletons. Early Human Development, 2009, 85, 117-124.
McFadden, D., Martin, G.K. Stagner, B.B., and Maloney, M.M., Sex differences in distortion-product and transient-evoked otoacoustic emissions compared. J. Acoust. Soc. Am., 2009, 125, 239-246.
McFadden, D. Masculinization of the mammalian cochlea. Hearing Research, 2009, 252, 37-48.
Walsh, K.P., Pasanen, E.G., and McFadden, D. Properties of a nonlinear version of the stimulus-frequency otoacoustic emission. J. Acoust. Soc. Am., 2010, 127, 955-969.
Walsh, K.P., Pasanen, E.G., and McFadden, D. Overshoot measured physiologically and psychophysically in the same human ears. Hearing Research, 2010, 268, 22-37.
McFadden, D., Walsh, K.P., Pasanen, E.G., and Grenwelge, E.M. Overshoot using very short signal delays. J. Acoust. Soc. Am., 2010, in press**
