Suzanne H. Mitchell
Associate Professor
Behavioral Neuroscience, OHSU
e-mail: mitchesu@ohsu.edu
Major Areas:
Human Psychopharmacology; Reinforcement and Learning; Impulse Control
Previous Positions
Research Associate, University of Chicago
Assistant Professor, University of New Hampshire
Education
B.Sc. (1985) University of Hull, England
M.Sc. (1987) University of Hull, England
Ph.D. (1992) State University of New York at Stony Brook
Research Interests
Broadly, my research focuses on the effects of behavioral costs on whether a behavior is performed. Specifically, I examine costs like the delay that must be experienced before a reward is available, the energy that must be expended to obtain a reward, and the uncertainty that must be experienced before the reward is finally won. Using a choice procedure in which participants select either a smaller less costly reinforcer or a larger but more costly reinforcer, I investigate factors influencing the participant's level of impulsiveness, procrastination and risk-taking.
My research with nonhuman animals examines the behavioral and physiological mechanisms underlying an individual's sensitivity to delay, effort and uncertainty. I am interested in the role of neurotransmitters such as serotonin, as well as the role of certain areas like prefrontal cortex.
My research with human participants examines how sensitivity to delay, effort and uncertainty are affected by drug use and abuse and how different psychiatric disorders might be defined by disturbances in these characteristics.
Selected Recent Publications
Mitchell SH (2004) Effects of short-term nicotine deprivation on decision-making: Delay, uncertainty and effort discounting. Nicotine & Tobacco Research, 6, 819-828.
Mitchell SH & Rosenthal AJ (2003) Effects of multiple delayed rewards on delay discounting in an adjusting amount procedure. Behavioural Processes, 64, 273-286.
Mitchell SH (1999). Measures of impulsivity in cigarette smokers and nonsmokers. Psychopharmacology, 146, 455-464.
Richards JB, Mitchell SH, de Wit H & Seiden LS (1997) Assessing the effects of reinforcer magnitude and level of deprivation on reinforcer value using a titrating procedure. Journal of the Experimental Analysis of Behavior, 67, 353-366.