Dr. Joshua S. Rodefer

Assistant Professor of Psychology

Joshua RodeferDr. Josh Rodefer (Ph.D. University of Minnesota, 1997,) holds the position of assistant professor of Psychology. His specialization is in the area of cognitive and biological psychology. His teaching is primarily directed towards neuroscience-related coursework including Psychology of Learning, Biopsychology, and Biological Foundations of Behavior Lab. His current program of research explores cognitive behaviors related to addiction and other neuropsychiatric disorders (e.g., anxiety, gambling, mood disorders, schizophrenia).


  • Bachelor of Science, Biopsychology, Denison University, 1987
  • Doctor of Philosophy, Psychology (Cognitive & Biological; minor: Neuroscience), University of Minnesota, 1997
  • Postdoctoral Research Fellow, University of North Carolina at Chapel Hill, 1997-1998
  • Postdoctoral Research Fellow, Harvard University, 1998-2001

Courses Taught

  • PSY 205 – Psychology of Learning
  • PSY 210 – Biopsychology
  • PSY 385 – Special Topics in Psychology


Cognitive and biological psychology

Research Interest

My interest in understanding the relationship between brain and behavior has driven my scientific curiosity for many years. My program of research strives to understand how environmental and pharmacological variables influence cognition, decision-making, and risk-taking related to neuropsychiatric disorders (e.g., drug abuse, schizophrenia). Using a translational approach, we aim to study how preclinical studies may inform the human condition.

I began graduate studies at the University of Minnesota under the mentorship of Drs. Marilyn Carroll and Bruce Overmier. My dissertation work focused on understanding how both pharmacological and behavioral interventions, and their combination, could decrease drug-seeking behaviors using a nonhuman primate model of drug self-administration (Carroll & Rodefer, 1993; Rodefer et al., 1996; Rodefer et al., 1999). After earning my Ph.D., I pursued a postdoctoral fellowship at UNC that focused on opioid-mediated reinforcement and analgesia (Cook et al., 1999). I expanded upon this in a second research fellowship at Harvard where our work focused on understanding the mechanisms of polydrug combinations (e.g. cocaine + heroin, aka “speedballs”) that are commonly reported in drug-using populations (Rowlett et al., 2005).

While at Harvard, I began a series of collaborative projects with Dr. Mark Baxter (now at Mt. Sinai School of Medicine in NYC) that shifted my orientation towards the psychopharmacology of cognition. The significance of this area includes the observation that most types of psychopathology have associated disrupted cognition (e.g., attention deficits in schizophrenia; evaluation of consequences in drug abuse; rumination in depression). Moreover, the increasing prevalence of dementia-related conditions (e.g., Alzheimer’s) is of increasing concern. This remains a critical problem as we presently lack effective treatments for cognitive impairments.

In a series of studies, we examined cholinergic contributions on cognition and demonstrated a novel observation involving the acetylcholine-muscarinic (ACh-m) antagonist scopolamine (Chen et al., 2004). Subsequently, we demonstrated how other pharmacological manipulations mimicked cognitive deficits commonly associated with schizophrenia (Rodefer et al., 2005). We found that when compared to control subjects, PCP-treated animals had significant and selective impairments that were reminiscent of those observed in patients with schizophrenia. These data suggested that the subchronic PCP-treatment regimen would be useful for evaluating potential novel treatments. We subsequently investigated some of these novel treatments in a series of published studies (Rodefer et al. 2008; Wallace et al., 2011; Rodefer et al., 2012).

My lab activities at Mercer continue these types of projects involving students (see Background and Publications for recent student conference research presentations) as well as incorporating new research questions involving developmental aspects to understand how drug and environmental experiences may alter cognition, decision-making, and addiction-related behaviors across the lifespan. Perhaps the best part of being a Mercer faculty member is the opportunity to mentor students. I believe very strongly in the mission to involve students in all phases of research as this was the aspect of my education from which I benefited the most.


  • LeCroy, V. R.* & Rodefer, J. S.(2019). The influence of job candidate LGBT associations on hiring decisions. North American Journal of Psychology, 21(2), 373-386. (pdf)
  • Breneiser, J. E., Rodefer, J. S., & Tost, J. R. (2018). Utilizing tutorial videos to enhance the learning of statistics in an online undergraduate psychology course. North American Journal of Psychology, 20(3), 715-730. (pdf)
  • Garrett, B., Hough, G. (with Kahn, M. C., & Rodefer, J. S.) (2017). Brain & behavior: An introduction to behavioral neuroscience (5th ed.). Thousand Oaks, CA: SAGE Publications.
  • Rodefer, J. S., Saland, S. K.*, & Eckrich, S. J.* (2012). Selective phosphodiesterase inhibitors improve performance on the ED/ID cognitive task in rats. Neuropharmacology, 62(3), 1182-1190. (pdf)
  • Wallace, T. L., Callahan, P. M., Tehim, A., Bertrand, D., Tombaugh, G., Wang, S., Xie, W., Rowe, W. B., Ong, V., Graham, E., Terry, A. V., Jr., Rodefer, J. S., Herbert, B., Murray, M., Porter, R., Santarelli, L., & Lowe, D. A. (2011). RG3487, a novel nicotinic α7 receptor partial agonist, improves cognition and sensorimotor gating in rodents. Journal of Pharmacology & Experimental Therapeutics, 336(1), 242-253. (pdf)
  • Rodefer, J. S., Nguyen, T. N.*, Karlson, J-J., & Arnt, J. (2008). Reversal of subchronic PCP-induced deficits in attentional set shifting in rats by sertindole and a 5-HT6 receptor antagonist: Comparison among antipsychotics. Neuropsychopharmacology, 33(11), 2657-2666. (pdf)
  • Ng, C-W, Noblejas, M. I., Rodefer, J. S., Smith, C. S., & Poremba, A. (2007). Double dissociation of attentional resources: Prefrontal versus cingulated cortices. Journal of Neuroscience, 27(45), 12123-12131. (pdf)
  • Rodefer, J. S., & Baxter, M. G. (2007). Brain Aging: Models, Methods and Mechanisms. In D.R. Riddle (Ed.), Cognitive aging in rodents (pp. 39-60). Boca Raton, FL: CRC Press.
  • Rodefer, J. S., Murphy, E. R.*, & Baxter, M. G. (2005). PDE10A inhibition reverses subchronic PCP-induced deficits in attentional set-shifting in rats. European Journal of Neuroscience, 21(4), 1070-1076. (pdf)
  • Rowlett, J. K., Rodefer, J. S., & Spealman, R. D. (2005). Self-administration of cocaine-opioid combinations by rhesus monkeys: Evaluation of the role of mu receptor efficacy using labor supply analysis. Journal of Pharmacology & Experimental Therapeutics, 31(3), 1289-1297. (pdf)
  • Chen, K. C.*, Baxter, M. G., & Rodefer, J. S. (2004). Central blockade of muscarinic cholinergic receptors disrupts affective and attentional set-shifting. European Journal of Neuroscience, 20(4), 1081-1088. (pdf)
  • Cook, C. D., Rodefer, J. S., & Picker, M. J. (1999). Selective attenuation of the antinociceptive effects of mu opioids by the putative dopamine D3 agonist 7-OH-DPAT. Psychopharmacology, 144(3), 239-247. (pdf)
  • Rodefer, J. S., Campbell, U. C., Cosgrove, K. P., & Carroll, M. E. (1999). Naltrexone pretreatment decreases the reinforcing effectiveness of ethanol and saccharin but not PCP or food in rhesus monkeys under concurrent progressive-ratio schedules in rhesus monkeys. Psychopharmacology, 141(4), 436-446. (pdf)
  • Rodefer, J. S., & Carroll, M. E. (1996). Progressive ratio and behavioral economic evaluation of the reinforcing efficacy of orally delivered phencyclidine and ethanol in monkeys: Effects of feeding conditions. Psychopharmacology, 128(3), 265-273. (pdf)
  • Carroll, M. E., & Rodefer, J. S. (1993). Income alters choice between drug and an alternative nondrug reinforcer in monkeys. Experimental and Clinical Psychopharmacology, 1(1), 110-120. (pdf)

Talks and Presentations

  • Rodefer, J. S. (2019, March). Neuroscience and educational considerations for dual-enrollment students. Invited plenary talk presented at the annual meeting of the National Alliance of Concurrent Enrollment Partnerships (NACEP), Savannah, GA
  • Fox, K. A.* & Rodefer, J. S. (2019, March). Investigation of cognition across the menstrual cycle.Poster presented at the annual Southeastern Psychological Association (SEPA) conference, Jacksonville, FL.
  • Henderson, J. C.*, Snider, D. S.*, & Rodefer, J. S. (2019, March). Conditioned reinforcing effects of ethanol in domestic house crickets. Poster presented at the annual Southeastern Psychological Association (SEPA) conference, Jacksonville, FL.
  • Briihl, D. S. & Rodefer, J. S. (2018, October). Making it meme-ingful for History of Psychology. Poster presented at the 17th Annual Society for the Teaching of Psychology Conference on Teaching, Phoenix, AZ
  • Clark, R. A.*, & Rodefer, J. S. (2018, March). Cannabis users’ performance on measures of impulsivity and executive function.Talk presented at the annual Southeastern Psychological Association (SEPA), Charleston, SC.
  • Rodefer, J. S., Schlitter, E. M.*, Henderson, J .C.*, & Alexander, E. A.* (2018, March). Effects on concurrent risperidone and phencyclidine on rodent cognition. Talk presented at the annual Southeastern Psychological Association (SEPA), Charleston, SC.
  • Kiselica, B. P.* & Rodefer, J. S. (2017, March). Examination of impulsivity and risky decision-making in the Iowa Gambling Task in a sample of college smokers. Poster presented at the annual Southeastern Psychological Association (SEPA) conference, Atlanta, GA.
  • Rodefer, J. S., Griffin, J. L.*, Gatewood, F. V.* (2016, September). Stress related to vocational rehabilitation and vulnerability to substance use. Invited talk presented at annual Southeastern Region of the National Rehabilitation Association, Savannah, GA.
  • Rodefer, J. S., Arias, R. R.*, Eckrich, S. J.* (2015, May). Adolescent nicotine exposure impairs cognition during adulthood. Poster presented at the meeting of the Association of Psychological Science, New York.
  • Rhoden, R.*, Eckrich, S. J.*, Cepeda, S. L.*, & Rodefer, J. S. (2013, November). Cognitive and behavioral effects of adolescent exposure to nicotine. Poster presented at the meeting of Society for Neuroscience, San Diego, CA.
  • Rodefer, J. S. & Eckrich, S. J.* (2012, November). Cholinergic contributions to risky decision-making in the rat. Talk presented at the meeting of Society for Neuroscience, New Orleans, LA.
  • Keene, L. N., Rodefer, J. S., Robinson, S. R., & Kleven, G. A. (2011, November). Transient juvenile behavioral deficits after low-dose prenatal toxin exposure. Poster presented at the International Society for Developmental Psychology meeting, International Society for Developmental Psychology, Washington, DC.
  • Rodefer, J. S. (2009, March). Nicotinic agonists as treatments for cognitive dysfunction. Invited plenary talk presented at the international meeting of Frontiers in Medicinal Chemistry meeting, Heidelberg Germany.
  • Pouzet, B., Langlois, X., Willems, R., & Rodefer, J. S. (2008, October). Effect of olanzapine in a rat model of executive function and correlation to receptor in vivo potency. Talk presented at Neuroscience Aquitaine Meeting, Mediterranean Neuroscience society, Areachon FR.

*Indicates student co-author

Contact Dr. Joshua S. Rodefer

(478) 301-2364