Seeking to discover fundamental principles of learning in animals, we have specialized in behavioral studies of Pavlovian conditioning. Our early work focused on the issue of whether Pavlovian conditioned stimuli (CSs) lose their neutrality because (1) they provide information about impending biologically important unconditioned stimuli (USs) versus (2) occur close in time to those USs. This interest led us to ask whether conditioning might occur in truly random control procedures. There, CSs and USs are presented randomly and independently in time so that CSs, though occurring close to USs, can provide no reliable information about them. Because of this feature, truly random controls were proposed as procedures that would leave CSs neutral. We found, however, that they could make the CS excitatory and later showed that a crucial factor was the order in which chance CS-US pairings occurred relative to unpaired USs.

John J.B. Ayres Pavlovian Conditioning and Animal Learning Specifically, conditioning tended to be weak if unpaired USs occurred before chance pairings but strong otherwise. We then provided evidence that this result occurs because of context blocking. If the conditioning environment (the context) becomes conditioned before the discrete CS, it blocks conditioning to the CS. Otherwise, the CS loses its neutrality. We also searched for conditioning in backward conditioning procedures. Here, the CS cannot possibly predict an impending US because CS occurs after US. Even so, we showed that a single backward pairing can condition a CS. We also showed that responses evoked by backward CSs, though weaker than those evoked by forward CSs, have a similar topography, survive long retention intervals, transfer across contexts, can be extinguished, and can show spontaneous recovery. These features are hallmarks of normal (forward) conditioning.

Having found that conditioning can occur even when CSs provide no information about USs, we turned to models that stress temporal relations among events. We used "real time" models to test computer-simulated predictions. More recently, we have addressed the question of whether deficits in performance caused by blocking, overshadowing, or by CS preexposure (latent inhibition) are due to learning failures or to failures to express a well learned association. Our work has favored the learning-failure view. At present we are shifting our attention to clinical problems. We are using animal models of Pavlovian fear conditioning to search for optimal ways of eliminating human phobias.

Representative Publications:

Ayres, J.J.B., Philbin, D., Cassidy, S., Bellino, L., and Redlinger, E. (1992). Some parameters of latent inhibition. Learning and Motivation 23: 269-287.

 

Bevins, R.A., and Ayres, J.J.B. (1992). One-trail backward excitatory fear conditioning transfers across contexts. Behaviour Research and Therapy, 30:551-554.

 

Albert, M., Ricker, S., Bevins, R.A., and Ayres, J.J.B. (1993). Extending continuous versus discontinuous conditioned stimuli before versus after unconditioned stimuli. J. Exp. Psych: Anim. Behav. Proc. 19: 255-264.

Bevins, R.A., and Ayres, J.J.B. (1994). Factors affecting rats' location during conditioned suppression training. Anim. Learn. Behav. 22: 302-308.
Bevins, R.A., and Ayres, J.J.B. (1994). A deficit in one-trail context fear conditioning is not due to opioid analgesia. Pharmacology Biochemistry and Behavior, 49:183-186.

 

Kim, S.D., Rivers, S., Bevins, R.A., and Ayres, J.J.B. (1996) Conditioned stimulus determinants of conditioned response form in Pavlovian fear conditioning. J. Exp. Psych: Anim. Behav. Proc. 22: 87-104.

 

Bevins, R.A., McPhee, J.E., Rauhut, A.S., and Ayres, J.J.B. (1997). Converging evidence for one-trial context fear conditioning with an immediate shock: Importance of shock potency. J. Exp. Psych.: Anim. Behav. Proc. 23: 312-324.

 

Albert, M., and Ayres, J.J.B. (1997). One-trial simultaneous and backward excitatory fear conditioning in rats: Lick suppression, freezing, and rearing to CS compounds and their elements. Animal Learning & Behavior, 25:210-220.

 

Ayres, J.J.B. (1998) Fear conditioning and avoidance. In W. O'Donohue (Ed.), Learning and behavior therapy, pp. 122-145. Boston: Allyn and Bacon.

 

Rauhut, A.S., McPhee, J.E., and Ayres, J.J.B. (1999) Blocked and overshadowed stimuli are weakened in their ability to serve as blockers and second-order reinforcers in Pavlovian fear conditioning. J. Exp. Psych.: Anim. Behav. Proc. 25:45-67.

 

Rauhut, A.S., McPhee, J.E., DiPietro, N.T. & Ayres, J.J.B. (2000) Conditioned inhibition training of the competing cue after compound conditioning does not reduce cue competition. Animal Learning & Behavior, 28, 92-108.

 

Bevins, R.A., Rauhut, A.S., McPhee, J.E., & Ayres, J.J.B. (2000). Context fear conditioning with immediate shock: The roles of transport and contextual cues. Animal Learning & Behavior, 28, 162-171.

 

Rauhut, A.S., Thomas, B. L., & Ayres, J.J.B (in press). Treatments that weaken Pavlovian conditioned fear and resist its renewal in rats. Implications for treating human phobias. J. Exp Psych: Anim. Behav. Proc. .

 

McPhee, J.E., Rauhut, A.S., & Ayres, J.J.B. (conditionally accepted pending revisions). Evidence for learning-deficit versus performance-deficit theories of latent inhibition in Pavlovian fear conditioning. Learning and Motivation.

 

 

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