Andrew R. Delamater, Ph.D.
Animal and human associative learning, especially Pavlovian and instrumental conditioning. Specific interests include the the study of Pavlovian extinction phenomena and the nature of reward representations in appetitive and aversive learning situations. Additional interests include study of complex conditional discrimination learning and computational modeling of simple learning.
My research interests focus on an analysis of associative learning processes revealed primarily in Pavlovian and instrumental learning paradigms, but also in human classification learning paradigms. Issues pertaining to the associative structures that mediate learning are of special interest, e.g., the rules that govern changes in connections strengths, the nature of the elements of those structures, and how such structures ultimately might lead to performance. Each of these issues are examined in the context of understanding how conditioned (CS) and unconditioned stimuli (US) are represented within an associative structure.
I approach the issue of representation from several levels. First, behavioral studies attempt to empirically document what features of stimuli are "coded" within these representations. For example, work in my lab (and in others) has demonstrated that sensory characteristics of the US are coded during Pavlovian and instrumental conditioning, and that associations with these sensory representations remain fully intact after extinction (e.g., Delamater, 1996; 2004; 2012).
A second way in which I approach the issue of representation is through connectionist modeling of Pavlovian learning (Delamater, 2012). In this research I am exploring how the addition of a hidden layer alters the way we think about simple conditioning.
A third way in which I approach the issue of representation is through an interest in its neural mechanisms. We have recently been exploring the role of basolateral amygdala, orbitofrontal cortex, and gustatory cortex in the coding of sensory-specific associations learned in flavor preference and magazine approach and Pavlovian-instrumental transfer (PIT) paradigms (e.g., Delamater, 2007; Scarlet, et al, 2012). Moreover, we are also looking at possible dissociations between learning about sensory and temporal qualities of reward by focusing on different behavioral and neural manipulations as a means of making this dissociation.
Research Facilities. The human associative learning lab is equipped with Power Macintoshes permitting msec timing accuracy in a variety of reaction time tasks. The animal associative learning lab is equipped with three 8-box and one 4-box computer controlled experimental stations, animal colony rooms (housing up to 300 rodents), an animal breeding room, separate surgery and histology rooms, as well as imaging microscopes. The running stations are well designed to perform a wide variety of associative learning tasks which can incorporate multiple auditory and visual stimuli, multiple responses, and multiple reinforcements. Several additional computers exist for computational modeling and quantitative analysis. Graduate student offices are within these labs or across the hall in a separate office suite.
Delamater, A.R. (2012). On the nature of CS and US representations in Pavlovian learning. Learning & Behavior, 40, 1-23. PMID: 21786019
Delamater, A.R. (2012). Issues in the extinction of specific stimulus-outcome associations in Pavlovian conditioning. Behavioural Processes, 90, 9-19.
Scarlet, J., Delamater, A.R., Campese, V, Fein, M., & Wheeler, D.S. (2012). Differential involvement of the basolateral amygdala and the orbitofrontal cortex in the formation of sensory-specific associations in conditioned flavor preference and magazine approach paradigms. European Journal of Neuroscience, 35, 1799-1809.
Delamater, A.R. (2011). At the interface of learning and cognition: An associative learning perspective. International Journal of Comparative Psychology, 24, 389-411.
Nadler, N., Delgado, M., & Delamater, A.R. (2011). Pavlovian to instrumental transfer of control in a human learning task. Emotion, 11, 1112-1123. PMID: 21534664.
Delamater, A.R. (2011). Partial reinforcement and latent inhibition effects on stimulus-outcome associations in flavor preference conditioning. Learning & Behavior, 39, 259-270.
Delamater, A.R., Kranjec, A., & Fein, M. (2010). Differential outcome effects in Pavlovian biconditional and ambiguous occasion setting tasks. Journal of Experimental Psychology: Animal Behavior Processes, 36, 471-481.
Scarlet, J., Campese, V., & Delamater, A.R. (2009). Sensory-specific associations in flavor preference reversal learning. Learning & Behavior, 37, 179-187.
Ranaldi, R., Egan, J., Kest, K., Fein, M., & Delamater, A.R. (2009). Repeated heroin in rats produces behavioral sensitization and enhances appetitive Pavlovian and instrumental learning involving food reward. Pharmacology, Biochemistry, and Behavior, 91, 351-357.
Delamater, A.R., Campese, V., & Westbrook, R.F. (2009). Renewal and spontaneous recovery, but not latent inhibition, are mediated by GABA in appetitive conditioning. Journal of Experimental Psychology: Animal Behavior Processes, 35, 224-237.
Delamater, A.R., & Holland, P.C. (2008). The influence of CS-US interval on several different indices of learning in appetitive conditioning. Journal of Experimental Psychology: Animal Behavior Processes. 34, 202-222.
Delamater, A.R. (2007). The role of orbitofrontal cortex in sensory-specific encoding of associations in Pavlovian and instrumental conditioning. In G. Schoenbaum, E. Murray, S. Ramus, & J. Gottfried (Eds.) Linking Affect to Action: Critical Contributions of the Orbitofrontal Cortex. Annals of the New York Academy of Sciences. 1121,152-173
Delamater, A.R., & Oakeshott, S. (2007). Learning about multiple attributes of reward. In B. Balleine, K Doya, J. O’Doherty, & M. Sakagami (Eds.) Reward and Decision Making in Cortico-basal Ganglia Networks. Annals of the New York Academy of Sciences. 1104, 1-20.
Delamater, A.R. (2007). Extinction of conditioned flavor preferences. Journal of Experimental Psychology: Animal Behavior Processes. 33, 160-171.
Delamater, A.R., Campese, V., LoLordo, V.M., & Sclafani, A. (2006). Unconditioned stimulus devaluation effects in nutrient-conditioned flavor preferences. Journal of Experimental Psychology: Animal Behavior Processes, 32, 295-306.
Delamater, A.R. (2004). Experimental extinction in Pavlovian conditioning: Behavioural and neuroscience perspectives. The Quarterly Journal of Experimental Psychology, 57B, 97-132.
Delamater, A.R., LoLordo, V.M., & Sosa, W. (2003). Outcome- specific conditioned inhibition in Pavlovian backward conditioning. Learning & Behavior, 31, 393-402.
Delamater, A.R., & Joseph, P. (2000). Common coding in symbolic matching tasks with humans: Training with a common consequence or antecedent. The Quarterly Journal of Experimental Psychology, 53B, 255- 273.
Delamater, A.R., Sclafani, A., & Bodnar, R.J. (2000). Pharmacology of sucrose-reinforced place preference conditioning: Effects of naltrexone. Pharmacology, Biochemistry, & Behavior, 65, 697-704.
Delamater, A.R., Sosa, W., & Katz, M. (1999). Elemental and configural processes in patterning discrimination learning. The Quarterly Journal of Experimental Psychology, 52B, 97-124.
Delamater, A.R. (1998). Associative mediational processes in the acquired equivalence and distinctiveness of cues. Journal of Experimental Psychology: Animal Behavior Processes, 24, 467-482.
Delamater, A. R. (1997). Selective reinstatement of stimulus-outcome associations. Animal Learning & Behavior.
Delamater, A.R. (1996) Effects of several extinction treatments upon the integrity of Pavlovian stimulus-outcome associations. Animal Learning & Behavior, 24, 437-449.
Delamater, A. R. (1995). Outcome-selective effects of intertrial reinforcement in a Pavlovian appetitive conditioning paradigm with rats. Animal Learning & Behavior, 23, 31-39.
Delamater, A. R., & LoLordo, V. M (1991). Event revaluation procedures and associative structures in Pavlovian conditioning. In L. Dachoswki & C. Flaherty (Eds.). Current topics in animal learning: Brain, emotion, and cognition. Hillsdale, N.J.: Erlbaum.
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