Andrew R. Delamater, Ph.D.
andrewd@brooklyn.cuny.edu
Biographical Sketch
B.A. - American University, 1982
Research Interests. Animal and human associative learning, especially Pavlovian and instrumental conditioning. Specific interests include the role of associative factors in perceptual learning, configural learning, and classification learning. Much of this research is approached from a connectionist modeling perspective.
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. Furthermore, data collected from acquired equivalence and negative patterning tasks suggest that abstract CS representations may be learned for the purpose of categorizing functionally similar stimuli, as well as for representing stimulus compounds either elementally or configurally.
A second way in which I approach the issue of representation is through connectionist modeling of Pavlovian learning. In this research I am exploring how the addition of a hidden layer alters the way we think about simple conditioning. A currently favorite model is one that permits for both direct CS-US and indirect CS-hidden unit-US connectivity (see also Schmajuk & DiCarlo, 1992), but which also may permit for changes in learning rate parameters as a function of prediction error (cf., Pearce & Hall, 1980).
A third way in which I approach the issue of representation is through an interest in the pharmacological and neuroanatomical basis of reinforcement. Towards this end I am exploring neural net models of instrumental conditioning, particularly, to determine if reinforcer- devaluation and outcome-specific transfer can be demonstrated with neuroscience-inspired models (e.g., see Donahoe, Burgos, & Palmer, 1993). In addition, I am empirically examining the pharmacological basis of food- reinforced conditioned place preference learning. The overall hope from these studies is that knowledge of the underlying neuropharmacology and neuroanatomy will help inform us as to how behavior-level notions of representation might be instantiated in the brain.
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 two 8-box computer controlled experimental stations, as well as an animal colony (housing up to 100 rodents). These systems are well designed to perform a wide variety of 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.
Representative Publications
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.
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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.
Undergraduate Course Home Pages
Psychology
53.1 - Learning