Stephen B. Klein

Contemporary Learning Theories: Pavlovian Conditioning and the Status of Traditional Learning Theory

Volume I: Contents: R.R. Mowrer, S.B. Klein, Traditional Learning Theory and the Transition to Contemporary Learning Theory. Part I:Theories of Pavlovian Conditioning. P.J. Durlach, Learning and Performance in Pavlovian Conditioning: Are Failures of Contiguity Failures of Learning or Performance? R.R. Miller, L.D. Matzel, Contingency and Relative Associative Strength. A.G. Baker, P. Mercier, Attention, Retrospective Processing and Cognitive Representations. G. Hall, R. Honey, Perceptual and Associative Learning. A.R. Wagner, S.E. Brandon, Evolution of a Structured Connectionist Model of Pavlovian Conditioning (AESOP). A. Tomie, W. Brooks, Sign-Tracking: The Search for Reward. Part II:Current Status of Traditional Learning Theory. D.J. Levis, The Case for a Return to a Two-Factor Theory of Avoidance: The Failure of Non-Fear Interpretations. A. Dickinson, The Expectancy Theory of Animal Conditioning. Volume II: Contents: R.R. Mowrer, S.B. Klein. Part I:Introduction: A Contrast Between Traditional and Contemporary Learning Theory. Part II:Theories of Instrumental Conditioning. J. Allison, The Nature of Reinforcement. R.M. Church, Theories of Timing Behavior. S.F. Maier, Learned Helplessness: Event Co-Variation and Cognitive Changes. F. Vaccarino, B.B. Schiff, S.E. Glickman, A Biological View of Reinforcement. Part III:Biological Constraints in Learning. V.M. LoLordo, A. Droungas, Selective Associations and Adaptive Specializations: Food Aversion and Phobias. J. Garcia, L. Brett, K. Rusiniak, Limits of Darwinian Conditioning. A.L. Riley, C.L. Wetherington, Schedule-Induced Polydipsia: Is the Rat a Small Furry Human? W. Timberlake, G.A. Lucas, Behavior Systems and Learning: From Misbehavior to General Principles.

Resistance to extinction of a taste aversion: effects of level of training and procedures used in acquisition and extinction.

Two studies investigated the relationship between acquisition and extinction procedures on the development and elimination of a taste aversion. In the first experiment, subjects were given either forced or free choice acquisition to a common acquisition criterion. Then, their aversion was extinguished under either the free or forced choice procedure. The results of the first study showed that the greatest resistance to extinction was produced with a forced acquisition and free extinction procedure and the least resistance was produced by a free acquisition and forced procedure. Experiment 2 employed an equal number of acquisition trials (one or three) under either free or forced acquisition followed by either free or forced extinction. The results of Experiment 2 found that resistance to extinction was greater with three compared with one acquisition trial, but the acquisition technique did not influence resistance to extinction. As in the first experiment, extinction was more rapid with forced extinction. It appears that the strength of a taste-illness association is primarily dependent on the number of CS-US associations. Thus, when a common criterion is used, forced subjects take longer to extinguish their aversion due to their stronger taste-illness association. When an equivalent number of pairings is used, extinction rats are equal in free and forced animals (even though acquisition intake was higher in forced animals).

The influence of context and UCS intensity on the UCS preexposure effect in a flavor aversion paradigm

Abstract Three studies were conducted to evaluate the influence of environmental context and UCS preexposure intensity on the acquisition of a flavor aversion. In the first study, rats were exposed to two UCS-alone presentations at one of three dose levels of LiCl. The rats were given the two UCS preexposures in one of two contexts (familiar or novel). Following the UCS-alone treatment, all of the subjects received two pairings of sucrose and LiCl (1.25 meq) in the familiar context. Animals receiving UCS preexposures in the same context as used during conditioning consumed significantly more sucrose than did saline control animals. In contrast, the influence of prior UCS preexposure was not evident when UCS preexposure was experienced in a context different from that experienced during conditioning. In Experiment 2, all animal received UCS preexposure and conditioning in the novel room. Animals received either two or four preexposures at 0, 1.25, or 3.75 meq dose of LiCl. Two UCS preexposures at 3.75 meq dose produced a stronger UCS preexposure effect than did the 1.25 meq dose. Animals in Experiment 3 received two exposures to either 0-, 1.25-, or 3.75-meq LiCl in one of two contexts, followed by conditioning with the 1.25-meq LiCl dose in the same context as preexposure. Greater UCS interference occurred in animals preexposed to LiCl in the novel rather than familiar environment, with no specific dose effects in either context. These observations are discussed in terms of context blocking and generalization decrement models of the UCS preexposure effect.

Backward Second-Order Conditioning in Flavor Aversion Learning

Three experiments are reported which addressed the possibility that a neutral-flavor stimulus (CS2) can become aversive by pairing it with a previously established aversive-flavor stimulus (CS1). Unlike previous higher-order conditioning studies in which CSl followed CS2 (CS2-CS1 pairings), the present studies reversed this order (CS1-CS2 pairings) to determine the extent that backward second-order conditioning produces an aversion to CS2. In Experiment 1, rats received zero, one, or three pairings of a walnut-flavored solution (CS1) with LiCI. The walnut flavor was then presented just prior to forced consumption of a neutral lemon-flavored solution (CS2). A significant aversion developed to lemon only when three walnut-LiCI pairings were used. Experiment 2 manipulated the flavors used as CS1 and CS2 (lemon or walnut). Results indicated that regardless of the flavors used, a significant aversion developed to CS2 as a result of CS1-CS2 pairings. In Experiment 3, the level of aversion to CS2 with the backward higher-order conditioning paradigm was compared to forward higher-order conditioning. An unconditioned stimulus (UCS) alone treatment and a handling control treatment were included to evaluate the level of neophobia to novel flavors. Results showed that the percentages of CS2 (lemon) flavor consumed relative to total consumption was significantly lower in the backward higher order conditioning group than in the UCS alone and handling control treatments. The forward higher-order conditioning group was quite variable and differed from the control groups at the.08 level. These findings are discussed in terms of higher-order conditioning and flavor aversion learning.

The Elusiveness of Gustatory Potentiation of an Environmental Aversion

Two experiments investigated conditions that influence whether or not the presence of a flavor cue potentiates acquisition of an environmental aversion. Experiments 1 and 2 exposed rats to either a salient sucrose flavor or nonsalient water with black box-illness pairings. Half of the rats in the sucrose and water treatment groups became ill after exposure to the black chamber in their home cage. The other half of the rats in the two treatment conditions became ill in the black box. The results of each study indicated that a strong environmental aversion was established when illness was associated with exposure to the black box. The aversiveness of the black chamber was indicated by both less time spent in the black side and reduced intake in the black chamber. The presence of sucrose during conditioning did produce a stronger black box aversion than did water. Reliable potentiation of the environmental aversion, however, was seen only when the illness experience occurred in the black chamber but not when illness occurred in the home cage. A weaker aversion to the black chamber was also found in the water groups when illness occurred shortly after experience with the black box than when illness immediately followed exposure to the black chamber.