Conditioned reinforcement and complex discrimination: can conditioned reinforcing value be specific to a complex of three cues?

The present experiment is concerned with the nature of the cues that might acquire conditioned reinforcing value, and the ways in which such cues might interact with one another. Red and green colored keylights were differentially paired with food dependent upon the houselight con­ text (A or B) and the trial type (training or choice/forced), The duration of the colored keylights was varied between groups in an attempt to manipulate the effectiveness of the short-term memory oftrial-type cues at the trial's end. The red and green stimuli were of30 sec duration for Group 30 and of 3 sec duration for Group 3. The results indicated that the choices ofthe pigeons in Group 30 were influenced by the houselight context present and by the keylight color. The choices of the pigeons in Group 3 seemed to be influenced by the houselight context present, the keylight color, and the memory of trial-type cues. Memory cues for trial antecedents were not overshadowed by presumably more salient external houselight stimuli for the pigeons in Group 3. Two alterna­ tive explanations for the results are discussed, and determined to be unlikely based on the results of an earlier experiment. The present results are related to a model of the conditioned reinforc­ ing value of momentary stimuli and of transmission of conditioned reinforcing value. Much recent interest has focused on complex discrimi­ nation learning (e.g., Fedorchak & Bolles, 1986; Zen­ tall, Hogan, & Edwards, 1984). Unfortunately, until re­ cently, little has been done to explore the ways in which complex discrimination migbt influence the acquisition and demonstration of conditioned reinforcement. Three recent experiments have directly addressed this issue (e.g., Astley & Perkins, 1985; Hancock, 1982; Winter & Per­ kins, 1982). In the Hancock (1982) experiment, condi­ tioned reinforcing value was decreased markedly when a potential conditioned reinforcer was preceded by one stimulus on training trials and by another on test trials. In their experiments, Winter and Perkins (1982) and Ast­ ley and Perkins (1985) varied the duration of stimuli and demonstrated that the conditioned reinforcing value of stimuli could be restricted to contexts distinguished by the prevailing short-term memories (STMs) of antecedent events, In the present experiment, this general approach to discovering the cues that effectively acquire conditioned reinforcing value was followed. In the three studies cited above, pairs of cues (i.e., the component stimulus and the STM of antecedents) provided the basis for differen­ tial conditioned reinforcing value. The present experiment was designed to determine whether conditioned reinforc­ ing value would be restricted to an even more complex set of available cues. The present study included both onThis research was submitted in partial fulfillment of the requirements for the PhD degree at Kansas State University. The author would like to gratefully acknowledge the assistance of Charles C. Perkins in all aspects of this research and the helpful comments of Wayne Poniewaz on an earlier version of this manuscript. Requests for reprints should be sent to the author at Cornell College, Mt. Vernon, IA 52314.