Conditioned approach and withdrawal behavior in pigeons: Effects of a novel extraneous stimulus during acquisition and extinction

Three experiments examined the effects of complete removal of reinforcement and of the introduction of a novel stimulus on conditioned approach and withdrawal behavior exhibited by pigeons in an autoshaping paradigm. Experiment 1 indicated that complete omission of food from the experimental situation resulted in the gradual disappearance of both approach and withdrawal behavior in subjects that had received either explicitly paired or explicitly unpaired conditioning. Subsequent presentation of a novel visual stimulus reinstated both approach and withdrawal. Experiment 2 replicated these findings in a within-subjects, discriminative paradigm. In Experiment 3, presenting the novel visual stimulus during acquisition when approach and withdrawal behaviors were asymptotic did not produce significant disruption of performance. These data suggest that removal of reinforcement leads to the disappearance of withdrawal as well as approach performance, and that subsequent presentation of a novel stimulys reinstates whatever behavior was dominant prior to extinction—a finding that seems analogous to results of experiments concerning proactive interference.     

Psychometric and instructional validation approaches in the hierarchical sequencing of learning tasks

Two strategies used to test prerequisite relationships among intellectual skills were employed to examine the sequence of three types of subtraction tasks. A psychometric validation strategy yielded results similar to an instructional validation strategy. This finding provides support for the use of the more efficient psychometric approach for validating large numbers of learning hierarchies in relatively short periods of time.     

Property

This paper first reviews material dealing with the question of whether possession and related behaviours are innately determined or secondary. It is considered that the significance of property-related behaviour can best be understood by reference to its ontogenesis, and to the social context, and to the intentions of the actor. Some relevant material is reviewed, and it is proposed that some forms of acquisition and possession of property may be limited to societies with a high degree of role flexibility and mobility and have to do with the building and maintenance of self-respect.