Foraging for brain stimulation: toward a neurobiology of computation

The self-stimulating rat performs foraging tasks mediated by simple computations that use interreward intervals and subjective reward magnitudes to determine stay durations. This is a simplified preparation in which to study the neurobiology of the elementary computational operations that make cognition possible, because the neural signal specifying the value of a computationally relevant variable is produced by direct electrical stimulation of a neural pathway. Newly developed measurement methods yield functions relating the subjective reward magnitude to the parameters of the neural signal. These measurements also show that the decision process that governs foraging behavior divides the subjective reward magnitude by the most recent interreward interval to determine the preferability of an option (a foraging patch). The decision process sets the parameters that determine stay durations (durations of visits to foraging patches) so that the ratios of the stay durations match the ratios of the preferabilities.     

Extracting the coherent core of human probability judgement: a research program for cognitive psychology

Human intuition is a rich and useful guide to uncertain events in the environment but suffers from probabilistic incoherence in the technical sense. Developing methods for extracting a coherent body of judgement that is maximally consistent with a person's intuition is a challenging task for cognitive psychology, and also relevant to the construction of artificial expert systems. The present article motivates this problem, and outlines one approach to it.     

Using a Narrative Metaphor: Implications for Theory and Clinical Practice

The evolution of family therapy from a cybernetic metaphor to a narrative metaphor has led us to think differently about therapy, about clients, and about ourselves as therapists. In this article we pursue how this different way of thinking has informed a theoretical understanding of a narrative therapy approach and consequently has opened space for different ways of working clinically. We begin by tracing the evolution to narrative; we consider the implications of social constructionism and its political effects; and we complete the discussion by focusing on narrative theory. We then show how the clinical work follows logically and is coherent with the theoretical considerations. We describe, and illustrate with clinical examples, an innovative approach to working with couples and families with adolescents. In this work we pay attention to the larger cultural stories, including gender constructions, and to personal stories that persons have created to make meaning out of their experience as they interact with one another in a reciprocal meaning-making process. Interventions focus on externalizing the problem narrative that is influencing the client(s), mapping the effects of the problem pattern and/or the totalizing view persons might have of others, and creating space for client(s) to notice preferred actions and intentions. Finally, we close the loop by asking questions of ourselves and others about the effects of working from a narrative metaphor.     

Nodality effects during equivalence class formation: An extension to sight-word reading and concept development

Three students with moderate disabilities were taught to read and match-to-sample sight words comprising stimulus sets based upon the four food groups. We taught students conditional discriminations within four four-member sets using a single-sample/four-comparison procedure. Students were taught A-B, B-C, and C-D conditional discriminations for each of the four potential stimulus classes. Subsequent probes tested for relations based upon symmetry and one-node and two-node transitivity. The performances for all students indicated that symmetric relations emerged before one-node transitive relations, and that one-node transitive relations emerged before two-node transitive relations. These results are consistent with a pattern of responding, referred to as a "nodality effect," in which relations with fewer nodes are demonstrated prior to the demonstration of relations with a greater number of nodes. These results extend this area of research to sight-word reading for students with moderate disabilities.     

BALANCING SOCIAL ACCEPTABILITY WITH TREATMENT EFFECTIVENESS OF AN INTRUSIVE PROCEDURE: A CASE REPORT

The debate over social acceptability of intrusive procedures has led some school districts to adopt policies allowing punishment for only the most extreme forms of destructive behavior. We investigated the effectiveness of selectively implementing punishment for only the most severe topographies of aggression and property destruction, while less extreme behaviors were ignored. Results indicated that severe behaviors were reduced to near-zero levels only when both severe and less severe behaviors were similarly punished.     

HYPOTHESIS-BASED INTERVENTIONS FOR TANTRUM BEHAVIORS OF PERSONS WITH DEVELOPMENTAL DISABILITIES IN SCHOOL SETTINGS

We conducted a functional assessment of problem behaviors of 2 students with developmental disabilities in their classroom environments. Results of the assessments showed that although there were more tantrums in demand than in no-demand conditions, the function of the behavior was to gain attention (positive reinforcement) rather than to avoid or escape demands (negative reinforcement); demand conditions apparently served a discriminative function for the availability of attention. Therefore, intervention was based on the positive reinforcement hypothesis, resulting in a substantial reduction of tantrums for both subjects.