Valerie A. Davey

The Negative Effects of Positive Reinforcement in Teaching Children with Developmental Delay

Interactive modeling is frequently used in teaching skills to children with developmental delay. This study compared the performance of 12 children (7 males, 5 females; 4–10 years of age) each trained in two tasks, one through interactive modeling (with or without verbal reinforcement) and the other through passive observation. Results showed that passive modeling produced better rated performance than interactive modeling and that verbal reinforcement was counterproductive. These findings suggest that current instructional strategies may need to be reconsidered for children with developmental delay.

The role of stimulus preexposure in problem solving by Octopus vulgaris

Abstract Octopus vulgaris is able to open transparent glass jars closed with plastic plugs and containing live crabs. The decrease in performance times for removing the plug and seizing the prey with increasing experience of the task has been taken to indicate learning. However, octopuses’ attack behaviors are typically slow and variable in novel environmental situations. In this study the role of preexposure to selected features of the problem-solving context was investigated. Although octopuses failed to benefit from greater familiarity with the training context or with selected elements of the task of solving the jar problem, the methodological strategies used are instructive in potentially clarifying the role of complex problem-solving behaviors in this species including stimulus preexposure and social learning.

Conditioned antisickness: indirect evidence from rats and direct evidence from ferrets that conditioning alleviates drug-induced nausea and emesis.

In a direct test of conditioned antisickness (CAS; B. T. Lett, 1983) theory, the authors measured emesis in ferrets and found those with a history of forward pairings of pentobarbital and lithium to have fewer and shorter bouts of emesis on test, whether induced by lithium or, in a subsequent test, by the highly emetogenic anticancer drug cisplatin. In an indirect test of her CAS theory, B. T. Lett (1992) paired interoceptive (drug) or place cues with lithium chloride toxicosis and found that rats with a forward-pairings history ate less food than controls on a forward-pairing test, consistent with conditioned sickness rather than CAS. But rats eat dirt or clay in response to sickness and adaptively eat small amounts of food when clay is not available. We substituted clay (kaolin) for food in a partial procedural replication of B. T. Letts (1992, Experiment 1) experiment and found that rats with a history of forward pairings of pentobarbital and lithium ate less kaolin, which is consistent with CAS.

Verbal Prompting, Hand-over-Hand Instruction, and Passive Observation in Teaching Children with Developmental Disabilities

In hand-over-hand modeling with response-contingent verbal prompts, tasks are divided into identifiable sequential components, and the achievement of each component is marked by the delivery of some form of verbal prompt. In a within-subjects design, children were trained in one skill with response-contingent verbal prompts and in a second skill with simple passive observation. A separate group of children were trained with less rigorous verbal prompting in one skill and with passive observation in a second. Consistent with previous research, we found that passive modeling was overall significantly more effective than hand-over-hand modeling and that passive modeling was significantly more effective than hand-over-hand modeling with response-contingent prompting. Our evidence therefore indicates that current methods for teaching basic skills to children with severe developmental delays may require reassessment because simple observation of modeled skills appears to be more effective than more labor-intensive instruction.

Methodological issues in drug-drug conditioning in rats: nonassociative factors in heart rate and avfail.

Sodium pentobarbital injections followed 30 min later by d-amphetamine sulfate produce an effect over trials in the form of an increase in heart rate in response to pentobarbital in relation to rats that receive the 2 drugs 24 hr apart (long-delayed control: Revusky, Davey, & Zagorski, 1989). This study found equivalent increases in heart rate in forward and backward groups in relation to a long-delayed control regardless of whether training or testing was carried out in a heart rate recording apparatus or in the home cage, which suggests that a drug interaction due to drug administrations in forward and backward groups has yet to be eliminated in accounting for the heart rate effect. Comparison of backward and long-delayed controls in a drug-drug procedure that used a taste aversion test revealed that both forward and delayed pairings can produce attenuated aversions in relation to a backward group regardless of whether the unconditional stimulus is amphetamine (Experiment 1) or lithium chloride (Experiment 2).

Antisickness conditioning using a nausea-producing nondrug cue.

Most drugs induce conditioned taste aversions and are therefore commonly supposed to produce nausea or sickness. Paradoxically, some drugs appear to lose induction capability when made to serve as a cue for a second drug that produces more severe sickness, perhaps through selective association with a hypothetical homeostatic or antisickness aftereffect of sickness. Using drug-drug pairings had made antisickness conditioning theory difficult to validate. We report here that rotation serves in lieu of a drug cue in rats. Rotation-drug pairings eliminate drug interactions and enable the sorts of parametric manipulations required to validate the theory. By postulating a common sickness mechanism to explain both taste aversion and aversion failure, the theory places the phenomenon within an adaptive evolutionary framework. Successful application could yield a direct countermeasure to severe nausea in clinical settings.

Conditioned antisickness: heat as an internal stimulus in conditioning taste aversion and aversion failure in rats.

Heat was found to be effective as a conditional stimulus in the aversion failure procedure (S. Revusky, H. K. Taukulis, L. A. Parker, & S. Coombes, 1979) and was also found to be effective as an unconditional stimulus using a taste aversion procedure in which rats exposed to high ambient temperature following saccharin consumption showed robust saccharin aversions relative to unpaired and unheated controls. The antisickness and taste aversion conditioning evidence force reexamination of the view that toxic heat effects are referred to the external environment. Together with other recent evidence from this laboratory, these data support the hypothetical antisickness mechanism of aversion failure, which requires that toxic heat serve as an internal stimulus.