Variations in the sensitivity of instrumental responding to reinforcer devaluation

In five experiments hungry rats were trained to make a lever press response for a sucrose reinforcer. That sucrose was subsequently devalued by conditioning a food-aversion to it, and the ability of the rats to integrate knowledge about the instrumental contingency with that gained from aversion training was assessed in an extinction test. Experiment I showed successful integration following limited but not extended instrumental training. Experiment II suggested that the crucial factor was the spacing of training; successful integration was seen after massed but not distributed training. The third experiment implicated distributed experience with the reinforcer, rather than distributed response practice, in failures of integration. Experiment IV showed that if the distribution of food-aversion learning was dissimilar to that of instrumental training then a failure of integration could result; this finding was able to account for the distribution of training effects seen in previous studies, but not the effect of extended training. Experiment V replicated the extended training effect seen in Experiment I, and provided evidence that this may reflect the degree of exposure to the reinforcer rather than the extent of response practice.     

Sensitivity training and the school counsellor

Sensitivity training is defined and described, with a distinction drawn between 'human relation' type training and personal growth groups. The learning assumptions and goals are outlined, with a review of research on outcomes. The relationship between sensitivity training and therapy is discussed, and a case is made for training all British school counsellors in human relations skills.     

Practical Possibilities

Abstract: That inferences of the form "If M then S and possibly M, therefore possibly S" are invalid in possible worlds modal logics can be viewed as another fallacy of material implication. However, this paper argues that properly analyzing this and related inferences requires treating the possibility involved as a practical modality. Specifically, ordinary language propositions of the form "It is possible that M" must be understood to mean that there is a non-negligible probability of M being the case. But this entails reexamining the very idea of logical validity.