Intrinsic reinforcing properties of putatively neutral stimuli in an instrumental two-lever discrimination task

Four experiments examined the influence of a stimulus presented after one response in a two-lever choice task. In Experiment 1, food-deprived rats trained on a concurrent variable-interval extinction schedule responded more often on the extinction lever when such responding periodically produced a visual stimulus than when it did not. In Experiments 2 and 3, a similar signal-induced enhancement effect was found even when food was delivered randomly with respect to responding on both levers or when no food was presented. In Experiment 4, a response-contingent visual stimulus elevated responding to the lever on which it was presented, but an auditory cue suppressed responding. These findings indicate that visual stimuli may possess intrinsically reinforcing properties for rats.     

‘On the move’: primary age children in transition

The focus of this article is the experience of the growing numbers of children who, as one of the consequences of increasing globalisation, move between cultures internationally as a result of their parents' occupations. Beginning with a review of research relating to transition, the article goes on to describe a study at an international school in Thailand which, it is argued, is similar in terms of the globally‐mobile nature of its student population to many other such schools worldwide. Using a computer‐based questionnaire, the views of primary‐age children were explored in relation to various dimensions of the transition process. Findings highlighted the importance of recognising the impact of such moves on young children, and of schools being aware of the different stages of transition that children might be experiencing so that appropriate support may be provided.     

Do they really need to raise their hands? Challenging a traditional social norm in a second grade mathematics classroom

In an attempt to examine dialogue within a second grade classroom, students were encouraged to participate in whole-class mathematics discussions without raising their hands before speaking. Beneficial social and sociomathematical norms developed in place of this traditional social norm. Effects of this change on the dialogue and written mathematical explanations of a class of second grade students are described. Focus was placed on student participation in whole-class discussions. The study helped to determine the effects of student-centered dialogue on students' mathematical explanations and justifications as demonstrated in the students' discussions, participation, and written expression related to their mathematics learning.     

Instrumental responding by rats on free-operant schedules with components that schedule response-dependent reinforcer omission: Implications for optimization theories

In two experiments, we assessed whether rats optimize the number of reinforcers per response. In Experiment 1, one group of rats was trained to leverpress for food reinforcement on a simple variable-interval (VI) 60-sec schedule. For another group, a negative fixed-ratio component was imposed on the VI schedule to produce a conjoint contingency in which reinforcement became available on the VI schedule but was omitted when the ratio criterion was satisfied. In Experiment 2, one group of rats responded on a VI schedule and also received response-independent food. For another group, responding above a certain rate canceled the response-independent food. Despite the negative contingency experienced by the groups in Experiments 1 and 2, responding was maintained at a level at which the number of obtained reinforcers was reduced substantially below the maximum number possible. In addition, in both experiments, the groups that experienced the negative contingency responded at a lower rate than did a yoked control group that experienced the same frequency of reinforcement but lacked the negative component. These results demonstrate that although rats do not optimize their behavior with respect to reinforcement, they are nevertheless sensitive to some aspect of the instrumental contingency in operation.