CHILDREN'S PERCEPTIONS OF CHANGES IN SIZE OF TELEVISED IMAGES

Using a Piagétan perspective, this study investigated the ways in which elementary school children perceive changes in the size of a televised image (in this case, a candy bar). The findings suggest that younger children perceive changes in image size from a medium shot to a close-up as changes in the object itself. Children's responses to changes in the televised image parallel their responses to traditional conservation tasks, but conservation of televised images occurs at a later age. In addition, children appear to use different cognitive skills to interpret how a zoom or a cut transforms the size of a televised image. When a zoom is used, children more readily perceive the object as “growing larger.”     

Instrumental responding following reinforcer devaluation

In two experiments, hungry rats were given instrumental lever-press training for an appetitive reinforcer and, in addition, were exposed to another type of food which was not contingent on lever pressing. In the first experiment, exposure to each type of food was on separate days, whereas in the second experiment rats were exposed to each type of food in strict alternation within each session. Subsequently, a food aversion was conditioned to the reinforcer for the experimental group and to the non-contingent food for the control group. In both experiments, animals with an aversion to the reinforcer responded less in an extinction test than animals with an aversion to the non-contingent food. Subsequent reacquisition tests confirmed that the aversion to the non-contingent food in the control group was of comparable strength with that to the reinforcer in the experimental group. The results were discussed in terms of whether the reinforcer is encoded in the associative structure set up by exposure to an instrumental contingency.