Coordinating Actions

The motor system composes complex actions by combining simpler submovements. This presumably involves sharing information about the progress of one submovement with the centres controlling another submovement, to ensure that the second happens in an appropriate relation to the first. This process is called coordination. In this paper Idiscuss evidence that coordinating actions indeed involves an active process of sharing information about the current state of movements. Coordination appears to be qualitatively different from the process of reacting to external stimuli. This may reflect the importance of predictive representations in coordination. Finally, the processes underlying coordination appear to be organized in a response-specific fashion, as a number of relatively independent circuits. The development and tuning of these circuits may, in part, be what makes an action "skilled".     

Response error and processing biases in confidence judgment

Previous studies showed that random error can explain overconfidence effects typically observed in the literature. One of these studies concluded that, after accounting for random error effects in the data, there is little support for cognitive‐processing biases in confidence elicitation. In this paper, we investigate more closely the random error explanation for overconfidence. We generated data from four models of confidence and then estimated the magnitude of random error in the data. Our results show that, in addition to the true magnitude of random error specified in the simulations, the error estimates are influenced by important cognitive‐processing biases in the confidence elicitation process. We found that random error in the response process can account for the degree of overconfidence found in calibration studies, even when that overconfidence is actually caused by other factors. Thus, the error models say little about whether cognitive biases are present in the confidence elicitation process. Copyright © 2008 John Wiley & Sons, Ltd.     

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.”