Attention is limited in terms of both capacity (i.e., amount of information attended) and selectivity (i.e., the degree to which non-attended information is nonetheless processed). One of the seminal theories in the field, load theory, predicts that these two aspects of attention interact in systematic ways. Specifically, load theory predicts that when the amount of information to attend is less than the available capacity, spare attention will naturally leak out to unattended items. While load theory has found a great deal of empirical support, the robustness of the findings has recently been called into question, in particular with respect to the extent to which the predictions are borne out across different tasks and populations. Here we report tests of perceptual load effects in two different tasks (change detection and enumeration) and in two populations (adults and 7- to 8-year-old children). Adults' accuracies did not demonstrate the predicted interaction between the capacity and selection dimensions, whereas children's performance, in addition to being overall worse than adults, did show the interaction. The overall lower accuracy of children was seen to be the result of a larger performance decrement in response to capacity demands, distracting information, and their interaction. Interestingly, while these results were seen at the level of the two tasks, there was no within-participants correlation across tasks. Overall, these results suggest that maturation-related changes attenuate the magnitude of distractor effects in attention, which in turn limits the evidence for interactions between capacity and selection in high-functioning populations.
Keywords: Cognitive development; Perceptual load; Selective attention.