Developmental change in the nature of attention allocation in a dual task.

Younger children have more difficulty in sharing attention between two concurrent tasks than do older participants, but in addition to this developmental change, we documented changes in the nature of attention sharing. We studied children 6–8 and 10–14 years old and college students (in all, 104 women and 76 men; 3% Hispanic, 3% Black or African American, 3% Asian, 7% multiracial, and 84% White). On each dual-task trial, the participant received an array of colored squares to be retained for a subsequent probe recognition test and then an easy or more difficult signal requiring a quick response (a speeded task, clicking a key on the same side of the screen as the signal or the opposite side). Finally, each trial ended with the presentation of the array item recognition probe and the participant's response to it. In our youngest age group (6–8 years), array memory was often displaced by the speeded task performed under load, especially when it was the opposite-side task, but speeded-task accuracies were unaffected by the presence of an array memory load. In contrast, in older participants (10–14 years and college students), the memory load was maintained better, with some cost to the speeded task. With maturity, participants were better able to adopt a proactive stance in which not only present processing demands but also upcoming demands were taken into account, allowing them to balance the demands of the two tasks.