文摘
A forced-choice reaction time (RT) task was used to assess developmental changes in filtering and the concomitant ability to narrow the focus of the attentional lens. Participants included 20 children in each of four age groups (4, 5, 7, and 9 years), as well as 20 adults between the ages of 21 and 29 years. Conditions varied with regard to the presence or absence of distractors and their proximity to a target stimulus, and the presence or absence of a visual window within which the target stimulus was presented. Age-related differences in the ability to filter task-irrelevant stimuli were found. The performance of 4-year-old children was adversely affected with the presence of distractors located at both 5.7° and 0.95° of visual angle from target stimuli, whereas that of children aged 5, 7, and 9 was negatively affected only with distractors 0.95° of visual angle from the target. Adults' performance was not adversely affected by the presence of distractors. Developmental differences in focusing attention were further highlighted by the finding that the presence of a visual window cue was only associated with faster RTs among 4-year-old children. These results are discussed in terms of the zoom-lens metaphor of visual attention, and the development of the ability to vary the size of an attentive zoom-lens in response to task requirements.
