Abstract
Attentional resolution (Cavanagh & Intriligator, 2001) is defined as the smallest region in space that can be selected by visual attention. The size of this region has shown to become more fine-grained during development (Wolf & Pfeiffer, 2009). In the present study, we investigated how the attentional resolution in different age groups (grades 1, 3, 5, and 7 as compared to an adult sample) is influenced by a variation of load. Using a multiple object tracking paradigm, we varied the number of objects to manipulate the load and the distance between target and distractors to assess thresholds of attentional resolution. Results indicate a dissociation between the impact of load on adults' and children's attentional resolution. More specifically, while an increase in object number does not affect the attentional resolution of adults, it certainly does so in children. However, here an interaction could be observed. Increasing the number of objects from one to two only had an effect on the attentional resolution of the smaller children only (grades 1 and 3). For three targets, however, the attentional resolution of the older children (grades 5 and 7) was affected as well. Thus a change in attentional resolution towards a coarser resolution could be observed the more objects were involved and the smaller the children were. Our results thus touch two theoretical positions and possibly resolve their apparent contradiction. It is still an unresolved issue whether attentional resolution can be manipulated by task difficulty (Alvarez & Franconeri, 2007) or whether it is independent of any variation in task demands (Cavanagh & Intriligator, 2001). Our results indicate that attentional resolution is stable as long as the task does not touch the capacity limits of attention. If it does, a compromise between attentional resolution and attentional load has to be made.