Distractibility in infancy: the effects of distractor characteristics and type of attention.

Two experiments investigated the role of distractor characteristics and type of object-directed attention on infants' distraction latencies during object exploration. In Experiment 1, 7- and 10-month-old infants' distraction latency was a function of both attention and the characteristics of the distractors. Infants took longer to turn toward distractors during focused object-directed attention than when engaged in more casual attention. In addition, their latencies were longer regardless of attention type when the distractors were unimodal (e.g., consisting of only a visual or an auditory component) than when they were bimodal (e.g., consisting of both auditory and visual components). Experiment 2 demonstrated that infants exhibit shorter distraction latencies toward complex than simple bimodal distractors. These results are discussed in the context of Allport's (1989) model of attention and suggest that infants' allocation of attentional resources, as measured by distraction latencies, is influenced both by the characteristics of the distractor and by the type of infants' object-directed attention.

Endogenous visuospatial precuing effects as a function of age and task demands.

This experiment examined the effects of age on processing resource capacity using an endogenous visuospatial precuing task and four levels of resource demands. Younger and older adults made speeded two-choice responses to dim and bright targets that required a line-orientation or a lexical decision. An arrow preceding target onset served as an attentional cue to affect the spatial distribution of resources. It provided accurate information about the target's location on most trials and inaccurate or neutral information on the remaining trials. Although older adults were slower than younger adults under all conditions and were more affected by the resource demand manipulations, they exhibited a pattern of precuing effects across conditions that was similar to that of the younger adults. Results are consistent with the idea that the visuospatial attention system remains relatively unaffected by aging. However, the data speak against the idea that capacity reduction is the primary contributor to age-related slowing.