Developmental changes in visual search are determined by changing visuospatial abilities and task repetition: A longitudinal study in adolescents

The development of foraging organization

In foraging tasks, multiple targets must be found within a single display. The targets can be of one or more types, typically surrounded by numerous distractors. Visual attention has traditionally been studied with single target search tasks, but adding more targets to the search display results in several additional measures of interest, such as how attention is oriented to different features and locations over time. We measured foraging among five age groups: Children in Grades 1, 4, 7, and 10, as well as adults, using both simple feature foraging tasks and more challenging conjunction foraging tasks, with two target types per task. We assessed participants' foraging organization, or systematicity when selecting all the targets within the foraging display, on four measures: Intertarget distance, number of intersections, best-r, and the percentage above optimal path length (PAO). We found that foraging organization increases with age, in both simple feature-based foraging and more complex foraging for targets defined by feature conjunctions, and that feature foraging was more organized than conjunction foraging. Separate analyses for different target types indicated that children's, and to some extent adults', conjunction foraging consisted of two relatively organized foraging paths through the display where one target type is exhaustively selected before the other target type is selected. Lastly, we found that the development of foraging organization is closely related to the development of other foraging measures. Our results suggest that measuring foraging organization is a promising avenue for further research into the development of visual orienting.

What underlies visual selective attention development? Evidence that age-related improvements in visual feature integration influence visual selective attention performance

Visual selective attention (VSA) improves across childhood. Conjunction search tasks require integrating multiple visual features in order to find a target among distractors and are often used to measure VSA. Motivated by the visual system's architecture and developmental changes in neural connectivity, we predicted that feature integration across separate visual pathways (e.g., color and motion) should develop later than feature integration within the same visual pathways (e.g., luminance and motion). A total of 89 4- to 10-year-old children completed a visual search task that manipulated whether feature integration was between separate parallel visual pathways or within the same visual pathway. We first examined whether color-motion integration was associated with a performance cost relative to luminance-motion integration across childhood. We found that color-motion integration was worse than luminance-motion integration in early childhood but that this difference decreased with age. We also examined whether luminance-motion and color-motion visual search performance developed differently across childhood. Reaction time (RT) visual search slopes for the luminance-motion condition were both stable across childhood and steeper overall than those for the color-motion condition. In contrast, RT search slopes for the color-motion condition became steeperincrease across childhood. Finally, we found that age-related improvements in color-motion integration, relative to luminance-motion integration, were associated with longer color-motion search rates across childhood. These data suggest that age-related improvements in color-motion feature integration may increase competition between color-motion targets and distractors, thereby increasing the amount of time needed to process distractors as nontargets during the selection process.