Aging and the development of automaticity in conjunction search.

In two experiments, younger and older observers carried out feature searches for targets defined by their luminance contrast and orientation. Additionally, they received consistent-mapping (CM) training in luminance contrast by orientation conjunction search, followed by a brief exposure to conjunction search under reversal conditions. In Experiment 1, display size effects on reaction time suggested that both younger and older observers were conducting a parallel search in all conditions and showed equivalent disruption at reversal. Experiment 2 was a substantive replication of the first using more difficult conjunction search displays. In addition to latency, we measured the number, duration, and feature-based selectivity of fixations made during conjunction search. Display size effects were larger than in Experiment 2 and were of equivalent magnitude in younger and older people. There were no age differences in improvement in conjunction search and minimal age differences in disruption following reversal. Both age groups demonstrated early in training that they could select items possessing target features (i.e., the color white), and both age groups demonstrated that they could not completely reverse this selectivity when these features no longer defined the target. These experiments have several implications for models of visual attention and age differences therein.