Working-memory capacity predicts the executive control of visual search among distractors: The influences of sustained and selective attention

Abstract

Variation in working-memory capacity (WMC) predicts individual differences in only some attention-control capabilities. Whereas higher WMC subjects outperform lower WMC subjects in tasks requiring the restraint of prepotent but inappropriate responses, and the constraint of attentional focus to target stimuli against distractors, they do not differ in prototypical visual-search tasks, even those that yield steep search slopes and engender top-down control. The present three experiments tested whether WMC, as measured by complex memory span tasks, would predict search latencies when the 1–8 target locations to be searched appeared alone, versus appearing among distractor locations to be ignored, with the latter requiring selective attentional focus. Subjects viewed target-location cues and then fixated on those locations over either long (1,500–1,550 ms) or short (300 ms) delays. Higher WMC subjects identified targets faster than did lower WMC subjects only in the presence of distractors and only over long fixation delays. WMC thus appears to affect subjects' ability to maintain a constrained attentional focus over time.

Keywords:

• Working memory
• Executive control
• Attention
• Visual search
• Individual differences

Acknowledgments

We are grateful to Christopher Barona, Lauren Betheil, Chris Burgin, Alex Cereceres, Brian Clark, Kristen Currie, Candice Dixon, Wilfred Drath, Tasha Hicks, Cassandra Mallard, Daniel McCord, Nicholas Rau, Jessica Sherard, Teresa Shippey, Brian Troxler, and Ashley Zimmerman for data-collection assistance. Bradley Poole is now at SA Technologies, Marietta, GA, USA.

Notes

¹ For a methodological discussion of individual-differences and developmental research producing similar discrepancies between ANOVA-based interactions on one hand and correlation- or regression-based results on the other hand, see Salthouse (2000).