Current theories concerning individual differences in working memory capacity (WMC) suggest that WMC reflects the ability to control the focus of attention and resist interference and distraction. The current set of experiments tested whether susceptibility to distraction is partially responsible for the established relationship between performance on complex span tasks and the Raven's Advanced Progressive Matrices (RAPM). This hypothesis was examined by manipulating the level of distraction among the incorrect responses contained in RAPM problems, by varying whether the response bank included the most commonly selected incorrect response. When entered hierarchically into a regression predicting a composite score on span tasks, items with highly distracting incorrect answers significantly improved the predictive power of a model predicting an individual's WMC, compared to the model containing only items with less distracting incorrect responses. Additional analyses were performed examining the types of errors that were made. A second experiment used eye-tracking to demonstrate that these effects seem to be rooted in differences in susceptibility to distraction as well as strategy differences between high and low WMC individuals. Results are discussed in terms of current theories about the role of attentional control in performance on general fluid intelligence tasks. (Contains 4 tables and 5 figures.)