Two experiments examined visual search performance both by itself and in conjuction with concurrent, non-visual activity to assess the involvement of attention in the array size effect. Short-term retention was the concurrent activity in Experiment i, and changing S-R mapping during search was the activity in Experiment n. In both experiments, reaction time increased with array size (4, 8, or 12 letters) and concurrent activity, but their effects were additive. The results were interpreted as

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... nfirming predictions derived from unlimited-capacity theories of visual search and are related to findings with similar procedures in the memory search paradigm.