Time pressure effects on information processing in overlapping tasks: evidence from the lateralized readiness potential.

Information processing is impaired when two tasks are performed concurrently. The interference between the tasks is commonly attributed to structural bottlenecks or strategic scheduling of information processing. The present experiment investigated the effects of time pressure for the second of two responses on information processing in overlapping tasks by recording the lateralized readiness potential (LRP). Time pressure shortened the latency of the second response by diminishing the time devoted to motoric processing. In addition, task interference decreased under time pressure, which is probably due to the relatively early availability of the central bottleneck stage rather than to increased overlap of central stages. The LRP also provided direct evidence for an additional bottleneck following response selection, possibly due to supramodal refractoriness of response initiation.