AUTOMATICITY VERSUS TIME-SHARING IN TIMING AND TRACKING DUAL-TASK PERFORMANCE

Two experiments investigated the interfering effects of a manual track ing task on timing performance. Subjects generated a series of 5-s tem poral productions under control (timing only) and experimental (timing + pursuit rotor tracking) conditions. Timing was more variable under experimental conditions, a finding consistent with attentional models which argue that timing tasks compete with concurrent distracter tasks for limited processing resources. A pretest-posttest paradigm was emp loyed to evaluate the hypothesis that practice on the tracking task wo uld lessen its attentional demands and thereby attenuate the interfere nce effect. Experiment 1 involved single-task practice (tracking alone ). Single-task practice leads to automaticity, the ability to perform a skilled task using fewer processing resources. Pretest-posttest comp arisons showed that such practice reduced interference in timing. Expe riment 2 involved dual-task practice(timing + tracking). Dual-task pra ctice promotes the development of timesharing, the ability to efficien tly switch attention between multiple tasks. In this case, practice fa iled to reduce the interference effect in timing. The results suggest that effective strategies for timing in dual-task situations must allo w one to closely monitor the ongoing flow of temporal events.