Deciding the existence of a time-sharing ability: A combined theoretical and methodological approach

Experimental and statistical methods for examining individual differences in dual-task performance and time-sharing ability are reviewed and criticized. Previous data and analysis procedures are generally inadequate to evaluate a time-sharing ability. Errors resulting from unsophisticated use of correlational and factor analytic procedures are described. Four previous studies that concern time-sharing are considered in detail. The nature of task selection, scoring methods, and control of practice and reliability issues are discussed. Based on a reanalysis of available data, a time-sharing ability is not rejected. Simulation, incorporation of theory in planning models, and crucial tests of the hypotheses are proposed as methods for assessing the time-sharing ability.