Time-Sharing is Not a Unitary Ability.

Abstract : The results of the experiments lead to the conclusion that time-sharing is not a single general ability, but rather is dependent upon several more specific, and perhaps independent, processing limitations. These include: (1) an inability early in practice to simultaneously select, or retrieve, multiple responses from memory; (2) a persisting inability to initiate multiple independent responses simultaneously; (3) an inability to process, or at least efficiently process, contiguous inputs from separate modalities owing to the need for a modality-specific attentional focus; and (4) an inability to efficiently process multiple inputs from within the same modality owing to the existence of structural interference. It is suggested that the prediction of performance on complex criterion task combinations such as entailed in piloting or air traffic control requires specification of which of these component abilities is required by the criterion situations, and the tailoring or predictor tasks based on this specification.