Multi-modal information processing for visual workload relief

Abstract

Subjects simultaneously performed two single-dimensional compensatory tracking tasks, one with the left hand and one with the right hand. The tracking performed with the left hand was considered the primary task and was performed with a visual display or a quickened kinaesthetic-tactual(KT) display. The right-handed tracking was considered the secondary task and was carried out only with a visual display. Although the two primary task displays had afforded equivalent performance in a critical tracking task performed alone, in the dual-task situation the quickened KT primary display resulted in superior secondary visual task performance. Comparisons of various combinations of primary and secondary visual displays in integrated or separated formats indicated that the superiority of the quickened KT display was not simply due to the elimination of visual scanning. In an additional condition, a quickened signal obtained from an off-line KT display was used to drive a primary visual display. Performance was equivalent to previous dual visual task situations, indicating that quickening per se also was not the immediate cause of the observed KT superiority. Results are discussed in terms of S-R compatibility differences, competition for modality-dependent processing resources, task discriminability, and the role of sensory buffers in maintaining multi-task frames of reference under conditions of shifting attention.