Two experiments are reported that demonstrate that visual search for a signal from a number of potential signal sources in a sustained monitoring task is dependent upon previous visual-load history. It is shown that both temporal and spatial variations in load produce performance decrements, and occasionally increments, that cannot be predicted from static-load experiments. These data are not consistent with previous attempts to explain performance changes associated with workload history. An interpretation is offered in terms of the persistence of information-processing strategies across changing task conditions.
Get full access to this article
View all access options for this article.
References
1.
Allnutt, M (1982). Human factors: Basic principles. In R. Hurst and L. Hurst (Eds.), Pilot Error (pp. 1–22). London: Granada.
2.
Conrad, R (1955). Some effects of performance in perceptual load. Journal of Experimental Psychology, 49, 315–322.
3.
Cumming, R. W., and Croft, P. G. (1973). Human information processing under varying task demand. Ergonomics, 16, 581–586.
4.
Goldberg, D. R., and Stewart, M. R. (1980). Memory overload or expectancy effect? ‘Hysteresis’ revisited. Ergonomics, 23, 1173–1178.
5.
Goldstein, I. L., and Dorfman, O. W. (1978). Speed and load stress as determinants of performance in a time sharing task. Human Factors, 20, 603–609.
6.
Mackworth, N. H., and Mackworth, J. H. (1958). Visual search for successive decisions. British Journal of Psychology, 49, 210–231.
7.
Poulton, E. C. (1982). Influential companions: Effects of one strategy on another in the within-subjects designs of cognitive psychology. Psychological Bulletin, 91, 673–690.
8.
Raouf, A., Hatami, S., and Chaudhary, K. (1981). CRT display terminal task pacing and its effect on performance. In G. Salvendy and M. J. Smith (Eds.), Machine pacing and occupational stress (pp. 347–354). London: Taylor and Francis.
