Citation

Andorre-Gruet V, Queinnec Y. Int. J. Ind. Ergonomics 1998; 21(3-4): 179-186.

Copyright

(Copyright © 1998, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

With the advent of new technologies, computerized display systems have superseded the wall presentation of information in control rooms. These changes would influence the supervision of a continuous process, characterized with high mental demands. It is important to assess if the types of displays are relevant for the needs of the operators supervising the process during day and night shifts. Inadequate information processing induced by some types of presentation of the information as well as temporal fluctuations in human reasoning may have consequences on the reliability and the operators' workload. In line with many experimental and field studies on shiftwork effect, we then expect that the survey activity of a continuous process will quantitatively and qualitatively vary according to the level of vigilance. Our study was performed in a control room of a chemical plant. We investigated the supervisory activity of controllers working on 3 x 8 shifts with shift changes at 4 am, noon and 8 pm. All the screen pages they selected were recorded over 18 whole shifts. Data were treated according to the frequency of consultation and the type of information gathering. We observed quantitative and qualitative alterations in supervisory activity on normal operation according to cognitive demands of the task and to the internal state of the operator. The call frequency was higher in the afternoon than at night, when the level of vigilance is the lowest. When analysing the type of information called, differences also appeared according to the time of the day. For example, the consultation of trend pages was higher at night than in the other shifts. The operators would adopt different supervisory behavior during day and night shifts, looking for various types of information displayed. These strategies of supervision could suggest that modes of information processing would depend on circadian variations.

Relevance to industry: Analysis of controllers' supervisory activity in genuine working conditions and real time will help to assess the adaptation of work tools to the cognitive demands. It can also lead to recommendations about work organization (work schedules, time of recovery, number of crews, etc.) and the design of human - computer interfaces.