title: Viewing the workload of vigilance through the lenses of the NASA-TLX and the MRQ.
abstract: OBJECTIVE
  The aim of this study was to compare the effectiveness of a new index of perceived mental workload, the Multiple Resource Questionnaire (MRQ), with the standard measure of workload used in the study of vigilance, the NASA Task Load Index (NASA-TLX).
  
  
  BACKGROUND
  The NASA-TLX has been used extensively to demonstrate that vigilance tasks impose a high level of workload on observers. However, this instrument does not specify the information-processing resources needed for task performance. The MRQ offers a tool to measure the workload associated with vigilance assignments in which such resources can be identified.
  
  
  METHODS
  Two experiments were performed in which factors known to influence task demand were varied. Included were the detection of stimulus presence or absence, detecting critical signals by means of successive-type (absolute judgment) and simultaneous-type (comparative judgment) discriminations, and operating under multitask vs. single-task conditions.
  
  
  RESULTS
  The MRQ paralleled the NASA-TLX in showing that vigilance tasks generally induce high levels of workload and that workload scores are greater in detecting stimulus absence than presence and in making successive as compared to simultaneous-type discriminations. Additionally, the MRQ was more effective than the NASA-TLX in reflecting higher workload in the context of multitask than in single-task conditions. The resource profiles obtained with MRQ fit well with the nature of the vigilance tasks employed, testifying to the scale's content validity.
  
  
  CONCLUSIONS
  The MRQ may be a meaningful addition to the NASA-TLX for measuring the workload of vigilance assignments.
  
  
  CONCLUSIONS
  By uncovering knowledge representation associated with different tasks, the MRQ may aid in designing operational vigilance displays.
authors.forename: Victor S
authors.initials: VS
authors.lastname: Finomore
authors.forename: Tyler H
authors.initials: TH
authors.lastname: Shaw
authors.forename: Joel S
authors.initials: JS
authors.lastname: Warm
authors.forename: Gerald
authors.initials: G
authors.lastname: Matthews
authors.forename: David B
authors.initials: DB
authors.lastname: Boles
mesh_terms: D000293:Adolescent; D000328:Adult; D001288:Attention / Q000502:physiology*; D005260:Female; D006801:Humans; D007600:Judgment; D008297:Male; D010465:Perception; D011237:Predictive Value of Tests; D011795:Surveys and Questionnaires; D013647:Task Performance and Analysis; D016526:Workload / Q000523:psychology*; D055815:Young Adult