The Independence and Interdependence of Coacting Observers in Regard to Performance Efficiency, Workload, and Stress in a Vigilance Task

Gregory J. Funke, Joel S. Warm, Carryl L. Baldwin, Andre Garcia, Matthew E. Funke, Michael B. Dillard, Victor S. Finomore, Gerald Matthews, Eric T. Greenlee

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Objective We investigated performance, workload, and stress in groups of paired observers who performed a vigilance task in a coactive (independent) manner. Background Previous studies have demonstrated that groups of coactive observers detect more signals in a vigilance task than observers working alone. Therefore, the use of such groups might be effective in enhancing signal detection in operational situations. However, concern over appearing less competent than one's cohort might induce elevated levels of workload and stress in coactive group members and thereby undermine group performance benefits. Accordingly, we performed the initial experiment comparing workload and stress in observers who performed a vigilance task coactively with those of observers who performed the vigilance task alone. Method Observers monitored a video display for collision flight paths in a simulated unmanned aerial vehicle control task. Self-reports of workload and stress were secured via the NASA-Task Load Index and the Dundee Stress State Questionnaire, respectively. Results Groups of coactive observers detected significantly more signals than did single observers. Coacting observers did not differ significantly from those operating by themselves in terms of workload but did in regard to stress; posttask distress was significantly lower for coacting than for single observers. Conclusion Performing a visual vigilance task in a coactive manner with another observer does not elevate workload above that of observers working alone and serves to attenuate the stress associated with vigilance task performance. Application The use of coacting observers could be an effective vehicle for enhancing performance efficiency in operational vigilance.

Original languageEnglish
Pages (from-to)915-926
Number of pages12
JournalHuman Factors
Issue number6
StatePublished - Sep 1 2016


  • coacting groups
  • evaluation apprehension
  • multiobserver independence/dependence
  • stress
  • vigilance
  • workload


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