Cusp Catastrophe Models for Cognitive Workload and Fatigue in a Verbally Cued Pictorial Memory Task

Objective: The aim of this study was to evaluate two cusp catastrophe models for cognitive workload and fatigue. They share similar cubic polynomial structures but derive from different underlying processes and contain variables that contribute to flexibility with respect to load and the ability to compensate for fatigue. Background: Cognitive workload and fatigue both have a negative impact on performance and have been difficult to separate. Extended time on task can produce fatigue, but it can also produce a positive effect from learning or automaticity. Method: In this two-part experiment, 129 undergraduates performed tasks involving spelling, arithmetic, memory, and visual search. Results: The fatigue cusp for the central memory task was supported with the quantity of work performed and performance on an episodic memory task acting as the control parameters. There was a strong linear effect, however. The load manipulations for the central task were competition with another participant for rewards, incentive conditions, and time pressure. Results supported the workload cusp in which trait anxiety and the incentive manipulation acted as the control parameters. Conclusion: The cusps are generally better than linear models for analyzing workload and fatigue phenomena; practice effects can override fatigue. Future research should investigate multitasking and task sequencing issues, physical-cognitive task combinations, and a broader range of variables that contribute to flexibility with respect to load or compensate for fatigue. Applications: The new experimental medium and analytic strategy can be generalized to virtually any realworld cognitively demanding tasks. The particular results are generalizable to tasks involving visual search

Catastrophe Models for Cognitive Workload and Fatigue in a Vigilance Dual Task

Objective: This study investigated two cusp catastrophe models for cognitive workload and fatigue for a vigilance dual task, the role of emotional intelligence and frustration in the performance dynamics, and the dynamics for individuals and teams of two participants. Background: The effects of workload, fatigue, practice, and time on a specific task can be separated with the two models and an appropriate experimental design. Group dynamics add further complications to the understanding of workload and fatigue effects for teams. Method: In this experiment, 141 undergraduates responded to target stimuli that appeared on a simulated security camera display at three rates of speed while completing a jigsaw puzzle. Participants worked alone or in pairs and completed additional measurements prior to or after the main tasks. Results: The workload cusp verified the expected effects of speed and frustration on change in performance. The fatigue cusp showed that positive and negative changes in performance were greater if more work on the secondary task was completed and whether the participants who started with the fast vigilance condition demonstrated less fatigue. Conclusion: The results supported the efficacy of the cusp models and suggested, furthermore, that training modules that varied speed of presentation could buffer the effects of fatigue. Application: The cusp models can be used to analyze virtually any cognitively demanding task set. The particular results generalize to vigilance tasks, although a wider range of conditions within vigilance tasks needs to be investigated further