| Nonlinear Dynamics, Psychology, and Life Sciences, Vol. 19, Iss. 2, Apr, 2015, pp. 173-200 @2015 Society for Chaos Theory in Psychology & Life Sciences Catastrophe Models for Cognitive Workload and Fatigue in N-Back Tasks Abstract: N-back tasks place a heavy load on working memory, and thus make
good candidates for studying cognitive workload and fatigue (CWLF). This
study extended previous work on CWLF which separated the two phenomena with
two cusp catastrophe models. Participants were 113 undergraduates who
completed 2-back and 3-back tasks with both auditory and visual stimuli simultaneously.
Task data were complemented by several measures hypothesized to be related to
cognitive elasticity and compensatory abilities and the NASA TLX ratings of
subjective workload. The adjusted R2 was .980 for the workload model, which
indicated a highly accurate prediction with six bifurcation (elasticity versus rigidity)
effects: algebra flexibility, TLX performance, effort, and frustration; and
psychosocial measures of inflexibility and monitoring. There were also
two cognitive load effects (asymmetry): 2 vs. 3-back and TLX temporal demands.
The adjusted R2 was .454 for the fatigue model, which contained two bifurcation variables
indicating the amount of work done, and algebra flexibility as the
compensatory ability variable. Both cusp models were stronger than the
next best linear alternative model. The study makes an important step forward by
uncovering an apparently complete model for workload, finding the role of
subjective workload in the context of performance dynamics, and finding CWLF dynamics
in yet another type of memory-intensive task. The results were also consistent with
the developing notion that performance deficits induced by workload and deficits
induced by fatigue result from the impact of the task on the workspace and
executive functions of working memory respectively. Keywords: working memory, cognitive workload, fatigue, catastrophe |