Catastrophe models for cognitive workload and fatigue in N-back tasks.

Area of Science:

• Cognitive Psychology
• Human Factors Engineering
• Neuroscience

Background:

• N-back tasks are effective for studying cognitive workload and fatigue (CWLF) due to their high working memory demands.
• Previous research separated workload and fatigue phenomena using cusp catastrophe models.

Purpose of the Study:

• To extend previous work on CWLF by applying cusp catastrophe models to N-back tasks.
• To investigate the dynamics of cognitive workload and fatigue in a memory-intensive task.
• To explore the relationship between subjective workload, cognitive elasticity, and compensatory abilities.

Main Methods:

• 113 undergraduates completed 2-back and 3-back tasks with simultaneous auditory and visual stimuli.
• Data included task performance, measures of cognitive elasticity, compensatory abilities, and NASA TLX subjective workload ratings.
• Two cusp catastrophe models were developed for workload and fatigue.

Main Results:

• The workload model achieved a high adjusted R2 of .980, identifying six bifurcation effects (flexibility, TLX performance, effort, frustration, inflexibility, monitoring) and two cognitive load effects (task difficulty, temporal demands).
• The fatigue model had an adjusted R2 of .454, with two bifurcation variables (work done, algebra flexibility) as the compensatory ability.
• Both cusp models demonstrated superior predictive power compared to linear models.

Conclusions:

• This study presents a comprehensive model for workload dynamics and highlights the role of subjective workload in performance.
• The findings reveal CWLF dynamics in a memory-intensive task, differentiating workload impacts on the workspace and fatigue impacts on executive functions.
• The results support the notion that workload and fatigue deficits stem from distinct cognitive mechanisms within working memory.