EFFECTS OF COGNITIVE WORKLOAD ON DECISION ACCURACY, SHOOTING PERFORMANCE, AND CORTICAL ACTIVITY OF SOLDIERS

The purpose of this research was to investigate dynamic cortical processes of soldiers during simulated shooting scenarios as a function of task demand. Task demand was varied among three two-level factors: task load (single, dual), decision load (no-decision, decision), and target exposure time (short, long). Dependent variables were measured at subjective, behavioral, and physiological levels. Subjective measures were self-reports of workload and stress, behavioral measures were primary and secondary task performance, and physiological measures were event-related spectral perturbation (ERSP, where event-related refers to target onset times) in theta (4-7 Hz) and alpha (11-13 Hz) frequency bands. Results from analyses of the subjective report data revealed that time stress and decision load main effects significantly influenced workload perceptions. Analyses of the shooting performance data revealed that the time stress main effect was significant for decision accuracy, shooting accuracy, and response time, and analyses of secondary task performance data revealed a time stress main effect for arithmetic accuracy. The interaction between time stress and decision load was also significant for shooting accuracy and arithmetic accuracy. Results from analyses of the ERSP data revealed that peak theta power differed as a function of time stress and peak alpha power differed as a function of task load and decision load. Overall, the results suggest that time stress had the most profound and widespread effects on workload perceptions and performance. Cortical responses exhibited different oscillatory patterns of communication at different frequencies and topographic regions in response to the different task demand factors.