Publication Date


Document Type


Committee Members

John Flach (Advisor), Robert O'donnell (Committee Member), Tamera Schneider (Committee Member), Wayne Shebilske (Committee Member)

Degree Name

Doctor of Philosophy (PhD)


This study demonstrated that in a group of seventeen active duty soldiers, performance on an attack combat simulation significantly degraded after approximately 30 h of sleep deprivation. In addition, individual differences were identified, as approximately half of the participants maintained performance throughout the sleep deprivation period, while other participants degraded in performance. The main objective of this study was to test the efficacy of micro-level cognitive performance and subject state factors to account for this dichotomy in performance that was particular to the last testing session. Results showed that performance on a decision making test with rapid reaction time constraints was predictive of performance changes on the attack combat scenario. It was also found that individuals who were able to sustain performance made secondary task errors after 18 hours of continued wakefulness, suggesting a strategic change of task shedding, followed by a heightened sense of secondary task awareness. This study also demonstrated that stress appraisals did not significantly change under continued wakefulness, nor did stress appraisals explain performance differences. It was also found that individuals who were capable of maintaining performance exhibited an increase in levels of anxiety over the continued wakefulness period. This finding can be explained in the context of the inverted-U hypothesis, which states that performance inhibiting stressors such as continued wakefulness will lead to less arousal and poorer performance while performance facilitation will occur under additional stressors that increase arousal, such as anxiety. It is concluded that the ability to manage increases in task demands involves making adjustments to subject state variables. Further studies should investigate personality factors that predict this ability. The present study suggests that self-regulation properties are operating for individuals who are able to sustain performance under fatigue.

Page Count


Department or Program

Department of Psychology

Year Degree Awarded