Restrictions in working memory capacity during parachuting: a possible cause of ‘no pull’ fatalities

Working memory capacity of novice and experienced parachutists was compared under three conditions: prior to exiting the aircraft, on landing and during a control, non‐jumping day. Analysis of the operation span task revealed significant impairments in both storage and processing capacities of working memory prior to jumping. Storage capacity continued to be impaired in novice parachutists on landing whilst experienced parachutists showed full recovery. Neither group showed impairment in processing capacity on landing. Significant increases in heart rate were found for both groups in the jump and landing conditions compared to baseline but no differences existed between novices and experienced parachutists. Initial analyses support processing efficiency theory and suggest that cognitive processing may be slowing down during a jump. However, post hoc analysis of incorrect responses suggest that executive function may actually become disrupted. The results are reviewed in the context of ‘no pull’ parachuting fatalities. Copyright © 2007 John Wiley & Sons, Ltd.     

Combat Exposure and Risk for Suicidal Thoughts and Behaviors Among Military Personnel and Veterans: A Systematic Review and Meta‐Analysis

Due to seemingly mixed empirical results, questions persist about the possible role of deployments and combat exposure. We conducted a narrative review and meta‐analysis of 22 published studies to integrate findings regarding the relationship of deployment‐related predictors (i.e., deployment, deployment to a combat zone, combat experience, and exposure to specific combat events) with suicide‐related outcomes (i.e., suicide ideation, attempt, and death). Across all predictors and outcomes, the combined effect was small and positive, r = .08 [0.04, 0.13], and marked by significant heterogeneity, I² = 99.9%, Q(21)=4880.16, p < .0001, corresponding to a 25% increased risk for suicide‐related outcomes among those who have deployed. Studies examining the relationship between exposure to killing and atrocities (k = 5) showed the largest combined effect, r = .12 [0.08, 0.17], and less heterogeneity, I² = 84.4%, Q(4)=34.96, p < .0001, corresponding to a 43% increased risk for suicide‐related outcomes among those exposed to killing or atrocity. Implications for theory, research, and clinical practice are discussed.