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

Abstract

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.

State anxiety and cortisol reactivity to skydiving in novice versus experienced skydivers

“…Interestingly, these authors noted a number of cases in which very experienced skydivers suffered fatal skydiving related accidents due to apparent cognitive failures associated with a lack of engagement with emergency recovery procedures. Further, in their study, Leach and Griffith [14] noted that the novice and experienced skydivers exhibited similar memory deficits (relative to a non-jump control condition) while in the plane, immediately prior to skydiving. Elevated cortisol has been associated previously with memory deficits [23], suggesting that elevated levels of cortisol may be a mechanism underpinning memory deficits in both novice and experienced skydivers.…”

“…Leach and Griffith [14] also failed to observe a difference in sympathetic arousal (heart rate) in response to skydiving between novice and experienced skydivers. Interestingly, these authors noted a number of cases in which very experienced skydivers suffered fatal skydiving related accidents due to apparent cognitive failures associated with a lack of engagement with emergency recovery procedures.…”

“…From this perspective, it would be expected that experienced skydivers, who have had greater exposure to skydiving and should therefore have greater levels of perceived control, would demonstrate reduced cortisol reactivity compared to novice or first time jumpers. Studies which have investigated this suggestion have typically focussed on reactivity of the SAM axis and observed post-jump increases in heart rate in both novice and experienced jumpers, but no differences between the groups [5,13,14]. Similarly, although experienced skydivers also demonstrate post-jump increases in cortisol [15], no studies to date have compared novice versus experienced skydivers in relation to reactivity of the HPA axis.…”

Memory and the operational witness: Police officer recall of firearms encounters as a function of active response role.

“…More recently in a study involving 861 soldiers in a similar survival training simulation, Morgan, Southwick, Steffian, Hazlett, and Loftus (2013) observed that memories for stressful events, like memories for more mundane events, are susceptible to misleading post-event information. Challenging field environments are also associated with significant impairment in selective and sustained attention (Leach & Ansell, 2008) and reduced working memory capacity (Leach & Griffith, 2008). Focusing on the performance of police officers in simulated operational settings, Hope et al (2012) examined the effects of physiological stress, as a function of exertion, on recall and recognition and found that police officers who had been exerted prior to and during encoding reported significantly fewer correct details about an encounter, and were significantly less likely than non-exerted officers to identify an encountered target individual.…”

Heart rate variability and critical flicker fusion frequency changes during and after parachute jumping in experienced skydivers

“…Hare et al (2013) showed recently that the anxiety state is higher before a skydive in novice, relative to experienced jumpers. Interestingly, studies which have investigated HR have observed increases in heart rate in both novice and experienced jumpers (Roth et al 1996;Allison et al 2012;Leach 2008) which suggests that the increase in HR in experienced jumpers is not solely induced by psychological stress. In particular, at 4000 m of height, skydivers are exposed to acute hypoxia which by itself is known to induce autonomic shifts in cardiovascular regulation by the Autonomic Nervous System (ANS) (Liu et al 2001;Chen et al 2008;Zhang et al 2014;Buchheit et al 2004).…”