Effects of acute hypoxic exposure on multiple-object tracking ability of flight trainees

Introduction: Acute hypoxic exposure can threaten flight safety by impairing the cognitive function of civil aviation pilots. This study aimed to investigate the effects of acute moderate hypoxia on pilots' dynamic visual attention using a multiple-object tracking (MOT) paradigm. Methods: Twenty-nine male flight trainees were recruited to perform the MOT task while exposed to a simulated hypoxic environment. Their reaction time and accuracy in each trial were recorded. Results: When tracking four target disks, participants' accuracy was significantly lower under hypoxic conditions compared with normoxic conditions. Meanwhile, when tracking six targets, their reaction times significantly shortened. Discussion: The results indicate that hypoxia can lower the upper limit of multiple-object tracking capacity from four objects to three. Hypoxia appears to shift the speed-accuracy trade-off toward faster responses at the expense of accuracy. First-click response indicates that flight trainees with better tracking skills tended to display faster and more accurate first-click responses. The negative impact of hypoxia on participants varies between individuals and is more pronounced when tracking a larger number of objects. These findings provide a theoretical basis for improving the selection and hypoxic training of pilots flying at high altitude and for optimizing cockpit human-machine interaction interfaces.