Distortion of prospective time perception underwater

Background: The few prior studies of time perception underwater have reached contradictory conclusions as to how, and if, time perception becomes distorted when submerged. The current paper expands upon this limited data by describing two studies of prospective time production in scuba divers. Methods: Study 1 (n=32)compared performance, on a 30 second (s) interval time production task, in deep water (35m-42m) with a shallow water control (3-12m). Using the same task, study 2 (n=31)tested performance at the surface and at a range of depths underwater (1m; 11m; 20m; 30m; 40m). Results: Study 1 revealed time production to be significantly longer in deep water compared to shallow water. In study 2 time production at the surface was not significantly different from that at 1m but productions at 11m-40m were significantly longer than at both 1m and on the surface. Time productions between 11m-40m did not differ significantly. Discussion: It was concluded that divers judge less time to have passed underwater than is objectively the case from a depth of 11m but that this effect does not deteriorate significantly once past 11m. This distortion of time perception underwater was attributed to the action of narcosis.