Is cognitive performance impaired in pressure chamber situation?

The effect of air pressure on cognitive processing was studied in a pressur e chamber which simulated diving conditions. The pressure used corresponded to a depth of 50 meters, currently used in sport conditions. We hypothesis ed that cognitive slowing and consequently, erroneous processing would appe ar. The theoretical construct of Working Memory proposed by Baddeley (1992) was used to operationalise the experimental hypothesis. Three experimental situations were used to compare performance at depth of 0 and 50 meters. First, a simple reaction time experiment was performed : t he subjects had to press on a button as rapidly as possible in reaction to a signal appearing on a computer screen. In the second experimental situati on, the subject's digit memory span war calculated in order to measure the efficiency of the Articulatory Loop (a subcomponent of the Working Memory i n which speed of processing is highly involved); this measure involves the estimation of the longest series a subject can recall without error ill the correct order. In the third situation, two conditions of mental arithmetic were used. In both conditions, the subjects had to choose the,missing digi t in a series of arithmetic problems (multiplication and addition) appearin g on the screen [from 4 proposed solutions] (for example, problem : 6 + * = 15; solutions: 8 5 9 7). Two levels of difficulty were used : simple and c omplex problems differentiated by the number of digits. The results showed that air pressure had no effect on reaction time and onl y an effect of learning, ie. of automatisation of the task. Memory Span was significantly lower at 50 meters (6.75) than at 0 meter (7.58). Concerning the mental arithmetic, simple problems were solved more rapidly than compl ex and both were performed more rapidly at 0 than at 50 meters. More import antly, the number of errors teas larger at 50 than at 0 meters. Diving depth seems to influence processing speed, but only when the task do esn't imply automatic responses, rather controlled responses. Perturbation due to depth increases with the amount of control necessary : the consequen ces for sport diving are clearly important.