Study of Sensory Deprivation, Pain and Personality Relationships for Space Travel.

p , ROLONGED SPACE travel by man may require severe social restrictions, and stringent conditions of sensory and perceptual impoverishment. These conditions of space travel are similar to phenomena generally investigated in studies of sensory deprivation. Studies in sensory deprivation have indicated many detrimental effects in performance due to impoverished sensory environment. 23, 25 It has often been reported that subjects in such studies experienced perceptual aberrations,Z, 6, r, 22, 27 increased anxiety and feelings of insecurity.S, 25 Performance on objective tests under reduced sensory input conditions has been found to be significantly reduced as compared to performance under higher level of sensory ir~put. 12 It has been observed that motor coordination and the precision of motor performance is impaired3 r Given the information in the literature on the effects of sensory deprivation on performance, it appeared desirable to find ways to avoid degradation in performance so far as space travel was concerned without material change in design of spacecraft. Accordingly, it was hypothesized that the ~bility to withstand conditions of sensory deprivation might be a normally distributed characteristic similar in its distribution to other human characteristics. A number of studies provided evidence for such a point of view, since it was reported that some subjects "hallucinated" and developed emotional reactions within a few hours after being placed in impoverished perceptual conditions, while others, under the same conditions, experienced few or no incidents of imagery. 1 Another hypothesis advanced by Petrie 26. el seemed attractive, namely, that sensitivity to pain is negatively correlated to sensory deprivation sensitivity and positively correlated to certain personality variables. This line of reasoning led to an hypothesis as to the nature of the problem and its solution ~or space travel: Since there appears to be an inverse relationship between sensitivity to pain, personality and performance under reduced sensory input conditions, men ought to be selected who are most sensitive to pain because they would be able to endure reduced sensory input conditions for a long time without degradation in performanee; while conversely, those who could stand pain for a long time could not endure reduced sensory input conditions and would show abnormal performance.