Subjects who were placed in darkness for a week but who were otherwise exposed to a normal and varied sensory environment showed an increase in tactual acuity and in sensitivity to heat and pain. This cutaneous supersensitivity was still present several days after the termination of visual deprivation.

Changes in cutaneous sensitivity after prolonged exposure to unpatterned light! Ab8tract Ss who were exposed to diffuse, homogeneous illumination for a week showed an increase in tactual acuity and in sensitivity to heat and pain. This cutaneous supersensitivity, however, was not as pronounced as that occurring after a week of darkness. Problem Of the various behavioral effects produced by prolonged exposure to sensory and perceptual deprivation, Qne of the most perplexing is an increase in pain sensitivity (Vernon & McGill, 1961) and in tactual acuity as measured by both a two-point threshold (Doane et al., 1959) and a tactual fusion method (Zubek, 1964). Recently, Zubek et al. (1964) demonstrated that anoverall reduction in the level of visual, auditory, tactualproprioceptive, and social stimulation is not essential for the appearance of this cutaneous supersensitivity. It can occur following visual deprivation alone. In this study, the Ss, who were exposed to a week of darkness, showed a pronounced increase in tactual acuity and in sensitivity to heat and pain. This effect of visual deprivation was uniform. It was shown by all experimental Ss, on all skin areas, and on all cutaneous measures. Furthermore, the effects were still present several days after the termination of darkness. The purpose of the present study is to determine whether similar effects will result from prolonged exposure to diffuse, homogeneous illumination. If this should occur, it will suggest that these cutaneous effects have resulted from an absence of pattern vision rather than an absence of visual stimulation per se.