Pain is a complex, ubiquitous phenomenon that can be debilitating and costly. Although it is well known that some individuals can easily tolerate pain while others are more intolerant to pain, little is known of the neurophysiological bases of these differences. Because differences in sensory information processing may underlie variability in tolerance to pain and because measures of sensory gating are used to explore differences in sensory information processing, sensory gating among college students (N = 14) who are tolerant or intolerant to pain was investigated. This investigation explored the hypothesis that those who were more tolerant to pain would evidence greater sensory gating. Pain tolerance was first determined using a cold pressor task. Sensory gating was then determined by the amount of attenuation of the amplitude of a second painful, electrical, somatosensory stimulus (S2) in relation to the amplitude of an identical first stimulus (S1) in a paired-stimulus evoked potential (EP ) paradigm. The results obtained showed the intolerant group exhibiting greater physiological reactivity than the tolerant group, indicating that the tolerant group attained greater sensory gating than the intolerant group. / Ph. D.