Forty-eight Ss were requested to discriminate spontaneous changes of at least 0.1 degree C in their peripheral finger temperature (PFT). They were randomly assigned to one of 3 groups: in the first group ("KR") Ss were given a feedback after each discrimination; in the second group ("NKR") Ss were given no feedback after each discrimination; in the third group ("RKR") Ss were given a random feedback after each discrimination. Results indicated that in the "Knowledge-of-Results" group discrimination was significantly higher than in both "No-Knowledge-of-Results" and "Random-Knowledge-of-Results" groups. Within the first group, there was a significant difference in a discrimination index between Ss "aware" and Ss "unaware" of their PFT changes, which remained significant even when the effects of individual variability of PFT and of the regularity of PFT changes were partialled out.