Two studies were reported which attempted to estimate the stability and construct validity of human salivary response as a measure of individual differences (IDs) in physiological arousal. Twenty-second base line estimates and 20-second response levels to four drops of lemon juice were measured, with the former value being removed from the latter to form the salivary score for a given subject. The first study obtained a test-retest correlation over 24 hours for the net salivation score of 0.78 (N = 25; p<.001). The second study involved the measurement of the threshold of fusion of paired light flashes [two-flash threshold (TFT)], a previously validated index of arousal, as well as salivation. The correlation between net salivation and TFT on 25 subjects was -.57 (p<.01). It was concluded that the salivary measure has demonstrated promising psychometric properties for use in ID research. (Author)