Two experiments examined the effects of facial expressions of emotion as conditioned stimuli (CSs) on human electrodermal conditioning and on a continuous measure of expectancy of the shock unconditioned stimulus. In Experiment 1, the CS+ was a picture of a person displaying an angry face and CS- was a neutral face. For half of the subjects, the expressions were depicted by males, for the other half by females. Male subjects showed larger skin conductance responses to pictures of males than did females. The responding of female subjects was the same regardless of the sex of the person in the picture. In Experiment 2, the CS+ and CS- were pictures of an angry or a happy face. For half of the subjects, the expressions were depicted by adult males, for the other half by preadolescent males. Subjects displayed greater differentiation when an adult male depicting anger was employed as the CS+ than when a preadolescent male depicting anger was the CS+. There were no differences when an adult or a child displayed happiness.