Conducted 2 experiments with a total of 77 undergraduates which required them to "smile" and "frown" without awareness of the nature of their expressions. Ss reported feeling more angry when frowning and more happy when smiling. Ss also reported that cartoons viewed while they were smiling were more humorous than cartoons viewed while they were frowning. Results are interpreted as indicating that an individual's expressive behavior mediates the quality of his emotional experience. (19 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).