A series of studies of eight acted emotions compared acoustical measurements, respondents' identifications, and vocal ratings. Predictions were made as to which of these three approaches would be most accurate in differentiating between emotions within a pair. Emotion pairs were classified as logically similar and/or perceptibly similar. Logically similar emotion pairs (such as sadness/depression or anger/hate) were better distinguished by vocal/acoustic analysis. Perceptibly similar but logically dissimilar emotions (such as anger, fear, and joy) were better distinguished by respondents' identifications. Multivariate statistics were used to compare the respondents' identification space, and vocal rating space, and the acoustical measurement space.