This research reports the development of a semantic differential for rating nonverbal style of expressiveness in a population of expectant mothers. Mothers' nonverbal features (facial expression, gestures, voice quality) were emphasized as uniquely valid indices of emotional attitudes towards parenthood and as the principal forms of interpersonal stimulation to which infants would be exposed. In the final trimester of pregnancy, 46 primiparous mothers, representing a range of ages and ethnic and social class backgrounds, were interviewed on videotape, discussing childhood, marital adjustment, and expectations about parenthood. Interview selections were then presented to judges under three stimulus conditions: total videotape, videotrack, or audiotrack. Each mother's expressive style was rated on 12 bipolar adjective scales pertaining to affective tone, energy level, and involvement. Studies demonstrated the reliability of this instrument and procedure as well as the usefulness of nonverbal measures in descriptive and predictive analyses. (Author/RH)