Minimal cues in the vocal communication of affect: Judging emotions from content-masked speech

Vocal expressions of emotions taken from a recorded version of a play were content. masked by using electronic filtering, randomized splicing and a combination of both techniques in addition to a no-treatment condition in a 2×2 design. Untrained listener-judges rated the voice samples in the four conditions on 20 semantic differential scales. Irrespective of the severe reduction in the number and types of vocal cues in the masking conditions, the mean ratings of the judges in all four groups agreed on a level significantly beyond chance expectations on the differential position of the emotional expressions in a multidimensional space of emotional meaning. The results suggest that a minimal set of vocal cues consisting of pitch level and variation, amplitude level and variation, and rate of articulation may be sufficient to communicate the evaluation, potency, and activity dimensions of emotional meaning. Each of these dimensions may be associated with a specific pattern of vocal cues or cue combinations. No differential effects of the type of content-masking for specific emotions were found. Systematic effects of the masking techniques consisted in a lowering of the perceived activity level of the emotions in the case of electronic filtering, and more positive ratings on the evaluative dimension in the case of randomized splicing. Electronic filtering tended to decrease, randomized splicing tended to increase inter-rater reliability.