Affect Expression: Global and Local Control of Voice Source Parameters

This paper explores how the acoustic characteristics of the voice signal affect. It considers the proposition that the cueing of affect relies on variations in voice source parameters (includ-ing f 0 ) that involve both global, uniform shifts across an utterance, and local, within-utterance changes, at prosodically rele-vant points. To test this, a perception test was conducted with stimuli where modifications were made to voice source parameters of a synthesised baseline utterance, to target angry and sad renditions. The baseline utterance was generated with the ABAIR Irish TTS system, for one male and one female voice. The voice parameter manipulations drew on earlier production and perception experiments, and involved three stimulus series: those with global, local and a combination of global and local adjustments. 65 listeners judged the stimuli as one of the fol-lowing: angry, interested, no emotion, relaxed and sad , and in-dicated how strongly any affect was perceived. Results broadly support the initial proposition, in that the most effective signalling of both angry and sad affect tended to involve those stimuli which combined global and local adjustments. However, results for stimuli targeting angry were often judged as interested , in-dicating that the negative valence is not consistently cued by the manipulations in these stimuli.