Are Affective Speakers Effective Speakers? – Exploring the Link Between the Vocal Expression of Positive Emotions and Communicative Effectiveness

This thesis explores the effect of vocal affect expression on communicative effectiveness. Two studies examined whether positive speaker affect facilitates the encoding and decoding of the message, combining methods from Phonetics and Psychology. The first study explored the relationship between perceived affective state and communicative effectiveness. To obtain a range of naturally occurring variation in affect, 200 speakers were asked to report their emotional state using the Brief Mood Introspection Scale after providing speech samples elicited in a Map Task paradigm in which speakers described a predefined route. In addition, one group of listeners (N=80) listened to a sentence with identical verbal content across speakers to rate how happy the speaker sounded; another group of listeners (N=600) was asked to draw the route on a map with just the landmarks while listening to the recorded descriptions. A measure of description quality in terms of linguistic content was obtained, as well a measure of listener comprehension in form of a route deviation estimate. The results showed that perceived happiness, which was, interestingly, not correlated with self-reported happiness, contributed to listener comprehension over and above linguistic content. The happier speakers sounded the better listeners followed their descriptions, independently of verbal content. Perceived happiness was associated with faster speech rate, higher F0 and F1, wider F0 range and lower values for jitter. Path analyses showed that vocal correlates of positive affect influence communicative effectiveness in two ways: directly, by increasing perceptual salience (e.g., a raise in F1 can be associated