Branka Zei-Pollermann 1

1 Vox Institute, , Geneva

This paper presents the results of research on vocal indicators of affective stance in hypnotherapy and medical interviews (128 seances of hypnosis and 26 pre-anesthesia interviews). Samples of the physicians’ voices were extracted on the basis of the semantic content of the interview (in hypnotherapeutic encounters before and during the induction of hypnosis, and in pre-anesthesia interviews during the examination of the patient and while talking about the risks of anesthesia. Vocal characteristics of affective stance considered appropriate for each of the topics were modeled, and a series of questionnaires was applied to assess the quality of communication, the efficiency of hypnotherapy. and emotional states of the patients. Acoustic analyses of doctor’s voices yielded a series of parameters related to F0, vocal energy and the rate of delivery. The statistical results show high levels of significance for a number of parameters thus confirming most of the predicted acoustic configurations for the different types of affective stances. For example: the speech rate and pitch variability were positively correlated to the success of hypnotherapy. A number of vocal characteristics were significantly related to various dimensions of the communication quality scale (RCS-O). The results showed the Trust dimension was negatively correlated with mean F0 (r = -.72; P<.01) and mean voiced energy (r = -.44; P<.05). According to our hypotheses, an affective stance described as reassuring and calming - appropriate for announcing the risks – is conceptually close to the Composure-dimension. The Pearson correlation coefficient between the Composure-dimension and mean F0 was highly significant  (r = -.73 with two tailed significance, P = .000). Mean F0 was also negatively correlated with the Intimacy-dimension  (r = -.57; P = .003). It then follows that when announcing the risks of anesthesia, lower levels of F0 seem to be more appropriate than higher ones.

In conclusion our results have confirmed most of our hypotheses regarding vocal correlates of affective stance in hypnotherapy and medical interviews. The findings appear to globally follow the pattern of vocal signalling of informative salience high vs. low, and higher vs. lower affective arousal.