The actors' voices have a strong emotional impact on the audience. Actors were not born with this ability but acquired it through persistent practice of many breathing techniques and voice projection exercises. Some scientific studies from recent years have shown that emotions, and especially the intense ones, are automatically impregnated in the speaker's voice, and through it are transmitted to the public, especially if the speaker has developed certain skills of verbal expression. However, the neural mechanisms that underlie these phenomena have not been fully elucidated until now, although research in this field has gained an increasing scope in recent years.
This study presents a scientific experiment that explored the relationship between the intensity of emotions conveyed through voice, the way of using the resonant cavities on the vocal tract route and the spectral composition of the voice. In this study, a group of actors were monitored for 30 days as they practiced breathing techniques to control their resonant cavities in order to amplify the emotional impact of their voices. During the training period the actors were audio recorded daily while performing the same text and loading it with the same emotion. Additionally, on the first and last day of training, the actors were each given an MRI (of the brain) while performing the respective text.
In this study the actors practiced the same breathing techniques for using all the resonant cavities until they felt that their voices conveyed those emotions with great power. The audio recordings from the first and last day were analyzed with human raters and AI algorithms and the intensity of emotion conveyed by their voices was estimated on a scale of 1 to 5. In parallel, specialized equipment and software packages were used to measure the spectral composition of these recordings. All the results obtained, those from the human evaluators and those from the AI algorithms, indicated an increase in the intensity of the emotions conveyed by the actors' voices at the end of the training, when they used their resonant cavities to the maximum. In addition, the spectrum analyzers showed that the recordings at the end of the training had a wider and denser spectral composition than that of the first day. The MRI results also showed that the areas of the brain responsible for transmitting emotions through voice were more oxygenated on the last day of training. This study thus shows that the mechanisms of emotion transmission through the voice are based on its spectral composition. The denser the spectral composition of the voice, the greater the intensity of the transmitted emotions, and to achieve this, the breathing techniques practiced by actors can be used.