Investigating the phonetic expression of successful motivation

Abstract

Object of study: Motivation is an essential concept for manifold domains. Whenever a person is confronted with an inconvenient, but necessary task, a stimulation of the person’s inherent motives can ensure its successful performance. As communication is one of the most intuitive ways to create a motivating stimulation, its effect should be noticeable in everyday human-human interaction, but also in more specific domains such as training, teaching or nursing care. So far, the motivational patterns in speech have not been studied intensively. Research progress exists on the rhetoric structure of convincing speeches [1] and on the phonetic expression of related concepts such as charisma [2], persuasion [3] and volition [4], but it is so far unclear if and how these results can be extended to the expression of motivation likewise. Methodology: The present study provides a comprehensive acoustic phonetic analysis of motivational speech. We collected, annotated and processed 50 minutes of speech data representing less and more successful degrees of motivation. Based on these, we identified and analyzed a set of phonetic features potentially relevant for motivational impact. The data consists of the audio extracted from 6 motivational YouTube videos, each presented by a different female speaker aged between 16 and 30 years. The aim of these videos is to motivate their audience to engage in sports and to be on a healthy diet. While presenters’ age and gender, video topic and structure as well as upload date are fairly constant, the videos differ in their online ratings. We used online ratings as an indicator to differentiate between more and less successful motivation. This leaves us with 3 videos of less successful (15 minutes), and 3 videos of more successful motivation (35 minutes). The data were force-aligned both on a phone and syllable level, and corrected manually. Interpausal units are used as a measure of utterance segmentation. We hypothesized that the following phonetic features differ significantly between less and more successful levels of motivation, and analyzed them within interpausal units using Praat scripts: • Pitch: mean, median, range (log Hertz) and coefficient of variation • Intensity: mean, median, range (dB) and coefficient of variation • Speaking rate (syllables/second) Results and conclusions: A comparison of the parameter distributions of two speakers with different levels of motivation indicates that highly motivational speech is faster, but less variable in terms of tempo. Also, highly motivational speech seems to be characterized by a higher pitch median, a higher pitch range and a more variable pitch in terms of coefficient of variation. Regarding intensity, we observe an overall louder articulation and a less variable pattern for intensity range, which is also supported by findings from the coefficient of variation. In sum, motivational speech appears to behave similarly to charismatic speech, but somewhat more balanced, i.e. more homogeneous, in terms of tempo and intensity variation. We plan to augment this characterization by investigating and comparing the prosodic patterns of individual speakers.