Many graduate students fear public speaking, yet for many of us it is a pervasive aspect of graduate life. Standing in front of a group of people, whether for an in-class presentation, at a weekly department lunch, or to lead tutorials and lectures, can be frightening. Though we may be confident in our knowledge of the material, often this confidence fades when we are confronted by the faces of our audience. Thankfully, science has come to our rescue, armed with empirical research that suggests ways in which we can convey confidence to our audience through our voices, even when that confidence may be lacking. Qualities of voice have been shown to influence perceptions of speaker confidence, and vocal confidence exerts persuasive power. This information has practical applications to the many domains of graduate life that involve public speaking, both in the classroom and beyond.
What Do We Know About Vocal Confidence?
Psychological scientists have long recognized that people’s voices convey a rich variety of information beyond the mere content of what they are saying. However, very little attention has been given to how the characteristics of a speaker’s voice affect the success she has in persuading others. This is particularly surprising given the prevalence of oral communication in day-to-day interactions — and the fact that an extensive body of literature has accumulated demonstrating how vocal perception influences the communication process (e.g., Juslin & Scherer, 2005). One vocal feature that has been shown to play a key role in delivering a successful persuasive appeal is the perceived confidence of the speaker. So what characteristics of voice reflect speaker confidence?
I began exploring this question during my first year of graduate studies after a rather excruciating experience in which I spoke in front of a room packed with both colleagues and professors, each of whom was in the process of forming their initial impressions of me as an academic. Had my delivery of the material reflected the level of confidence I had in my knowledge of it, the talk would have been a resounding success. Sadly, this was not the case. The realization that speaking in front of an audience would play an integral role in advancing my career as an academic led me to wonder how I could convey a sense of confidence to my audience even when I didn’t feel especially confident.
One answer to this question emerged when I was combing through literature on the variety of factors that influence our perceptions of others. I noticed that a number of studies had shown that perceptions of confidence reliably varied according to certain characteristics of a speaker’s voice. For example, several experiments have demonstrated that confident speakers typically communicate at a louder volume (Kimble & Seidel, 1991; Scherer, London, & Wolf, 1973), finish their sentences using falling intonation (Brennan & Williams, 1995; Smith & Clark, 1993), and communicate at an increased rate of speed relative to less confident speakers (Miller, Maruyama, Beaber, & Valone, 1976; Scherer, London, & Wolf, 1973).
How Does Vocal Confidence Influence Persuasion?
In thinking of how I might apply this research to what has become a very routine component of my academic life, I needed to understand how these different qualities of voice actually reflect speaker confidence. Coming from a rich academic lineage firmly rooted in the explanatory power of the Elaboration Likelihood Model (ELM; Petty & Cacioppo, 1986), I turned to this proven theoretical framework to guide my research. So what does the ELM have to say about vocal confidence?
According to the ELM, when people are able and motivated to carefully consider the merits of an argument, a variable (e.g., perceptions of speaker confidence) can bias their processing of a message to be either more or less favorable. On the other hand, when people are not able or motivated to think carefully (e.g., because they are texting a friend rather than listening to your presentation), the ELM suggests they should attend more to very simple cues in the environment (e.g., whether or not you sound confident) to guide them in reacting to the message.
Having investigated vocal confidence in considerable depth, I suggest that when people are able to devote cognitive resources toward processing a message, they use their assessment of a speaker’s level of vocal confidence to determine the positivity or negativity of their thoughts. In turn, their thoughts influence their attitude toward the message. However, when people are distracted, perceptions of speaker confidence do not influence the favorability of their thoughts. Instead, they use their perception of speaker confidence as a cue from which to directly infer their attitude toward the message (Guyer & Fabrigar, 2015). I had the pleasure of presenting my findings on this question at the 2015 APS Annual Convention.
How Can We Apply This Knowledge?
While vocal confidence is by no means a magic bullet guaranteeing that you — or your material — will be well received, it certainly can increase the likelihood that your audience will view you and what you have to say in a favorable light. Nevertheless, there is no substitute for hard work. As fellow graduate students, you are all too familiar with the amount of time, effort, and commitment required to succeed in our highly competitive field. Being self-aware rather than self-conscious is key. Rehearse your material out loud. Take note of where both the pitch and intonation in your voice rise and fall. Unless you are posing a question to your audience, your intonation should fall at the end of a sentence. When anxious, we naturally tend to raise the pitch of our voice. Rehearsing out loud will help you stay calm so that you speak at your natural baseline. Finally, be mindful of the speed at which you speak. While short pauses can be used to great effect, research overwhelmingly shows that fast talkers are perceived as more confident and are more persuasive than those who speak slowly.
What I find most fascinating about this emerging topic is the enormous potential to bridge research conducted predominantly for theoretical or conceptual reasons with its practical application in real-life situations. For example, consider how understanding vocal properties might increase the effectiveness of sales pitches. Clearly those in politics, education, health care, and business could benefit from communication training. More broadly, the widespread fear of public speaking could be mitigated by teaching people how to convey information in a confident manner and thus enhance its impact on their audiences. From both a practical and a theoretical standpoint, this emerging line of research holds great promise for advancing our understanding and application of perhaps the most empirically overlooked aspect of communication: the voice.
References and Further Reading
Brennan, S. E., & Williams, M. (1995). The feeling of another’s knowing: Prosody and filled pauses as cues to listeners about the metacognitive states of speakers. Journal of Memory and Language, 34, 383–398.
Guyer, J. J., & Fabrigar, L. R. (2015, May). Investigating the multiple roles of vocal confidence in attitude change. Poster presented at the annual convention of the Association for Psychological Science, New York, NY.
Juslin, P. N., & Scherer, K. R. (2005). Vocal expression of affect. In J. Harrigan, R. Rosenthal, & K. R. Scherer (Eds.), The new handbook of methods in nonverbal behavior research. (pp. 65–135). New York, NY: Oxford University Press.
Kimble, C. E., & Seidel, S. D. (1991). Vocal signs of confidence. Journal of Nonverbal Behavior, 15, 99–105.
Miller, N., Maruyama, G., Beaber, R. J., & Valone, K. (1976). Speed of speech and persuasion. Journal of Personality and Social Psychology, 34, 615–624.
Petty, R. E., & Cacioppo, J. T. (1986). Communication and persuasion: Central and peripheral routes to attitude change. New York, NY: Springer-Verlag.
Scherer, K. R., London, H., & Wolf, J. J. (1973). The voice of confidence: Paralinguistic cues and audience evaluation. Journal of Research in Personality, 7, 31–44.
Smith, V. L., & Clark, H. H. (1993). On the course of answering questions. Journal of Memory and Language, 32, 25–38.
Smith, S. M., & Shaffer, D. R. (1995). Speed of speech and persuasion: Evidence for multiple effects. Personality and Social Psychology Bulletin, 21, 1051–1060.