1. Queen’s University, Kingston, Ontario, Canada
The Effects of Vocal Intonation on Perceptions of Speaker Confidence and Attitudes
Joshua J. Guyer, Leandre R. Fabrigar, Thomas Vaughan-Johnston & Nicole Seligman
Queen’s University, Kingston, Ontario, Canada
1. Abstract
4. Method
6. Results & Discussion
Participants (N = 306) listened to an audio recording that proposed strong or weak arguments in favor of working for the university in exchange for a reduction in tuition. Next, participants were asked to provide ratings of the speaker along a variety of dimensions, including speaker confidence. Participants then indicated their attitude towards the proposed tuition-reduction program. Finally, participants listed up to 10 thoughts they had while listening to the recording and rated the favorability of those thoughts. We employed a 5(Vocal intonation: strongly falling, vs. moderately falling, vs. baseline, vs. moderately rising, vs. strongly rising) x 2(Argument quality: strong vs. weak) between subjects factorial. Vocal intonation (i.e., rising or falling at the end of a sentence) was manipulated using digital audio software (PRAAT©) to ensure no properties of voice other than intonation were altered.
Manipulation checks revealed that vocal intonation and argument quality were successfully manipulated. Follow up tests using path analyses indicated that relative to the speaker’s natural baseline, when intonation rose sharply at the end of a sentence, this had a negative impact on ratings of speaker confidence. Decreased ratings of speaker confidence negatively biased thoughts towards the topic, which in turn led to less favorable attitudes. By contrast, when intonation moderately fell at the end of a sentence, this positively influenced ratings of speaker confidence. Increased ratings of speaker confidence positively biased thoughts, which led to more favorable attitudes. Taken together, under conditions that promote the increased scrutiny of a message, our data suggest that vocal intonation may have an asymmetrical effect of perceptions of speaker confidence. That is, whereas rising intonation negatively influenced perceptions of confidence only with relatively extreme exemplars, falling intonation positively influenced perceptions of confidence at only moderate levels. As expected, as perceptions of confidence increased, this positively biased thoughts which in turn led to more favorable attitudes.
Participants.
306 undergraduate psychology students participated in return for course credit
5(Vocal Intonation: strongly falling vs. moderately falling vs. baseline vs. moderately rising vs. strongly rising) x 2(Argument quality: strong vs. weak) between participants factorial.
After being seated at a computer, all participants were given headphones and instructed to listen to an audio passage that presented moderate arguments in favor of working for Queen’s university in exchange for a reduction in tuition. After listening to the audio recording, participants were asked to provide ratings of the speaker along a variety of dimensions, including vocal intonation and speaker confidence. The presentation order of these questions were randomized. Participants then completed a measure assessing their attitudes towards the topic. Finally, a cognitive response tasking was presented in which participants listed up to 10 thoughts about the topic and then rated the favorability of their thoughts.
All questions used 7-point rating scales.
Vocal Confidence Manipulation Check:
Confirming expectations, an ANOVA revealed a significant main effect of vocal intonation on ratings of speaker confidence, F(4, 296) = 8.45, p < .001, partial η2 = .10. Pairwise comparisons using the LSD test indicated that relative to the natural baseline of the speaker (M = 5.32, SE = .18), no difference in ratings of confidence emerged when intonation was moderately rising (M = 5.36, SE = .17), p = .86. However, when vocal intonation was strongly rising (M = 4.48, SE = .18), ratings of confidence were significantly reduced compared both with the natural baseline, p < .001, as well as with moderately rising intonation, p < .001.
Interestingly, an asymmetrical effect of vocal intonation on ratings of speaker confidence was found at the other end of the vocal intonation continuum. That is, relative to baseline, a significant increase in ratings of confidence emerged when intonation was moderately falling (M = 5.89, SE = .18), p = .02. However, no difference was found when intonation was strongly falling (M = 5.50, SE = .17) compared both with baseline, p = .45, and with moderately falling intonation, p = .12. These data reveal a pattern of effects that suggest changes in a speaker’s vocal intonation does not necessarily have a symmetrical effect on perceptions of speaker confidence, (see Figure 1).
Argument Quality Manipulation Check:
Confirming expectations, an ANOVA revealed a significant main effect of argument quality on attitudes, F(1, 296) = , p < .001, partial η2 = .37, such that strong arguments (M = 5.28, SE = .10), elicited significantly more favorable attitudes toward the university service plan compared with weak arguments (M = 3.34, SE = .10), (see Figure 2).
The Effects of Vocal Intonation on Attitude:
Results of an ANOVA indicated a significant main effect of vocal intonation on attitude, F(4, 296) = 2.51, p = .04, partial η2 = .03, (see Figure 3). Pairwise comparisons revealed no difference in attitude when comparing the speaker’s natural baseline (M = 4.52, SE = .17), with moderately rising intonation (M = 4.35, SE = .16), p = .47. However, relative to baseline, strongly rising intonation led to significantly less favorable attitudes (M = 3.88, SE = .18), p < .01. No differences emerged when comparing baseline with either moderately falling intonation (M = 4.52, SE = .17), p = .99, or strongly falling intonation (M = 4.28, SE = .16), p = .31. Not surprisingly, given that strongly raised intonation at the end of a sentence suggests a high degree of uncertainty, the data revealed that attitudes were significantly less favorable in response to a speaker with strongly rising intonation compared with moderately rising, p = .04, baseline, p < .01, moderately falling, p < .01, and at a marginally significantly level, strongly falling intonation, p < .09. No intonation x argument quality interaction was anticipated and none emerged, F(4, 296) = 1.51, p = .20, partial η2 = .02.
The Effects of Vocal Confidence on Attitude:
As anticipated, the data revealed vocal intonation had the expected effect on ratings of speaker confidence. Next, increased confidence should bias a person’s thoughts to be more positive towards the message. This is exactly what the data shows. Thoughts should have a powerful impact on a person’s attitude. Once again, the data confirms this is correct. The final path evaluates the direct effect of speaker confidence on attitudes. Because this is high elaboration situation, the ELM predicts speaker confidence should not have a direct impact on attitudes by functioning as a cue. Supporting the theory, this is precisely what we found. No direct effect of vocal intonation on attitude was predicted and none emerged, (see Figure 4). These results suggest that when carefully processing a message, speaker confidence biases the favorability of thoughts but does not impact attitudes by functioning as a peripheral cue.
Design.
Procedure.
Measures.
5. Results
Figure 1.
Figure 2.
2. Introduction
Although a great deal of research has looked at those variables that influence persuasion, one area that hasn’t received a lot of attention are the different properties of a speaker’s voice. This is somewhat surprising because so much of communication and of course persuasion takes place orally. We know that beyond the content of what we say, our voice also contains a rich variety of information, so intuitively it makes sense that how we say something should also play a role in how successful we are at persuading others. Now while there are certainly lots of characteristics of voice that matter, one characteristic that intuitively should affect the persuasion process is how confident the speaker is perceived to be.
For example, research has found that confident speakers talk louder (Kimble & Seidel, 1991; Scherer, London, & Wolf, 1973), finish their sentences using falling vs. raised intonation (Brennan & Williams, 1995; Smith & Clark, 1993), and speak faster (Miller, Maruyama, Beaber, & Valone, 1976; Scherer et al., 1973), relative to unconfident speakers. Although a small body of research has demonstrated that various qualities of voice are related to perceptions of speaker confidence, few studies have investigated the role of speaker confidence in the persuasion process. To date, empirical investigations of this relationship have focused only on a narrow spectrum of rate of speech (Miller, et al., 1976; Smith & Shaffer, 1995). For instance, Miller et al., (1976) demonstrated that a message spoken at a rapid rate of speech generated significantly more persuasion compared with a slower version of the same message. Later research by Smith and Shaffer (1995) qualified this finding with data suggesting an interaction between speech rate and argument quality.
Although a few studies have examined how rate of speech influences persuasion, research has yet to investigate how other properties of voice such as vocal intonation may influence the success of a persuasive appeal. Thus, our first goal was to determine how judgements of speaker confidence are influenced across a broader range of vocal intonation, and further, how these perceptions of confidence influence attitudes when people are carefully processing a message. Our predictions regarding how voice affects persuasion are drawn from the elaboration likelihood model.
Figure 3.
Figure 4.*
7. Future Directions
Investigating whether a broader spectrum of speech rate influences confidence and persuasion via similar mechanisms under high-thought conditions.
Investigating whether amount of processing is the mechanism responsible for the effects of speech rate and intonation on speaker confidence and attitudes under moderately thoughtful conditions.
3. Present Study
Goals: Test the effects of a broader range of vocal intonation on judgements of speaker confidence and attitude.
Determine whether speaker confidence is responsible for the effects of vocal intonation on persuasion and the nature of this relationship.
*Figure 4. Coefficients for each vocal intonation path reflect comparison with baseline vocal intonation. All coefficients unstandardized.
Solid lines indicate significant paths. Dotted lines indicate non-significant paths.
Contact Information: Joshua J. Guyer –