Investigating Multiple Roles of Vocal Confidence in Attitude Change Joshua J. Guyer & Leandre R. Fabrigar Queen’s University, Kingston, Ontario, Canada, 1. Abstract 4. Method 6. Results & Discussion We examined how the interplay between vocal speed and vocal intonation influenced attitude change across levels of elaboration. The design was a 2 (Vocal speed: fast vs. slow) x 2 (Vocal intonation: rising vs. falling) x 2(Elaboration: high vs. low) between participants factorial. Vocal speed and vocal intonation were manipulated using digital audio software (PRAAT©) to ensure no properties of voice other than rate of speech and intonation were altered. First, participants listened to an audio recording that proposed moderate 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. Finally, participants indicated their attitude towards the proposed tuition-reduction program. Manipulation checks revealed all variables were successfully manipulated. A moderated mediation analysis indicated the effects of vocal speed and vocal intonation on cognitive responses and post-persuasion attitudes were in line with the patterns expected under high – and low elaboration according to the Elaboration Likelihood Model (ELM; Petty & Cacioppo, 1984). First, we sought to ensure that both vocal manipulations produced the expected effects on ratings of speaker confidence. Confirming expectations, participants rated the speaker in the increased vocal speed condition (M = 5.39), as significantly more confident than the speaker in the decreased vocal speed condition (M = 4.51), F(1, 394) = 34.26, p < .001, partial η2 = .08 (see Figure 1). Next, participants rated the speaker in the falling intonation condition (M = 5.51), as significantly more confident than the speaker in the raised intonation condition (M = 4.39), F(1, 394) = 55.75, p < .001, partial η2 = .13 (see Figure 2). No interaction between vocal speed and vocal intonation was found, thus suggesting the impact of these variables was additive as opposed to interactive. Our elaboration manipulation confirmed the total number of topic-relevant thoughts generated in the high elaboration condition (M = 4.52), was significantly greater than in the low elaboration condition (M = 3.59), F(1, 386) = 13.91, p < .001 (see Figure 3). Next, we conducted a moderated mediation analyses using ratings of vocal confidence and participant’s cognitive responses as mediators of the relationship between vocal speed and vocal intonation on post-attitude. As per Figure 4, under high elaboration, both vocal speed and vocal intonation had their expected effects on ratings of speaker confidence. Next, increased confidence should bias a person’s cognitive responses to be more positive towards the message. This is exactly what the data shows. Finally, cognitive responses should have a positive impact on a person’s topic-relevant attitude. Indeed, the data show this to be the case. The final path evaluates the direct effect of speaker confidence on post-message attitudes. Because this is high elaboration situation, the ELM predicts speaker confidence should act as a biasing factor and impact thoughts but not have a direct impact on attitudes by functioning as a cue. Both effects were as expected, thus supporting the model. Finally, we conducted a Sobel mediational test to confirm that cognitive responses mediated the relationship between ratings of speaker confidence and post-message attitudes. As expected, the data revealed a highly significant effect, z = 3.32, p < .001. In line with the ELM, no further paths reached significance. These results suggest that when able to devote cognitive resources towards processing a message, individuals use their assessments of a speaker’s vocal confidence as a determinant of the positivity or negativity of their thoughts. As per Figure 5, under low elaboration both vocal speed and vocal intonation significantly predicted ratings of speaker confidence. Next, speaker confidence should not bias participant’s thoughts but instead be used as a cue and directly impact attitudes. This is what we found. Although the direct effect of confidence on post-message attitudes was significant under low elaboration, a comparison of this coefficient across levels of elaboration failed to reveal a significant difference across paths, although the effect was in the right direction. Next, we conducted a follow-up test of the coefficients reflecting the direct effect of speaker confidence on cognitive responses across levels of elaboration. Supporting the theory, confidence was a significantly greater predictor of cognitive responses under high compared with low elaboration, z = 1.93, p = .05. Next, thoughts should be a significant predictor of attitudes under low elaboration but somewhat weaker than under high elaboration. Although a significant effect of cognitive responses on post-message attitudes was found, a comparison of the coefficients across levels of elaboration was only marginally significant, z = 1.77, p = .08. These results suggest that when effortful processing is inhibited, perceptions of speaker confidence do not influence the positivity or negativity of the recipient’s topic-relevant thoughts but rather directly impact the message recipient’s attitude by functioning as a peripheral cue. Participants. 394 undergraduate psychology students participated in return for course credit 2 (Vocal Speed: increased vs. decreased) x 2 (Vocal Intonation: rising vs. falling) x 2 (Elaboration: high vs. low) 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. The vocal characteristics of the speaker were digitally manipulated along two dimensions: speech rate and intonation. Thus, the speaker either spoke fast or slow, with rising or falling intonation. All participants were also assigned to either a high or low elaboration condition. After listening to the audio recording, participants were asked to provide ratings of the speaker along a variety of dimensions, including rate of speed and speaker confidence. The presentation order of these questions were randomized. Finally, participants completed a measure assessing their attitudes towards the topic. All questions used 7-point rating scales. The topic of the passage presented moderate arguments in favor of working for Queen’s university in exchange for a reduction in tuition. Design. Procedure. Measures. 2. Introduction Attitude change has long been a central topic in social psychology. Given the vast literature on persuasion, one would think that a great deal would be known about how the qualities of speakers’ voices affect the persuasion process. Unfortunately, very few empirical investigations have explored the impact of voice on attitude change. Of the various characteristics that a voice might have, one characteristic that intuitively should play an important role in the persuasion process is how confident a speaker is perceived to be. For instance, several experiments have demonstrated that confident speakers typically communicate at a louder volume relative to unconfident speakers (Kimble & Seidel, 1991; Scherer, London, & Wolf, 1973). Somewhat intuitively, speakers who finish their sentences using raised intonation are perceived as significantly less confident relative to speakers who finish their sentences using falling intonation (Brennan & Williams, 1995; Smith & Clark, 1993). Finally, research indicates that confident speakers typically communicate at an increased rate of speech relative to unconfident speakers (Miller, Maruyama, Beaber, & Valone, 1976; Scherer et al., 1973). 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 the role of vocal speed (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. While the effects of vocal speed on persuasion have been investigated under moderate levels of elaboration (Smith & Shaffer, 1995), research has not examined how vocal qualities might influence attitude change when people are pushed to be under either high or low levels of processing. Thus, this research seeks not only to examine how variables other than rate of speech influence attitude change, but also how these variables might play a role under high – and low levels of elaboration. 5. Results Figure 1. Figure 2. Figure 3. * * * * * * Means having an * are significantly different at p < .001. Figure 4. Figure 5. 3. Present Study 7. Future Directions Goals: Create a more precise way of manipulating vocal qualities using a digital recording process. Investigate other hallmarks of vocal confidence such as vocal intonation. Determine whether these hallmarks of vocal confidence affect persuasion in an additive or an interactive fashion. Determine the core processes responsible for the effects of vocal confidence on persuasion. Current research is investigating the processes by which vocal speed and vocal intonation influence attitude change under high – and low elaboration as a function of argument quality – strong/weak arguments. Current research is also investigating the effects of a wider range of each variable on attitude change using strong and weak arguments. Figures 4 & 5. Unstandardized regression coefficients. Solid lines indicate significant paths. Dotted lines indicate non-significant paths. Contact Information: Joshua J. Guyer – joshua.guyer@queensu.ca