Investigating Multiple Roles of Vocal Pitch in Attitude Change Joshua J. Guyer, Leandre R. Fabrigar, Amanda C. Maracle, Matthew P.H. Kan, & Gabrielle Terry Queen’s University, Kingston, Ontario, Canada, 1. Abstract 4. Method 6. Results & Discussion We examined the mechanisms by which vocal pitch influenced persuasion across levels of elaboration. The design was a 2 (Vocal pitch: raised pitch vs. lowered pitch) x 2 (Elaboration: high vs. low) between participants factorial. Pitch was manipulated using digital audio software (PRAAT©) so no other properties of voice were altered. Participants listened to an audio recording proposing moderate arguments in favor of phosphate-based detergent. Next, participants rated the speaker along a variety of dimensions. Participants then listed up to 10 thoughts they had while listening to the recording and rated the favorability of those thoughts to the topic. Finally, participants indicated their attitude towards phosphate-based detergents. Manipulations of pitch and elaboration were successful. Moderated mediation analyses revealed pitch influenced perceptions of confidence under high elaboration, which then affected persuasion via biasing cognitive responses. Under low elaboration, pitch also influenced confidence, which then served as a peripheral cue to directly influence persuasion. First, we sought to ensure that our manipulation of vocal pitch was successful. The data indicated that participants perceived the speaker with raised vocal pitch (M = 3.91), as having a significantly higher pitched voiced than the speaker with lowered vocal pitch (M = 2.47), F(1, 269) = 70.19, p < .001, partial η2 = .21 (see Figure 1). Next, our manipulation check of elaboration confirmed the total number of topic-relevant thoughts generated in the high elaboration condition (M = 3.69), was significantly greater than in the low elaboration condition (M = 2.36), F(1, 269) = 28.75, p < .001, partial η2 = .10 (see Figure 2). An analysis using proportion of relevant thoughts produced a high comparable result. Finally, we sought to confirm that vocal pitch produced the expected effects on ratings of speaker confidence. In line with expectations, participants rated the speaker in the lowered vocal pitch condition (M = 4.68), as significantly more confident than the speaker in the raised vocal pitch condition (M = 3.04), F(1, 269) = 88.28, p < .001, partial η2 = .25 (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 pitch on post-attitude. As per Figure 4, under high elaboration, vocal pitch had the 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, which in turn guide their attitudes towards the target. As per Figure 5, under low elaboration vocal pitch 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. Indeed, our data revealed the direct effect of confidence on post-message attitudes was significant. Moreover, a comparison of this coefficient across levels of elaboration revealed a significant difference across paths, z = 2.58, p < .01. Next, we conducted a follow-up test of the coefficients reflecting the direct effect of speaker confidence on cognitive responses across levels of elaboration. Although the difference across levels of elaboration was not found to be significant, the effect was moving in the correct direction, z = .53, p = .72. Next, thoughts should be a significant predictor of attitudes under low elaboration but somewhat weaker than under high elaboration. Once again supporting the theory, a comparison of the coefficients across levels of elaboration revealed thoughts were a significantly greater predictor of attitudes under high compared with low elaboration, z = 3.18, p < .001. 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. 273 undergraduate psychology students participated in return for course credit 2 (Vocal pitch: raised vs. lowered) 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 phosphate-based detergent. The vocal characteristics of the speaker were digitally manipulated by either raising (+120hz) or lowering (-20hz)the vocal pitch of the speaker. 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 pitch and speaker confidence. The presentation order of these questions were randomized. Participants then listed up to 10 thoughts they had while listening to the recording and rated the favorability of those thoughts to the topic. Finally, participants completed a measure assessing their attitudes towards the topic. All questions used 7-point rating scales. 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. Yet to be explored however is the potential influence that a speaker’s vocal pitch may have on a listeners' perceptions of speaker confidence and how variation in the speaker’s vocal pitch might differentially influence attitude change under conditions that promote either high or low thought. Thus, this research seeks not only to examine how variables other than rate of speech influence attitude change, but also the different processes through which attitude change may occur under high – and low levels of elaboration. 5. Results Figure 1. Figure 2. Figure 3. * * * * * * Means with an * are significantly different at p < .001. Figure 4. Figure 5. 3. Present Study Goals: Create a more precise way of manipulating vocal qualities using a digital recording process. Investigate other hallmarks of vocal confidence such as vocal pitch. Determine the core processes responsible for the effects of vocal confidence on persuasion. 7. Future Directions Figures 4 & 5. Unstandardized regression coefficients. Solid lines indicate significant paths. Dotted lines indicate non-significant paths. Current research is investigating the processes by which a wider range of both vocal speed and vocal intonation influence attitude change under moderate elaboration as a function of argument quality – strong/weak arguments. Contact Information: Joshua J. Guyer – joshua.guyer@queensu.ca