researchers (e.g., Miller, et al., 1976) as an explanation of fast rate enhancement ... mel, 1972; Smith, Brown, Strong & Rencher, 1975; Street & Brady,. 1982).
TALKING FAST AND C H A N G I N G ATTITUDES: A CRITIQUE AND CLARIFICATION W. Gill Woodall Judee K. Burgoon
ABSTRACT: Previous research on the effects of vocal rate on credibility
and persuasion has not carefully considered several methodological and theoretical issues. An investigation was conducted that controlled for a number of methodological factors, and considered different explanatory possibilities. Results indicated more complex and constrained relationships between rate of vocalization, credibility, and persuasion than some previous research had found, and were consistent with research in the person perception literature. Support for a straightforward credibility bolstering explanation was not found, and other explanatory rationales were considered. Those who talk fast, whether they are car salespersons, characters in television and radio commercials, or friends engaged in a heated discussion, often seem to have a persuasive advantage: their fast rate of speaking seems to enhance our impressions of them as well as the impact of their persuasive arguments. Above and beyond our own day-to-day experience, recent empirical evidence suggests that fast talking does indeed enhance source credibility and persuasion.~'Miller, Maruyama, Beaber and Valone (1976) demonstrated in two field experiments that rapid speech augments source credibility a0d as a result enhances receiver agreement with a source. Marketing research (LaBarbara & MachLachlan, 1979; MachLachlan, 1979), as well as investigations by Mehrabian and his colleagues (cf. Mehrabian & Williams, 1969) provide additional support for a fast vocal rate enhancement relationship. Some investigators (e.g., Miller, et al.) have found the W. Gill Woodall is with the University of New Mexico while Judee K. Burgoon is a Professor of Communication at the University of Arizona. 126
Iournal of Nonverbal Behavior 8(2), Winter 1983 © 1984 Human Sciences Press
127 W. GILL WOODALL, JUDEE K. BURGOON
research so convincing that they claim the evidence may suggest a new lawlike generalization: "Beware of the fast talker." However, closer scrutiny of both everyday experience and available empirical evidence may suggest more complex and limited relationships between rate of speech, source credibility and attitude change. There are a number of theoretical issues and methodological concerns to be raised that call into question the support claimed for a straightforward fast rate enhancement hypothesis. We intend to explore those issues and concerns here, and to investigate some mediating factors which may lead to more qualified relationships. A credibility bolstering rationale has been posed by some researchers (e.g., Miller, et al., 1976) as an explanation of fast rate enhancement effects. This rationale states that faster rates of vocalization operate to heighten a speaker's source credibility, and in turn leads to receivers' change in attitudes. However, past research on the effects of vocal rate variation on credibility and attitude change has provided evidence that does not necessarily fit well with a credibility bolstering explanation. Although one investigation found no relationship between vocal rate variation and source credibility ratings [Addington, 1971), several studies have shown that variations in speech rate do affect receivers' impressions of speakers (Gundersen & Hopper, 1976; Mehrabian & Williams, 1969; Miller, et al., 1976; Pearce, 1971; Pearce & Brommel, 1972; Smith, Brown, Strong & Rencher, 1975; Street & Brady, 1982). Ratings of intelligence, objectivity, knowledgeability, and some credibility dimensions were all positively affected by faster vocalization in these investigations. However, it would be premature to conclude that an increased rate uniformly enhances all credibility dimensions. Street and Brady (1982) have argued that judgments of competence and judgments of sociability represent two different evaluative domains that speech rate affects in different ways. These investigators suggest that competence related judgments are based on speech stereotypes that link faster rates with stronger levels of competence, and as such these judgments would be enhanced by increases in speech rate. On the other hand, social attractiveness judgments may be based on perceptions of rate similarity between speaker and listener. Since moderate rates are most likely to be similar to listeners' own rate levels, moderate rates of speech may be judged to be most socially attractive. Thus, we would expect
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fast vocal rates to positively affect credibility dimensions such as competence and extroversion, while other credibility dimensions in the social domain (composure, character and sociability) may be enhanced by moderate levels of vocal rate. Personality perception research supports this expectation by indicating that dynamic speakers (those with faster delivery and more pitch variety) tend to be perceived as aggressive, bold, energetic, tough minded, task oriented, and extroverted while a conversational delivery (slower rate and less pitch variety) is associated with being honest and people oriented (Addington, 1968; Brown, Strong & Rencher, 1973; 1974; Pearce & Conklin, 1971 ; Schweitzer, 1970). Street and Brady (1982) have also provided recent evidence that indicates vocal rate does differentially affect competence and sociability based judgments as suggested above. While a relatively clear picture of the relationships between vocal rate and credibility judgments may be emerging, evidence that indicates faster vocal rates result in persuasion is inconclusive. Some investigations (MachLachlan, 1979; Mehrabian & Williams, 1969; Miller, et al., 1976) have shown that fast rate messages result in attitude change, or at least the source being perceived as persuasive, while other studies (Gundersen & Hopper, 1976; Pearce & Conklin, 1971; Wheeless, 1971) have failed to find that faster messages lead to persuasion. Further, some of these investigations (Gundersen & Hopper, 1976; Pearce & Conklin, 1971) found fast vocal rates enhanced dynamism and competence related credibility judgments, but not subjects' attitudes. If speaking faster serves only to enhance dynamism and competence related credibility judgments, then a weaker version of the credibility bolstering explanation should be posed, i.e., that speaking faster enhances judgments of extroversion and competence which in turn leads to receiver agreement with the source. Even so, a weak point of this rationale is that, as several researchers in persuasion and nonverbal communication have pointed out (cf. Kiesler, Collins & Miller, 1969, p. 107; Knapp, 1978), bolstering a source's credibility does not always automatically lead to attitude change. Indeed, this apparently explains those cases where faster rates influenced subjects' credibility judgments, but not their attitudes. A second explanatory possibility that has received less empirical attention in this area of research is a distraction rationale (cf. Osterhouse & Brock, 1970). This rationale suggests that a fast
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vocal rate moderately distracts receivers, disrupts their attempts to counterargue against a counterattitudina] message, and makes receivers more susceptible to persuasion. Miller, et al. (1976) discounted a distraction explanation in evaluating the results of their studies. Discounting the distraction explanation may have been premature however, since the key variables of distraction and counterarguing were not measured in their investigations. On the other hand, Chaiken and Eagly (1976) found that nonverbal cues across written, audio, and audiovisual conditions provided increasing sources of distraction that led to increasing levels of persuasion across these modalities. The experimental conditions of this study indicated that the increasing amount of nonverbal cues across written, audio and audiovisual modalities led to increased distraction and persuasion of receivers, and as such, provided support for a distraction explanation. Thus, while a distraction explanation for vocal rate effects cannot yet be discounted, it is unclear whether simply speaking faster provides enough of a source of distraction to inhibit the receiver counterarguing and produce the receiver's yielding of attitudes. Rather, as investigators have suggested (Chaiken & Eagly, 1976; Stacks & Burgoon, 1981), potential nonverbal sources of distraction such as a fast vocal rate should be further investigated to determine whether they do lead to decreased counterarguing and increased persuasion. A third explanation can be derived from a recently developed resistance to persuasion model which incorporates elements of both of the previous explanations (Burgoon, Cohen, Miller & Montgomery, 1978). This rationale claims that inducing receivers to focus on a message's source and delivery aspects rather than message content constitutes a distraction that reduces receiver counterarguing and makes the receiver yielding more likely. In the investigations that provide supporting evidence for the model, Burgoon, et al. induced receiver focusing on source characteristics or message content via experimental instructions. It is quite possible however, that such receiver 'sets' may be induced during message reception by nonverbal cues themselves, focusing receivers toward nonverbal presentational aspects of delivery and away from message content. Such a situation, while resulting in heightened credibility, would at the same time produce moderate distraction, reduce receiver counterarguing and increase chances for persuasion. Once again, whether a faster vocal rate can have such effects needs to be explored, particularly in terms of distrac-
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tion, counterarguing, credibility and receiver yielding of attitudes. In order to provide clear support for any of the above rationales, we felt that several previously ignored methodological factors needed attention. One such factor is the channel or channels that a varied rate message is presented on to receivers. Studies that have reported faster vocal rates affecting persuasion presented the messages via the audio channel only (e.g., MachLachlan, 1979; Miller, et al., 1976), and as such the generalizability of this evidence is limited to audio-only reception conditions (such as telephone conversations and radio). If we are interested in extending the generalizability of the research to reception conditions that contain visual as well as audio information (such as television and face-to-face encounters), then the experimental context needs to be broadened to include the visual channel as well. The mere presence of visual information (such as a speaker's face and body), even when other nonverbal cues and factors are controlled, could alter the impact of increased vocal rate on persuasion as well as credibility, distraction and counterarguing. On a broader theoretical level, research that examines the effects of only one particular nonverbal behavior without placing it in its normal communicative context is counter to recent exhortations for more integrative and synthetic research in the nonverbal communication area (Knapp, Wiemann & Daly, 1978; Weitz, 1974, p. 267). Certainly, such research tells us little about postulated relationships in face-to-face multichannel settings. In an effort to place vocal rate in its behavioral context, channel of presentation was systematically considered in this investigation. Another methodological concern involves the manner in which researchers have manipulated rate of speech in their investigations. It seems likely that some slow and fast rate manipulations are unrepresentative of the normal range of speaking rates across which conversational speech varies. Some investigators {Allen, Anderson & Hough, 1968; Monroe & Ehninger, 1974) have estimated the vocal rate conversational range to be 120-180 words per minute (wpm), while Street (1982) found that judges who used comprehensibility and abnormality as decision criteria identified the lower and upper limits of the vocal rate range at 140-225 wpm. Both fast and slow wpm rates reported by Miller, et al. in their investigations fall outside the 120-180 wpm estimated range (slow and fast wpm rates were 102 and 195 wpm
131 W. GILL WOODALL, JUDEE K. BURGOON
respectively in experiment one, and 111 and 195 wpm in experiment two), and exceed the lower limit of Street's judgmental range. Other investigators (MachLachlan and his colleagues, for example) use time compression techniques that accelerate rate of speech far beyond it's normal range (rates of 250-300 wpm are often reported) and as such use manipulations not representative of everyday interactions. One concern is that these rate manipulations artificially inflate the influence of rate of vocalization on outcome variables such as credibility and persuasion. If we are interested in testing relationships that have bearing on everyday human interaction, then rate manipulations should be well within the conversational range. In the following investigation, we made certain that rate manipulations were kept within that range. One final methodological consideration is the extent to which topics used in previous investigations were sufficiently counterattitudinal. Miller, et al., for instance, used topics such as 'the dangers of consuming caffeine' or 'consuming hydroponically grown vegetables'. Although such topics may be novel (thus reducing the possibility that a stock set of counterarguments could be used to resist by subjects), it was not demonstrated that such topics were strongly counter to subjects' held attitudes. While not all attempts at persuasion need involve strongly counterattitudinal topics, it is important to examine cases that are clearly counterattitudinal. Given the supposed impact that nonverbal cues have on receiver yielding, it is important to demonstrate that such impact extends to strongly counterattitudinal situations. Further, since the bulk of research on nonverbal cues and persuasion has not dealt with counterattitudinal messages, extension of research in this direction is warranted. Finally, since the credibility, distraction and Burgoon, et al. explanations predict counterattitudinal situations, it is important to empirically test whether they actually do predict in those cases. In view of these methodological criticisms, we set out to provide a broadened experimental context in which to investigate the relationships between vocal rate, credibility, distraction, counterarguing and yielding. The strongest and clearest support for any given rationale would be derived from an experimental design that manipulates vocal rates within the conversational range, presents the message on both audio and audiovisual channels, and uses a persuasive message that is demonstrably counter to subjects' held
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attitudes. Under such conditions, we expect receivers' competence and dynamism related source credibility judgments to be most positively affected by a fast rate message, and receivers' judgments along the source credibility factors of composure, character and sociability to be most positively affected by a normal rate message. However, our expectations for the relationships between vocal rate, distraction, counterarguing and persuasion in this experimental context are less clear and remain investigative. As a result, we have framed our expectations in terms of two hypotheses and four research questions. Hi: Fast rate messages will result in higher ratings of extroversion and competence by receivers than normal rate messages. H2: Normal rate messages will result in higher ratings of composure, character, and sociability by receivers than fast rate messages. Question I:
Question 2:
Question 3:
Question 4:
Will recipients of a counterattitudinal message be more persuaded by a source speaking at a fast rate than a source speaking at a normal rate? Will recipients of a fast rate counterattitudinal message be more distracted than those who receive a normal rate message? Will recipients of a fast rate counterattitudinal message be less likely to counterargue than those who receive a normal rate message? Will receivers' reactions in terms of credibility, distraction, counterarguing and attitude change be different when normal and fast rate messages are presented on audiovisual channels than when they are presented on the audio channel only? METHOD
Subjects Subjects were 128 freshman, sophomore and junior level students enrolled in basic speech courses at a large Southeastern University. Subjects were given extra credit in their courses for participation in the experiment.
133 w. GILL WOODALL, JUDEE K. BURGOON
Procedure Upon arrival at an experimental lab, subjects were informed that the Center for Communication Research was interested in how people receive and react to recorded messages. Subjects were randomly assigned to experimental testing rooms where they were exposed to either a videotaped or audiotaped version of the counter-attitudinal message; they then completed the dependent measures. Afterwards, all participants in the experiment were debriefed.
Design A post-test only design was employed in this investigation 1-o avoid sensitizing subjects to the attitudinal topic (Burgoon & King, 1974). Subjects were randomly assigned to one of four experimental exposure conditions: (I) normal rate message presented on both audio and visual channels, (2) fast rate message presented on both audio and visual channels, (3) normal rate message presented on audio channel only, (4) fast rate message presented on the audio channel only (Note I). To control for any idiosyncratic speaker effects, two male speakers each performed the four experimental conditions. As a result, the design used was a 2 (levels of speakers) × 2 (levels of rate) x 2 (levels of channel) factorial. Where speaker blocking effects resulted in F values less than 1.00, the effects were dropped from the analysis (as suggested by Snedecor & Cochran, 1967).
Message and Videotape Construction The counterattitudinal message presented four main arguments, each with three subpoints, advocating a 20% increase in undergradute tuition, and was 677 words in length. Results from another undergraduate subject sample (N=65) indicated that such a message would be counterattitudinal. Responses toward the topic on the three measures (a Likert-type, agree-disagree scale; four semantic differential items; and the known interval scale, Burgoon & Burgoon, Note 2) indicated negative evaluations and disagreement with the topic (M for agree-disagree item = 2.10 on a scale of I to 7; M for semantic differential items = 9.62 with a range of 4 to 28; M for known interval scale = 3.62 on a scale of .66 to 11.21). In constructing the message, a number of verbal variables that might affect its comprehensibility and persuasiveness were controlled for, those being average sentence length, index of contingency and intensity of language. Obtained levels of these indices indicated the message to be comprehensible and persuasive (Note 3). A critical review of the message's understandability and persuasiveness by a pane× of four
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communication instructors further insured its effectiveness. Two speakers, who were experienced graduate student actors similar in age, physical appearance and dress, delivered the persuasive message and were videotaped (Note 4). The speakers were instructed to deliver the message in what they considered to be a normal rate of speaking, and then again at a fast rate of speech. The average rate of speech for the normal rate conditions was 154 wpm, while the average obtained rate in the fast condition was 181 wpm. Individual wpm rates for the normal rate condition were 161 wpm for speaker 1 and 148 wpm for speaker 2, while the fast rate condition wpm for speaker 1 was 184 wpm and 178 wpm for speaker 2. Speakers were further instructed to vary only their rate of vocalization and use no hand gestures, and to keep other nonverbal features of their performances, such as quality and type of facial expression, intonation, loudness and phrasing as controlled and constant across conditions as possible. Speakers delivered the message in a pleasant but serious manner (Note 5). Technical aspects of videotape production, such as camera position and shots, lighting, and audio levels were held constant across recordings.
Dependent Measures Subjects' attitudes toward a 20% increase in undergraduate tuition were measured by four seven-interval semantic differential scales bounded by the bipolar adjective pairs: good-bad, foolish-wise, pleasantunpleasant, and valuable-worthless. Cronbach's (1951) coefficient alpha reliability for the four items was .89. Attitudes were also measured by an eleven-interval scale with weighted known intervals (Burgoon & Burgoon, Note 2). Each position on the Known Interval Scale has an associated weight derived from successive interval scaling (dislike intensely = .66, terrible -- 2.49, very bad = 3.24, bad = 4.17, poor = 5.01, neutral = 6.00, fair -- 6.99, good = 7.83, very good = 8.73, excellent -- 9.51, like intensely = 11.21). In the present study, the Known Interval Scale correlated highly with the semantic differential measure (r = .86). Fifteen semantic differential scales were used to assess five dimensions of source credibility (McCroskey, Jensen & Valencia, 1973). Coefficient alpha reliabilities for the five credibility dimensions were .81 for competence, .81 for composure, .83 for extroversion, .63 for character and .75 for sociability. Extent to which subjects were distracted during message reception was measured in two ways: (1) five seven-interval scales bounded by the adjective pairs: comfortable-uncomfortable, distracted-not distracted, tense-relaxed, and attentive-inattentive (coefficient alpha reliability for the five items was .78), and a recall measure which assessed the extent to which subjects could recall arguments presented in the message. Trained judges score subjects written responses for recall of arguments. Scoring reliability determined by intra-
135 W. GILL WOODALL, JUDEE K. BURGOON
class correlation was found to be high (rl = .96). Finally, counterarguing behavior was assessed by having subjects list what they thought during or immediately after the message. Two independent judges scored the subjects' responses as counterarguments if the response indicated a negative consequence of the positions advocated, constituted an attack on the validity of the message, or derogated the source. Reliability of the judges' scoring computed by an intraclass correlation was found to be high (ri = .89).
RESU LTS
A 2 × 2 × 2 analysis of variance for unequal n (cf. Kerlinger & Pedhazur, 1973) was used to analyze subjects' credibility, attitude, distraction and counterarguing responses. Hypothesis one predicted a main effect for rate of speech on the extroversion and competence dimensions of credibility. A near significant rate main effect for extroversion was obtained, F (1,123) = 3.44, p = . 0 6 , while the rate main effect for competence was nonsignificant. Magnitude of variance accounted for by the rate main effect for extroversion, estimated by the omega statistic (Winer, 1971, p. 428430) was .03. Power of the tests of main effect (Cohen, 1969) for extroversion and competence was low (.30 and .07 respectively). The order of the extroversion means were in the predicted direction, with the fast rate mean (22.22) greater than the normal rate mean (21.03). Thus, the results provide only tentative and partial support for hypothesis one. Hypothesis two predicted a vocal rate main effect for the composure, character, and sociability dimensions of credibility. A significant rate main effect for the composure dimension, F (1, 123) = 7.55 p < . 0 5 , omega = .08, and a near significant trend for character, F (1,124) = 2.76, p--.09, omega -- .03, were obtained in the analysis, while the sociability rate main effect proved nonsignificant. Power for the composure test proved to be moderate (.42), while power for the character test (.20) and the sociability test (.09) was found to be low. The means for the composure and character main effects were in the predicted direction with the normal rate means more favorable than the fast rate means: Composure means were 17.96 and 15.65 while character means were 18.51 and 17.50 for normal and fast rate conditions respectively. Overall then, hypothesis t w o received partial support, with the composure results providing support and the character trend
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providing tentative support for the prediction. Research question one asked whether a fast rate presentation would be more persuasive than a normal rate presentation. The results indicated the answer to be negative. Rate main effects for both the semantic differential and known interval measures were nonsignificant, and thus no differences in persuasion between normal and fast rates were detected in the analysis. Power for both of these tests was found to be low (.04 in both cases). In answering research question two, a significant rate main effect was obtained that indicated the fast rate message to be more distractng than the normal rate message, F (1,123) -- 3.73, p