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Acoustic markers of political power Danielle Duez Laboratoire Parole et Langage, CNRS UPRES-A, 6057 Université de Provence 29 avenue Robert Schuman 13621 Aix en Provence FRANCE The effect of political power on acoustic variables was examined in three political speeches given by François Mitterrand at different periods of his career. F0 data were not found to reflect the extent of Mitterrand's power. On the other hand, temporal organization appeared to mirror the politician's distance from power. When Mitterrand was both a challenger and an opponent, articulation rate was more rapid, while in the two presidential speeches, he showed a slower articulation rate, which seems to be a feature of power. The pause structure appeared to reflect the place of the politician within the social hierarchy in such a way that the higher the status, the longer and the more frequent the pauses. There seems to be a balance between what is being said and what is left unsaid: silence becomes a power symbol. 2 INTRODUCTION Speech conveys linguistic information as well as information on the personal characteristics of the individual. Abercrombie (1967) referred to the latter as indexical information and distinguished three classes of indices: 1) those which indicate membership in a group, 2) those which characterize an individual, and 3) those which reveal the changing state of the speaker. Subsequently, Laver and Trugdill (1979) adopted Abercrombie’s typology but referring to the three classes of indices as social markers, physical markers, and psychological markers. The first class refers to group characteristics such as regional or dialectal affiliation, social status, educational status, occupation, and social role. The second class refers to individual characteristics such as sex, age, and state of health, The third class describes the speaker's personality and affective state. Laver and Trugdill (1979) further refined their typology by distinguishing markers which are not consciously manipulated by the speaker and have an informative function, from those which respond to the speaker’s intention of signalling an affect or social role and have a communicative function. These authors called the former extralinguistic features, and the latter paralinguistic features. Experimental research conducted in the area of paralinguistic information has tended to focus less on the communication of affect and more on markers of personality, particularly as conveyed by dynamic features. Markers of anxiousness and extroversion have been investigated more than the other features. However, the data collected for these two personality traits have yielded partly conflicting results. While Murray (1971) and Rochester (1973) observed a lower proportion of silences in the speech of highly anxious speakers than in that of slightly anxious speakers, Siegman (1978) reported more frequent longer pauses for anxious speakers. Similar discrepancies were also observed in the data on extroversion. Siegman and Pope (1965) found extroversion to be associated with shorter latencies, fewer "filled" brief pauses, and fewer silent pauses, while Ramsay (1968) did not obtain a significant extroversion effect for the silent-pause ratio, and suggested that the length of a silence may be the critical variable that distinguishes introverts from extroverts. Siegman’s explanations (1978) based on individual differences in cognitive activity were not supported by Scherer’s findings (1979a) on personality trait markers in German and American speakers. Scherer obtained different results for the two speech communities. He suggested an effect of intercultural differences and pointed out the necessity of taking psychosocial factors into account. Although speech is a social phenomenon, social speech markers have attracted little attention in the experimental research on paralinguistic information. Social-role markers in speech have mainly been investigated in studies on speech styles. For example, Crystal and Davy (1969) described intonation, pitch range, loudness, rhythmicity, and rate in conversations, sport commentaries, news, conversations, cricket and funeral state commentaries, sermons, and lectures. They mentioned the following recurrent features for conversations: hesitations, short and often incomplete tonal units, frequent F0 falls, and high speech rate variability. For read speech samples, they reported a tendency towards short units and isochronous rhythm, narrow pitch range, and a lack of disruptions. A comparative approach has also been adopted in more recent studies on speech styles. Lucci (1983) analyzed prosodic features (rhythm, pauses, rate, intonation, emphatic stress) in lectures, conversations, news readings, and lecture readings by four French speakers. Although he excluded speech spontaneity cues, the role of acoustic variables in speech style identification was stressed. Fónagy and Fónagy (1976) studied rhythmic and intonational patterns in French 3 conversations, news, and read fairy tales, and reported stereotypes for the different speech styles. For example, news reports are characterized by irregular rhythmic patterns, frequent emphatic stress, and sudden pitch falls. The authors also had subjects identify some of these patterns in and out of context (in excerpts). They found these patterns to be interpreted differently, and suggested that their meaning may depend on the situational context. Other studies have systematically investigated a given parameter across different speech styles. Graddol (1986) explored the contrasting pitch characteristics of males and females reading two kinds of text (neutral technical prose and dramatic dialogue) and examined female and male speech as a function of social conditioning. He demonstrated that each speech style has a different set of pitch characteristics. Duez (1982) analyzed and compared the frequency, duration, and distribution of pauses in French political speeches, political interviews, and casual interviews, and interpreted the results obtained as a function of spontaneity and the relationship between the speaker and his audience. Non-silent pauses such as filled pauses, lengthened syllables, repeats, and false starts were found to be less frequent and shorter in political interviews than in casual interviews, which are less constraining. The total duration of silent pauses was found to be 50% greater in political speeches than in interviews, even though the content of the speech in the former case is known to the speaker, and despite the fact that there were practically no hesitations. It was suggested that some pauses, particularly the unexpected ones and the longest ones, have an illocutionary function and serve to increase the strength of the argumentation. Significant pause-time and speechrate differences across politicians were also observed. One of the reasons for these differences might be a high degree of inter-speaker variability (Goldman-Eisler, 1968). Another reason might be the heterogeneity of political status. The politicians came from various political horizons, played various positions in the political "chess-game", and thus had a different relationship to power. These differences may induce different speech strategies, which may be reflected at the acoustic level. The purpose of the present study was to further refine the phonetic description of political speeches and to test the above assumption that political power has an effect on speech style. Three political speeches given by François Mitterrand at three different periods of his career were analyzed. The first speech was produced in 1974 when Mitterrand was both a challenger and an opponent, the second was a presidential speech (1984), and the third took place in a particular and interesting situation in which Mitterrand was both the incumbent president and a candidate to a new presidential mandate (1988). He had the same social status as in 1984, but the role he played may have depended on a strategic choice. The comparison of speeches produced by the same politician is one way of neutralizing individual variations and focusing on relevant situational markers. Several acoustic parameters such as articulation rate, and the duration, frequency, and distribution of pauses, were studied and compared in the three speeches. The acoustic analysis was extended to the fundamental frequency range of the voice since this parameter has been shown to be relevant to the characterization of speech style (Graddol, 1986; Léon, 1971-93). It was assumed that the above variables are significant indicators of power, and their comparison should allow us to characterize both the "presidential" style and the "challenger" style. METHOD Corpus The corpus consisted of three speeches produced by François Mitterrand in 1974, 1984, and 1988. The 1974 and 1988 speeches were recorded from high quality FM broadcasts on a Revox A77 tape recorder at 19 cm/sec. The 1984 speech was obtained directly from the INA 4 (International Audiovisual Institute). Table 2 gives their duration. The situation in which each political speech occurred was defined according to Hymes's model (1972). Situational variables Hymes (1972) proposed that all speech events take place in a specific situation which can be defined in terms of basic concepts such as ’setting’, ’purpose’ and ’participants’. The place and the physical position of the participants vis-à-vis each other are features of setting, as well as the moment, or period when the speech events occur. Speech purposes are the communicative intents of the speaker(s). Social markers, physical markers, and psychological markers (as defined by Laver and Trugdill, 1979) are features of the participants, as are the relationships between the participants at an interpersonal or social-institutional level. Setting. Because each of the speeches studied here was televized and broadcast, there was no direct contact between the speaker and his listeners or viewers. François Mitterrand was in front of a microphone (and/or a TV camera), in a non-public locale such as the Elysee Palace or a TV studio, whereas each elector was (potentially at least) watching a TV screen, at home or in a public place, e.g. a bistro, a pub, or a department store. Purpose. The three speeches were of the same activity type: public argumentation. They had the same purpose: persuading the voter of the merits of a program or a decision. The speeches produced in 1974 and 1988 were part of an electoral campaign. The 1984 speech differed partially since it was a presidential communication event. However, this difference is more apparent than actual, since the president had to unremittingly campaign to sustain his popularity (Gerstlé, 1992). Participants. In 1974, François Mitterrand was both a challenger and an opponent. He denounced the errors of the current administration and called for change. In 1984, he was president and at the top of the power ladder. His legitimacy was not questioned, but he had to pacify social relationships and convince the French of the necessity of a referendum. In 1988, he was the current president and a candidate to a new mandate. According to Gerstlé (1992), his campaign was predicated on his being the incumbent. He did not attack his opponents, but simply reminded the electorate about the program he already had underway. Acoustic variables The long-term modulation of intensity (of the present signal) is partly influenced by the emotional states and the personality of the speaker. Therefore, it should be interesting and worthwhile investigating these variations as a function of the situation of communication. Unfortunately, these values are at best difficult to interpret, due to the large number of factors that affect the amplitude of a signal such as ambient noise and varying distance and angle with respect to the microphone. Moreovere, amplitudes often undergo automatic volume control in broadcast or televized signals. Consequently, the analysis of acoustic variables was only concerned with duration and fundamental-frequency measurements. Fundamental frequency (Fo) measurements. F0 values were computed on the voiced part of the signal. The method of analysis was based on the cross-correlation between the power spectrum and a comb function (Espesser, 1981-82). The raw data were checked for octave shifts resulting from second harmonic readings, and then reinterpreted when 5 necessary. The following F0 data were computed for each speech: the minimum + 5%, the mean, the maximum - 5%, the standard deviation, and the range (5% to 95%). Temporal measurements and temporal variables. After phonetic transcription from the tape recordings alone, the oscillograms were segmented while listening to the tapes. The total speech time was subdivided into total articulation time and total pause time. Non-silent pauses and silent pauses were classified according to the following definitions. I. Silent pause: any interval on the oscillographic trace where the amplitude is indistinguishable from that of background noise. A silent pause is never shorter than the "minimum" duration taken to be equal to the average duration of an intervocalic stop increased by four standard deviations. II. Filled pause: any occurrence of a French hesitation interjection such as euh, eh, hein. III. False start: any sequence of segments that is intended to start the next utterance but is interrupted and replaced by another that will get completed. IV. Repeat: any unintended repetition of a sequence of phonetic segments. V. Lengthened syllable: any syllable in which the vowel is abnormally prolonged. In addition, the following definition was used. VI. Articulated sequence: any sequence of phonetic segments (excluding filled pauses, false starts, and repeats) delimited by two silent pauses. The silent-pause ratio was obtained by dividing the total duration of silent pauses by the total speech time. The mean number of syllables of an articulated sequence was calculated by dividing the total number of syllables by the number of articulated sequences. The mean duration of a silent pause was obtained by dividing the total pause time by the number of silent pauses. The articulation rate was obtained by dividing the total number of syllables by total articulation time (total speech time minus total pause time). Pause location. The location of the silent pauses was studied by syntactic type. Four types were considered: pauses located between sentences, with a falling contour; those located between clauses, with a continuation rise, as defined by Dubois and Dubois-Charlier (1970); pauses occurring between phrases, which result from the segmentation of sentences and clauses, again as defined by Dubois and Dubois-Charlier (1970); and within phrase pauses, i.e. unexpected pauses within a sense group (Grammont, 1914). 6 RESULTS Fundamental frequency Table I. F0 data for Mitterrand's three political speeches. _______________________________________________________________ Political Speech F0 measurements 1974 1984 1988 Minimum F0 +5% (Hz) 65 65 65 117 136 128 Mean F0 (Hz) Maximum F0 -5% (Hz) 238 260 242 Standard Deviation (Hz) 34 34 34 F0 Range 5%-95% (Hz) 173 195 177 ________________________________________________________________ Table 1 gives the means in Hz of the various F0 measures made for each speech. We can see that the 1984 speech differs from the 1974 and 1988 speeches: the minimum values are identical but the mean, range, and maximum values are all markedly larger for the 1984 speech than for the other two speeches, which are comparable. Since the 1984 speech used an extended range of F0 without altering the baseline, one would indeed expect a higher maximum and a higher mean, as can be seen in the data. Temporal variables Table II. Temporal data for three Mitterrand's three political speeches. Standard deviations are in parentheses. Political Speech Time measure 1974 1984 1988 Total speech time 2’04" 6’00" 3’ 23" Total pause-time ratio (%) 29.1 39.0 33.5 Mean articulated-sequence duration (syll) 9 7.4 7 (0.58) (0.42) (0.53) Mean pause duration (in ms) 605 972 792 (63) (45) (57) Articulation rate (syll./s) 5.5 4.7 4.7 (1.3) (1.2) (1) __________________________________________________________________ Articulation rate. The mean articulation rates for each speech were 5.3 syll./s (1974), and 4.7 syll./s (1984 and 1988). The difference between the articulation rates of the 1974 speech and the 1988 speech is statistically significant (p=0.05) contrary to the difference between the articulation rates of the 1984 speech and the 1988 speech (p=0.89). Changes in articulation rate seem to mark the different steps in the argumentation. The 1974 speech began with a denunciation of the opponents’ failings. In the second part, Mitterrand tried to convince listeners by talking about a world of justice. The articulation rate in the first part was 5.9 syll./sec, which is slightly higher than the articulation ratein the second part (5.5 syll). The 7 difference between the two articulation rates is statistically significant (t=79, p=0.0001). The first part of the 1984 speech was a reminder of the President’s responsabilities: the articulation rate was 5.25 syll./sec. In the second and third parts where Mitterrand presented the need for a referendum, which implied a change in the constitution, he spoke with a solemn tone and his articulation rate was slower (4.73 and 4.76 syll./sec, respectively). Mitterrand opened the 1988 speech by addressing a question about the President’s role; his mean articulation rate was 5.35 syll./sec. He continued by drawing a portrait of the ideal president, and then described his home and foreign policy program. Mean articulation rate in these three parts was slow 4.7 syll./sec, 4.6 syll./sec, and 4.8 syll./sec, respectively. Finally, a fast "à bientôt" (see you soon) (6 syll./sec) created a certain proximity between himself and the electorate. The cross-speech comparison of the total pause-time ratios indicated a higher percentage of pause time in the 1984 speech (39%) than in the 1974 speech (29%); that of the 1988 speech was intermediate (33.4%). These differences may be related to differences in mean silent-pause durations. Mean silent-pause duration was shorter in the 1974 speech (581 ms) than in the 1988 speech (792 ms), which in turn was shorter than in the 1984 speech (972 ms). The difference between the three speeches is statistically significant (ANOVA: F(2,295)=39, p=0.001). The results obtained for mean articulated-sequence durations expressed in syllables revealed that the pauses were less frequent in the 1974 speech (every 9 syllables) than in the 1984 speech (every 7.4 syllables) and in the 1988 speech (every 7 syllables). This difference is statistically different (ANOVA, F(2,300)=3.5, p=0.03). Table III. Mean duration (MD) expressed in ms, standard deviation (SD), and number of silent pauses (N), by location in Mitterrand's political speeches. Political Speech 1974 1984 1988 Location MD SD N MD SD N MD SD N Between sentences 827 96 13 2102 67 22 1521 80 15 Between clauses 644 65 21 1112 50 35 907 63 21 Between phrases 637 40 30 663 40 77 534 50 48 Within phrases 357 7 384 6 405 ___________________________________________________________________ 1 Silent pauses. Silent pause durations by location in the sentence and the power situation are shown in Table 3. In the three speeches studied here, the pause distributions had a similar overall pattern: silent pauses between sentences and clauses were more frequent and longer than pauses between phrases, the latter being longer and more frequent than pauses within phrases. This is quite apparent in Table 3. Differences in the three speeches can be readily noticed, however. Between-sentence pauses were longer in the 1984 speech (2102 ms) than in the 1988 speech (1521 ms), the latter being longer than in the 1974 speech (827 ms). A similar tendency was observed for pauses located between clauses, whose corresponding values were 1112 ms (1984), 907 ms (1988), and 644 ms (1974). These differences are statistically significant (ANOVA between-sentence pauses: F (2, 47)= 71, p = 0.0001; between-phrase pauses: F (2, 74) = 15, p = 0.0001). The duration of pauses located betweenand within-phrases was very similar in the three speeches. The average durations obtained for pauses located between phrases were 637 ms (1974), 663 ms (1988) and 534 ms (1984); they are not statistically different (F (2, 154) = 0.98, p = 0.37). The corresponding values for pauses within phrases were 357 ms (1974), 384 ms (1984), and 405 ms (1988). Note that the 8 use of within-phrase pauses was more marked in the 1974 speech (7 out of the 71 pauses) than in the 1984 and 1988 speeches (6 out of 140 and 1 out of 85, respectively). Non-silent pauses.Only the 1974 speech exhibited non-silent pauses, and only a limited number of them. One false start was identified. There were also six filled pauses located at phrase boundaries. Two of them were associated with a silent pause; they were 330 ms and 350 ms long. Non-silent pauses are a characteristic of spontaneous speech. Located before an infrequent word, they leave time for word searching (Beattie and Butterworth, 1979); located at the head of a phrase, they leave time for programming the next phrase (Boomer, 1965; Cook, 1971). In political speeches, the text is known and learned in advance, and this helps the speaker not to hesitate. Non-silent pauses may be due to anxiety and emotion. One may also assume that non-silent pauses are voluntary, rhetorical hesitations used to create a certain proximity between the politician and his audience. GENERAL DISCUSSION A major objective of the present study was to examine to what extent acoustic F0 and duration variables reflect the speaker's social relationship to power. In general, measures based on the F0 deviations have proven that the realization of pitch is not an exclusively linguistic phenomenon, but is also influenced by paralinguistic and extralinguistic factors. Mean-F0 values and F0 ranges were shown to depend on the speaker's personality (see Scherer, 1979b and 1981), sex (Helfrich, 1979), and emotions (Scherer, 1992). For example, F0 was found to increase with increases in stress or emotional tension (Scherer, 1979b, 1981). The interaction of these various factors makes the interpretation of F0 variations quite difficult. However, some similar trends were observed for F0 ranges in the three speeches. They all have a wide range, with values close to those obtained for lectures and acting, and larger than those obtained for interviews and conversations (Lucci, 1983; Johns-Lewis, 1986). A wide F0 range may be partly due to high F0 values, which in turn may reflect the frequent occurrence of emphatic stress. Graddol (1986) stated that the F0 range is a speech-style marker. The present results suggest that a wide F0 range is a characteristic of public modes, e.g. of public address for a multiple audience. The mean-F0 values were found to be higher in the two presidential speeches (more particularly in the 1984 one) than in the opponent speech. If one assumes that Mitterrand is more dominant and self confident in the former speeches than in the latter, the tendencies observed mean that F0 values disagree with the findings on pitch symbolism in which low pitch is associated with aggressivity, dominance while the meaning of high pitch is non threatening, submissive, in need of the receiver cooperation (Ohala, 1983 and 1984). One of the reasons for this difference may be Mitterrand’s age (66 years old in 1983) since the average F0 of men appears to rise from about 65 years on (Helfrich, 1979). A second reason may be a tendency to stay within a relatively larger range of frequencies in the presidential speeches, giving them a more solemn tone: mean-F0 values increase as there is less intimacy and greater distance between the interactants (Johns-Lewis, 1986). A third reason may be the experimental and measurement procedures adopted here. Mean F0 and F0 range are global measures which do not give account of the F0 contours, that change over time. In a perceptual investigation of spontaneous-speech samples in which F0 was shifted downward or upward, Ohala (1984) has shown that a steep terminal fall was the one feature which contributed most to making a voice dominant. The present analysis constitutes but a first attempt to explore the role of F0 in the process of persuasion and political power. Further research is needed to investigate the way in which F0 contours are involved in communicating power situations and used to induce the appropriate emotions and attitudes in the listener. 9 Of greater interest are the results obtained for the temporal variables. An increase in articulation rate has been found to be linked to a speaker's degree of practice (Goldman-Eisler, 1968) and to the formalness of the style (Duez, 1982-91). The present results suggest that being in a situation of power has an effect on articulation rate. As a challenger, Mitterrand wanted to accumulate arguments, and increased articulation rate in order to do so. As the incumbent president, Mitterrand was master of the situation; he controlled his speech time and kept a relatively slow articulation rate. Interestingly, articulation rate in the two presidential speeches (4.5 syll./sec) is close to that obtained for Georges Pompidou’s presidential speech (Duez, 1982-91). The results obtained for pause time in the three speeches confirm previous findings on political speeches, and in a more general way, on speech styles with an illocutionary function. In this type of speech, pause distribution correlates with the syntactic structure of the text, making decoding easier: speakers approach "ideal communication" as defined by GoldmanEisler (1968). However, speakers do not seem to be solely concerned with marking syntactic boundaries. Sometimes, they neglect to mark sentence boundaries while at other times making strikingly long pauses or unexpected pauses. In the present case, the longest pauses lasted more than 2000 ms, which is close to the rhetorical pauses reported by Clemmer, O’Connell, and Loui (1979) and Kowal (1982). Unexpected pauses were most often associated with an emphatic accent. Their occurrence strikes the listener and helps emphasize the next word or the next argument. The existence of such pauses has also been noted in studies on President de Gaulle’s political speeches (Léon, 1971), on American and German speeches (Kowal, 1982), and in American sermons (Gumperz, 1982). They may be an enhancement technique favored by public speakers. A comparison of the silent pause time of the three speeches allowed us to characterize each one. In the speech produced in 1974, pauses tended to be less frequent and their duration was close to that of pauses in Mitterrand’s interviews (Duez, 1982-91). As an opponent and a challenger, Mitterrand had to use time as efficiently as possible. In the presidential speech of 1984, pauses were strikingly long and frequent, especially at sentence and phrase boundaries. Mitterrand did not have to argue to justify a program; he had power and explained a decision calmly and gravely. Pause time allowed him to maintain a balance between what was being said and what was left unsaid. Interestingly, a similar use of pause duration was found in Georges Pompidou’s speech mentioned above (Duez, 1982-91). In the 1988 speech, pause time was intermediate between that of the 1974 and 1984 speeches. It reflects Mitterrand’s specific situations: both president and candidate. As a candidate, Mitterrand tried to sway as many voters as he could to his side. One way to do so was to fill time with ideas and arguments. As the incumbent President, he could be satisfied with striking the balance. According to Gerstlé (1992), Mitterrand’s late declaration and intervention intended to reduce the distance between the president and a "president-candidate" as much as possible. The results obtained for articulation rate and speech pause time are clearly in line with this interpretation. A slow articulation rate and silence may be speech markers of power. Temporal variables may be regarded as power-situation markers in political speeches. In a more general way, they may reflect the social distance which exists between politicians and their listeners. The relationship between the social distance, the interpersonal distance and the speaker's voice was first investigated by Hall (1959 and 1966). Hall divided distance between participants into four categories (intimate, informal, social-consultative and public) and related each social distance to a specific interpersonal distance and speakers' voice characteristics. For example, the public distance (the one of interest here) is characterized by the so-called "icy style" i.e. the style typical of individuals meant to remain strangers to each other (as defined by Joos, 1962). A careful articulation, a loud voice and a slow speech rate 10 are features of this style. The specific temporal organisation (slow articulation rate and pause time) in Mitterrand's presidential speeches perfectly examplifies some aspects of the icy style. It may be used to symbolize to the extreme the public distance which separates the president from his fellow citizens. However, the above assumption raises a certain number of questions, one of them being its representativeness. Although Mitterrand’s political speeches reflect symbolic power situations, our data concern a single French speaker in very specific roles. This investigation must be extended to other speakers, other activity types, and other cultures. Another question is how listeners use temporal variables to evaluate the speaker’s relationship with power. For example, studies on identification of a speaker's profession have shown that even though this is a difficult task, subjects'responses are never at random. Prosodic cues allow listeners to identify professions and styles (Fónagy and Fonagy, 1976; and Fonagy, 1978). 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