Pitch-Matching Accuracy in Trained Singers and Untrained Individuals: The Impact of Musical Interference and Noise

Transcription

1 Pitch-Matching Accuracy in Trained Singers and Untrained Individuals: The Impact of Musical Interference and Noise Julie M. Estis, Ashli Dean-Claytor, Robert E. Moore, and Thomas L. Rowell, Mobile, Alabama Summary: The effects of musical interference and noise on pitch-matching accuracy were examined. Vocal training was explored as a factor influencing pitch-matching accuracy, and the relationship between pitch matching and pitch discrimination was examined. Twenty trained singers (TS) and 20 untrained individuals (UT) vocally matched tones in six conditions (immediate, four types of chords, noise). Fundamental frequencies were calculated, compared with the frequency of the target tone, and converted to semitone difference scores. A pitch discrimination task was also completed. TS showed significantly better pitch matching than UT across all conditions. Individual performances for UT were highly variable. Therefore, untrained participants were divided into two groups: 10 untrained accurate and 10 untrained inaccurate. Comparison of TS with untrained accurate individuals revealed significant differences between groups and across conditions. Compared with immediate vocal matching of target tones, pitch-matching accuracy was significantly reduced, given musical chord and noise interference unless the target tone was presented in the musical chord. A direct relationship between pitch matching and pitch discrimination was revealed. Across pitch-matching conditions, TS were consistently more accurate than UT. Pitch-matching accuracy diminished when auditory interference consisted of chords that did not contain the target tone and noise. Key Words: Pitch matching Pitch discrimination Pitch memory Musical interference Singers. INTRODUCTION Singing is a complex process, using the respiratory, phonatory, resonatory, articulatory, and auditory systems to create melodious vocal tones. In the general population, there is a significant variation in singing ability. Individuals may be classified as accurate singers or inaccurate singers. To sing accurately, individuals must first be able to accurately hear, differentiate, store, and then vocally reproduce pitches. Inaccurate singers, or monotones, may have difficulty with these abilities. 1 Thus, pitch discrimination and pitch-matching tasks may be useful in understanding factors that differentiate accurate singers from those who are unable to sing accurately. Trained musicians and singers perform more accurately on pitch discrimination and pitch-matching tasks than most untrained individuals (UT). 2 4 Research suggests reliance on working memory during pitch discrimination tasks. 5 7 Adding time delays between tones, 8 presenting tonal interference between the reference tone and comparison tone, 6,9 and using tones of differing timbre 10,11 negatively affect pitch discrimination accuracy. In addition to discriminating between two individual pitches, individuals also determine differences between combinations of pitches. Hubbard 12 investigated the ability to discriminate major triad chords in different positions (ie, tonic, first inversion, and others). A chord is the simultaneous sounding of more than two notes at a time. A triad consists of three specific notes sounded simultaneously. It is considered to be in root position when all of the intervals between the notes are in thirds, Accepted for publication October 23, From the Department of Speech Pathology and Audiology, College of Allied Health Professions, University of South Alabama, Mobile, Alabama. Address correspondence and reprint requests to Julie M. Estis, Ph.D., CCC-SLP, Department of Speech Pathology and Audiology, College of Allied Health Professions, HAHN 1119, 307 N. University Blvd., Mobile, AL jestis@usouthal.edu Journal of Voice, Vol. 25, No. 2, pp /$36.00 Ó 2011 The Voice Foundation doi: /j.jvoice with the bottom note being the tonic note, or root, of the major or minor scale on which it is based (eg, a C major chord consists of the notes middle C, E, and G). Conversely, it is said to be an inversion when the bottom note of the chord is either the third or fifth of the triad (eg, the first inversion of a C major chord consists of the notes E [third], G [fifth], and C [tonic]). The stimulus triads were simple major triads, so that people could participate in the study, regardless of musical training. All participants were considered untrained. Participants were asked to determine whether or not two sequentially presented target chords were the same or different. Results of the study indicated that listeners could accurately discriminate chords based on the same root note. Hence, whether or not the chord was in root position, or inverted, the participants could tell if the chords were the same, or different, harmonically. These results imply that the ability to discriminate among the triads is based on cognitive processes rather than on perception of harmonics alone or on previous musical training. Most research investigating pitch processing and pitch memory has focused on pitch discrimination tasks. Although findings from pitch discrimination tasks may be implied for pitch-matching abilities, it is necessary to systematically and directly study pitch-matching abilities in a variety of populations and with varied types of stimuli and interference to understand the relationship between pitch processing and vocal production of pitch. Thus, many aspects of pitch matching remain uncertain. The known prerequisites for accurate pitch matching include accurate pitch discrimination skills, normal auditory functioning, and good control of the vocal mechanism. 11 Auditory feedback has also been shown to play an important part in accurate pitch matching, particularly for trained and professional singers. 13 Much like pitch discrimination, pitch-matching skills are also known to vary across populations (eg, TS vs UT). Estis et al 14 investigated pitch memory in a pitch-matching task, specifically exploring the role of time delays on pitch-

2 174 matching ability. Results of the study indicated decreased pitchmatching accuracy with increasing time intervals of silence (5, 15, and 25 seconds) between the presentation of target tones and vocal pitch-matching productions. Also, this study indicated that some individuals with no formal vocal training performed as well as vocally trained individuals, whereas a subset of UT performed poorly on all pitch-matching tasks. It remains to be determined which types of interference (eg, time, vocal tones, pure tones, chords, and others) are most detrimental to pitch-matching performance. In addition, there has been evidence to suggest a relationship between abilities in pitch discrimination and pitch matching; however, research in this area has resulted in mixed findings based on the populations studied and the tasks used to measure pitch discrimination performance. 3,6,11 Therefore, the purpose of the present investigation was to determine the effects of different types of auditory interference between stimuli and vocal match productions on pitch matching in males and females as well as to further investigate the relationship between pitch discrimination and pitchmatching abilities. This study also investigated the relationship between vocal training and pitch-matching abilities with various types of interference, by including two groups of participants: trained singers (TS) and UT. The different types of interference were musical chords of varying relation to the target tones and pink noise. If tonal information and speech information are held within specialized mechanisms in working memory, then chords, particularly ones that are less related to the target, should be detrimental to pitch memory and ultimately pitch matching. The following research questions were addressed: 1. Are there differences in pitch-matching accuracy given various types of interferences (musical chords with target in root position, musical chords with the root a perfect fourth away from the target, musical chords with the root a major second away from the target, unrelated minor second chords an octave away, and pink noise) among TS and UT? 2. Is there a relationship between the ability to discriminate between pitches and the ability to match pitches? METHODS Participants The participants were 20 females and 20 males between the ages of 19 and 32 years (mean [M] ¼ 23.05, standard deviation [SD] ¼ 3.08). All participants were native speakers of English; had no significant history of voice pathology or voice treatment; demonstrated adequate vocal function as evidenced by jitter (frequency perturbation), shimmer (amplitude perturbation), and noise-to-harmonic ratio (amount of noise in the signal) within one SD of the mean, as calculated by Multi-Dimensional Voice Profile-Advanced (MDVP-A) voicing analysis software version and compared with MDVP-A database means and SDs; and passed an audiometric hearing screening. Participants were divided into two groups based on vocal training. Twenty participants were TS. Participants in the TS group had a minimum of 3 years of individual voice training and at Journal of Voice, Vol. 25, No. 2, 2011 least 1 year of collegiate musical theory. The remaining 20 participants were UT who had no individual training from a professional vocal instructor. Stimuli For all pitch-matching tasks, stimuli were complex tones with the following fundamental frequencies: 262 (C4), 294 (D4), 330 (E4), 348 (F4), and 392 Hz (G4) for female participants; and 131 (C3), 147 (D3), 164 (E3), 175 (F3), and 196 Hz (G3) for male participants. These frequencies were chosen because they are within the normal singing range of females and males in the third and fourth octaves of the musical scale. Tones and chords were generated using a Yamaha Portable Grand keyboard (model YPG-625; Buena Park, CA) on a piano setting. The stimuli were then recorded and saved onto a computer as WAV files. Stimuli were edited with Adobe Audition (version 1.5) such that each tone had a duration of 1.5 seconds and was gated on and off with 10-millisecond linear ramps. Stimuli for the five interference conditions were created for each target note (Table 1). For the five interference conditions, there was a 1.5-second silence interval between the target tone and the interference (chords or noise), which also had a duration of 1.5 seconds. There were four chord interference conditions. In the first condition (chord 1), the target tone was the root note of the interfering chord, which was a major triad (eg, for the C3 and C4 targets, the interfering chord was C E G). In the second condition (chord 2), the root of the interference chord was a perfect fourth above the target (eg, for the D3 and D4 targets, the interfering chord was G B D). In the third condition (chord 3), the interfering chord had a root note that was a major second above the target (eg, for the E3 and E4 targets, the interfering chord was F] A] C]); and in the fourth condition (chord 4), the interfering chord had a root note that was an interval of an octave plus a minor second, or ninth, above the target tone (eg, for the F3 and F4 targets, the interfering chord was be G [ B [ D [ ). It should be noted that the target note in its root position was sounded in chord 1, at the interval of a perfect fifth in chord 2, and was not sounded in chords 3 and 4. The progression of the four triadic conditions systematically increased intervallic distance or harmonic association from the target pitch. In addition to four types of musical interference, an aperiodic noise condition was created. Specifically, pink noise with a spectrum similar to that of speech was generated with Adobe Audition sound editing software (version 1.5). For the pitch discrimination task, Adobe Audition sound editing software (version 1.5) was used to create complex tonal stimuli. Five complex tones were created for the male and female participants based on the normal signing range for males and females. The frequencies for the male participants were 104, 107, 110, 113, and 116 Hz. The frequency interval between complex tones was 50 cents. Each tone had a duration of 1.5 seconds and was gated on and off with 10-millisecond linear amplitude ramps. Each complex tone was paired with each of the other complex tones and with an identical complex tone for a total of 25 pairs of tones. This resulted in tone pairs differing by 0, 50, 100, 150, or 200 cents. Each tone in a pair was separated by a 0.5-second silent interval. Five complex

3 Julie M. Estis, et al Musical Interference and Noise Impact Pitch Matching 175 TABLE 1. Complex Tones and Interfering Chords for Pitch-Matching Tasks Males Females Target Note Coordinating Frequency (Hz) Chords Target Note Coordinating Frequency (Hz) Chords C : C E G C4 262 Chord 1: C E G 2: F A C Chord 2: F A C 3: D F] A Chord 3: D F] A 4: D [ FA [ Chord 4: D [ FA [ D : D F] A D4 294 Chord 1: D F] A 2: G B D Chord 2: G B D 3: E G] B Chord 3: E G] B 4: E [ GB [ Chord 4: E [ GB [ E : E G] B E4 330 Chord 1: E G] B 2: A C] E Chord 2: A C] E 3: F] A] C] Chord 3: F] A] C] 4: F A C Chord 4: F A C F : F A C F4 348 Chord 1: F A C 2: B [ D F Chord 2: B [ DF 3: G B D Chord 3: G B D 4: G [ B [ D [ Chord 4: G [ B [ D [ G : G B D G4 392 Chord 1: G B D 2: C E G Chord 2: C E G 3: A C] E Chord 3: A C] E 4: A [ CE [ Chord 4: A [ CE [ tones were created for the female participants in the same manner at 200, 206, 212, 218, and 224 Hz. Tonal stimuli were presented via a Fostex 7301B3E (Tokyo, Japan) amplified speaker at 75 db sound pressure level (SPL) for all experimental tasks. Volume settings were measured before the onset of the study to ensure that all output was consistently at 75 db SPL. In addition, sound level measurements were repeated after the study to ensure that output level remained consistent. Procedures All procedures were conducted during a 1-hour session in a double-walled, sound-attenuated booth. Preexperimental tasks were completed first. Participants read and signed a Statement of Informed Consent. A bilateral pure tone hearing screening was conducted using a Grason-Stadler, Inc (GSI-17; Milford, NH) portable audiometer, calibrated in compliance with American National Standards Institute 15 guidelines. Pure tones at 500, 1000, 2000, and 4000 Hz were presented at 25 db HL via TDH 50 (Telephonics, Farmingdale, NY) supra-aural headphones. Participants were instructed to raise their hand when a tone was heard. Failure to respond at any frequency at either ear precluded participation in the study. Voice analysis was completed using the MDVP-A to ensure that there were no current voice problems that may have adversely affected performance on pitch-matching tasks or accuracy of acoustic measurement of pitch-matching responses. A head-mounted microphone was placed at approximately 3 4 cm from the left corner of each participant s mouth for recording responses. Participants sustained the /a/ sound at a comfortable loudness level for 4 seconds. The subsequent vocal responses were routed through the head-mounted microphone, then digitized at a sampling rate of 48.8 khz, and recorded and timed by the MDVP-A software. Responses were recorded and analyzed using the Computerized Speech Lab (CSL) and MDVP-A software to determine if jitter, shimmer, and noiseto-harmonic ratio values were within 1 SD of the mean based on the MDVP-A database. After preexperimental procedures, all participants completed an immediate pitch-matching task, a pitch matching with interference task, and a pitch discrimination task, in that order. For all pitch-matching tasks, stimulus tones were presented one at a time via a Fostex 7301B3E amplified speaker. Each tone was presented twice randomly. During the immediate pitchmatching task, participants listened to each stimulus tone and then attempted to vocally match the pitch of each target tone by sustaining /a/ for 4 seconds immediately after presentation of the stimulus. Responses were timed and analyzed using the MDVP-A software. Participants pitch-matching responses were recorded via the head-mounted microphone, digitized at a 48.8 khz sampling rate by the CSL and saved to the computer s hard drive for MDVP-A analysis. For the pitch matching with interference tasks, participants listened to each stimulus tone followed by a musical chord (chords 1 4) or pink noise and attempted to vocally match the targets by producing an /a/ sound immediately after the interference. The stimuli were randomized by ECos/Win stimulus presentation software (AVAAZ Innovations, Inc., Ontario, Canada). Each target note (C, D, E, F, and G) was presented twice for each condition, which resulted in a total of 50 vocal responses.

4 176 For the pitch discrimination paradigm, participants were seated at a desk in front of a computer monitor and a mouse. Each participant was seated approximately 1 m away from a Fostex 7301B3E amplified speaker, from which pairs of complex stimulus tones were presented one at a time. Participants were asked to discriminate between the presented stimuli. Participants received instructions to judge whether the tones presented were the same in pitch or if they were different in pitch by selecting either same or different on the computer screen with the mouse. Participants completed two experimental blocks for a total of 50 pitch discrimination trials. For each block, 25 pitch discrimination stimulus pairs were presented randomly by the ECos/Win presentation software. Participant responses and progress were monitored by the researcher via a networked computer from outside the room. RESULTS For the pitch-masking tasks, the average semitone difference between the two attempted vocal matches and each target tone was used to measure the dependent variable, pitch-matching accuracy. The fundamental frequency (F 0 ) of the target complex tone and average F 0 of the pitch-matching attempts were used to calculate difference in semitones with the following formula: sds ¼ 12 log 10 f 2 log 10 f 1 log 10 2 where sds is semitone difference scores, f 1 is F 0 of the target tone, and f 2 is the absolute value of the average F 0 of trials 1 and The average semitone difference was calculated in this manner for the immediate and five interference pitchmatching conditions for each target note. Pitch discrimination accuracy, a second dependent variable, was measured by calculating percent correct scores on the pitch discrimination task for each participant (eg, [no. correct judgments/no. total judgments in trial] ¼ % correct pitch discrimination judgments). Descriptive and statistical analyses of pitchmatching accuracy Individual performances on the pitch-matching tasks for each condition are shown in Figures 1 6. Mean semitone difference scores and SDs were calculated across all pitch-matching conditions for each group: TS and UT (Table 2). Examination of individual performances, as well as group means and SDs, for pitch-matching accuracy revealed consistently accurate performance across TS, whereas UT presented varying abilities. This variability within the UT groups is evidenced by large SDs. In fact, 10 out of 20 of the UT showed an average semitone difference from the target tones of more than 1 semitone in the immediate pitch-matching Some UT, however, displayed pitch-matching abilities similar to the TS. To determine if training significantly impacted pitchmatching performance, given musical chord and noise interference, an omnibus, 2 (group) 3 6 (pitch-matching conditions) repeated-measures analysis of variance (ANOVA) with vocal training as the between-subjects factor and pitch-matching Journal of Voice, Vol. 25, No. 2, 2011 FIGURE 1. Individual mean semitone difference scores in the immediate pitch matching condition as the within-subjects factor was performed. Results showed a significant main effect for group (TS vs UT) F(1,38) ¼ , P < 0.001, h 2 p ¼ with TS showing significantly better pitch-matching accuracy than UT. There was no significant main effect of pitch-matching condition and no significant interaction. Examination of individual performances as well as group means and SDs revealed high variability in the UT, with some individuals presenting very poor accuracy across all pitchmatching conditions. To further explore differences across pitch-matching conditions, the UT was divided based on pitch-matching accuracy in the immediate pitch-matching Two groups of UT were created: UT-accurate (UT-A) (10 participants with mean semitone difference scores less than 1 semitone from the target tone; M ¼ , SD ¼ ) and UT-inaccurate (UT-I) (10 participants with mean difference scores more than 1 semitone from the target tone; M ¼ , SD ¼ ). This division of participants based on performance led to three groups with significantly FIGURE 2. Individual mean semitone difference scores in chord 1

5 Julie M. Estis, et al Musical Interference and Noise Impact Pitch Matching 177 FIGURE 3. Individual mean semitone difference scores in chord 2 FIGURE 5. Individual mean semitone difference scores in chord 4 different pitch-matching accuracy in the immediate pitchmatching condition F(2,37) ¼ , P < 0.001, h 2 p ¼ See Figure 7 for group means and SDs for semitone difference scores across pitch-matching conditions. Because the UT-I group performed poorly on pitch-matching tasks regardless of interference, examination of the impact of interference on pitch matching was compared between the TS group and the UT-A group. Therefore, descriptive statistics and a 2 (group) 3 6 (condition) repeated-measures ANOVA with group as the between-subjects factor and pitch-matching condition as the within-subjects factor were conducted. Mauchly s test of sphericity was significant, indicating that sphericity could not be assumed (w ¼ 0.032, P < 0.001); therefore, Huynh-Feldt corrections were used. A significant main effect for pitchmatching condition was shown F(2.608,73.036) ¼ 4.255, P ¼ 0.011, h 2 p ¼ The accuracy of the TS diminished with several conditions; however, their performance was more consistent and accurate than that of the UT-A group. Analysis of between-subject effects yielded a significant main effect for group F(1,28) ¼ 5.651, P ¼ 0.016, h 2 p ¼ The interaction was nonsignificant. Post hoc pairwise comparisons revealed that chord 2 (P ¼ 0.007), chord 3 (P < 0.001), chord 4 (P < 0.001), and noise (P ¼ 0.007) interference conditions were significantly different from performance in the immediate Also, there is a significant difference in performance between the chord 3 and chord 4 conditions and between the chord 3 and the noise conditions. Descriptive and statistical analyses of pitch discrimination To examine the relationship between pitch discrimination and pitch-matching skills, which the fourth research question in the current study raised, pitch discrimination accuracy (measured in percent correct scores) descriptive and statistical analyses were conducted. SDs were calculated for each group. Mean percent correct scores were calculated for each individual (Figure 8). Group means were higher for TS (M ¼ 94%, SD ¼ ) than UT (M ¼ 82%, SD ¼ ). FIGURE 4. Individual mean semitone difference scores in chord 3 FIGURE 6. Individual mean semitone difference scores in the noise

6 178 Journal of Voice, Vol. 25, No. 2, 2011 TABLE 2. Group M and SD of Semitone Difference Scores for TS and UT Trained Singers Untrained Individuals Pitch-Matching Condition M SD M SD Immediate Chord Chord Chord Chord Noise A 1 (pitch discrimination accuracy) 3 2 (group) ANOVA was conducted to determine if differences in pitch discrimination accuracy existed among the four experimental groups. A significant main effect was found for group F(1,38) ¼ , P < 001, h 2 p ¼ The post hoc pairwise comparisons indicated that the TS group performed significantly better on the pitch discrimination task than the UT group. A Pearson product-moment correlation revealed a significant correlation between overall pitch discrimination scores and immediate pitch-matching accuracy (r ¼ 575, P ¼ <0.001), across all participants. The shared variance between pitch discrimination performance and pitch-matching accuracy was 33% (r 2 ¼ 0.331). DISCUSSION Group differences in pitch-matching accuracy Primarily, this study sought to investigate the impact of specific types of auditory interference on pitch-matching abilities in TS and UT, specifically using musical chords with target in root position (chord 1); musical chords with the root a perfect fourth above the target and the target sounding as the fifth of the chord (chord 2); musical chords with the root a major second away from the target or supertonic (chord 3); unrelated chord a ninth away (chord 4); and pink noise (noise), which were then compared with pitch-matching accuracy immediately after target tone presentation (immediate). It was proposed that TS would have superior pitch-matching abilities when compared with UT, and that some untrained singers would possess abilities similar to their trained counterparts. This was in accordance with findings from previous studies. 1,11,14 As expected, between-group differences existed in pitch-matching performance across all pitch-matching conditions. The TS were consistently accurate when vocally matching target tones. The untrained group of participants, however, showed varied levels of pitch-matching accuracy, with some individuals nearly as accurate as the TS and others very inaccurate, producing responses several musical notes away from the target tones. Untrained participants were further grouped according to pitch-matching accuracy in the immediate condition (10 untrained accurate participants and 10 untrained inaccurate participants) for additional analysis of pitch-matching accuracy across the experimental conditions. Timbre and time have been found to negatively impact pitchmatching abilities in both TS and UT. 1,11,14 The current investigation adds to these findings, suggesting that pitch-matching accuracy is reduced when some types of musical chord interference and noise interference are presented to TS and untrained accurate participants. The chord 1 condition yielded pitchmatching accuracy similar to that in the immediate condition as expected. For the chord 1 and chord 2 conditions, the target tone was in the root or fifth position of the chords, giving participants an opportunity to hear the target tone a second time. FIGURE 7. Mean semitone difference scores for TS, UT-A, and UT-I groups. FIGURE 8. Individual percent correct scores in the pitch discrimination task.

7 Julie M. Estis, et al Musical Interference and Noise Impact Pitch Matching 179 However, chords that did not contain the target tone (chord 3 and chord 4 conditions) negatively impacted pitch-matching accuracy. As anticipated, results showed increasingly significant differences between the immediate condition and chord 2, chord 3, and chord 4 conditions. The chord 3 (musical chords with the root a major second away from the target) and chord 4 (unrelated chord a ninth above) conditions were found to be most detrimental to the untrained accurate singers when compared with their scores in the immediate Noise interference also significantly reduced pitch-matching accuracy. In summary, the current study reveals that TS have pitch-matching skills superior to those of UT. However, some UT demonstrate pitch-matching accuracy similar to TS. This indicates that, in addition to musical exposure and learning, innate factors may play a role in pitch-matching abilities. The consistently accurate performance observed in TS suggests that vocal training fine-tunes the underlying mechanisms involved in pitch matching, thereby enhancing pitch-matching accuracy. Specifically, practice and training likely improve the efficiency of the vocal mechanism, allowing the TS to quickly and precisely configure the vocal folds for production of a specific pitch. Additionally, musical training yields improved cognitive representations for musical notes, enhancing the efficiency of the perceptual and memory resources for pitch. Group differences in pitch discrimination accuracy The second research question addressed the relationship between pitch discrimination and pitch matching. For the current study, it was proposed that TS would perform better in the pitch discrimination task than their untrained counterparts based on the findings of Amir et al, 17 which showed enhanced auditory abilities of TS compared with those of UT. As expected, between-group differences existed among participants for the pitch discrimination task. In accordance with findings from similar studies, it was also hypothesized that pitch discrimination and pitch matching would be correlated given overlapping systems involved in these tasks. 11,17 19 Results showed a strong relationship between pitch discrimination and pitch matching. Overall, participants who displayed accurate pitch discrimination skills also showed accurate pitch discrimination skills and vice versa. It is important to note that 10 out of the 20 UT in this investigation were considered inaccurate with average mean semitone differences of at least 1 semitone away from the target. Of those 10, two showed good pitch discrimination skills but had extremely poor pitch-matching skills, as they were each approximately 3 semitones off of the target in the immediate pitch-matching conditions. Performance of these outliers is similar to that of the participants in an investigation by Bradshaw and McHenry, 18 which examined pitch discrimination and pitch-matching abilities in only inaccurate adults. There was no significant correlation between pitch discrimination and pitch matching. Despite the variability in pitch discrimination among those with poor pitch-matching abilities, a strong overall relationship between pitch discrimination and pitch matching remains. SUMMARY Musical training enhances pitch-matching accuracy. For TS, pitch-matching ability remains strong despite musical and noise interference. Pitch-matching accuracy varies considerably among UT. Those who show accurate pitch matching without a musical background are more susceptible than TS to reduced pitch-matching accuracy when chords that do not contain the target tone and noise interference are presented. Those who are unable to adequately match pitch show poor performance with and without musical and noise interference. This study also supports previous research showing a strong relationship between pitch discrimination and pitch-matching abilities. This study provides insight into the underlying processes involved in pitch matching and pitch discrimination. Results suggest that pitch memory is enhanced by musical training, although some individuals without training appear to show naturally strong pitch memory skills. Questions remain regarding the exact cognitive, perceptual, and physiological mechanisms involved in pitch matching. Future research exploring neurological, auditory, and physiological correlates may explain the variation in pitch matching among the general population and the effects of vocal training on these underlying systems. Results of this study imply that individuals who demonstrate poor pitch matching and poor pitch discrimination may require additional training. For example, vocal function exercises, 20 which require patients to sustain sounds at various frequencies, are used by speech language pathologists to treat a variety of vocal pathologies. Some patients may demonstrate difficulty with these tasks because of reduced pitch perception and pitch-matching abilities. These patients may require modifications to the typical treatment protocol. Also, choral directors and teachers of singing may consider incorporating similar pitch matching and pitch discrimination tasks into their auditioning process to screen UT. This would allow for determination of those who show naturally strong pitch-matching and pitch discrimination abilities. REFERENCES 1. Watts C, Murphy J, Barnes-Burroughs K. Pitch matching accuracy of trained singers, untrained subjects with talented singing voices, and untrained subjects with nontalented singing voices in conditions of varying feedback. J Voice. 2003;17: Fujioka T, Trainor L, Ross B, Kakigi R, Pantev C. Musical training enhances automatic encoding of melodic contour and interval structure. J Cogn Neurosci. 2004;16: Murry T, Zwirner P. Pitch matching ability of experienced and inexperienced singers. J Voice. 1991;5: Schueller M, Bond Z, Fucci D, Gunderson F, Vaz P. Possible influence of linguistic and musical background on perceptual pitch-matching tasks: a pilot study. Percept Mot Skills. 2004;99: Deutsch D. The deterioration of pitch information in memory [unpublished doctoral dissertation]. San Diego, CA: University of California at San Diego; Moore R, Keaton C, Watts C. The role of pitch memory in pitch discrimination and pitch matching. J Voice. 2007;21: Pechmann T, Mohr G. Interference in memory for tonal pitch: implications for a working-memory model. Mem Cogn. 1992;20: Harris J. The decline of pitch discrimination with time. J Exp Psychol. 1952;43:96 99.

8 180 Journal of Voice, Vol. 25, No. 2, Deutsch D. Tones and numbers: specificity of interference in short-term memory. Science. 1970;168: Erickson M, Perry S. Can listeners hear who is singing? A comparison of three-note and six-note discrimination tasks. J Voice. 2003;17: Watts C, Moore R, McCaghren K. The relationship between vocal pitchmatching skills and pitch discrimination skills in untrained accurate and inaccurate singers. J Voice. 2005;19: Hubbard T. Listeners can discriminate among major chord positions. Percept Mot Skills. 1998;87: Mürbe D, Pabst F, Hofmann G, Sundberg J. Significance of auditory and kinesthetic feedback to singers pitch control. J Voice. 2002;16: Estis J, Coblentz J, Moore R. Effects of increasing time delays on pitchmatching accuracy in trained singers and untrained individuals. J Voice. 2009;23: American National Standards Institute. Specification for Audiometers. ANSI S New York, NY: American National Standards Institute; Baken R, Orlikoff R. Clinical Measurement of Speech and Voice. New York, NY: Thomas Learning; Amir O, Amir N, Kishon-Rabin L. The effect of superior auditory skills on vocal accuracy. J Acoust Soc Am. 2003;113: Bradshaw E, McHenry M. Pitch discrimination and pitch matching abilities of adults who sing inaccurately. J Voice. 2005;19: Moore R, Estis J, Gordon-Hickey S, Watts C. Pitch discrimination and pitch matching abilities with vocal and nonvocal stimuli. J Voice. 2008;22: Stemple J, Glaze L, Klaben B. Clinical Voice Pathology: Theory and Management. San Diego, CA: Singular;