Modelling Mandarin tone perception-production link through critical perceptual cues.

Theoretical accounts posit a close link between speech perception and production, but empirical findings on this relationship are mixed. To explain this apparent contradiction, a proposed view is that a perception-production relationship should be established through the use of critical perceptual cues. This study examines this view by using Mandarin tones as a test case because the perceptual cues for Mandarin tones consist of perceptually critical pitch direction and noncritical pitch height cues. The defining features of critical and noncritical perceptual cues and the perception-production relationship of each cue for each tone were investigated. The perceptual stimuli in the perception experiment were created by varying one critical and one noncritical perceptual cue orthogonally. The cues for tones produced by the same group of native Mandarin participants were measured. This study found that the critical status of perceptual cues primarily influenced within-category and between-category perception for nearly all tones. Using cross-domain bidirectional statistical modelling, a perception-production link was found for the critical perceptual cue only. A stronger link was obtained when within-category and between-category perception data were included in the models as compared to using between-category perception data alone, suggesting a phonetically and phonologically driven perception-production relationship.

EEG-based assessment of temporal fine structure and envelope effect in mandarin syllable and tone perception.

In recent years, speech perception research has benefited from low-frequency rhythm entrainment tracking of the speech envelope. However, speech perception is still controversial regarding the role of speech envelope and temporal fine structure, especially in Mandarin. This study aimed to discuss the dependence of Mandarin syllables and tones perception on the speech envelope and the temporal fine structure. We recorded the electroencephalogram (EEG) of the subjects under three acoustic conditions using the sound chimerism analysis, including (i) the original speech, (ii) the speech envelope and the sinusoidal modulation, and (iii) the fine structure of time and the modulation of the non-speech (white noise) sound envelope. We found that syllable perception mainly depended on the speech envelope, while tone perception depended on the temporal fine structure. The delta bands were prominent, and the parietal and prefrontal lobes were the main activated brain areas, regardless of whether syllable or tone perception was involved. Finally, we decoded the spatiotemporal features of Mandarin perception from the microstate sequence. The spatiotemporal feature sequence of the EEG caused by speech material was found to be specific, suggesting a new perspective for the subsequent auditory brain-computer interface. These results provided a new scheme for the coding strategy of new hearing aids for native Mandarin speakers.

Development of Mandarin Lexical Tone Identification in Noise and Its Relation With Working Memory.

PURPOSE: This study aimed to examine the developmental trajectory of Mandarin tone identification in quiet and two noisy conditions: speech-shaped noise (SSN) and multitalker babble noise. In addition, we evaluated the relationship between tonal identification development and working memory capacity. METHOD: Ninety-three typically developing children aged 5-8 years and 23 young adults completed categorical identification of two tonal continua (Tone 1-4 and Tone 2-3) in quiet, SSN, and babble noise. Their working memory was additionally measured using auditory digit span tests. Correlation analyses between digit span scores and boundary widths were performed. RESULTS: Six-year-old children have achieved the adultlike ability of categorical identification of Tone 1-4 continuum under both types of noise. Moreover, 6-year-old children could identify Tone 2-3 continuum as well as adults in SSN. Nonetheless, the child participants, even 8-year-olds, performed worse when tokens from Tone 2-3 continuum were masked by babble noise. Greater working memory capacity was associated with better tone identification in noise for preschoolers aged 5-6 years; however, for school-age children aged 7-8 years, such correlation only existed in Tone 2-3 continuum in SSN. CONCLUSIONS: Lexical tone perception might take a prolonged time to achieve adultlike competence in babble noise relative to SSN. Moreover, a significant interaction between masking type and stimulus difficulty was found, as indicated by Tone 2-3 being more susceptible to interference from babble noise than Tone 1-4. Furthermore, correlations between working memory capacity and tone perception in noise varied with developmental stage, stimulus difficulty, and masking type.

Development of Achieving Constancy in Lexical Tone Identification With Contextual Cues.

PURPOSE: The aim of this study was to explore when and how Mandarin-speaking children use contextual cues to normalize speech variability in perceiving lexical tones. Two different cognitive mechanisms underlying speech normalization (lower level acoustic normalization and higher level acoustic-phonemic normalization) were investigated through the lexical tone identification task in nonspeech contexts and speech contexts, respectively. Besides, another aim of this study was to reveal how domain-general cognitive abilities contribute to the development of the speech normalization process. METHOD: In this study, 94 five- to eight-year-old Mandarin-speaking children (50 boys, 44 girls) and 24 young adults (14 men, 10 women) were asked to identify ambiguous Mandarin high-level and mid-rising tones in either speech or nonspeech contexts. Furthermore, in this study, we tested participants' pitch sensitivity through a nonlinguistic pitch discrimination task and their working memory using the digit span task. RESULTS: Higher level acoustic-phonemic normalization of lexical tones emerged at the age of 6 years and was relatively stable thereafter. However, lower level acoustic normalization was less stable across different ages. Neither pitch sensitivity nor working memory affected children's lexical tone normalization. CONCLUSIONS: Mandarin-speaking children above 6 years of age successfully achieved constancy in lexical tone normalization based on speech contextual cues. The perceptual normalization of lexical tones was not affected by pitch sensitivity and working memory capacity.

Effect of Vibrotactile Stimulation on Auditory Timbre Perception for Normal-Hearing Listeners and Cochlear-Implant Users.

The study tests the hypothesis that vibrotactile stimulation can affect timbre perception. A multidimensional scaling experiment was conducted. Twenty listeners with normal hearing and nine cochlear implant users were asked to judge the dissimilarity of a set of synthetic sounds that varied in attack time and amplitude modulation depth. The listeners were simultaneously presented with vibrotactile stimuli, which varied also in attack time and amplitude modulation depth. The results showed that alterations to the temporal waveform of the tactile stimuli affected the listeners' dissimilarity judgments of the audio. A three-dimensional analysis revealed evidence of crossmodal processing where the audio and tactile equivalents combined accounted for their dissimilarity judgments. For the normal-hearing listeners, 86% of the first dimension was explained by audio impulsiveness and 14% by tactile impulsiveness; 75% of the second dimension was explained by the audio roughness or fast amplitude modulation, while its tactile counterpart explained 25%. Interestingly, the third dimension revealed a combination of 43% of audio impulsiveness and 57% of tactile amplitude modulation. For the CI listeners, the first dimension was mostly accounted for by the tactile roughness and the second by the audio impulsiveness. This experiment shows that the perception of timbre can be affected by tactile input and could lead to the developing of new audio-tactile devices for people with hearing impairment.

Tone perception development in Mandarin-speaking children with cochlear implants.

OBJECTIVE: The purpose of this study was to examine the longer-term effects of cochlear implant (CI) use on tone perception by evaluating improvement in Mandarin tone recognition in children with CIs 2 and 3 years post CI activation, and to explore the effects of implant age, chronological age and duration of CI use on the development of tone perception. METHODS: Tone perception was assessed in 29 bilateral profound hearing impaired children (mean chronological age = 4.6 years, SD = 0.7 years) with unilateral CIs at 24 and 36 months after CI activation using the tone perception subtest in the Mandarin Early Speech Perception (MESP-T) test. RESULTS: Children's tone recognition for tone pairs and individual tones improved significantly between 2 and 3 years post CI use, showing an increase in average tone recognition score from 73.2% to 81.8%, which was significantly higher than chance level (i.e. 50%). There was no significant correlation between tone recognition ability and either implant age or chronological age at two evaluation points. Further analysis revealed that the tone recognition score for tone pair 2-3 was significantly lower than that for other tone pairs except for tone pair 2-4. CONCLUSIONS: Longer CI experience can significantly improve tone recognition ability in CI children between 2 and 3 years post CI activation.

Audiovisual Mandarin Lexical Tone Perception in Quiet and Noisy Contexts: The Influence of Visual Cues and Speech Rate.

PURPOSE: Armed with the theory of embodied cognition proposing tight interactions between perception, motor, and cognition, this study aimed to test the hypothesis that speech rate-altered Mandarin lexical tone perception in quiet and noisy environments could be affected by the bodily dynamic cross-modal information. METHOD: Fifty-three adult listeners completed a Mandarin tone perception task with 720 tone stimuli in auditory-only (AO), auditory-facial (AF), and auditory-facial-plus-gestural (AFG) modalities, at fast, normal, and slow speech rates under quiet and noisy conditions. In AF and AFG modalities, both congruent and incongruent audiovisual information were designed and presented. Generalized linear mixed-effects models were constructed to analyze the accuracy of tone perception across different conditions. RESULTS: In Mandarin tone perception, the magnitude of enhancement of AF and AFG cues across three speech rates was significantly higher than that of the AO cue in the adverse context of noise, yet additional metaphoric gestures did not show significant differences from the facial information. Furthermore, the performance of auditory tone perception at the fast speech rate was significantly better than that at the normal speech rate when the inputs were incongruent between auditory and visual channels in quiet. CONCLUSIONS: This study provided compelling evidence showing that integrated audiovisual information plays a vital role not only in improving lexical tone perception in noise but also in modulating the effects of speech rate on Mandarin tone perception in quiet for native listeners. Our findings, supporting the theory of embodied cognition, are implicational for speech and hearing rehabilitation among both young and old clinical populations.

Visual-Auditory Integration and High-Variability Speech Can Facilitate Mandarin Chinese Tone Identification.

PURPOSE: Previous studies have demonstrated that tone identification can be facilitated when auditory tones are integrated with visual information that depicts the pitch contours of the auditory tones (hereafter, visual effect). This study investigates this visual effect in combined visual-auditory integration with high- and low-variability speech and examines whether one's prior tonal-language learning experience shapes the strength of this visual effect. METHOD: Thirty Mandarin-naïve listeners, 25 Mandarin second language learners, and 30 native Mandarin listeners participated in a tone identification task in which participants judged whether an auditory tone was rising or falling in pitch. Moving arrows depicted the pitch contours of the auditory tones. A priming paradigm was used with the target auditory tones primed by four multimodal conditions: no stimuli (A-V-), visual-only stimuli (A-V+), auditory-only stimuli (A+V-), and both auditory and visual stimuli (A+V+). RESULTS: For Mandarin naïve listeners, the visual effect in accuracy produced under the cross-modal integration (A+V+ vs. A+V-) was superior to a unimodal approach (A-V+ vs. A-V-), as evidenced by a higher d prime of A+V+ as opposed to A+V-. However, this was not the case in response time. Additionally, the visual effect in accuracy and response time under the unimodal approach only occurred for high-variability speech, not for low-variability speech. Across the three groups of listeners, we found that the less tonal-language learning experience one had, the stronger the visual effect. CONCLUSION: Our study revealed the visual-auditory advantage and disadvantage of the visual effect and the joint contribution of visual-auditory integration and high-variability speech on facilitating tone perception via the process of speech symbolization and categorization. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.21357729.

The Effects of Training Variability and Pitch Aptitude on the Overnight Consolidation of Lexical Tones.

PURPOSE: Although variability of training materials has the potential to benefit the learning of lexical tones, the benefit is contingent on an individual's pitch aptitude. Previous studies did not segregate immediate learning and consolidation after an overnight interval, and little is known about how pitch aptitude differences affect consolidation. This study examined whether pitch aptitude predicts overnight consolidation of Cantonese level tones through high-variability (HV) and low-variability (LV) training. METHOD: Two groups of Mandarin-speaking participants were first assessed in terms of pitch threshold and tone discrimination, which tapped into different aspects of pitch aptitude. They then received Cantonese level tone identification training in either an HV or an LV condition. The participants were trained in the evening, were tested after training, and returned after 24 hr for overnight consolidation assessment. RESULTS: The results indicate that pitch aptitude, measured through pitch threshold, may have predicted overnight consolidation and training progress of the HV group but not those of the LV group. In the HV group, compared with high-aptitude learners, low-aptitude learners benefited temporarily from training variability but did not consolidate the tonal knowledge as much as their high-aptitude counterparts did after 24 hr. CONCLUSIONS: The findings suggest that individual learners had difficulty learning nonnative tones by virtue of memory consolidation. Higher pitch aptitude ability (pitch threshold) may provide protection against the decay of learned tones and facilitate tone consolidation. The findings imply that the early emergence of tonal representation is a dynamic process among individuals of nonnative speakers who are exposed to training variability. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.20539998.

Age-Related Differences of Mandarin Tone and Consonant Aspiration Perception in Babble Noise.

PURPOSE: This study investigated the categorical perception of Mandarin tones and consonant aspiration contrasts in babble noise among adults and adolescents aged 12-14 years, and explored the association between working memory and categorical perception. METHOD: Twenty-four adults and 20 adolescents with Mandarin as their native language were recruited. Their performances of phonemic identification and discrimination in babble noise and quiet conditions, digit span tasks, and nonword repetition were assessed. RESULTS: Results indicated that, firstly, in the noise condition, both adults and adolescents showed wider boundary widths and lower between-category accuracies when perceiving aspiration of consonants than in the quiet condition, and the categorical boundary of tone perception in adolescents showed a transitional tendency toward Tone 1. Secondly, discrimination of consonant aspiration in adolescents needed to be further developed. Lastly, the accuracy of nonword repetition in adolescents was lower than that in adults, and adults with better auditory verbal working memory had better performance on tone perception. CONCLUSIONS: Our results provided evidence that tone perception is acquired easier than consonant aspiration perception, and tone perception is more robust and less susceptible to noise interference. Categorical perception performance relates to the capacity and utilization of auditory verbal working memory in some ways.

Categorical Perception of Lexical Tones in Mandarin-Speaking Seniors.

PURPOSE: This study aims to investigate the different degeneration processes of categorical perception (CP) of Mandarin lexical tones in the normal aging population and the pathological aging population with mild cognitive impairment (MCI). METHOD: In Experiment I, we compared the identification and discrimination of Tone 1 and Tone 2 across young adults, seniors aged 60-65 years, and older seniors aged 75-80 years with normal cognitive abilities. In Experiment II, we compared lexical tone identification and discrimination across young adults, healthy seniors, and age-matched seniors with MCI. RESULTS: In Experiment I, tone perception was intact in seniors aged below 65 years. Those aged above 75 years could also maintain normal tone identification, whereas they showed poorer tone discrimination correlated with age-related poorer hearing level. In Experiment II, healthy seniors showed normal CP of Mandarin tones. Tone identification was also normal in those with MCI, whereas their tone discrimination had significantly degenerated. CONCLUSIONS: In the normal aging population, age-related hearing loss decreased signal audibility, accounting for poorer discrimination of Mandarin lexical tones in seniors above 75 years. In the pathological aging population with MCI, the poorer discrimination of lexical tones may be attributed to the additive effect of age, hearing loss, and cognitive impairment (e.g., impaired working memory and long-term phonological memory). This study uncovered the roles of low-level sensory processing and high-level cognitive processing in lexical tone perception in the Chinese aging population.

A New System of Cantonese Tones? Tone Perception and Production in Hong Kong South Asian Cantonese.

Studies in language contact have identified many instances of linguistic variation and grammatical innovations introduced by speakers from multi-ethnic urban neighborhoods. This study focuses on the variety of Cantonese spoken by South Asian youths in Hong Kong, specifically their production and perception of Hong Kong Cantonese tones. Our findings show that the South Asian Cantonese speakers have a smaller tonal inventory than the canonical six-tone system of standard Hong Kong Cantonese and their tonal discrimination abilities are also more impoverished relative to their ethnic Chinese peers. Further analysis shows a positive correlation between tonal discrimination accuracy and tonal realization distinctness among the South Asian speakers, but not among the ethnic Chinese. These findings suggest that South Asian Cantonese speakers might have developed a distinct tone system from their ethnic Chinese peers.

Dialect Effects on Mandarin Tone Perception Development.

This study aimed to characterize factors that influence early dialect development in a language environment with multiple dialects. Children were evaluated for these dialect effects compared with normal hearing referenced measures of speech and language development that are commonly implemented in hearing-impaired children. Dialect exposure and use were assessed longitudinally in Chinese children (2-6 years old) that were raised in a community where Putonghua (PTH) and Sichuanhua (SCH) Mandarin dialects were used. Lexical tones in these dialects are different. A total of 20 boys and 20 girls (2 years old at the beginning of the study) that attended the same nursery school were included in this study. SCH was used by the majority of subjects <4 years old. The majority of subjects >4 years old used either dialect, with a few users of both dialects at this age. PTH tone perception did not differ significantly as a function of dialect use. Tone recognition and discrimination were >90% accurate by 6 years old, in contrast to previous results for children with minimal exposure and use of PTH. Children with approximately ⩾50% PTH exposure might be accurately assessed with norm-referenced speech materials spoken in PTH, regardless of their preferred dialect. However, the current norm-referenced assessments of children with minimal PTH exposure and nonusers of the dialect might be inaccurate.

Pure tone discrimination with cochlear implants and filter-band spread.

For many cochlear implant (CI) users, frequency discrimination is still challenging. We studied the effect of frequency differences relative to the electrode frequency bands on pure tone discrimination. A single-center, prospective, controlled, psychoacoustic exploratory study was conducted in a tertiary university referral center. Thirty-four patients with Cochlear Ltd. and MED-EL CIs and 19 age-matched normal-hearing control subjects were included. Two sinusoidal tones were presented with varying frequency differences. The reference tone frequency was chosen according to the center frequency of basal or apical electrodes. Discrimination abilities were psychophysically measured in a three-interval, two-alternative, forced-choice procedure (3I-2AFC) for various CI electrodes. Hit rates were measured, particularly with respect to discrimination abilities at the corner frequency of the electrode frequency-bands. The mean rate of correct decision concerning pitch difference was about 60% for CI users and about 90% for the normal-hearing control group. In CI users, the difference limen was two semitones, while normal-hearing participants detected the difference of one semitone. No influence of the corner frequency of the CI electrodes was found. In CI users, pure tone discrimination seems to be independent of tone positions relative to the corner frequency of the electrode frequency-band. Differences of 2 semitones can be distinguished within one electrode.

Infant Pitch and Timbre Discrimination in the Presence of Variation in the Other Dimension.

Adult listeners perceive pitch with fine precision, with many adults capable of discriminating less than a 1 % change in fundamental frequency (F0). Although there is variability across individuals, this precise pitch perception is an ability ascribed to cortical functions that are also important for speech and music perception. Infants display neural immaturity in the auditory cortex, suggesting that pitch discrimination may improve throughout infancy. In two experiments, we tested the limits of F0 (pitch) and spectral centroid (timbre) perception in 66 infants and 31 adults. Contrary to expectations, we found that infants at both 3 and 7 months were able to reliably detect small changes in F0 in the presence of random variations in spectral content, and vice versa, to the extent that their performance matched that of adults with musical training and exceeded that of adults without musical training. The results indicate high fidelity of F0 and spectral-envelope coding in infants, implying that fully mature cortical processing is not necessary for accurate discrimination of these features. The surprising difference in performance between infants and musically untrained adults may reflect a developmental trajectory for learning natural statistical covariations between pitch and timbre that improves coding efficiency but results in degraded performance in adults without musical training when expectations for such covariations are violated.

The effects of native prosodic system and segmental context on Cantonese tone perception by Mandarin and Japanese listeners.

This study explores the effects of native prosodic system and segmental context on the perception of Cantonese tones by Mandarin and Japanese listeners. In Experiment 1, 13 Mandarin and 13 Japanese subjects took part in a two-alternative forced-choice discrimination test of Cantonese tones in different segmental contexts (familiar vs unfamiliar). In Experiment 2, 20 Mandarin listeners participated in a perceptual assimilation task that examined the cross-language perceptual similarity between Mandarin and Cantonese tones. Results showed that Mandarin listeners were comparable to Japanese counterparts in discriminability, but the former attended more to pitch contour differences while the latter were more sensitive to pitch height. Moreover, the effect of segmental context was significant exclusively in the Mandarin group, whereas the Japanese group performed stably across syllables in discriminating Cantonese tones. It seemed that unfamiliar context rendered lower perceptual similarity, which further hindered corresponding discrimination by the Mandarin group. In addition, segmental effects were mainly observed in the assimilation patterns of category goodness or uncategorized-categorized. These findings suggested that non-native tone perception could be modulated by listeners' native prosodic structures in a finer way.

Aging Effect on Mandarin Chinese Vowel and Tone Identification in Six-Talker Babble.

Purpose The purpose of this study was to measure Mandarin Chinese vowel-plus-tone identification in quiet and noise for younger and older listeners. Method Two types of noise served as the masker, namely, six-talker babble and babble-modulated noise, at two signal-to-noise ratios (SNRs) of -4 and -8 dB. Fourteen listeners from both age groups were recruited, and three sets of data analyses were conducted: the identification of vowel plus tone, the identification of vowel, and the identification of tone. Results Younger listeners outperformed older listeners in all listening conditions, whereas the younger-older listener difference became greater in noise than in quiet, indicating a more detrimental effect of noise for older listeners than for younger listeners. In addition, vowel identification showed slightly better scores than tone identification in noise, suggesting that noise appeared to affect tone perception more negatively than vowel perception in Mandarin Chinese. At -4 dB SNR, there was a significantly greater amount of informational masking (IM) and a greater amount of energetic masking (EM) for older listeners than for younger listeners. At -8 dB SNR, there was a greater amount of EM for older listeners than for younger listeners but with no group difference in the amount of IM. Conclusion These results suggest that older listeners received a more negative impact of noise for Mandarin Chinese phonemic and tone recognition and had a larger amount of IM or EM from competing speech noise than younger listeners, depending on the SNR.

Characteristics of Effective Auditory Training: Implications From Two Training Programs That Successfully Trained Nonnative Cantonese Tone Identification in Monolingual Mandarin and Bilingual Mandarin-Taiwanese Tone Speakers.

Purpose Auditory training is important in pedagogical and clinical settings. In search of a more effective perceptual program for training new suprasegmental categories, this study examined the effect of two auditory programs that incorporated five elements that have previously been identified to be effective for training nonnative segmental and suprasegmental speech sounds on the identification of a complex foreign lexical tone system (Cantonese) that contrasts both pitch shapes and pitch heights. To investigate the training outcomes in learners with different tonal systems, monolingual Mandarin-speaking learners who have a smaller native tonal system that contrasts pitch shapes only and bilingual Mandarin-Taiwanese-speaking learners who have a larger native tonal system that contrasts both pitch shapes and pitch heights were recruited for training. Method Thirty Mandarin-speaking monolinguals and 33 Mandarin-Taiwanese-speaking bilinguals in Taiwan were randomly assigned to two training programs, one with different tones and the other with the same tone preceding the target words in the same training block, and received six 90-min training sessions within 2 weeks. They took a Cantonese Tone Identification Test before training and after each training session. Twenty Cantonese native speakers in Hong Kong served as the reference group and took the same Cantonese Tone Identification Test. Results The two training programs were equally effective. Before training, the monolinguals performed poorer than the bilinguals. After training, the monolinguals and bilinguals in both training programs identified the six Cantonese tones in new words, new utterances, and novel speakers with comparable results, and their overall accuracy did not differ from that of the Cantonese native speakers. Conclusions Though learners with a larger and more complex native tonal system have initial advantage in learning nonnative tones, the intensive high-variability full-set training programs that provide explicit phonetic instruction and contrastive feedback of nonnative tones effectively promote nonnative tone acquisition in learners of different tone languages. The findings revealed factors affecting nonnative tone acquisition in tone speakers. The design of the two programs can be adopted in future programs for effective auditory training of segmental and suprasegmental speech sounds.

High-Variability Phonetic Training Benefits Lexical Tone Perception: An Investigation on Mandarin-Speaking Pediatric Cochlear Implant Users.

Purpose Lexical tone perception is known to be persistently difficult for individuals with cochlear implants (CIs). The purpose of this study was to evaluate the efficacy of high-variability phonetic training (HVPT) in improving Mandarin tone perception for native-speaking children with CIs. Method A total of 28 Mandarin-speaking pediatric CI recipients participated in the study. Half of the children with CIs received a five-session HVPT within a period of 3 weeks. Identification and discrimination of lexical tones produced by familiar talkers (used during training) and novel talkers (not used during training) were measured before, immediately after, and 10 weeks after training termination. The other half untrained children served as control for the identical pre- and posttests. Results Lexical tone perception significantly improved in both trained identification task and untrained discrimination task for the trainees. There was also a significant effect in transfer of learning to perceiving tones produced by novel talkers. Moreover, training-induced gains were retained for up to 10 weeks after training. By comparison, no significant pre-post changes were observed in the control group. Conclusion The results provide the first systematical assessment for the efficacy of the HVPT protocol for Mandarin-speaking pediatric CI users with congenital hearing loss, which supports the clinical utility of intensive short-term HVPT in these children's rehabilitative regimens.

The left dorsal stream causally mediates the tone labeling in absolute pitch.

Absolute pitch (AP) refers to the ability to effortlessly identify given pitches without any reference. Correlative evidence suggests that the left posterior dorsolateral prefrontal cortex (DLPFC) is responsible for the process underlying pitch labeling in AP. Here, we measured the sight-reading performance of right-handed AP possessors and matched controls under cathodal and sham transcranial direct current stimulation of the left DLPFC. The participants were instructed to report notations as accurately and as fast as possible by playing with their right hand on a piano. The notations were simultaneously presented with distracting auditory stimuli that either matched or mismatched them in different semitone degrees. Unlike the controls, AP possessors revealed an interference effect in that they responded slower in mismatching conditions than in the matching one. Under cathodal stimulation, this interference effect disappeared. These findings confirm that the pitch-labeling process underlying AP occurs automatically and is largely nonsuppressible when triggered by tone exposure. The improvement of the AP possessors' sight-reading performances in response to the suppression of the left DLPFC using cathodal stimulation confirms a causal relationship between this brain structure and pitch labeling.