The separation between music and speech: evidence from the perception of Cantonese tones

Instrumental music training relates to intensity assessment but not emotional prosody recognition in Mandarin

Building on research demonstrating the benefits of music training for emotional prosody recognition in nontonal languages, this study delves into its unexplored influence on tonal languages. In tonal languages, the acoustic similarity between lexical tones and music, along with the dual role of pitch in conveying lexical and affective meanings, create a unique interplay. We evaluated 72 participants, half of whom had extensive instrumental music training, with the other half serving as demographically matched controls. All participants completed an online test consisting of 210 Chinese pseudosentences, each designed to express one of five emotions: happiness, sadness, fear, anger, or neutrality. Our robust statistical analyses, which included effect size estimates and Bayesian factors, revealed that music and nonmusic groups exhibit similar abilities in identifying the emotional prosody of various emotions. However, the music group attributed higher intensity ratings to emotional prosodies of happiness, fear, and anger compared to the nonmusic group. These findings suggest that while instrumental music training is not related to emotional prosody recognition, it does appear to be related to perceived emotional intensity. This dissociation between emotion recognition and intensity evaluation adds a new piece to the puzzle of the complex relationship between music training and emotion perception in tonal languages.

Effect of musical expertise on the perception of duration and pitch in language: A cross-linguistic study

This study adopts a cross-linguistic perspective and investigates how musical expertise affects the perception of duration and pitch in language. Native speakers of Chinese (N = 44) and Estonian (N = 46), each group subdivided into musicians and non-musicians, participated in a mismatch negativity (MMN) experiment where they passively listened to both Chinese and Estonian stimuli, followed by a behavioral experiment where they attentively discriminated the stimuli in the non-native language (i.e., Chinese to Estonian participants and Estonian to Chinese participants). In both experiments, stimuli of duration change, pitch change, and duration plus pitch change were discriminated. We found higher behavioral sensitivity among Chinese musicians than non-musicians in perceiving the duration change in Estonian and higher behavioral sensitivity among Estonian musicians than non-musicians in perceiving all types of changes in Chinese, but no corresponding effect was found in the MMN results, which suggests a more salient effect of musical expertise on foreign language processing when attention is required. Secondly, Chinese musicians did not outperform non-musicians in attentively discriminating the pitch-related stimuli in Estonian, suggesting that musical expertise can be overridden by tonal language experience when perceiving foreign linguistic pitch, especially when an attentive discrimination task is administered. Thirdly, we found larger MMN among Chinese and Estonian musicians than their non-musician counterparts in perceiving the largest deviant (i.e., duration plus pitch) in their native language. Taken together, our results demonstrate a positive effect of musical expertise on language processing.

The more the better? Effects of L1 tonal density and typology on the perception of non-native tones

This study investigates the effects of L1 tonal density and typology on naïve listeners' perception of L2 Cantonese tones and pitch-equivalent pure tones. Native speakers of two canonical tone languages (Vietnamese and Mandarin) and a pitch-accent language (Japanese) with varying degrees of tonal density were recruited as listeners in a discrimination task followed by a perceptual assimilation task. Results implied that Mandarin listeners with a sparser tone inventory exhibited significantly better performance than Vietnamese listeners, suggesting that denser tonality in L1 did not facilitate or even interfere with L2 tone perception. Furthermore, both groups of canonical tone listeners processed pitch contours in a domain-general manner, with comparable performance in the perception of lexical tones and pure tones. However, Japanese listeners of the pitch-accent language perceived pure tones better than lexical tones, showing a domain-specific mechanism. These findings suggest that both L1 tonal density and typology may modulate the perception of non-native tones.

The effect of tone language background on cue integration in pitch perception

This study explores the effect of native language and musicality on voice quality cue integration in pitch perception. Previous work by Cui and Kang [(2019). J. Acoust. Soc. Am. 146(6), 4086-4096] found no differences in pitch perception strategies between English and Mandarin speakers. The present study asks whether Cantonese listeners may perform differently, as Cantonese consists of multiple level tones. Participants completed two experiments: (i) a forced choice pitch classification experiment involving four spectral slope permutations that vary in fo across an 11 step continuum, and (ii) the MBEMA test that quantifies listeners' musicality. Results show that Cantonese speakers do not differ from English and Mandarin speakers in terms of overall categoricity and perceptual shift, that Cantonese speakers do not have advantages in musicality, and that musicality is a significant predictor for participants' pitch perception strategies. Listeners with higher musicality scores tend to rely more on fo cues than voice quality cues compared to listeners with lower musicality. These findings support the notion that voice quality integration in pitch perception is not language specific, and may be a universal psychoacoustic phenomenon at a non-lexical level.

Musical training alters neural processing of tones and vowels in classic Chinese poems

Long-term rigorous musical training promotes various aspects of spoken language processing. However, it is unclear whether musical training provides an advantage in recognizing segmental and suprasegmental information of spoken language. We used vowel and tone violations in spoken unfamiliar seven-character quatrains and a rhyming judgment task to investigate the effects of musical training on tone and vowel processing by recording ERPs. Compared with non-musicians, musicians were more accurate and responded faster to incorrect than correct tones. Musicians showed larger P2 components in their ERPs than non-musicians during both tone and vowel processing, revealing increased focused attention on sounds. Both groups showed enhanced N400 and LPC for incorrect vowels (vs. correct vowels) but non-musicians showed an additional P2 effect for vowel violations. Moreover, both groups showed enhanced LPC for incorrect tones (vs. correct tones) but only non-musicians showed an additional N400 effect for tone violations. These results indicate that vowel/tone processing is less effortful for musicians (vs. non-musicians). Our study suggests that long-term musical training facilitates speech tone and vowel processing in a tonal language environment by increasing the attentional focus on speech and reducing demands for detecting incorrect vowels and integration costs for tone changes.

Enduring musician advantage among former musicians in prosodic pitch perception

Musical training has been associated with various cognitive benefits, one of which is enhanced speech perception. However, most findings have been based on musicians taking part in ongoing music lessons and practice. This study thus sought to determine whether the musician advantage in pitch perception in the language domain extends to individuals who have ceased musical training and practice. To this end, adult active musicians (n = 22), former musicians (n = 27), and non-musicians (n = 47) were presented with sentences spoken in a native language, English, and a foreign language, French. The final words of the sentences were either prosodically congruous (spoken at normal pitch height), weakly incongruous (pitch was increased by 25%), or strongly incongruous (pitch was increased by 110%). Results of the pitch discrimination task revealed that although active musicians outperformed former musicians, former musicians outperformed non-musicians in the weakly incongruous condition. The findings suggest that the musician advantage in pitch perception in speech is retained to some extent even after musical training and practice is discontinued.

Individual differences in nonnative lexical tone perception: Effects of tone language repertoire and musical experience

This study sought to understand the effects of tone language repertoire and musical experience on nonnative lexical tone perception and production. Thirty-one participants completed a tone discrimination task, an imitation task, and a musical abilities task. Results showed that a larger tone language repertoire and musical experience both enhanced tone discrimination performance. However, the effects were not additive, as musical experience was associated with tone discrimination performance for single-tone language speakers, but such association was not seen for dual-tone language speakers. Furthermore, among single-tone language speakers, but not among dual-tone language speakers, musical experience and musical aptitude positively correlated with tone discrimination accuracy. It is thus concluded that individuals with varying extents of tone language experience may adopt different strategies when performing tone discrimination tasks; single-tone language speakers may draw on their musical expertise while dual-tone language speakers may rely on their extensive tone language experience instead.

Phonetic and Lexical Encoding of Tone in Cantonese Heritage Speakers

Heritage speakers contend with at least two languages: the less dominant first language (L1), that is, the heritage language, and the more dominant second language (L2). In some cases, their L1 and L2 bear striking phonological differences. In the current study, we investigate Toronto-born Cantonese heritage speakers and their maintenance of Cantonese lexical tone, a linguistic feature that is absent from English, the more dominant L2. Across two experiments, Cantonese heritage speakers were tested on their phonetic/phonological and lexical encoding of tone in Cantonese. Experiment 1 was an AX discrimination task with varying inter-stimulus intervals (ISIs), which revealed that heritage speakers discriminated tone pairs with disparate pitch contours better than those with shared pitch contours. Experiment 2 was a medium-term repetition priming experiment, designed to extend the findings of Experiment 1 by examining tone representations at the lexical level. We observed a positive correlation between English dominance and priming in tone minimal pairs that shared contours. Thus, while increased English dominance does not affect heritage speakers' phonological-level representations, tasks that require lexical access suggest that heritage Cantonese speakers may not robustly and fully distinctively encode Cantonese tone in lexical memory.

Categorical Perception of Mandarin Pitch Directions by Cantonese-Speaking Musicians and Non-musicians

Purpose: This study is to investigate whether Cantonese-speaking musicians may show stronger CP than Cantonese-speaking non-musicians in perceiving pitch directions generated based on Mandarin tones. It also aims to examine whether musicians may be more effective in processing stimuli and more sensitive to subtle differences caused by vowel quality.

Methods: Cantonese-speaking musicians and non-musicians performed a categorical identification and a discrimination task on rising and falling continua of fundamental frequency generated based on Mandarin level, rising and falling tones on two vowels with nine duration values.

Results: Cantonese-speaking musicians exhibited a stronger categorical perception (CP) of pitch contours than non-musicians based on the identification and discrimination tasks. Compared to non-musicians, musicians were also more sensitive to the change of stimulus duration and to the intrinsic F₀ in pitch perception in pitch processing.

Conclusion: The CP was strengthened due to musical experience and musicians benefited more from increased stimulus duration and were more efficient in pitch processing. Musicians might be able to better use the extra time to form an auditory representation with more acoustic details. Even with more efficiency in pitch processing, musicians' ability to detect subtle pitch changes caused by intrinsic F₀ was not undermined, which is likely due to their superior ability to process temporal information. These results thus suggest musicians may have a great advantage in learning tones of a second language.

Dissociation of tone merger and congenital amusia in Hong Kong Cantonese

While the issue of individual variation has been widely studied in second language learning or processing, it is less well understood how perceptual and musical aptitude differences can explain individual variation in native speech processing. In the current study, we make use of tone merger in Hong Kong Cantonese, an ongoing sound change that concerns the merging of tones in perception, production or both in a portion of native speakers, to examine the possible relationship between tone merger and musical and pitch abilities. Although a previous study has reported the occurrence of tone merger independently of musical training, it has not been investigated before whether tone-merging individuals, especially those merging tones in perception, would have inferior musical perception and fine-grained pitch sensitivities, given the close relationship of speech and music. To this end, we tested three groups of tone-merging individuals with various tone perception and production profiles on musical perception and pitch threshold tasks, in comparison to a group of Cantonese speakers with congenital amusia, and another group of controls without tone merger or amusia. Additionally, the amusics were compared with tone-merging individuals on the details of their tone discrimination and production profiles. The results showed a clear dissociation of tone merger and amusia, with the tone-merging individuals exhibiting intact musical and pitch abilities; on the other hand, the amusics demonstrated widespread difficulties in tone discrimination yet intact tone production, in contrast to the highly selective confusion of a specific tone pair in production or discrimination in tone-merging individuals. These findings provide the first evidence that tone merger and amusia are distinct from each other, and further suggest that the cause of tone merger may lie elsewhere rather than being driven by musical or pitch deficits. We also discussed issues arising from the current findings regarding the neural mechanisms of tone merger and amusia.

The effect of Mandarin listeners' musical and pitch aptitude on perceptual learning of Cantonese level-tones

Contrary to studies on speech learning of consonants and vowels, the issue of individual variability is less well understood in the learning of lexical tones. Whereas existing studies have focused on contour-tone learning (Mandarin) by listeners without experience of a tonal language, this study addressed a research gap by investigating the perceptual learning of level-tone contrasts (Cantonese) by learners with experience of a contour-tone system (Mandarin). Critically, we sought to answer the question of how Mandarin listeners' initial perception and learning of Cantonese level-tones are affected by their musical and pitch aptitude. Mandarin-speaking participants completed a pretest, training, and a posttest in the level-tone discrimination and identification (ID) tasks. They were assessed in musical aptitude and speech and nonspeech pitch thresholds before training. The results revealed a significant training effect in the ID task but not in the discrimination task. Importantly, the regression analyses showed an advantage of higher musical and pitch aptitude in perceiving Cantonese level-tone categories. The results explained part of the level-tone learning variability in speakers of a contour-tone system. The finding implies that prior experience of a tonal language does not necessarily override the advantage of listeners' musical and pitch aptitude.

Musicians show enhanced perception, but not production, of native lexical tones

Many studies have reported a musical advantage in perceiving lexical tones among non-native listeners, but it is unclear whether this advantage also applies to native listeners, who are likely to show ceiling-like performance and thus mask any potential musical advantage. The ongoing tone merging phenomenon in Hong Kong Cantonese provides a unique opportunity to investigate this as merging tone pairs are reported to be difficult to differentiate even among native listeners. In the present study, native Cantonese musicians and non-musicians were compared based on discrimination and identification of merging Cantonese tone pairs to determine whether a musical advantage in perception will be observed, and if so, whether this is seen on the phonetic and/or phonological level. The tonal space of the subjects' lexical tone production was also compared. Results indicated that the musicians outperformed the non-musicians on the two perceptual tasks, as indexed by a higher accuracy and faster reaction time, particularly on the most difficult tone pair. In the production task, however, there was no group difference in various indices of tonal space. Taken together, musical experience appears to facilitate native listeners' perception, but not production, of lexical tones, which partially supports a music-to-language transfer effect.

Development of Phonetic Contrasts in Cantonese Tone Acquisition

Purpose Previous studies showed both early and late acquisition of Cantonese tones based on transcription data using different criteria, but very little acoustic data were reported. Our study examined Cantonese tone acquisition using both transcription and acoustic data, illustrating the early and protracted aspects of Cantonese tone acquisition. Method One hundred fifty-nine Cantonese-speaking children aged between 2;1 and 6;0 (years;months) and 10 reference speakers participated in a tone production experiment based on picture naming. Natural production materials with 30 monosyllabic words were transcribed by two native judges. Acoustic measurements included overall tonal dispersion and specific contrasts between similar tone pairs: ratios of average fundamental frequency height for the level tones (T1, T3, T6), magnitude of rise and inflection point for the rising tones (T2, T5), magnitude of fall, H1*-H2*, and harmonic-to-noise ratio for the low tones (T4, T6). Auditory assessment of creakiness for T4 was also included. Results Children in the eldest group (aged 5;7-6;0) were still not completely adultlike in production accuracy, although two thirds of them had production accuracy over 90%. Children in all age groups had production accuracy significantly higher than chance level, and they could produce the major acoustic contrasts between specific tone pairs similarly as reference speakers. Fine phonetic detail of the inflection point and creakiness was more challenging for children. Conclusion Our findings illustrated the multifaceted aspects (both early and late) of Cantonese tone acquisition and called for a wider perspective on how to define successful phonological acquisition. Supplemental Material https://doi.org/10.23641/asha.11594853.

Assessing the Link Between Perception and Production in Cantonese Tone Acquisition

Purpose Previous studies showed early production precedes late perception in Cantonese tone acquisition, contrary to the general principle that perception precedes production in child language. How tone production and perception are linked in 1st language acquisition remains largely unknown. Our study revisited the acquisition of tone in Cantonese-speaking children, exploring the possible link between production and perception in 1st language acquisition. Method One hundred eleven Cantonese-speaking children aged between 2;0 and 6;0 (years;months) and 10 adolescent reference speakers participated in tone production and perception experiments. Production materials with 30 monosyllabic words were transcribed in filtered and unfiltered conditions by 2 native judges. Perception accuracy was based on a 2-alternative forced-choice task with pictures covering all possible tone pair contrasts. Results Children's accuracy of production and perception of all the 6 Cantonese tones was still not adultlike by age 6;0. Both production and perception accuracies matured with age. A weak positive link was found between the 2 accuracies. Mother's native language contributed to children's production accuracy. Conclusions Our findings show that production and perception abilities are associated in tone acquisition. Further study is needed to explore factors affecting production accuracy in children. Supplemental Material https://doi.org/10.23641/asha.7960826.

An account of the Speech-to-Song Illusion using Node Structure Theory

In the Speech-to-Song Illusion, repetition of a spoken phrase results in it being perceived as if it were sung. Although a number of previous studies have examined which characteristics of the stimulus will produce the illusion, there is, until now, no description of the cognitive mechanism that underlies the illusion. We suggest that the processes found in Node Structure Theory that are used to explain normal language processing as well as other auditory illusions might also account for the Speech-to-Song Illusion. In six experiments we tested whether the satiation of lexical nodes, but continued priming of syllable nodes may lead to the Speech-to-Song Illusion. The results of these experiments provide evidence for the role of priming, activation, and satiation as described in Node Structure Theory as an explanation of the Speech-to-Song Illusion.

Musical training, bilingualism, and executive function: working memory and inhibitory control

The current study investigated whether long-term experience in music or a second language is associated with enhanced cognitive functioning. Early studies suggested the possibility of a cognitive advantage from musical training and bilingualism but have failed to be replicated by recent findings. Further, each form of expertise has been independently investigated leaving it unclear whether any benefits are specifically caused by each skill or are a result of skill learning in general.

To assess whether cognitive benefits from training exist, and how unique they are to each training domain, the current study compared musicians and bilinguals to each other, plus to individuals who had expertise in both skills, or neither. Young adults (n = 153) were categorized into one of four groups: monolingual musician; bilingual musician; bilingual non-musician; and monolingual non-musician. Multiple tasks per cognitive ability were used to examine the coherency of any training effects. Results revealed that musically trained individuals, but not bilinguals, had enhanced working memory. Neither skill had enhanced inhibitory control.

The findings confirm previous associations between musicians and improved cognition and extend existing evidence to show that benefits are narrower than expected but can be uniquely attributed to music compared to another specialized auditory skill domain. The null bilingual effect despite a music effect in the same group of individuals challenges the proposition that young adults are at a performance ceiling and adds to increasing evidence on the lack of a bilingual advantage on cognition.

Writing System Modulates the Association between Sensitivity to Acoustic Cues in Music and Reading Ability: Evidence from Chinese-English Bilingual Children

Music and language share many attributes and a large body of evidence shows that sensitivity to acoustic cues in music is positively related to language development and even subsequent reading acquisition. However, such association was mainly found in alphabetic languages. What remains unclear is whether sensitivity to acoustic cues in music is associated with reading in Chinese, a morphosyllabic language. The present study aimed to answer this question by measuring music (i.e., musical metric perception and pitch discrimination), language (i.e., phonological awareness, lexical tone sensitivity), and reading abilities (i.e., word recognition) among 54 third-grade Chinese-English bilingual children. After controlling for age and non-verbal intelligence, we found that both musical metric perception and pitch discrimination accounted for unique variance of Chinese phonological awareness while pitch discrimination rather than musical metric perception predicted Chinese lexical tone sensitivity. More importantly, neither musical metric perception nor pitch discrimination was associated with Chinese reading. As for English, musical metric perception and pitch discrimination were correlated with both English phonological awareness and English reading. Furthermore, sensitivity to acoustic cues in music was associated with English reading through the mediation of English phonological awareness. The current findings indicate that the association between sensitivity to acoustic cues in music and reading may be modulated by writing systems. In Chinese, the mapping between orthography and phonology is not as transparent as in alphabetic languages such as English. Thus, this opaque mapping may alter the auditory perceptual sensitivity in music to Chinese reading.

Musical experience facilitates lexical tone processing among Mandarin speakers: Behavioral and neural evidence

Music and speech share many sound attributes. Pitch, as the percept of fundamental frequency, often occupies the center of researchers' attention in studies on the relationship between music and speech. One widely held assumption is that music experience may confer an advantage in speech tone processing. The cross-domain effects of musical training on non-tonal language speakers' linguistic pitch processing have been relatively well established. However, it remains unclear whether musical experience improves the processing of lexical tone for native tone language speakers who actually use lexical tones in their daily communication. Using a passive oddball paradigm, the present study revealed that among Mandarin speakers, musicians demonstrated enlarged electrical responses to lexical tone changes as reflected by the increased mismatch negativity (MMN) amplitudes, as well as faster behavioral discrimination performance compared with age- and IQ-matched nonmusicians. The current results suggest that in spite of the preexisting long-term experience with lexical tones in both musicians and nonmusicians, musical experience can still modulate the cortical plasticity of linguistic tone processing and is associated with enhanced neural processing of speech tones. Our current results thus provide the first electrophysiological evidence supporting the notion that pitch expertise in the music domain may indeed be transferable to the speech domain even for native tone language speakers.

Pitch perception and production in congenital amusia: Evidence from Cantonese speakers

This study investigated pitch perception and production in speech and music in individuals with congenital amusia (a disorder of musical pitch processing) who are native speakers of Cantonese, a tone language with a highly complex tonal system. Sixteen Cantonese-speaking congenital amusics and 16 controls performed a set of lexical tone perception, production, singing, and psychophysical pitch threshold tasks. Their tone production accuracy and singing proficiency were subsequently judged by independent listeners, and subjected to acoustic analyses. Relative to controls, amusics showed impaired discrimination of lexical tones in both speech and non-speech conditions. They also received lower ratings for singing proficiency, producing larger pitch interval deviations and making more pitch interval errors compared to controls. Demonstrating higher pitch direction identification thresholds than controls for both speech syllables and piano tones, amusics nevertheless produced native lexical tones with comparable pitch trajectories and intelligibility as controls. Significant correlations were found between pitch threshold and lexical tone perception, music perception and production, but not between lexical tone perception and production for amusics. These findings provide further evidence that congenital amusia is a domain-general language-independent pitch-processing deficit that is associated with severely impaired music perception and production, mildly impaired speech perception, and largely intact speech production.

Top-Down Modulation on the Perception and Categorization of Identical Pitch Contours in Speech and Music

Whether pitch in language and music is governed by domain-specific or domain-general cognitive mechanisms is contentiously debated. The aim of the present study was to investigate whether mechanisms governing pitch contour perception operate differently when pitch information is interpreted as either speech or music. By modulating listening mode, this study aspired to demonstrate that pitch contour perception relies on domain-specific cognitive mechanisms, which are regulated by top-down influences from language and music. Three groups of participants (Mandarin speakers, Dutch speaking non-musicians, and Dutch musicians) were exposed to identical pitch contours, and tested on their ability to identify these contours in a language and musical context. Stimuli consisted of disyllabic words spoken in Mandarin, and melodic tonal analogs, embedded in a linguistic and melodic carrier phrase, respectively. Participants classified identical pitch contours as significantly different depending on listening mode. Top-down influences from language appeared to alter the perception of pitch contour in speakers of Mandarin. This was not the case for non-musician speakers of Dutch. Moreover, this effect was lacking in Dutch speaking musicians. The classification patterns of pitch contours in language and music seem to suggest that domain-specific categorization is modulated by top-down influences from language and music.

Music training and speech perception: a gene-environment interaction

Claims of beneficial side effects of music training are made for many different abilities, including verbal and visuospatial abilities, executive functions, working memory, IQ, and speech perception in particular. Such claims assume that music training causes the associations even though children who take music lessons are likely to differ from other children in music aptitude, which is associated with many aspects of speech perception. Music training in childhood is also associated with cognitive, personality, and demographic variables, and it is well established that IQ and personality are determined largely by genetics. Recent evidence also indicates that the role of genetics in music aptitude and music achievement is much larger than previously thought. In short, music training is an ideal model for the study of gene-environment interactions but far less appropriate as a model for the study of plasticity. Children seek out environments, including those with music lessons, that are consistent with their predispositions; such environments exaggerate preexisting individual differences.

Musical experience modulates categorical perception of lexical tones in native Chinese speakers

Although musical training has been shown to facilitate both native and non-native phonetic perception, it remains unclear whether and how musical experience affects native speakers’ categorical perception (CP) of speech at the suprasegmental level. Using both identification and discrimination tasks, this study compared Chinese-speaking musicians and non-musicians in their CP of a lexical tone continuum (from the high level tone, Tone1 to the high falling tone, Tone4). While the identification functions showed similar steepness and boundary location between the two subject groups, the discrimination results revealed superior performance in the musicians for discriminating within-category stimuli pairs but not for between-category stimuli. These findings suggest that musical training can enhance sensitivity to subtle pitch differences between within-category sounds in the presence of robust mental representations in service of CP of lexical tonal contrasts.

Brainstem encoding of speech and musical stimuli in congenital amusia: evidence from Cantonese speakers

Congenital amusia is a neurodevelopmental disorder of musical processing that also impacts subtle aspects of speech processing. It remains debated at what stage(s) of auditory processing deficits in amusia arise. In this study, we investigated whether amusia originates from impaired subcortical encoding of speech (in quiet and noise) and musical sounds in the brainstem. Fourteen Cantonese-speaking amusics and 14 matched controls passively listened to six Cantonese lexical tones in quiet, two Cantonese tones in noise (signal-to-noise ratios at 0 and 20 dB), and two cello tones in quiet while their frequency-following responses (FFRs) to these tones were recorded. All participants also completed a behavioral lexical tone identification task. The results indicated normal brainstem encoding of pitch in speech (in quiet and noise) and musical stimuli in amusics relative to controls, as measured by FFR pitch strength, pitch error, and stimulus-to-response correlation. There was also no group difference in neural conduction time or FFR amplitudes. Both groups demonstrated better FFRs to speech (in quiet and noise) than to musical stimuli. However, a significant group difference was observed for tone identification, with amusics showing significantly lower accuracy than controls. Analysis of the tone confusion matrices suggested that amusics were more likely than controls to confuse between tones that shared similar acoustic features. Interestingly, this deficit in lexical tone identification was not coupled with brainstem abnormality for either speech or musical stimuli. Together, our results suggest that the amusic brainstem is not functioning abnormally, although higher-order linguistic pitch processing is impaired in amusia. This finding has significant implications for theories of central auditory processing, requiring further investigations into how different stages of auditory processing interact in the human brain.

Brain signal variability as a window into the bidirectionality between music and language processing: moving from a linear to a nonlinear model

There is convincing empirical evidence for bidirectional transfer between music and language, such that experience in either domain can improve mental processes required by the other. This music-language relationship has been studied using linear models (e.g., comparing mean neural activity) that conceptualize brain activity as a static entity. The linear approach limits how we can understand the brain’s processing of music and language because the brain is a nonlinear system. Furthermore, there is evidence that the networks supporting music and language processing interact in a nonlinear manner. We therefore posit that the neural processing and transfer between the domains of language and music are best viewed through the lens of a nonlinear framework. Nonlinear analysis of neurophysiological activity may yield new insight into the commonalities, differences, and bidirectionality between these two cognitive domains not measurable in the local output of a cortical patch. We thus propose a novel application of brain signal variability (BSV) analysis, based on mutual information and signal entropy, to better understand the bidirectionality of music-to-language transfer in the context of a nonlinear framework. This approach will extend current methods by offering a nuanced, network-level understanding of the brain complexity involved in music-language transfer.