Camila Bruder

The human voice is remarkably versatile and can vary greatly in sound depending on how it is used. An increasing number of studies have addressed the differences and similarities between the singing and the speaking voice. However, finding adequate stimuli material that is at the same time controlled and ecologically valid is challenging, and most datasets lack variability in terms of vocal styles performed by the same voice. Here, we describe a curated stimulus set of vocalizations where 22 female singers performed the same melody excerpts in three contrasting singing styles (as a lullaby, as a pop song, and as an opera aria) and spoke the text aloud in two speaking styles (as if speaking to an adult or to an infant). All productions were made with the songs’ original lyrics, in Brazilian Portuguese, and with a/lu/sound. This ecologically valid dataset of 1320 vocalizations was validated through a forced-choice lab experiment (N = 25 for each stimulus) where lay listeners could recognize the intended vocalization style with high accuracy (proportion of correct recognition superior to 69% for all styles). We also provide acoustic characterization of the stimuli, depicting clear and contrasting acoustic profiles depending on the style of vocalization. All recordings are made freely available under a Creative Commons license and can be downloaded at https://osf.io/cgexn/.

Voice preferences are an integral part of interpersonal interactions and shape how people connect with each other. While a large number of studies have investigated the mechanisms behind (speaking) voice attractiveness, very little research was dedicated to other types of vocalizations. In this Registered Report, we proposed to investigate voice preferences with an integrative approach. To this end, we used a newly recorded and validated stimulus set of contrasting vocalizations by 22 highly trained female singers speaking and singing the same material (in Brazilian Portuguese) in contrasting styles (sung as a lullaby, as a pop song or as an opera aria; and spoken aloud as if directed to an adult audience and as if directed to an infant). We asked 62 participants to rate these vocalizations in terms of how much they liked them; and we compared the amount of shared taste (that is, how much participants agreed in their preferences) across styles. We found highly idiosyncratic preferences across all styles. Our predictions concerning shared taste were not confirmed: although shared taste was higher for lullaby than for pop singing, it was unexpectedly higher for operatic than pop singing, and higher for infant-directed than adult-directed speech. Conversely, our prediction of limited consistency in average preferences for some singers across styles was confirmed, contradicting sexual selection-based ideas of singing and speaking as ‘backup’ signals of individual fitness. Our findings draw attention to the role of individual differences in voice preferences and highlight the need for a broader approach to understanding the underlying mechanisms of voice preferences. Stage 1 recommendation and review history: https://rr.peercommunityin.org/articles/rec?id=357 . Stage 2 recommendation and review history: https://rr.peercommunityin.org/articles/rec?id=802 .

Both music and language are found in all known human societies, yet no studies have compared similarities and differences between song, speech, and instrumental music on a global scale. In this Registered Report, we analyzed two global datasets: (i) 300 annotated audio recordings representing matched sets of traditional songs, recited lyrics, conversational speech, and instrumental melodies from our 75 coauthors speaking 55 languages; and (ii) 418 previously published adult-directed song and speech recordings from 209 individuals speaking 16 languages. Of our six preregistered predictions, five were strongly supported: Relative to speech, songs use (i) higher pitch, (ii) slower temporal rate, and (iii) more stable pitches, while both songs and speech used similar (iv) pitch interval size and (v) timbral brightness. Exploratory analyses suggest that features vary along a “musi-linguistic” continuum when including instrumental melodies and recited lyrics. Our study provides strong empirical evidence of cross-cultural regularities in music and speech.

Why do we prefer some singers to others? We investigated how much singing voice preferences can be traced back to objective features of the stimuli. To do so, we asked participants to rate short excerpts of singing performances in terms of how much they liked them as well as in terms of 10 perceptual attributes (e.g.: pitch accuracy, tempo, breathiness). We modeled liking ratings based on these perceptual ratings, as well as based on acoustic features and low-level features derived from Music Information Retrieval (MIR). Mean liking ratings for each stimulus were highly correlated between Experiments 1 (online, US-based participants) and 2 (in the lab, German participants), suggesting a role for attributes of the stimuli in grounding average preferences. We show that acoustic and MIR features barely explain any variance in liking ratings; in contrast, perceptual features of the voices achieved around 43% of prediction. Inter-rater agreement in liking and perceptual ratings was low, indicating substantial (and unsurprising) individual differences in participants’ preferences and perception of the stimuli. Our results indicate that singing voice preferences are not grounded in acoustic attributes of the voices per se, but in how these features are perceptually interpreted by listeners.

Classical singers train intensively for many years to achieve a high level of vocal control and specific sound characteristics. However, the actual span of singers’ activities often includes venues other than opera halls and requires performing in styles outside their strict training (e.g., singing pop songs at weddings). We examine classical singers’ ability to adjust their vocal productions to other styles, in relation with their formal training. Twenty-two highly trained female classical singers (aged from 22 to 45 years old; vocal training ranging from 4.5 to 27 years) performed six different melody excerpts a cappella in contrasting ways: as an opera aria, as a pop song and as a lullaby. All melodies were sung both with lyrics and with a /lu/ sound. All productions were acoustically analyzed in terms of seven common acoustic descriptors of voice/singing performances and perceptually evaluated by a total of 50 lay listeners (aged from 21 to 73 years old) who were asked to identify the intended singing style in a forced-choice lab experiment. Acoustic analyses of the 792 performances suggest distinct acoustic profiles, implying that singers were able to produce contrasting sounding performances. Furthermore, the high overall style recognition rate (78.5% Correct Responses, hence CR) confirmed singers’ proficiency in performing in operatic style (86% CR) and their versatility when it comes to lullaby (80% CR) and pop performances (69% CR), albeit with occasional confusion between the latter two. Interestingly, different levels of competence among singers appeared, with versatility (as estimated based on correct recognition in pop/lullaby styles) ranging from 62 to 83% depending on the singer. Importantly, this variability was not linked to formal training per se. Our results indicate that classical singers are versatile, and prompt the need for further investigations to clarify the role of singers’ broader professional and personal experiences in the development of this valuable ability.

Singing is ubiquitous and highly relevant to human experience, but what governs our singing voice preferences is not understood. We take an empirical approach to determine the extent to which listeners’ liking of singing performances can be traced back to objective attributes of the voice stimuli. We show that which singing voices are liked cannot be explained based on purely acoustic features of the voice signal. Instead, perceptual features (partially) ground singing voice preferences, with a significant proportion of the variance in liking ratings explained based on perceptual features, such as (perceived) pitch accuracy, resonance, and articulation of singing performances.

Both music and language are found in all known human societies, yet no studies have compared similarities and differences between song, speech, and instrumental music on a global scale. In this Registered Report, we analyzed two global datasets: 1) 300 annotated audio recordings representing matched sets of traditional songs, recited lyrics, conversational speech, and instrumental melodies from our 75 coauthors speaking 55 languages; and 2) 418 previously published adult-directed song and speech recordings from 209 individuals speaking 16 languages. Of our six pre-registered predictions, five were strongly supported: relative to speech, songs use 1) higher pitch, 2) slower temporal rate, and 3) more stable pitches, while both songs and speech used similar 4) pitch interval size, and 5) timbral brightness. Exploratory analyses suggest that features vary along a “musi-linguistic” continuum when including instrumental melodies and recited lyrics. Our study provides strong empirical evidence of cross-cultural regularities in music and speech.

Subvocalization has been described as a series of attenuated movements of the vocal tract during silent reading and imagination. This two-part study investigated covert laryngeal activations among singers during the perception and imagination of music and text. In the first part, 155 singers responded to an online survey investigating their self-perceived corporal activation when listening to live or recorded singing. Respondents reported frequent corporal activation in their larynx and other body parts in response to live singing and, to a lesser extent, recordings. In the second part, an exploratory experiment was conducted to investigate physiological correlates of subvocalization in singers during the perception and imagery of melody and text stimuli, using simultaneous measurements of laryngeal activation both externally, with surface electromyography, and internally, with nasolaryngoscopy. Experimental results indicate the occurrence of subvocalization during imagination—but not during listening—of both stimuli and suggest that laryngoscopy is more sensitive to detection of subvocalization in singers. The results may point to vocal resonance or empathy in the perception of singers.