Spectro-temporal acoustical markers differentiate speech from song across cultures.

Humans produce two forms of cognitively complex vocalizations: speech and song. It is debated whether these differ based primarily on culturally specific, learned features, or if acoustical features can reliably distinguish them. We study the spectro-temporal modulation patterns of vocalizations produced by 369 people living in 21 urban, rural, and small-scale societies across six continents. Specific ranges of spectral and temporal modulations, overlapping within categories and across societies, significantly differentiate speech from song. Machine-learning classification shows that this effect is cross-culturally robust, vocalizations being reliably classified solely from their spectro-temporal features across all 21 societies. Listeners unfamiliar with the cultures classify these vocalizations using similar spectro-temporal cues as the machine learning algorithm. Finally, spectro-temporal features are better able to discriminate song from speech than a broad range of other acoustical variables, suggesting that spectro-temporal modulation-a key feature of auditory neuronal tuning-accounts for a fundamental difference between these categories.

Auditory cortex and beyond: Deficits in congenital amusia.

Congenital amusia is a neuro-developmental disorder of music perception and production, with the observed deficits contrasting with the sophisticated music processing reported for the general population. Musical deficits within amusia have been hypothesized to arise from altered pitch processing, with impairments in pitch discrimination and, notably, short-term memory. We here review research investigating its behavioral and neural correlates, in particular the impairments at encoding, retention, and recollection of pitch information, as well as how these impairments extend to the processing of pitch cues in speech and emotion. The impairments have been related to altered brain responses in a distributed fronto-temporal network, which can be observed also at rest. Neuroimaging studies revealed changes in connectivity patterns within this network and beyond, shedding light on the brain dynamics underlying auditory cognition. Interestingly, some studies revealed spared implicit pitch processing in congenital amusia, showing the power of implicit cognition in the music domain. Building on these findings, together with audiovisual integration and other beneficial mechanisms, we outline perspectives for training and rehabilitation and the future directions of this research domain.

Auditory and visual short-term memory: influence of material type, contour, and musical expertise.

Short-term memory has mostly been investigated with verbal or visuospatial stimuli and less so with other categories of stimuli. Moreover, the influence of sensory modality has been explored almost solely in the verbal domain. The present study compared visual and auditory short-term memory for different types of materials, aiming to understand whether sensory modality and material type can influence short-term memory performance. Furthermore, we aimed to assess if music expertise can modulate memory performance, as previous research has reported better auditory memory (and to some extent, visual memory), and better auditory contour recognition for musicians than non-musicians. To do so, we adapted the same recognition paradigm (delayed-matching to sample) across different types of stimuli. In each trial, participants (musicians and non-musicians) were presented with two sequences of events, separated by a silent delay, and had to indicate whether the two sequences were identical or different. The performance was compared for auditory and visual materials belonging to three different categories: (1) verbal (i.e., syllables); (2) nonverbal (i.e., that could not be easily denominated) with contour (based on loudness or luminance variations); and (3) nonverbal without contour (pink noise sequences or kanji letters sequences). Contour and no-contour conditions referred to whether the sequence can entail (or not) a contour (i.e., a pattern of up and down changes) based on non-pitch features. Results revealed a selective advantage of musicians for auditory no-contour stimuli and for contour stimuli (both visual and auditory), suggesting that musical expertise is associated with specific short-term memory advantages in domains close to the trained domain, also extending cross-modally when stimuli have contour information. Moreover, our results suggest a role of encoding strategies (i.e., how the material is represented mentally during the task) for short-term-memory performance.

Development of auditory cognition in 5- to 10-year-old children: Focus on musical and verbal short-term memory.

Developmental aspects of auditory cognition were investigated in 5-to-10-year-old children (n = 100). Musical and verbal short-term memory (STM) were assessed by means of delayed matching-to-sample tasks (DMST) (comparison of two four-item sequences separated by a silent retention delay), with two levels of difficulty. For musical and verbal materials, children's performance increased from 5 years to about 7 years of age, then remained stable up to 10 years of age, with performance remaining inferior to performance of young adults. Children and adults performed better with verbal material than with musical material. To investigate auditory cognition beyond STM, we assessed speech-in-noise perception with a four-alternative forced-choice task with two conditions of phonological difficulty and two levels of cocktail-party noise intensity. Partial correlations, factoring out the effect of age, showed a significant link between musical STM and speech-in-noise perception in the condition with increased noise intensity. Our findings reveal that auditory STM improves over development with a critical phase around 6-7 years of age, yet these abilities appear to be still immature at 10 years. Musical and verbal STM might in particular share procedural and serial order processes. Furthermore, musical STM and the ability to perceive relevant speech signals in cocktail-party noise might rely on shared cognitive resources, possibly related to pitch encoding. To the best of our knowledge, this is the first time that auditory STM is assessed with the same paradigm for musical and verbal material during childhood, providing perspectives regarding diagnosis and remediation in developmental learning disorders.