Invariance in pitch perception

Information in speech and music is often conveyed through changes in fundamental frequency (f0), the perceptual correlate of which is known as "pitch". One challenge of extracting this information is that such sounds can also vary in their spectral content due to the filtering imposed by a vocal tract or instrument body. Pitch is envisioned as invariant to spectral shape, potentially providing a solution to this challenge, but the extent and nature of this invariance remain poorly understood. We examined the extent to which human pitch judgments are invariant to spectral differences between natural sounds. Listeners performed up/down and interval discrimination tasks with spoken vowels, instrument notes, or synthetic tones, synthesized to be either harmonic or inharmonic (lacking a well-defined f0). Listeners were worse at discriminating pitch across different vowel and instrument sounds compared to when vowels/instruments were the same, being biased by differences in the spectral centroids of the sounds being compared. However, there was no interaction between this effect and that of inharmonicity. In addition, this bias decreased when sounds were separated by short delays. This finding suggests that the representation of a sound's pitch is itself unbiased, but that pitch comparisons between sounds are influenced by changes in timbre, the effect of which weakens over time. Pitch representations thus appears to be relatively invariant to spectral shape. But relative pitch judgments are not, even when spectral shape variation is naturalistic, and when such judgments are based on representations of the f0.

The Effects of Soundscapes in Relieving Stress in an Urban Park

Urban parks are important urban public spaces that guarantee people recreation, create positive emotions and relieve stress. Emerging research has shown that natural soundscapes are associated with restorative landscapes in urban parks. However, there is still a lack of knowledge on the use of physiological indexes to evaluate the effects of natural sounds versus human-based sounds on stress relief. In this study, the three physiological indexes of skin conductance level, heart rate and heart rate variability were collected in Fuzhou West Lake Park with the help of Ergo LAB data platform, and a soundscape perception evaluation questionnaire was used to assess the degree of soundscape perceptions in the sample sites. The differences in the stress relieving effects of different urban park environments were analysed by applying the median test, the Wilcoxon test was applied to analyse the effects of soundscapes and urban park environments on relieving stress, and regression analysis was used to identify the important factors of restorative soundscapes. The results found that urban park environments provide a certain degree of stress relief, but the stress relieving effects of different urban park environments vary and that natural spaces play an important role in relieving stress. Urban park soundscapes are key to restorative environmental design, with natural sounds such as birdsong and stream sound being important factors of restorative soundscapes.

Distinct higher-order representations of natural sounds in human and ferret auditory cortex

Little is known about how neural representations of natural sounds differ across species. For example, speech and music play a unique role in human hearing, yet it is unclear how auditory representations of speech and music differ between humans and other animals. Using functional ultrasound imaging, we measured responses in ferrets to a set of natural and spectrotemporally matched synthetic sounds previously tested in humans. Ferrets showed similar lower-level frequency and modulation tuning to that observed in humans. But while humans showed substantially larger responses to natural vs. synthetic speech and music in non-primary regions, ferret responses to natural and synthetic sounds were closely matched throughout primary and non-primary auditory cortex, even when tested with ferret vocalizations. This finding reveals that auditory representations in humans and ferrets diverge sharply at late stages of cortical processing, potentially driven by higher-order processing demands in speech and music.

Pitch discrimination is better for synthetic timbre than natural musical instrument timbres, despite familiarity

Pitch discrimination is better for complex tones than for pure tones, but how more subtle differences in timbre affect pitch discrimination is not fully understood. This study compared pitch discrimination thresholds of flat-spectrum harmonic complex tones with those of natural sounds played by musical instruments of three different timbres (violin, trumpet, and flute). To investigate whether natural familiarity with sounds of particular timbres affects pitch discrimination thresholds, this study recruited musicians who were trained on one of the three instruments. We found that flautists and trumpeters could discriminate smaller differences in pitch for artificial flat-spectrum tones, despite their unfamiliar timbre, than for sounds played by musical instruments, which are regularly heard in everyday life (particularly by musicians who play those instruments). Furthermore, thresholds were no better for the instrument a musician was trained to play than for other instruments, suggesting that even extensive experience listening to and producing sounds of particular timbres does not reliably improve pitch discrimination thresholds for those timbres. The results show that timbre familiarity provides minimal improvements to auditory acuity, and physical acoustics (i.e., the presence of equal-amplitude harmonics) determine pitch-discrimination thresholds more than does experience with natural sounds and timbre-specific training.

Natural sound characteristics explain perceptual categorization

As we interact with our surroundings, we encounter the same or similar objects from different perspectives and are compelled to generalize. For example, we recognize dog barks as a distinct class of sound, despite the variety of individual barks. While we have some understanding of how generalization is done along a single stimulus dimension, such as frequency or color, natural stimuli are identifiable by a combination of dimensions. To understand perception, measuring the interaction across stimulus dimensions is essential. For example, when identifying a sound, does our brain focus on a specific dimension or a combination, such as its frequency and duration? Furthermore, does the relative relevance of each dimension reflect its contribution to the natural sensory environment? Using a 2-dimension discrimination task for mice we tested untrained generalization across several pairs of auditory dimensions. We uncovered a perceptual hierarchy over the tested dimensions that was dominated by the sound’s spectral composition. A model tuned to the predictability inherent in natural sounds best explained the behavioral results, suggesting that the perceptual hierarchy parallels the predictive content of natural sounds.

Imprinting on time-structured acoustic stimuli in ducklings

Filial imprinting is a dedicated learning process that lacks explicit reinforcement. The phenomenon itself is narrowly heritably canalized, but its content, the representation of the parental object, reflects the circumstances of the newborn. Imprinting has recently been shown to be even more subtle and complex than previously envisaged, since ducklings and chicks are now known to select and represent for later generalization abstract conceptual properties of the objects they perceive as neonates, including movement pattern, heterogeneity and inter-component relationships of same or different. Here, we investigate day-old Mallard ( Anas platyrhynchos ) ducklings’ bias towards imprinting on acoustic stimuli made from mallards’ vocalizations as opposed to white noise, whether they imprint on the temporal structure of brief acoustic stimuli of either kind, and whether they generalize timing information across the two sounds. Our data are consistent with a strong innate preference for natural sounds, but do not reliably establish sensitivity to temporal relations. This fits with the view that imprinting includes the establishment of representations of both primary percepts and selective abstract properties of their early perceptual input, meshing together genetically transmitted prior pre-dispositions with active selection and processing of the perceptual input.

Do visual and audio experiences affect overall satisfaction and restorative potential of the soundscape for different visiting duration in urban blue space?

People could have a relatively great visiting experience in blue space no matter from visual or audio perspectives. However, blue space gained less attention in previous soundscape researches. More and more studies have proved the effect of visual and audio experience on visiting satisfaction or even the restorative potential of the soundscape. This study conducted an on-site survey in different blue spaces in Xi'an, China to explore how the visual, audio, and overall visiting satisfaction and the restorative potential of soundscape interacted in blue space. Furthermore, the relationships among them were also explored in different visiting duration. The results suggested that (1) Visual satisfaction didn't change over time while the soundscape satisfaction, overall satisfaction, and soundscape restoration peaked when people had stayed for 1 to 3 hours. (2) For four dimensions of soundscape restoration, Fascination peaked in 30 minutes to 1 hour, and Capability peaked in 30min-3h while Being-away and Extent remained constant. (3) As for overall satisfaction and soundscape restoration, the vision mainly contributed to them in the first 1 hour, while the hearing mainly contributed during 1 to 3 hours of experience. (4) As for POS (perceived occurrences) of sound sources, people could hear more natural sounds and human sounds in 30min-3h than in the first 30min. This study emphasized the importance of soundscape function in the planning and designing of urban blue space.

Onomatopoeia and Cat Vocalisations

Onomatopoeia—the imitation of natural sounds—is a common phenomenon in human language, though imitations of the same sounds might appear different cross-linguistically. It is true that onomatopoeia is not like ordinary language, but how does it differ from natural vocalisation? While the distinction between onomatopoeia and ordinary language has received ample treatment, its difference from natural sounds have so far received less attention from linguistics. This study aims to investigate the phonetic differences between onomatopoeic cat sounds in ten languages and natural cat vocalisations. The findings show some segmental and phonotactical distinctions due to the direct representation of these words regarding their meanings, which clearly indicates that this phenomenon in world languages is not arbitrary and offers strong evidence of iconicity. While arbitrariness is the norm in human language and has an essential impact on language development, there are clearly some nonarbitrary aspects of human language, and onomatopoeia is notable among them.

Dis/connection Matters: Natural, Synthetic, and Digital

The world is experiencing new relations and transformations between natural, synthetic, and digital substances. Rather than considering these as materially distinct or ontologically separate, this Special Issue of TSANTSA interrogates how they are interlocked in socio-material processes of mediation, transmutation, and valuation. By conceptualizing the specificity of their separateness, the special issue makes possible the comparison and commensuration of their relationship, and to move beyond their essential qualities. What are the boundaries, leakages, or dis/connections between human and digital, natural and artificial, the organic and synthetic matters? Based on ethnographic research in laboratories, gold refineries, bio-tech microbial seeds and digitally-produced natural sounds, human-machine apps and cellular agriculture, each contribution theorizes the mediation, transmutation, and valuation of natural synthetics, the humanness of artificial intelligence, or the materiality of digital elements.