Acoustic Features Of Vocalizations Research Articles

Acoustic features of vocalizations in typically developing and autistic infants in the first year

We describe acoustic patterns across the five most prominent vocal types in typically developing infants (TD) and compare them with patterns in infants who develop autism (ASD) or a developmental disability (DD) not related to autism. Infant-directed speech (IDS) is a potentially important influence on such vocal acoustic patterns. Both acoustic patterns and effects of IDS are important for understanding the earliest origins of communication disorders. To compare duration, pitch and loudness of infant vocalizations for three groups of infants (TD, ASD, DD) in circumstances with high or low amounts of IDS. Two five-minute segments from each of 1259 all-day recordings across the first year were coded and acoustically analyzed for three groups of infants (130 TD, 44 ASD, 21 DD). Duration, mean fundamental frequency, and root mean square amplitude were determined for >162,000 infant utterances. Cries were longest and loudest, and vowel-like sounds were shortest of the five vocal types in all groups. TD infants showed significant alterations in vocal acoustics during periods of high IDS. Strong similarities in acoustic patterns occurred across the three groups, but only the TD group showed significant acoustic effects of IDS.

Maturation of Social-Vocal Communication in Prairie Vole (Microtus ochrogaster) Pups.

Impairments in social communication are common among neurodevelopmental disorders. While traditional animal models have advanced our understanding of the physiological and pathological development of social behavior, they do not recapitulate some aspects where social communication is essential, such as biparental care and the ability to form long-lasting social bonds. Prairie voles (Microtus ochrogaster) have emerged as a valuable rodent model in social neuroscience because they naturally display these behaviors. Nonetheless, the role of vocalizations in prairie vole social communication remains unclear. Here, we studied the ontogeny [from postnatal days (P) 8–16] of prairie vole pup ultrasonic vocalizations (USVs), both when isolated and when the mother was present but physically unattainable. In contrast to other similarly sized rodents such as mice, prairie vole pups of all ages produced isolation USVs with a relatively low fundamental frequency between 22 and 50 kHz, often with strong harmonic structure. Males consistently emitted vocalizations with a lower frequency than females. With age, pups vocalized less, and the acoustic features of vocalizations (e.g., duration and bandwidth) became more stereotyped. Manipulating an isolated pup's social environment by introducing its mother significantly increased vocal production at older (P12–16) but not younger ages, when pups were likely unable to hear or see her. Our data provide the first indication of a maturation in social context-dependent vocal emission, which may facilitate more active acoustic communication. These results help lay a foundation for the use of prairie voles as a model organism to probe the role of early life experience in the development of social-vocal communication.

Dominance status and copulatory vocalizations among male stump-tailed macaques in Thailand

Male copulation calls sometimes play important roles in sexual strategies, attracting conspecific females or advertising their social status to conspecific males. These calls generally occur in sexually competitive societies such as harem groups and multi-male and multi-female societies. However, the call functions remain unclear because of limited availability of data sets that include a large number of male and female animals in naturalistic environments, particularly in primates. Here, we examined the possible function of male-specific copulation calls in wild stump-tailed macaques (Macaca arctoides) by analyzing the contexts and acoustic features of vocalizations. We observed 395 wild stump-tailed macaques inhabiting the Khao Krapuk Khao Taomor Non-Hunting Area in Thailand and recorded all occurrences of observed copulations. We counted 446 male-specific calls in 383 copulations recorded, and measured their acoustic characteristics. Data were categorized into three groups depending on their social status: dominant (alpha and coalition) males and non-dominant males. When comparing male status, alpha males most frequently produced copulation calls at ejaculation, coalition males produced less frequent calls than alpha males, and other non-dominant males rarely vocalized, maintaining silence even when mounting females. Acoustic analysis indicated no significant influence of status (alpha or coalition) on call number, bout duration, or further formant dispersion parameters. Our results suggest that male copulation calls of this species are social status-dependent signals. Furthermore, dominant males might actively transmit their social status and copulations to other male rivals to impede their challenging attacks, while other non-dominant males maintain silence to prevent the interference of dominants.

Discrimination of karan fries cow’s individuality by the mean of their vocal acoustic features

Sound is one of the most important means of conveying information over long distances as well as in close vicinity. Utterance of animals becomes unique for them when they communicate their individuality or physiological state to the other co species partner. Present study was based on hypothesis of discrimination of individual identity through vocal signal of lactating karan fries (KF) cows. For this 25 KF cows were selected for recording of their vocal signal. Vocal call was recorded after separation of animal from their living herd in the morning hours. Acoustic features of vocalization of individual cow were extracted with the help of PRAAT acoustic analysis software. Analysis of all acoustic features extracted from 250 voice samples of 25 KF cows revealed that differences for amplitude, Total energy, pitch, intensity, formants, pulse, periods, unvoiced frames, voice breaks, jitter, shimmer, mean noise/harmonic ratio and mean harmonic/noise ratio were found highly significant (p less than 0.001). Out of these only few acoustic features viz. pulse, pitch, jitter, shimmer, voice break and formants were observed to have significant (p less than 0.05) difference between each and every individual KF cow. Among these feature formants frequency of every individual cow had a unique pattern in the distribution of frequency contour in their vocal spectrogram. Study concluded that vocal signal of KF cow have some unique feature at individual level, by which cow identification could be made.

Acoustic features of vocalization as a tool for estrus detection in Murrah buffaloes

Twelve Murrah buffaloes were selected from the institute herd and acoustic features like call duration, amplitude, total energy, mean pitch, mean intensity, formants (F1, F2, F3, F4, and F5), and N/H (Noise to Harmonic) ratio were analyzed. Call duration was significantly higher on day of estrus (1.52 ± 0.07 s) and proestrus (1.44 ± 0.07 s) than in metestrus (1.241 ± 0.04 s) and diestrus stages (0.981 ± 0.05 s). Total energy (0.121 ± 0.01 P2s), mean pitch (226.67 ± 14.11 Hz), maximum amplitude (0.959 ± 0.01 P), and mean intensity (85.05 ± 0.26 dB) was more (p < 0.05) in proestrus than in other stages. F1 (1131.94 ± 11.85 Hz) and F5 formants (6567.74 ± 12.62 Hz) were significantly higher (p < 0.05) during estrus, while F2 (2238.46 ± 26.53 Hz), F3 (3435.00 ± 19.33 Hz), and F4 formants (5127.71 ± 25.90 Hz) were higher (p < 0.05) in proestrus in comparison to other stages of estrous cycle. The identified acoustic features of voice in Murrah buffaloes were signficantly different in various stages of estrous cycle. These could be used as a tool for estrus detection management in buffaloes which have probems of silent estrus.

Acoustic features of prairie vole (Microtus ochrogaster) ultrasonic vocalizations covary with heart rate

Vocalizations serve as a conspecific social communication system among mammals. Modulation of acoustic features embedded within vocalizations is used by several mammalian species to signal whether it is safe or dangerous to approach conspecific and heterospecific mammals. As described by the Polyvagal Theory, the phylogenetic shift in the evolution of mammals involved an adaptive neuroanatomical link between the neural circuits regulating heart rate and the muscles involved in modulating the acoustic features of vocalizations. However, few studies have investigated the covariation between heart rate and the acoustic features of vocalizations. In the current study, we document that specific features of vocalizations covary with heart rate in a highly social and vocal mammal, the prairie vole (Microtus ochrogaster). Findings with the prairie vole illustrate that higher pitch (i.e., fundamental frequency) and less variability in acoustic features of vocalizations (i.e., less vocal prosody) are associated with elevated heart rate. The study provides the first documentation that the acoustic features of prairie vole vocalizations may function as a surrogate index of heart rate.

A note on acoustic analysis of dairy calves’ vocalizations at 1 day after separation from dam

The vocalizations of animals are very useful in assessing an emotional state and welfare because they involve information about various emotions. Hence, the findings of the acoustic features of vocalization can be used to improve the productivity and welfare of animals. This study was conducted to analyse the vocalizations of dairy calves separated from the dam. At 6 days after birth, 12 dairy calves were moved into an individual calf pen (3.0m×2.0m) bedded with sawdust and straw. One and a half litres of whole milk were fed twice daily and free access to water was allowed. The calves’ vocalizations were divided into humming vocalizations (HVs: low continuous calls without tone changed), semi-humming vocalizations (SHVs: low continuous calls with tone changed), and general vocalizations (GVs). These vocalizations were classified, based on the shapes of waveforms and spectrograms. Differences in the duration, fundamental frequency, intensity, and formants among the classified vocalizations were found (P<0.0001). Acoustic parameters except intensity and 3rd formant were not different between HVs and SHVs. These results suggest that vocalization analysis could be a useful tool in assessing the emotions of calves. Acoustic parameters are also useful in classifying vocalizations. Also, intensity and 3rd formant are advantageous in distinguishing HVs and SHVs.

Human listeners attend to size information in domestic dog growls

The acoustic features of vocalizations have the potential to transmit information about the size of callers. Most acoustic studies have focused on intraspecific perceptual abilities, but here, the ability of humans to use growls to assess the size of adult domestic dogs was tested. In a first experiment, the formants of growls were shifted to create playback stimuli with different formant dispersions (Deltaf), simulating different vocal tract lengths within the natural range of variation. Mean fundamental frequency (F0) was left unchanged and treated as a covariate. In a second experiment, F0 was resynthesized and Deltaf was left unchanged. In both experiments Deltaf and F0 influenced how participants rated the size of stimuli. Lower formant and fundamental frequencies were rated as belonging to larger dogs. Crucially, when F0 was manipulated and Deltaf was natural, ratings were strongly correlated with the actual weight of the dogs, while when Deltaf was varied and F0 was natural, ratings were not related to the actual weight. Taken together, this suggests that participants relied more heavily on Deltaf, in accordance with the fact that formants are better predictors of body size than F0.

Motor Mechanisms Relevant to Auditory-Vocal Interactions in Songbirds

Vocal learning through imitation underlies both human speech acquisition and song acquisition in oscine birds; both processes depend on auditory information. In songbirds, a specialized forebrain pathway is responsible for producing the learned temporal and acoustic features of vocalizations, and auditory input reaches every level of this pathway. Nucleus robustus archistriatalis (RA) is the source of the final common output from this pathway; RA is topographically organized into subregions that control the syringeal, respiratory and other effectors involved in vocal production. The acoustic features of learned vocalizations are primarily produced by specific patterns and combinations of syringeal muscle activity, while the overall temporal structure is primarily under respiratory control. In RA, and other vocal control structures, the individual bird's own learned song (BOS) is the most effective stimulus for eliciting auditory responses. Some neurons are 'combination-selective' in that they respond maximally to stimuli consisting of sequences of syllables from song. The recording sites that respond selectively to BOS tend to be located in more ventral parts of RA, the subregion that projects to motor neurons controlling syringeal muscles. These observations do not distinguish between motor feedback and perceptual hypotheses about the function of auditory responses in vocal motor pathways but are consistent with the idea that such responses may reflect a specific pattern of interaction between sensory and motor events that reflects vocal learning.