Auditory communication in domestic dogs: vocal signalling in the extended social environment of a companion animal

Domestic dogs produce a range of vocalisations, including barks, growls, and whimpers, which are shared with other canid species. The source–filter model of vocal production can be used as a theoretical and applied framework to explain how and why the acoustic properties of some vocalisations are constrained by physical characteristics of the caller, whereas others are more dynamic, influenced by transient states such as arousal or motivation. This chapter thus reviews how and why particular call types are produced to transmit specific types of information, and how such information may be perceived by receivers. As domestication is thought to have caused a divergence in the vocal behaviour of dogs as compared to the ancestral wolf, evidence of both dog–human and human–dog communication is considered. Overall, it is clear that domestic dogs have the potential to acoustically broadcast a range of information, which is available to conspecific and human receivers. Moreover, dogs are highly attentive to human speech and are able to extract speaker identity, emotional state, and even some types of semantic information

Expressing anger and joy with size code

ABSTRACT This paper reports our finding of the use of a proposed biological code -the size code in anger and joy speech. In searching for explanations for an F0 peak delay phenomenon related to angry speech that cannot be accounted for by known articulatory constraints, we hypothesized that the delay was due to the lowering of the larynx to exaggerate body size, a biological code known to be used by animals. Our analysis of the formant frequencies in existing emotional speech databases revealed that anger speech had lowered formants and joy speech had raised formants. The results confirm our hypothesis and suggest that the size code is being actively used by humans to express emotions

Why do large dogs sound more aggressive to human listeners: Acoustic bases of motivational misattributions

Previous research has highlighted that while human listeners are capable of estimating the body size of dogs using the acoustic components of their growls, they also rate growls from larger dogs as more being aggressive than growls from smaller dogs. The aim of this study was to investigate the relative contributions of two cues to body size, fundamental frequency (F0) and formant frequency dispersion (¿f) to perceived levels of aggression. We found that participants that had just made an accurate assessment of caller size based on these characteristics then misattributed aggressiveness levels on the basis of these same size-related acoustic cues. More specifically, stimuli in which F0 and/or ¿f were typical of larger dogs were rated as being more aggressive than stimuli typical of smaller dogs. Although both F0 and ¿f influenced aggressiveness ratings independently, their interaction also had a significant affect. These results are discussed with respects to the human tendency to generalise reliable between-class acoustic cues to within-class stimuli and the resulting potential for making perceptual misattributions. © 2010 Blackwell Verlag GmbH

Discrimination of Voice Pitch and Vocal-Tract Length in Cochlear Implant Users

International audienceObjectives: When listening to two competing speakers, normal-hearing (NH) listeners can take advantage of voice differences between the speakers. Users of cochlear implants (CIs) have difficulty in perceiving speech on speech. Previous literature has indicated sensitivity to voice pitch (related to fundamental frequency, F0) to be poor among implant users, while sensitivity to vocal-tract length (VTL; related to the height of the speaker and formant frequencies), the other principal voice characteristic , has not been directly investigated in CIs. A few recent studies evaluated F0 and VTL perception indirectly, through voice gender cat-egorization, which relies on perception of both voice cues. These studies revealed that, contrary to prior literature, CI users seem to rely exclusively on F0 while not utilizing VTL to perform this task. The objective of the present study was to directly and systematically assess raw sensitivity to F0 and VTL differences in CI users to define the extent of the deficit in voice perception. Design: The just-noticeable differences (JNDs) for F0 and VTL were measured in 11 CI listeners using triplets of consonant-vowel syllables in an adaptive three-alternative forced choice method. Results: The results showed that while NH listeners had average JNDs of 1.95 and 1.73 semitones (st) for F0 and VTL, respectively, CI listeners showed JNDs of 9.19 and 7.19 st. These JNDs correspond to differences of 70% in F0 and 52% in VTL. For comparison to the natural range of voices in the population, the F0 JND in CIs remains smaller than the typical male-female F0 difference. However, the average VTL JND in CIs is about twice as large as the typical male-female VTL difference. Conclusions: These findings, thus, directly confirm that CI listeners do not seem to have sufficient access to VTL cues, likely as a result of limited spectral resolution, and, hence, that CI listeners' voice perception deficit goes beyond poor perception of F0. These results provide a potential common explanation not only for a number of deficits observed in CI listeners, such as voice identification and gender categorization, but also for competing speech perception