Pet-directed speech (PDS) is often produced by humans when addressing dogs. Similar to infant-directed speech, PDS is marked by a relatively higher and more modulated fundamental frequency (f 0) than is adult-directed speech. We tested the prediction that increasing eye size in dogs, one facial feature of neoteny (juvenilisation), would elicit exaggerated prosodic qualities or pet-directed speech. We experimentally manipulated eye size in photographs of twelve dog breeds by −15%, +15% and +30%. We first showed that dogs with larger eyes (...) were indeed perceived as younger. We then recorded men and women speaking towards these photographs, who also rated these images for cuteness. Linear mixed-effects models demonstrated that increasing eye size by 15% significantly increased pitch range (f 0 range) and variability (f 0CV) among women only. Cuteness ratings did not vary with eye size, due to a possible ceiling effect across eye sizes. Our results offer preliminary evidence that large eyes can elicit pet-directed speech and suggest that PDS may be modulated by perceived juvenility rather than cuteness. We discuss these findings in the context of inter-species vocal communication. (shrink)

Existing evidence suggests that children from around the age of 8 years strategically alter their public image in accordance with known values and preferences of peers, through the self-descriptive information they convey. However, an important but neglected aspect of this 'self-presentation' is the medium through which such information is communicated: the voice itself. The present study explored peer audience effects on children's vocal productions. Fifty-six children were presented with vignettes where a fictional child, matched to the participant's age and sex, (...) is trying to make friends with a group of same-sex peers with stereotypically masculine or feminine interests. Participants were asked to impersonate the child in that situation and, as the child, to read out loud masculine, feminine and gender-neutral self-descriptive statements to these hypothetical audiences. They also had to decide which of those self-descriptive statements would be most helpful for making friends. In line with previous research, boys and girls preferentially selected masculine or feminine self-descriptive statements depending on the audience interests. Crucially, acoustic analyses of fundamental frequency and formant frequency spacing revealed that children also spontaneously altered their vocal productions: they feminized their voices when speaking to members of the ballet club, while they masculinized their voices when speaking to members of the rugby club. Both sexes also feminized their voices when uttering feminine sentences, compared to when uttering masculine and gender-neutral sentences. Implications for the hitherto neglected role of acoustic qualities of children's vocal behaviour in peer interactions are discussed. This article is part of the theme issue 'Voice modulation: from origin and mechanism to social impact '. (shrink)