The role of sex-related voice variation in children's gender-role stereotype attributions.

In the absence of clear sex differences in vocal anatomy, the expression of gender in pre-pubertal children's voices has a strong behavioural dimension. However, whether children are sensitive to this gender-related variation in the voice and use it to make inferences about their peers' masculinity and femininity remains unexplored. Using a cross-modal matching task, thirty-one 7- to 8-year-olds and forty-two adults were asked to associate prototypical voices of boys and girls, and their re-synthesized masculinized and feminized versions, to fictional stereotypically masculine, gender-neutral, and stereotypically feminine child characters. We found that listeners spontaneously associated stereotypically masculine and feminine descriptors of a child character with masculinized voices and feminized voices, respectively. Adults made overall more stereotypical associations and were less influenced by character sex than children. Our observations highlight for the first time the contribution of acoustic cues to gender stereotyping from childhood, and its potential implications for the gender schema literature. Statement of contribution What is already known on this subject? Research on stereotyping shows children's schematic processing of the visible aspects of gender expression Psychoacoustic research shows that variation in children's voices affects adults' judgments of their masculinity What does this study add? Children and adults linked voice variation to gender-stereotypical characterizations of child characters Adults made overall more stereotypical associations than children and were less influenced by character's sex Our results highlight the existence of a vocal component in children's and adults' gender schemas.

Communication of male quality in owl hoots.

The evolution of communication through intrasexual selection is expected to lead signalers to transmit honest information on their fighting ability. Here we studied the information encoded in the acoustic structure of the territorial calls of a nocturnal raptor. During territorial contests, male scops owls give hoots composed of a downward frequency shift followed by a stable plateau. We found that the frequency of the hoot was negatively correlated with the body weight of the vocalizer. We shifted the frequency contour of natural hoots in order to create resynthesized calls corresponding to individuals of varying body weight and used these stimuli in playback experiments simulating an intrusion into the territory of established breeders. Territory owners responded less intensely when they heard hoots simulating heavier intruders, and males with heavier apparent weight tended to give hoots with a lower plateau in response to playbacks simulating heavier intruders.