Document type scientific article published in Royal Society Open Science
Authors: Stuart K. Watson, Christian Nawroth, Alan G. McElligott, Federico Rossano, Simon W. Townsend
Abstract in French (translation): Domestic goats are capable of tracking the direction of human voices to solve a hidden-object search task
A little-explored aspect of vocal functionality is the ability to process the direction from which a vocalization originates as a cue for locating its referent. We therefore sought to determine whether domestic goats (Capra hircus, n = 29) could use human voices as a directional cue in a hidden-object search task. In each of the three conditions, the subjects were individually presented with a human experimenter concealed behind a barrier, as well as two identical containers, one of which contained food. In the “reward-oriented speech” condition, the experimenter made enthusiastic sounds directed toward the container holding the food while sitting closer to the empty container; the goat could then choose which container to explore. The subjects chose the container containing food at a rate higher than chance. The two control conditions were identical to the “reward-oriented speech” condition, except that the experimenter remained silent (“no-speech condition”) or directed their voice away from both containers (“non-reward-oriented speech condition”). The subjects did not choose the container containing food at a rate higher than chance in either of the control conditions.
Abstract in English (original) : An underexplored dimension of vocal referentiality is the ability to process the direction in which a vocalization is emitted as a cue towards its referent. Here, we investigated whether domestic goats (Capra hircus, n = 29) can use human voices as a directional cue in a hidden-object task. In each of three conditions, subjects were individually presented with a human experimenter obscured by a barrier, and two identical containers, one of which was baited with food. In the ‘reward-directed speech’ condition, the experimenter vocalized excitedly towards the baited container while sitting closer to the unbaited container, and then the goat was able to select which container to explore. Subjects chose the baited container at above chance level. Two control conditions were identical to the reward-directed speech condition, except that the experimenter was either silent (‘no speech condition’) or directed their voice away from both containers (‘non-reward-directed speech condition’). Subjects did not choose the baited container at above chance level in either control condition. We conclude that goats are capable of attending to the directional cues provided by human voices and discuss the possible roles of domestication and experience with humans in the emergence of this ability.
