Pet-directed speech improves horses\u2019 attention toward humans

Plotine Jardat,Ludovic Calandreau,Fabrice Reigner,Vitor Ferreira,Chloé Gouyet,Céline Parias,Léa Lansade

doi:10.1038/s41598-022-08109-z

Abstract

In a recent experiment, we showed that horses are sensitive to pet-directed speech (PDS), a kind of speech used to talk to companion animals that is characterized by high pitch and wide pitch variations. When talked to in PDS rather than adult-directed speech (ADS), horses reacted more favorably during grooming and in a pointing task. However, the mechanism behind their response remains unclear: does PDS draw horses’ attention and arouse them, or does it make their emotional state more positive? In this study, we used an innovative paradigm in which female horses watched videos of humans speaking in PDS or ADS to better understand this phenomenon. Horses reacted differently to the videos of PDS and ADS: they were significantly more attentive and their heart rates increased significantly more during PDS than during ADS. We found no difference in the expressions of negative or positive emotional states during PDS and ADS videos. Thus, we confirm that horses’ perception of humans can be studied by means of video projections, and we conclude that PDS attracts attention and has an arousing effect in horses, with consequences on the use of PDS in daily interactions with them.

Highlights

In a recent experiment, we showed that horses are sensitive to pet-directed speech (PDS), a kind of speech used to talk to companion animals that is characterized by high pitch and wide pitch variations
The attention index was significantly greater than 0, indicating that the horses were more attentive to the videos when the human was speaking in PDS rather than adult-directed speech (ADS), relative to the total time spent being attentive to the screen
The time spent in an alert posture was not lower during PDS sections than during ADS sections, and the time spent in a relaxed posture was not higher during PDS sections than during ADS sections

Summary

Introduction

We showed that horses are sensitive to pet-directed speech (PDS), a kind of speech used to talk to companion animals that is characterized by high pitch and wide pitch variations. Horses have excellent sociocognitive skills toward humans They recognize our emotions through vocalizations, facial expressions and odors[7–11], they know whether we are attentive to t hem[12] and what the intentions of our gestures a re[13]. In dogs and infants, the preference for IDS or PDS over ADS suggests a more positive emotional experience in response to the former. In our first study on PDS in horses, a more positive emotional state, linked to the positive emotional charge of PDS, could have lead horses to make more grooming attempts (as in26) It could have helped them follow the experimenter’s indications when pointing toward the food reward due to the better cognitive performance that results from a more positive emotional s tate[27,28]

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Conclusion