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BMC biology2022; 20(1); 106; doi: 10.1186/s12915-022-01311-5

Cross-species discrimination of vocal expression of emotional valence by Equidae and Suidae.

Abstract: Discrimination and perception of emotion expression regulate interactions between conspecifics and can lead to emotional contagion (state matching between producer and receiver) or to more complex forms of empathy (e.g., sympathetic concern). Empathy processes are enhanced by familiarity and physical similarity between partners. Since heterospecifics can also be familiar with each other to some extent, discrimination/perception of emotions and, as a result, emotional contagion could also occur between species. Here, we investigated if four species belonging to two ungulate Families, Equidae (domestic and Przewalski's horses) and Suidae (pigs and wild boars), can discriminate between vocalizations of opposite emotional valence (positive or negative), produced not only by conspecifics, but also closely related heterospecifics and humans. To this aim, we played back to individuals of these four species, which were all habituated to humans, vocalizations from a unique set of recordings for which the valence associated with vocal production was known. We found that domestic and Przewalski's horses, as well as pigs, but not wild boars, reacted more strongly when the first vocalization played was negative compared to positive, regardless of the species broadcasted. Domestic horses, Przewalski's horses and pigs thus seem to discriminate between positive and negative vocalizations produced not only by conspecifics, but also by heterospecifics, including humans. In addition, we found an absence of difference between the strength of reaction of the four species to the calls of conspecifics and closely related heterospecifics, which could be related to similarities in the general structure of their vocalization. Overall, our results suggest that phylogeny and domestication have played a role in cross-species discrimination/perception of emotions.
© 2022. The Author(s).
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Publication Date: 2022-05-24 PubMed ID: 35606806PubMed Central: PMC9128205DOI: 10.1186/s12915-022-01311-5Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research paper focuses on whether four different types of ungulates – domestic and Przewalski’s horses, pigs, and wild boars – are capable of distinguishing between positive and negative vocalizations, regardless of whether they’re made by their own species, closely related species, or humans. The results suggest that domestication and phylogenetic relations may impact an animal’s ability to recognize emotional expression across species.

Understanding Inter-Species Emotional Recognition

  • The basis of this exploration is the understanding that the ability to discern and respond to emotional expressions regulates interaction within a species and can lead to emotional synchrony (matching emotional states between the emitter and receiver) or more complex forms of empathy. This is heightened by familiarity and physical similarity.
  • It’s recognised that different species can also familiarize with each other to varying degrees. Consequently, the researchers hypothesized that discernment of emotions and subsequently, emotional contagion may occur between different species.

Methodology

  • In this study, the four different species were exposed to vocalizations from a unique collection of recordings. The associated emotional valence (positive or negative) with each vocal production was known.
  • While being accustomed to human presence, the animals were played back these vocalizations to assess their reactions.

Findings

  • The outcome demonstrated that domestic and Przewalski’s horses and pigs, but not wild boars, had a greater reaction when the first vocalization played was negative, regardless of the broadcasting species.
  • This indicates these animals distinguish between positive and negative vocalizations, not only from their own species but also from other species, including humans.
  • Interestingly, there was no noticeable difference in the reaction strength of the four species to the calls of their own species and related species. This is hypothesized to be due to similarities within their vocal structure.

Implications

  • The overall findings suggest that an animal’s evolution and domestication process seems to play a significant role in its capability to detect and respond to emotional expression across species.
  • Further research in this area could help strengthen our understanding of animal cognition, emotions, and inter-species communication, which would have enormous implications for animal welfare, human-animal relationships, and conservation efforts.

Cite This Article

APA
Maigrot AL, Hillmann E, Briefer EF. (2022). Cross-species discrimination of vocal expression of emotional valence by Equidae and Suidae. BMC Biol, 20(1), 106. https://doi.org/10.1186/s12915-022-01311-5

Publication

BMC biology
ISSN: 1741-7007
NlmUniqueID: 101190720
Country: England
Language: English
Volume: 20
Issue: 1
Pages: 106
PII: 106

Researcher Affiliations

Maigrot, Anne-Laure
  • Institute of Agricultural Sciences, ETH Zürich, Universitätsstrasse 2, 8092, Zurich, Switzerland.
  • Division of Animal Welfare, Veterinary Public Health Institute, Vetsuisse Faculty, University of Bern, Länggassstrasse 120, 3012, Bern, Switzerland.
  • Swiss National Stud Farm, Agroscope, Les Longs-Prés, 1580, Avenches, Switzerland.
Hillmann, Edna
  • Institute of Agricultural Sciences, ETH Zürich, Universitätsstrasse 2, 8092, Zurich, Switzerland.
  • Animal Husbandry and Ethology, Albrecht Daniel Thaer-Institut, Faculty of Life Sciences, Humboldt-Universität zu Berlin, Philippstrasse 13, 10115, Berlin, Germany.
Briefer, Elodie F
  • Institute of Agricultural Sciences, ETH Zürich, Universitätsstrasse 2, 8092, Zurich, Switzerland. elodie.briefer@bio.ku.dk.
  • Centre for Proper Housing of Ruminants and Pigs, Federal Food Safety and Veterinary Office, Agroscope, Tänikon, 8356, Ettenhausen, Switzerland. elodie.briefer@bio.ku.dk.
  • Department of Biology, Behavioral Ecology Group, Section for Ecology & Evolution, University of Copenhagen, 2100, Copenhagen Ø, Denmark. elodie.briefer@bio.ku.dk.

MeSH Terms

  • Animals
  • Auditory Perception
  • Behavior, Animal
  • Emotions / physiology
  • Empathy / physiology
  • Equidae / physiology
  • Equidae / psychology
  • Phylogeny
  • Swine / physiology
  • Swine / psychology
  • Vocalization, Animal / physiology

Conflict of Interest Statement

The authors declare that they have no competing interests.

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