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Annals of the New York Academy of Sciences2026; 1560(1); e70299; doi: 10.1111/nyas.70299

Evidence of Physiological Comodulation During Human-Animal Interaction: A Systematic Review.

Abstract: This review examines the evidence in the literature for physiological co-modulation during human-animal interaction, identifying studies that assessed comodulation via simultaneous measurement of physiological signals in both species, performing quantitative comparisons. We searched (last search: August 5, 2025) PubMed, EMBASE, Scopus, Google Scholar, Animal Studies Repository, Cochrane, and the Consensus App academic search engine. Risk of bias was assessed using an adapted version of the ROBINS-I V2 tool. The results, grouped by data analysis method, interaction context, and physiological parameter, were synthesized narratively in structured tables. Thirty-seven studies were included, focusing on dogs (n = 22) and horses (n = 15), framed primarily within the interaction contexts of animal-assisted therapy/intervention and companionship. Cardiac and hormonal measures were most frequently assessed. Most studies (n = 20) performed correlation analyses. Sample sizes ranged from 10 to 130 dyads. Comodulation was significant in 16 studies, partial in 16, and absent in 5. Time-series coupling methods yielded more consistent evidence than discrete-time correlations. Evidence, while not conclusive, supports physiological comodulation during human-animal interactions. However, the studies' heterogeneity limits generalizability; findings suggest comodulation may emerge under specific biological and methodological conditions, and future research should explicitly test its presence across contexts.
© 2026 The Author(s). Annals of the New York Academy of Sciences published by Wiley Periodicals LLC on behalf of The New York Academy of Sciences.
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Publication Date: 2026-06-05 PubMed ID: 42244242DOI: 10.1111/nyas.70299Google Scholar: Lookup
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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.

Overview

  • This review investigates whether physiological signals from humans and animals become coordinated during their interactions, by analyzing studies that simultaneously measured these signals in both species.
  • It synthesizes existing evidence regarding this physiological co-modulation, focusing primarily on interactions involving dogs and horses, and examines the strength and consistency of this phenomenon across various methods and contexts.

Background and Objective

  • The concept of physiological co-modulation refers to the synchronization or coupling of physiological processes, such as heart rate or hormone levels, between interacting humans and animals.
  • Understanding this co-modulation can provide insights into the biological and emotional connections that form during human-animal interactions.
  • The review aimed to systematically identify and evaluate studies that assessed physiological signals simultaneously in both humans and animals during interactions to assess evidence for co-modulation.

Methods

  • A comprehensive literature search was conducted across multiple scientific databases including PubMed, EMBASE, Scopus, Google Scholar, the Animal Studies Repository, Cochrane, and the Consensus App academic search engine, with the last search on August 5, 2025.
  • Inclusion criteria required studies to perform simultaneous physiological measurements in both species during their interactions.
  • The risk of bias in included studies was assessed using an adapted version of the ROBINS-I V2 tool (a methodology for evaluating non-randomized studies).
  • Data synthesis was narrative and structured, grouping results by:
    • Methods of data analysis (e.g., correlation analyses, time-series coupling methods)
    • Context of interaction (such as animal-assisted therapy or companionship)
    • Physiological parameters measured (e.g., cardiac or hormonal measures)

Included Studies and Populations

  • Thirty-seven studies met inclusion criteria.
  • Subjects primarily involved dogs (22 studies) and horses (15 studies).
  • The main contexts examined were animal-assisted therapy/intervention and companion animal interactions.
  • Sample sizes varied widely, from 10 to 130 human-animal dyads per study.
  • Physiological signals most frequently assessed were cardiac measures (e.g., heart rate) and hormonal levels (e.g., cortisol).

Key Findings

  • Physiological comodulation was:
    • Significantly observed in 16 studies.
    • Partially observed in another 16 studies, indicating some but not complete evidence of co-modulation.
    • Absent in 5 studies.
  • Studies using time-series coupling methods—which analyze continuous physiological signals over time—provided more consistent evidence for co-modulation compared to studies relying on discrete-time correlation analyses.
  • The heterogeneity among studies—differences in species, contexts, physiological measures, and analysis methods—limits broad generalizability of findings.
  • Evidence suggests that physiological co-modulation may depend on specific biological factors (such as the species or individual differences) and methodological factors (such as how and when physiological data is collected and analyzed).

Implications and Recommendations for Future Research

  • Although the existing evidence is not definitive, the presence of physiological co-modulation during human-animal interactions appears plausible.
  • Further research should focus on explicitly testing the conditions under which co-modulation occurs, potentially improving standardization in methodologies and experimental designs.
  • Broader exploration of different species, interaction contexts, and physiological parameters would help clarify the generalizability of co-modulation effects.
  • Advanced analytical techniques, such as continuous time-series analyses, should be prioritized to better capture dynamic physiological coupling.
  • Understanding this physiological synchronization may have applications in fields like animal-assisted therapy, enhancing welfare and therapeutic outcomes.

Cite This Article

APA
Bargigli G, Frassineti L, Baragli P, Scopa C, Vignoli A, Lanata A. (2026). Evidence of Physiological Comodulation During Human-Animal Interaction: A Systematic Review. Ann N Y Acad Sci, 1560(1), e70299. https://doi.org/10.1111/nyas.70299

Publication

Annals of the New York Academy of Sciences
ISSN: 1749-6632
NlmUniqueID: 7506858
Country: United States
Language: English
Volume: 1560
Issue: 1
Pages: e70299

Researcher Affiliations

Bargigli, Ginevra
  • ComPBioS, Department of Information Engineering, University of Florence, Florence, Italy.
Frassineti, Lorenzo
  • ComPBioS, Department of Information Engineering, University of Florence, Florence, Italy.
Baragli, Paolo
  • Department of Veterinary Sciences, University of Pisa, Pisa, Italy.
Scopa, Chiara
  • Department of Veterinary Sciences, University of Pisa, Pisa, Italy.
Vignoli, Aglaia
  • Department of Health Sciences, University of Milan, Milan, Italy.
Lanata, Antonio
  • ComPBioS, Department of Information Engineering, University of Florence, Florence, Italy.

Grant Funding

  • National Recovery and Resilience Plan

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