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

Area of Science:

• Human-animal interaction research
• Physiological synchronization studies
• Biomedical signal analysis

Background:

• Human-animal interaction (HAI) is increasingly recognized for its physiological impact.
• Understanding physiological co-modulation offers insights into the depth of the human-animal bond.
• Previous research has explored various aspects of HAI, but a synthesized view of physiological co-modulation is lacking.

Purpose of the Study:

• To systematically review and synthesize evidence on physiological co-modulation during human-animal interactions.
• To identify studies measuring simultaneous physiological signals in humans and animals.
• To compare findings based on data analysis, interaction context, and physiological measures.

Main Methods:

• Comprehensive literature search across multiple academic databases (PubMed, EMBASE, Scopus, etc.) up to August 5, 2025.
• Inclusion of 37 studies focusing on dogs and horses, primarily in animal-assisted therapy/intervention and companionship contexts.
• Risk of bias assessment using an adapted ROBINS-I V2 tool and narrative synthesis of results in structured tables.

Main Results:

• Physiological co-modulation was significant in 16 studies, partial in 16, and absent in 5.
• Cardiac and hormonal measures were most frequently assessed.
• Time-series coupling methods provided more consistent evidence than discrete-time correlations.

Conclusions:

• Evidence supports the occurrence of physiological co-modulation during human-animal interactions, though not conclusively.
• Heterogeneity among studies limits generalizability of findings.
• Future research should investigate co-modulation across diverse contexts and employ robust methodologies to clarify its presence and conditions.