Older adults looking at dog pictures - psychobiological effects

Catia Correia-Caeiro; Teresa Romero; Kun Guo; Daniel S Mills

doi:10.1016/j.actpsy.2025.105221

Older adults looking at dog pictures - psychobiological effects

Acta Psychol (Amst). 2025 Jun 30:258:105221. doi: 10.1016/j.actpsy.2025.105221. Online ahead of print.

Authors

Catia Correia-Caeiro¹, Teresa Romero², Kun Guo³, Daniel S Mills⁴

Affiliations

¹ Human Biology & Primate Cognition, Institute of Biology, Leipzig University, Talstrasse 33, 04103 Leipzig, Germany; Comparative Cultural Psychology, Max Planck Institute for Evolutionary Anthropology, Deutscher Platz 6, 04103 Leipzig, Germany; School of Psychology, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK; Department of Life Sciences, University of Lincoln, Lincoln, LN6 7DL, UK. Electronic address: catia_caeiro@hotmail.com.
² Department of Life Sciences, University of Lincoln, Lincoln, LN6 7DL, UK; Centre for Comparative and Evolutionary Psychology, School of Psychology Sport, and Health Sciences, University of Portsmouth, Portsmouth, PO1 2DY, UK.
³ School of Psychology, University of Lincoln, Brayford Pool, Lincoln, LN6 7TS, UK.
⁴ Department of Life Sciences, University of Lincoln, Lincoln, LN6 7DL, UK.

PMID: 40592090
DOI: 10.1016/j.actpsy.2025.105221

Abstract

Dogs are often used therapeutically (e.g., Pets at Therapy - PAT dogs) to visit elderly residents and those in care to promote social engagement and quality of life. Earlier studies reported that mutual gaze between dogs and owners induces a mutual change in physiology, with the release of oxytocin being a crucial mediator. However, it is not exactly known which types of cues trigger this mechanism, in particular whether these beneficial effects necessarily derive from the direct eye contact when gazing at a real-life dog or if it can be caused by the visual stimulus of a dog's eyes only in a picture. Therefore, in this study we tested if looking at static dog images could have physiological and/or psychological effects in older adults, by collecting salivary oxytocin, heart rate, optimism scores, testing cooperativeness/competitiveness, and examining gaze patterns when looking at dog pictures in three conditions: dogs facing the observer, dogs facing sideways, or control pixelated pictures. Contrary to our main predictions, we did not find any significant changes in oxytocin, optimism scores, nor cooperation levels associated with the pictures per se. However, older participants made less competitive decisions after looking at the dog's face and men also experienced a reduction in heart rate when looking at these pictures. These results indicate that simply direct eye contact via a picture of a dog is sufficient for some significant effects, which may be gender dependent, but does not trigger the expected full psychobiological effects reported in previous studies with real-life dogs.

Keywords: Cooperation; Heart rate; Optimism; Oxytocin; Visual perception.