For this purpose, 17 healthy family dogs stood calmly on a high-precision pressure measurement plate while they alternately viewed happy, angry, or no human faces on a television screen. The movement of the "Center of Pressure" (COP), the center of body pressure, was measured - a biomechanical marker that captures the smallest, often imperceptible, fluctuations in posture and allows conclusions about body stability.
The surprising result: When comparing balance changes across the three conditions (happy, angry, no image), no clear difference emerged. However, a fascinating pattern was revealed in the details: The researchers grouped the individual reactions of each dog and identified two distinct types - those whose stance became more stable and those whose stance became less stable.
When viewing happy faces, approximately 65% of the dogs exhibited overall lower COP values (stabilizing), while 35% showed higher values (destabilizing). When looking at angry faces, 53% showed stabilizing reactions, while 47% exhibited destabilizing responses. In other words, the emotional arousal triggered by viewing both facial expressions directly affected the body balance of each dog in an individual manner.
This finding aligns with what was already known from the previous study: It is not solely the emotion (positive or negative) but rather the arousal it triggers that influences the body’s response. "Our results suggest that dogs not only recognize emotional information from faces on a television screen but also physically process it -evident in tiny changes in their postural stability. This highlights the importance of the experiences dogs have had with specific human facial expressions and how the individual emotionality and sensitivity of our dogs are influenced," says Nadja Affenzeller from the Clinical Centre for Small Animal Health and Research at Vetmeduni.
The article "Happy and angry human pictures differentially affect dogs’ postural stability" by Nadja Affenzeller, Christiane Lutonsky, Masoud Aghapour et al. was published in Scientific Reports.
* Weak Knees: Harsh Words Throw Dogs Off Balance
Scientific contact:
Dr. med. vet. Nadja Affenzeller Dip ECAWBM (BM) MSc FTA MRCVS
Klinisches Zentrum für Kleintiere
Veterinärmedizinische Universität Wien (Vetmeduni)
nadja.affenzeller@vetmeduni.ac.at