Dogs Don't Need Their Eyes to Balance. Humans Absolutely Do.
Blindfold a healthy person and ask them to stand still. Their balance deteriorates noticeably. Now do the same thing to a healthy dog. Barely a wobble. That, in a simplified form, is the core finding of a new study published in Scientific Reports, which used static posturography to directly compare how humans and dogs maintain postural stability — and what happens to that stability when vision is removed.
The research, conducted by a team from the University of Veterinary Medicine Vienna, assessed 22 healthy young adult humans and 22 healthy young pet dogs on a pressure measurement platform under two conditions: eyes open and eyes closed (or, for the dogs, blindfolded). Using a set of five center of pressure parameters — mediolateral displacement, craniocaudal displacement, COP path length, average sway speed, and support surface — the researchers calculated Romberg indices for each. The Romberg index is a well-established way to quantify how much an individual's balance degrades when vision is taken away. A higher value means greater reliance on visual input. A lower value means the body is leaning more heavily on proprioception and vestibular input to stay upright.
What the Data Showed
Across three of the five parameters — craniocaudal displacement, COP path length, and average sway speed — humans and dogs differed significantly. Humans showed markedly higher Romberg indices across all three, meaning that when vision was removed, their balance degraded considerably more than the dogs' did. They swayed more front-to-back, their center of pressure traced a longer path across the platform, and they moved faster trying to compensate.
Dogs, by contrast, showed low Romberg indices across those same parameters. Removing vision had comparatively little effect on their postural stability. Their proprioceptive and vestibular systems, it appears, are more than adequate to keep them balanced without visual input doing much of the heavy lifting.
The two parameters where humans and dogs did not differ significantly were mediolateral displacement and support surface. Both species use similar compensatory strategies to manage side-to-side sway and to adjust the area over which they distribute their weight. The difference, then, is not universal. It is specific to the front-to-back axis and to the overall efficiency of postural correction — the dimensions most affected by the shift from four points of contact to two.
The Biomechanics Behind It
The explanation is largely architectural. Bipedal stance is inherently less stable than quadrupedal stance. Humans balance on a relatively narrow base with a high center of mass, which creates an ongoing mechanical challenge that the nervous system has to solve continuously. To do that well, the human balance system leans heavily on vision. It is not a weakness, exactly — it is an adaptation to a fundamentally demanding postural situation. But it does mean that when vision is removed, the system has less margin for error.
Dogs, with four limbs providing a wider, lower base of support, have a more mechanically forgiving starting point. Their center of mass sits lower relative to their base, and the distribution of weight across four paws gives the postural control system more inputs to work with and more stability to draw on. Vision becomes supplementary rather than essential. The proprioceptive signals coming from four contact points, combined with vestibular input, are sufficient to maintain stable quiet stance without visual confirmation.
The finding that mediolateral control was similar between species is consistent with this framing. Both bipeds and quadrupeds appear to use comparable strategies to manage side-to-side stability, even though the overall postural systems differ. The divergence is in the craniocaudal axis, which is the dimension most challenged by the upright, two-legged stance that humans adopted over the course of evolution.
Why This Matters Clinically
For veterinary rehabilitation practitioners, this study has direct implications. Static posturography is an increasingly used tool for assessing postural stability in dogs, particularly in cases of orthopedic disease, neurological conditions, and post-surgical recovery. Understanding how healthy dogs use their sensory systems to maintain balance provides a clearer baseline against which pathological changes can be measured.
If dogs under normal conditions rely minimally on vision to maintain quiet standing, then changes in that reliance — a dog that suddenly becomes much more vision-dependent for balance — may be a meaningful clinical signal. It could indicate proprioceptive deficits from a neurological lesion, pain-driven compensatory shifts in weight bearing, or vestibular dysfunction forcing the system to recruit vision as a backup. The Romberg index, adapted for veterinary use, offers a way to quantify that shift objectively rather than relying on clinical impression alone.
The study also reinforces the value of cross-species comparison as a research methodology. By putting humans and dogs through identical protocols on the same equipment, the researchers were able to isolate the variables that matter most: number of limbs, base of support geometry, and the resulting difference in sensory system hierarchy. That kind of direct comparative data is rare and clinically useful in ways that single-species studies are not.
The Takeaway for Practice
Postural stability assessment is no longer a niche research tool in veterinary medicine. As canine rehabilitation continues to mature as a specialty, objective measurement of balance is becoming part of standard clinical evaluation for orthopedic and neurological patients. This study adds to the evidence base by characterizing what normal canine postural control actually looks like at the sensory integration level — not just what it looks like on the platform in terms of raw sway numbers, but how the dog's nervous system is organizing its balance strategy.
The answer, it turns out, is that healthy dogs are remarkably good at this. They maintain stable posture across conditions with or without visual input, relying on a well-integrated proprioceptive and vestibular system that does not need a visual anchor to keep them upright. When that changes in a patient, it is worth asking why.
Source: Aghapour M, Affenzeller N, Lutonsky C, Peham C, Bockstahler B. "Different strategies of bipeds and quadrupeds to maintain postural stability: a comparison of healthy humans and dogs via static posturography." Scientific Reports, 2026. University of Veterinary Medicine Vienna.
