By Stephen Beech
Dogs can be “destabilized” by hearing angry human voices, reveals new research.
They may lose their balance – perhaps as the sounds induce emotional arousal, say veterinary scientists.
The study showed that dogs experienced both stabilization and destabilization of their balance when hearing angry or happy human voices.
But angry voices were linked to the biggest destabilising effects, according to the findings published in the journal PLOS One.
Study leader Dr. Nadja Affenzeller said: “For humans and animals alike, stable posture underpins the ability to stand still, walk, and perform other activities without falling.
“To maintain stability, our muscles rely on visual cues as well as the body’s sense of its own position.
“Recent research in humans suggests that external sounds may also influence stability, with high frequencies linked to destabilization and white noise to stabilization.
“However, few studies have examined how sound affects postural stability for animals.”
To help clarify, Dr. Affenzeller and her colleagues at the University of Veterinary Medicine, Vienna, Austria, measured changes in balance for 23 pet dogs on hearing recordings of happy and angry human voices.
The team used a standard research technique in which the dogs stood on a pressure-sensing platform that detected small movements corresponding to five parameters linked with balance.
Compared with hearing no sound at all, hearing an angry human voice was associated with higher values of a parameter known as “support surface” – the area of the platform occupied by the swaying path of a dog’s center of pressure.
Dr. Affenzeller said: “Higher support surface values indicate destabilization, with greater body movements to stay balanced.
“None of the four other stabilization parameters were consistently associated with either angry or happy voices.
“When the individual changes of all dogs were taken into account, the responses varied considerably between the dogs.”
She says happy voices were linked with destabilization for 57% of the dogs and, surprisingly, stabilization – or “freezing” – for 43%.
Angry voices were associated with the most severe destabilization in 30% of dogs, although 70% didn’t show stabilization changes.
Dr Affenzeller said: “These findings suggest angry and happy human voices may elicit emotional arousal that can both stabilise and destabilise balance.”
She added: “Further research could deepen understanding by exploring, for instance, whether prior experiences affect individual dogs’ reactions, and whether freezing in response to happy voices may be related to anticipatory adjustments in preparation for voluntary movements – such as an approach.”
