FTA:

> The second experiment, which involved 19 other dogs, was identical in design except that the owners wore headphones playing rock music to stop them from hearing the 'Bouba' and 'Kiki' sounds. The idea here was to remove any owner cues the dogs might have been following.

So they at least attempted to account for it.

Also, why do owners feel the need to unleash their dogs at you in self defense? This is very strange.