It fascinates me that there are so many intelligent people posting here that are unwilling to accept this very basic principle, or debate it, instead choosing to dismiss it outright with various logical fallacies.

If I had to guess, people are taking things a bit personally as an attack on their pets, as though requesting further evidence of higher order processing is insinuating that their pets don't really have the feelings they believe their pets do. (Nobody here commenting on the experiment's conclusions is claiming this, as far as I can tell; they're just asking for more conclusive and objective evidence before they believe such conclusions can be made.)

Some of the 'reasoning' being used ("Just ask any dog owner") is eerily familiar to the kind of reasoning people use when justifying homeopathy ("It worked for my cousin's ailment", which in the extreme leads to lovely things like Rhino poaching and whale hunting, something I'm sure these people abhor), the paranormal and supernatural ("I sensed something [and my senses are obviously infalible]", which in the extreme leads to a reduced quality of life), religious extremism ("Just ask anybody who's heard God's voice") etc.