Back in the day when I was in grad school, I worked with Ron Siegel on hallucinations in rhesus monkeys. Ron had a gadget called a parabolic mirror that made an object at the bottom of the mirror look like it was located a few inches higher. He wanted to see if rhesus monkeys would view this differently under the influence of a variety of hallucinogenic drugs.
I’m not sure that we discovered anything terribly profound–the poor monkeys were confused at best under the influence–but these were interesting times.
So I read with great interest about some more recent work on visual illusions in dogs. I am fascinated by comparative psychology anyway, and I love dogs, so this caught my eye. The experimental set-up looks like this:
You might recognize this as the famous Ebbinghaus-Titchener illusion. Humans see the circle surrounded by smaller dots as larger, but apparently, dogs do the reverse. Dogs apparently don’t fall for the Ponzo illusion, but do respond to the Muller-Lyer illusion like humans do.
You might also have seen the viral videos of pet owners holding up a sheet and then “disappearing.” Sarah Byosiere has launched What the Fluff? to allow pet owners to submit their own videos of their efforts to fool their pets. I will be watching these results closely! My personal hypothesis is that breed will matter. Human beings bred dogs to be stupid. After all, the cunning of the wolf is wonderful to watch but not so great to live with. The herding breeds, like my Australian shepherds, are not only closer to the wolf but also very, very smart. Dogs can demonstrate object permanence under some situations. My hunch is that the herding breeds would show more object permanence than less intelligent dogs.
Why dogs would respond differently than humans to a variety of visual illusions will require more information. We would have to consider why both humans and dogs see the illusions they do from an evolutionary and adaptive standpoint. In the meantime, I am definitely going to try this out with my dogs!
