What It's Like to Think With a Dog's Brain

April 29, 2010— -- Groucho Marx once said, "Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read."

But it is beginning to get lighter in there, thanks to modern cognitive science.

Groucho's quip graces the opening page of "Inside of a Dog: What Dogs See, Smell and Know," a new book by cognitive scientist and psychologist Alexandra Horowitz that goes a long way to suggest what it's like to think with a dog's brain -- to actually be a dog.

Combining new knowledge from hundreds of scientific and animal behavior studies, and mixing it in with a fine style guided by her own loving bemusement of dogs -- especially of her own Finnegan, rescued as a sick and needy pup from a shelter -- Horowitz gives us a fascinating picture of a dog's umwelt (OOM-velt) -- German for "their subjective or 'self-world'."

"Umwelt captures what life is like as the animal," she says.

We met Horowitz and Finnegan on a high plateau -- a grassy field hidden amid a circle of trees in New York's Central Park -- one day at 8 a.m.

There was one hour to go before leash laws came into effect, so we were surrounded by some two dozen joyous dogs of every size, shape, color and pedigree -- or lack thereof -- and as many wakening humans.

Racing around, sniffing, forming little groups and making up games, the liberated dogs turned it into a scene much like any elementary school playground, brimming over with the invention of play -- but play on steroids.

We more static humans stood in their midst, wrapped for a while in dog time.

"Actually, dogs see faster than humans, so to speak," Horowitz, who teaches psychology at Columbia University, told ABC News.