University of Colorado at Boulder sociologist and author Leslie Irvine is using what is known about human infants to prove a point many scientists won't formally examine - that domesticated dogs and cats each have unique personalities and are smarter than we think.
Irvine explores animals' sense of self and their interactions with humans in her new book, "If You Tame Me: Human Identity and the Value of Animals' Lives." She used a new approach to illustrating pet intelligence.
"I borrowed pieces of theory from the research on human infants," Irvine said. "I was influenced by that research and I tweaked it to apply it to animals. Human infants don't have language either, but we still assume that they have personalities and that they are going to have subjective experiences and emotions."
It is impossible, many scientists say, to confirm animal intelligence or emotion without superimposing human traits. Irvine believes the notion that dogs and cats and other animals have a sense of self isn't as far-fetched as it may seem.
"We know that pets feel fear, surprise, curiosity, frustration and anger," she said, adding that animals are like humans in that they express emotions in the context of relationships with other animals and human beings. Irvine said her work provides scientific verification that animals, and specifically pets, have emotions and personalities.
"If you are around two or three different dogs or cats, you can see they're not just cookie cutters of one another. They have very different personalities and preferences, and humans kind of intuitively know that," Irvine said.
For the skeptics who say awareness or emotion can't be proven in pets, Irvine makes two key points.
"When we're talking about issues of self and emotions, there's no way to prove them in other humans, either," said Irvine. "My happiness isn't the same as your happiness, but yet we talk about it as if we know exactly what someone else is experiencing."
Irvine also noted a recent German study of a border collie that indicated the dog understood more than 200 words. "It seems like every week there are newer, better studies coming out saying that animals have much more complex intellectual and emotional lives than we ever thought," she said.
After living with a human for a while, it isn't unusual for a dog or cat to sense human emotions and react accordingly, according to Irvine.
"If an animal is living with a person for a number of months or years, that animal will know when that person is experiencing tension or when the person is relaxed, or when the person is angry -- much in the same way that we know when our human friends would be feeling those emotions," she said.
Dog training, which teaches the dog how to control itself, illustrates the ability of the animal to reason, Irvine said. "You are teaching the dog to make a decision about a particular response. You can actually see the dog making up his or her mind, and they don't always do what we want them to do. You call them, and they look back at you but then they want to run after the squirrel. The dog has to actually figure out which option has a better reward."
For more information about Irvine's research, visit . For information on her book, visit .