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When New York psychologist Irene M. Deitch took her boxer, Kayo, along to counseling sessions, the dog would greet Deitch's clients by standing on his hind legs and kissing them smack on the lips. Soon Kayo became as valued a source of therapy as Deitch herself. What gave the dog such healing power? Animals offer people "unconditional positive regard," explains Deitch, now retired and professor emerita of psychology at the College of Staten Island. "No matter how we feel, we will always be valued by our pets.
Ever since humans domesticated dogs centuries ago, scientists have been trying to explain the intense love people feel for their animals. Some believe our pets experience the same emotions we do, so we bond with them as though they were humans. At the other extreme are those who say that animals trained us to become attached to them. But there's one point everyone agrees on: The more disconnected we become from each other because of e-mail, iPods, and work-at-home lifestyles, the deeper the bonds we form with our pets.
At the root of the human-animal love connection is the childlike charm of pets. Take dogs. Judging from various behaviors, such as their ability to understand 160 or so words and gestures, scientists have determined that an adult dog is roughly equivalent mentally to a 2-year-old toddler. Because humans are hardwired to nurture children, we automatically feel an affinity for dogs. But canines never grow up, nor do they bring the hassles or heartbreaks children do. "There's no deception, no subterfuge, no criticism," says James A. Serpell, section chief of behavior and human-animal interactions at the University of Pennsylvania School of Veterinary Medicine. "Animals don't do that stuff."
Humans find such loyalty irresistible. Dogs are descended from wolves. Even when removed from the wild, they retain an instinctive need to travel in packs. So we have become their new pack, some experts say. That's why dogs whine when we leave for work, making us feel guilty, then wag their tails and slobber all over us when we walk in the door. "You've left the pack, and when you return, they're saying: Thank God you're back,'" says Jeffrey M. Masson, author of several books on animal behavior.
Skeptics say pets are really nothing more than master con artists, and we their hapless victims. They point to a growing pile of evidence that wolves paved their own way to domestication as soon as humans started forming settlements and discarding food scraps. The closer the wolves approached people to score free meals from the garbage heap, the tamer they became, the studies suggest. Some scientists believe that, even today, dogs are constantly tricking us into believing they love us so we'll reciprocate by feeding them. If Buster cries when his master leaves, say these killjoys, it's not because he's sad to see him go but because he's worried that his meal ticket just walked out the door.
While most animal experts dismiss the meal-ticket theory, there's widespread agreement that people project their own emotions onto pets. That's often what's going on when the dog chews up the couch and his owner gives him antidepressants to cure his so-called separation anxiety. "We're losing a rational perspective on this love," says Jon Katz, who has written several books about his adventures running a sheep farm, most recently Dog Days, featuring his border collie, Rose. Katz's fans comment that Rose would be lost without him. But privately he tells his wife that, if something happens to him, she should just throw Rose over the fence of a neighboring sheep farm and the dog will be perfectly happy. "Animals don't make choices," Katz argues. "They react to things that take care of them." By Arlene Weintraub