One reason why cats are more popular than dogs in nursing homes is that they're easy to care for. But Sam Corson, the grandfather of the movement to place pets with the elderly, has a decided bias against cats.

Corson, an Ohio State University professor emeritus of psychobiology, thinks cats are perfectly agreeable creatures and owns one himself. But when the family is cutting capers in the kitchen or hugging in hallways, the dog joins in while the cat curls up in a corner, as if offended by such demonstrations. More importantly, Corson feels dogs are more effective social lubricants than cats, largely because when people walk them, they often meet other -- sometimes genial -- human beings.

"If we want to improve the quality of life," Corson says, "we would do better choosing dogs" -- which is, as it happens, a field being investigated.

Want a cat to lick your tears, come when you call, fear you enough to stay off the sofa when you're not around? Find a newborn kitten and start fonding it immediately. At least, that's the course indicated by the work of Eileen Karsh, a clinical psychologist at Temple University. Using domestic shorthairs for her research, Karsh found that early handling, beginning at three weeks, produces a much more affectionate grown cat -- a cat that is, uh, very much like a dog.