A scientific study published this month shows that the robotic dog Aibo is as effective as a real dog for treating loneliness in nursing homes. It has long been known that animal-assisted therapy (longhand for bringing a dog to visit long term care facilities a few times a month) can help reduce loneliness, but researchers decided to study whether it was really the furry pet that mattered or if a harder, plastic computerized object could do the job just as well. Turns out that when compared to a control group who didn't get any animal or robot attention, the patients who interacted with the robot improved just as much as those who got visits from a real dog.
If you have an elderly relative who tends to get lonely, we recommend purchasing a friendly robot for her (Aibos aren't on the market right now, but a Pleo could work). It may take a while for her to learn to charge it, but think about how much easier that is than taking care of a hungry, needy and messy cat or dog.