'One time, I couldn't find Paro and was looking for 'him' everywhere,' says one caretaker at the Kirara nursing home in Japan's Nanto City. 'Finally I found Paro sleeping in a patient's bed.' Paro is a robotic baby seal—covered with white fur—that was developed over 12 years at a cost of some $10 million by Japan's National Institute of Advanced Industrial Science and Technology. Nanto is one of the first cities in the world to experiment using robots to help care for the elder citizens. According to the nursing staff, Paro, which responds to human voices and loving touches, has become part of the family. In fact, nurses often find elderly patients covering the robot in blankets and trying to feed it snacks, even though Paro can't really eat. It's no surprise that Japan is turning to technology for help with one of its most troublesome problems: an aging population. Japan is said to be with 28% of the population expected to be 65 years or older by 2010.@Fewer young people would like to be caretakers. Perhaps robotic companions can ease some of the burden. But whether robots can adequately handle this responsibility—positively impacting both the health and well-being of the elderly—remains an open question. Alan Beck directs one such study. He said they placed Aibo, a robotic dog made by Sony, in the homes of isolated senior citizens to determine whether the robotic pet can improve quality of life. Though the final results have not yet been published, preliminary(初步的) conclusions indicate that the robotic dog is treated much like a family pet, drawing behaviors commonly associated with companionship, including sharing thoughts and feelings. Beck says participants felt more comfortable and less lonely with Aibo. Dr. Takanori Shibata, the creator of Paro, and his colleagues found that robot interaction lowered stress, elevated moods and decreased depression. Additionally, Paro encouraged communication and social behavior. among subjects. What's more, Shibata found that brain activity increased 50% in patients with dementia(痴呆)after just twenty minutes with Paro. Caretakers were positively affected as well. The robots not only decreased nurses'stress levels but also gave them something to discuss with their elderly patients. What are Paro and Aibo according to the author's introduction?