When older honeybees take on tasks usually handled by younger bees, aging of their brains is effectively changed, a new study finds. The discovery suggests that in humans, social involvement ought to be considered in addition to drugs as a way to treat age-related dementia(痴呆). “We knew from previous research that when bees stay in the nest and take care of larvae—the bee babies---they remain mentally able as long as we observe them,” explained Gro Amdam, who led the research at Arizona State University. “However, after a period of nursing, bees fly out gathering food and begin aging very quickly.” “After just two weeks, foraging(觅食的)bees have worn wings, hairless bodies, and more importantly, lose the brain function—-basically measured as the ability to learn new things,” Amdam said in a statement. Amdam and his colleagues wanted to find out what would happen if they “asked” the foraging bees to take care of larval babies again. To find out, they removed younger nurse bees from a nest, leaving the older foraging bees to face a choice: forage or care for the larvae. Some of the older returned to searching for food, and others switched to caring for the nest and larvae. After ten days, about fifty percent of the older bees that had chosen to care for the nest and larvae had “greatly improved their ability to learn new things.” The researchers also discovered changes in the proteins in the brains of the bees whose learning ability had improved. One of the proteins that changed, called Prx6, is also found in humans and is known to help protect against dementia. “Maybe social involvement is something we can do today to help our brains stay younger,” Amdam says. “Since the proteins being researched in people are the same proteins bees have, these proteins may be able to respond to specific social experiences.” Other studies have shown several non-drug methods can help improve brainpower in older people, including going for walks and taking music lessons. The findings, announced this week, are detailed in the journal Experimental Gerontology. 小题1:What does the underlined word “they” in Paragraph 4 refer to? （No more than 5 words） 小题2:When do the brains of older bees age very fast? （No more than 9 words） 小题3:What is Amdam’s suggestion for old people to prevent dementia? （No more than 6 words） 小题4:What is the best title for the text? （No more than 6 words）