An anonymous reader quotes a report from The New York Times, written by philosophy professor Lori Gruen: Sarah, who could have been deemed the world’s smartest chimp, was brought to the United States from Africa as an infant to work with David and Ann Premack in a series of experiments designed to find out what chimpanzees might think. In order to determine what, if anything, might be on Sarah’s mind, she was one of the first chimpanzees to be taught a human language. The Premacks taught her to use plastic magnetic tokens that varied in size and color to represent words. She formed sentences by placing the tokens in a vertical line. Ann Premack noted that her earliest words named “various interesting fruits,” so that Sarah “could both solve her problem and eat it.”
Sarah’s career established that not only do chimpanzees have complex thoughts, but also distinct personalities with strong preferences and prejudices. But this is just part of her remarkable life story. As she grew older she helped a diabetic chimpanzee named Abby, who she was living with, remember to get her medication. She was a loving, yet stern, aunt-like figure to a pair of young chimpanzees, Harper and Emma, and she helped Henry, a male chimpanzee who came from a situation of terrible abuse, get along with other chimpanzees. Since the time that Sarah was thought to have established that chimpanzees know what others might want or need, a growing number of investigators have tried to figure out if other animals have a theory of mind. Though there have always been skeptics, studies have suggested that crows, jays, ravens, other apes, monkeys, and maybe dogs, may know what others are thinking. In social animals, being able to glean what others might be thinking is a good strategy for getting along. For chimpanzees living in sanctuaries, it can facilitate care.