History contains numerous accounts of children raised by animals. The children in such cases often continue to act more animal than human, even when returned to human society. The psychologist Winthrop Kellogg wondered what would happen if the situation were reversed. What if an animal were raised by humans as a human. Would it eventually act like a human?
To answer this question, in 1931 Kellogg brought a seven-month-old female chimpanzee named Gua into his home. He and his wife then proceeded to raise her as if she were human, treating her exactly the same as they treated their ten-month-old son Donald.
Donald and Gua played together. They were fed together. And the Kelloggs subjected them both to regular tests to track their development. One such test was the suspended cookie test, in which the Kelloggs timed how long it took their children to reach a cookie suspended by a string in the middle of the room.
Gua regularly performed better on such tests than Donald, but in terms of language acquisition she was a disappointment. Despite the Kelloggs’s repeated efforts, the ability to speak eluded her. Disturbingly, it also seemed to be eluding Donald. Nine months into the experiment, his language skills weren’t much better than Gua’s. When he one day indicated he was hungry by imitating Gua’s “food bark,” the Kelloggs decided the experiment had gone far enough. Donald evidently needed some playmates of his own species. So on March 28, 1932 they shipped Gua back to the primate center. She died a year-and-a-half later of fever.
Comparative Tests on a Chimpanzee and Human Infant pt 1
Comparative Tests on a Chimpanzee and an Infant pt 2