Proved the one bad apple theory. Thought they could teach the Chimp to talk.
In 1931, psychologists Winthrop and Luella Kellogg raised their 10-month-old son, Donald, alongside a 7½-month-old chimpanzee named Gua, treating them as siblings for nine months. The experiment, aimed at studying environmental effects on development, was terminated prematurely when Donald began mimicking Gua's ape-like vocalizations and behaviors instead of the chimp learning to act human.