This paper addresses a number of different language experiments that have been performed with all four species of great apes
- gorillas, chimpanzees, orangutans, and bonobos, and the advantages, disadvantages, and relative success of each, including conducted experiments. The author discusses the physical limitations of the apes, the advantages of using sign language as opposed to keyboard and symbol-based language, and criticisms brought up by various skeptics. The paper also mentions other types of cognitive activities in which the apes have participated, including painting and learning a system of economic exchange. From the paper: "The Koko Project is currently the longest running and most successful of all the ape language projects. Patterson's goal was for Koko
to learn 200 signs - she now knows over a thousand, and understands at least 2,000 words of spoken English. She asks questions, she lies, she tells stories, she uses the negative, she uses and understands abstract words like love, hate, and death, and she even tells jokes. One of the most famous incidents involves a conversation between Koko and one of her teachers regarding the color of her blanket. As she was getting ready to go to bed, the teacher asked Koko what color the blanket was. Koko responded "red," even though the blanket was white. The teacher admonished her and asked her again, refusing to believe that Koko would make such a simple mistake. Still, Koko responded "red," and repeated it several times. The teacher was perplexed. Then Koko pulled a tiny piece of red lint off the blanket, pointed to it, and signed "red," and started laughing her deep, breathy, gorilla laugh. Humor, then, is another quality we humans can no longer claim for ourselves alone."