As a psychology student in the late 1990s, a large part of our cognitive and developmental courses was about language. The past few decades had seen a great deal of research into and development of new theories of language development, and the rise of the best-known name in the field of linguistics, Noam Chomsky.
In addition to reading about a chimp named Kanzi, we all got to know the gorilla named Koko. Being that it was a liberal arts education, and critical thinking was embedded in every topic covered, the professors presented both sides of a contentious debate that the lay public was unlikely to encounter. We learned about Penny Patterson, who worked with Koko, and her deeply held belief, formed through years of working with Koko, that the gorilla had learned to sign, and was doing so to communicate the same way we as humans do. That she was going beyond simply forming shapes with her hands to view them as true words and a way to express real thoughts and emotions. On the other side of the debate we have scientists like Herbert Terrace, who holds that based on the principles of behavioral psychology, chimps and gorillas are using signs as a simple behavior performed for the sole purpose of obtaining a reward, like food or attention.
As we cannot read the minds of these animals, we have to base our theories on the evidence in front of us. Great minds on both sides of the question point to behaviors that they believe support their case, always, as we know, through the lens of what they expect to see, or long to see. So, for now, I will simply mourn the loss of an individual who both answered old and sparked new questions about what it means to communicate and what it means to be human, whether she knew it or not. She passed away on June 19, 2018, at the age of 46. Rest in peace, Koko.