Chimpsky, not Chomsky: Did Nim the chimpanzee actually learn American Sign Language?

Nim Chimpsky raised the prospect of language among chimps but the experiment remains controversial today

By Matthew Rozsa

Staff Writer

Published June 25, 2023 10:00AM (EDT)

Three chimpanzees (Pan troglodytes) socializing. (Getty Images/PHOTOSTOCK-ISRAEL/SCIENCE PHOTO LIBRARY)
Three chimpanzees (Pan troglodytes) socializing. (Getty Images/PHOTOSTOCK-ISRAEL/SCIENCE PHOTO LIBRARY)

Humans are often thought to be the only animals capable of language. But it's difficult to prove a negative like this because we'll never definitively know the subjective interior monologues of other animals, if they even exist. Nonetheless, much research has been poured into the study of animal intellect and whether creatures like orcas, pigeons and octopuses share a similar type of sentience, especially when it comes to our close primate cousins, chimpanzees. One of the most outstanding and intriguing questions is whether chimps have language — and a little ape named Nim Chimpsky has only made the prospect more controversial. 

People who study languages almost universally know the name "Noam Chomsky." In addition to being the father of modern linguistics, the popular intellectual has written more than 150 books on myriad political and social subjects. As a result, the name "Noam Chomsky" is familiar not only to students of linguistics, but also political nerds and social justice advocates.

"Nim's signing wasn't spontaneous. He was unable to use words conversationally, let alone form sentences."

Noam Chomsky is, if nothing else, a bona fide celebrity — but who the heck is Nim Chimpsky?

No, that isn't a cringey pun. (Well, it isn't only a cringey pun.) Nim Chimpsky is the cheeky moniker that was once applied to a real-life chimpanzee. Because Chomsky (not Chimpsky) argues that human beings are uniquely "wired" to develop language, Columbia University psychology and psychiatry professor Herbert S. Terrace decided to work with psycholinguist Thomas Bever on training a chimpanzee how to "speak" using American Sign Language. The thusly dubbed Nim Chimpsky (as a playful rebuke to Chomsky's theories) did not, as many hoped, unequivocally prove that chimpanzees can develop language just like humans.

Then again, some people argue that Chimpsky did prove that. It's just that the matter remains, all these years later, intensely controversial.

As chronicled in the 2011 documentary "Project Nim," Terrace decided to see if Chimpsky could learn human language by placing the infant monkey into the home of one of his former students, Stephanie LaFarge. The goal was to see if Chimpsky could acquire human-like language if he was raised like a real human being. Starting in late 1973, Nim Chimpsky began his life/experiment — but controversy soon arose. Despite being treated kindly, Nim Chimpsky showed unexpected aggression toward his human caretakers. His behavior was so sporadically violent that, after he attacked one of the people taking care of him in 1977, Terrace moved Nim Chimpsky back to a regular laboratory. At that point, Terrace called off the experiment.

Additionally, Terrace and his colleagues reached a disappointing conclusion: Although Chimpsky had appeared to learn language — he moved his hands and body in a manner consistent with American Sign Language, using over 120 combinations, in order to seemingly ask for things like food and affection — the evidence indicated that he was simply mimicking the behavior of the humans around him. It is possible that Chimpsky understood at least some of the "words" he was forming, but it is also very, very far from being proven.

"Nim learned to sign to obtain food, drink, hugs and other physical rewards," Terrace later explained to Columbia University. "Nim often got the signs right, but that was because his teachers inadvertently prompted him by making appropriate signs a fraction of a second before he did. Nim's signing wasn't spontaneous. He was unable to use words conversationally, let alone form sentences."

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Nim Chimpsky simply wasn't happy being forced to live with humans.

Chimpsky's story ends first with a scare, and then rather anticlimactically: He was initially sold to a pharmaceutical animal testing laboratory, but after public outcry, moved to the Black Beauty Ranch in Texas. There he lived out his remaining days in peace until passing away of natural causes in 2000.

Yet the controversy about his legacy did not die with him. Speaking to Columbia University many years later, Terrace insisted that his experiments had proven the importance of words to the development of language. This still distinguishes Terrace's theory of language from Chomsky's, who argues that there is a "universal grammar" embedded in the neurology of every human brain which is unique to our species. Importantly, the presence of a universal grammar means humans can create an infinite number of meanings from a finite number of words. Yet if other animals can also form words, Terrace claims, this speaks to their ability to communicate regardless of whether they also form grammar.

"Those insights had a profound effect on linguistics and cognitive psychology," Terrace concluded to Columbia University. "But they said nothing about words, without which none of his grammars would work. At best, Chomsky's theories are limited to people who know words. Project Nim showed why learning words is crucial for mastering language."

Nim Chimpsky's life also opened up important questions about the ethics of animal research. Although Chimpsky was spared the horrid fate of living in a pharmaceutical laboratory, at least one of the humans who worked closely with him believes he was emotionally harmed by not being allowed to grow up with his own species.

"You could read [fear and apprehension] through his facial expression and his body language," recalled Bob Ingersoll, a graduate student at the University of Oklahoma who worked with Nim Chimpsky, in a retrospective interview with NPR. "It was very distressing to him and ... we were really worried about Nim and we spent quite a lot of time with him, making sure he was eating and drinking and not being picked on by the other chimps."

Indeed, Ingersoll even remembers smoking marijuana with Nim Chimpsky, stating that "although we were familiar with chimpanzees that did things like drinking and smoke cigarettes and that sort of thing, I'd never had a chimpanzee request weed from me. That was an eye-opener."

Yet ultimately, Ingersoll's main observation was that Nim Chimpsky simply wasn't happy being forced to live with humans.

"What he needed at that point was to be with other chimps," Ingersoll concluded. "Chimps don't need to be with humans. They need to have a chimp life. So my own personal need to hang out with Nim or walk with Nim wasn't as important to me as doing the right thing for Nim ... Chimpanzees in captivity is just not where they ought to be ... I would hope that one of the lessons that we learned from Nim's life is that keeping chimpanzees in cages is torture and really plays havoc on their mental health."

By Matthew Rozsa

Matthew Rozsa is a staff writer at Salon. He received a Master's Degree in History from Rutgers-Newark in 2012 and was awarded a science journalism fellowship from the Metcalf Institute in 2022.

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Aggregate American Sign Language Animal Intelligence Language Nim Chimpsky Noam Chomsky