For centuries, humanity has pondered the unique complexities of its own language. The question of whether apes can learn human-like language, especially sign language, has fascinated scientists and the public. This curiosity extends to understanding if our closest primate relatives share similar capacities for communication. Research in this area challenges conventional ideas about language and intelligence, prompting a deeper exploration into what defines linguistic ability.
Pioneering Ape Sign Language Studies
Early attempts to teach apes spoken language faced biological hurdles due to their differing vocal anatomy. This led researchers to explore gestural communication, specifically American Sign Language (ASL). A groundbreaking project began in 1967 with Washoe, a chimpanzee raised by Allen and Beatrix Gardner as if she were a deaf human child. Washoe learned approximately 350 ASL signs, using them spontaneously and combining them to form novel expressions like “water bird” for a swan. She also taught some signs to her adopted son, Loulis, suggesting cultural transmission.
Following Washoe, Koko, a gorilla, became another prominent subject in ape language research, learning a modified form of ASL. Francine Patterson, Koko’s primary researcher, reported that Koko acquired over 1,000 signs and understood around 2,000 spoken English words. Koko was observed inventing new signs by combining existing ones, such as “finger bracelet” for a ring. These studies often involved raising the apes in home-like settings.
The Project Nim study, led by Herbert Terrace, aimed to determine if a chimpanzee named Nim Chimpsky could learn ASL. Nim learned over 125 signs, but Terrace’s analysis concluded that Nim’s signing was primarily imitative and motivated by rewards, rather than spontaneous communication or true language acquisition. These pioneering efforts, while diverse in outcome, collectively propelled scientific inquiry into ape linguistic capabilities.
Beyond Mimicry: Understanding Ape Communication
The observed communication in ape sign language studies sparked considerable debate about whether it truly constitutes “language” in the human sense. Critics, such as linguist Noam Chomsky, argue that language is a uniquely human capacity, hardwired with specific grammatical structures. Herbert Terrace’s Project Nim findings supported this skeptical view, suggesting Nim’s signing lacked syntax, grammar, and spontaneity, appearing more as operant conditioning. The “Clever Hans effect” also became a central criticism, highlighting the risk of unconscious cues from human trainers.
However, proponents of ape language research offer counterarguments, pointing to instances of spontaneous sign use and their ability to combine signs creatively. Washoe’s combinations of signs and Koko’s novel sign inventions suggest a deeper understanding beyond mere mimicry. Some studies also indicate that apes demonstrate “displacement,” referring to objects or events not immediately present, a feature associated with human language. While apes may not exhibit the complex syntax and generative grammar of human language, their ability to learn and use symbols, and sometimes combine them meaningfully, continues to be explored.
Insights into Language and Cognition
Decades of research into ape sign language have influenced our understanding of language and the cognitive capacities of non-human primates. These studies show that apes possess intellectual abilities, including symbol learning, categorization, and sequential learning. While the debate regarding “true language” acquisition continues, the research reveals communicative potential in apes.
The findings suggest that ape communication, particularly through gestures, shares some underlying cognitive elements with human language. While apes may not exhibit human-like syntax or shared intentionality, their capacity to learn and use signs to express desires and emotions challenges a strictly human-centric view of language. This ongoing research contributes to a broader understanding of intelligence across species and offers insights into the evolutionary roots of human language, suggesting foundational elements may be present in our closest relatives.