28 Language and Thought

28.4 Do Other Species Have Language?

28-4 What do we know about other animals’ capacity for language?

Humans have long and proudly proclaimed that language sets us above all other animals. “When we study human language,” asserted linguist Noam Chomsky (1972), “we are approaching what some might call the ‘human essence,’ the qualities of mind that are, so far as we know, unique [to humans].” Let’s see if research on animal language supports claims that humans, alone, have language.

Animals display impressive comprehension and communication. Vervet monkeys sound different alarm cries for different predators: a barking call for a leopard, a cough for an eagle, and a chuttering for a snake. Hearing the leopard alarm, other vervets climb the nearest tree. Hearing the eagle alarm, they rush into the bushes. Hearing the snake chutter, they stand up and scan the ground (Byrne, 1991). To indicate such things as a type of threat—an eagle, leopard, falling tree, or neighboring group—monkeys will combine 6 different calls into a 25-call sequence (Balter, 2010). But is this language? This question launched many studies with chimpanzees.

In the late 1960s, psychologists Allen Gardner and Beatrix Gardner (1969) built on chimpanzees’ natural tendencies for gestured communication by teaching sign language to a young chimpanzee named Washoe. After four years, Washoe could use 132 signs; by her life’s end in 2007, she was using more than 245 signs (Metzler, 2011; Sanz et al., 1998). Washoe, for example, signed “You me go out, please.” Some word combinations seemed creative—saying water bird for “swan” or apple-which-is-orange for “orange” (Patterson, 1978; Rumbaugh, 1977). But some psychologists grew skeptical. Were the chimps language champs or were the researchers chumps? Consider, said the skeptics:

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Talking hands Human language appears to have evolved from gestured communications (Corballis, 2002, 2003; Pollick & de Waal, 2007). Even today, gestures are naturally associated with spontaneous speech, especially speech that has spatial content. Both gesture and speech communicate, and when they convey the same rather than different information (as they do in baseball’s sign language), we humans understand faster and more accurately (Hostetter, 2011; Kelly et al., 2010). Outfielder William Hoy, the first deaf player to join the major leagues (1892), reportedly helped invent hand signals for “Strike!” “Safe!” (shown here) and “Yerr out!” (Pollard, 1992). Referees in all sports now use invented signs, and fans are fluent in sports sign language.

Ape vocabularies and sentences are simple, rather like those of a 2-year-old child. And unlike speaking or signing children, apes gain their limited vocabularies only with great difficulty (Wynne, 2004, 2008). Saying that apes can learn language because they can sign words is like saying humans can fly because they can jump.
Chimpanzees can make signs or push buttons in sequence to get a reward. But pigeons, too, can peck a sequence of keys to get grain (Straub et al., 1979). The apes’ signing might be nothing more than aping their trainers’ signs and learning that certain arm movements produce rewards (Terrace, 1979).
Studies of perceptual set (described in another module) show that when information is unclear, we tend to see what we want or expect to see. Interpreting chimpanzee signs as language may be little more than the trainers’ wishful thinking (Terrace, 1979). When Washoe signed water bird, she may have been separately naming water and bird.
“Give orange me give eat orange me eat orange …” is a far cry from the exquisite syntax of a 3-year-old (Anderson, 2004; Pinker, 1995). To the child, “You tickle” and “Tickle you” communicate different ideas. A chimpanzee, lacking human syntax, might use the same sequence of signs for both phrases.

Controversy can stimulate progress, and in this case, it triggered more evidence of chimpanzees’ abilities to think and communicate. One surprising finding was that Washoe trained her adopted son Loulis to use the signs she had learned. After her second infant died, Washoe became withdrawn when told, “Baby dead, baby gone, baby finished.” Two weeks later, researcher-caretaker Roger Fouts (1992, 1997) signed better news: “I have baby for you.” Washoe reacted with instant excitement. Hair on end, she swaggered and panted while signing over and again, “Baby, my baby.” It took several hours for the foster mom and infant to warm to each other, but then Washoe broke the ice by signing, “Come baby” and cuddling Loulis. Without human assistance, Loulis eventually picked up 68 signs, simply by observing Washoe and three other language-trained chimps signing together.

Even more stunning was a report that Kanzi, a bonobo with a reported 384-word vocabulary, could understand syntax (rules of word order) in spoken English (Savage-Rumbaugh et al., 1993, 2009). Kanzi, who appears to have the receptive language ability of a human 2-year-old, has responded appropriately when asked, “Can you show me the light?” and “Can you bring me the [flash]light?” and “Can you turn the light on?” Given stuffed animals and asked—for the first time—to “make the dog bite the snake,” he put the snake to the dog’s mouth.

Comprehending canine Border collie Rico had a vocabulary of 200 human words. If asked to retrieve a toy with a name he had never heard, Rico would pick out a new toy from a group of familiar items (Kaminski et al., 2004). Hearing that name for the second time four weeks later, Rico more often than not would retrieve the same toy. Another border collie, Chaser, has set an animal record by learning 1022 object names (Pilley & Reid, 2011). Like a 3-year-old child, she can also categorize them by function and shape. She can “fetch a ball” or “fetch a doll.”

So, how should we interpret these studies? Are humans the only language-using species? If by language we mean verbal or signed expression of complex grammar, most psychologists would now agree that humans alone possess language. If we mean, more simply, an ability to communicate through a meaningful sequence of symbols, then apes are indeed capable of language.

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One thing is certain: Studies of animal language and thinking have moved psychologists toward a greater appreciation of other species, not only for our common traits but also for their own remarkable abilities. In the past, many psychologists doubted that other species could plan, form concepts, count, use tools, show compassion, or use language (Thorpe, 1974). Today, thanks to animal researchers, we know better. It’s true that humans alone are capable of complex sentences. Moreover, 2½-year-old children display some cognitive abilities, such as following an actor’s gaze to a target, that are unmatched even by chimpanzees (Herrmann et al., 2010). Humans, alone, also have a version of a gene (FOXP2) that helps enable the lip, tongue, and vocal cord movements of human speech (Lieberman, 2013). Humans with a mutated form of this gene have difficulty speaking words.

But is this language? Chimpanzees’ ability to express themselves in American Sign Language (ASL) raises questions about the very nature of language. Here, the trainer is asking, “What is this?” The sign in response is “Baby.” Does the response constitute language?

Nevertheless, other species do exhibit insight, show family loyalty, communicate with one another, care for one another, and transmit cultural patterns across generations. Working out what this means for the moral rights of other animals is an unfinished task.

For examples of intelligent communication and problem solving among orangutans, elephants, and killer whales, watch LaunchPad’s 6-minute Video: How Intelligent Are Animals?

RETRIEVAL PRACTICE

If your dog barks at a stranger at the front door, does this qualify as language? What if the dog yips in a telltale way to let you know she needs to go out?

These are definitely communications. But if language consists of words and the grammatical rules we use to combine them to communicate meaning, few scientists would label a dog’s barking and yipping as language.