The First Word: The Search for the Origins of Language (10 page)

According to Lieberman, the analogy between the computer and the brain prevents a true understanding of language. Even though formulas can describe a set of sentences, they don’t have much to do with how language is produced by the brain or how the brain and language evolved. “Syntax is not the touchstone of human language, and evolution is not logical,” declared Lieberman. “Evolution doesn’t give a damn about formal elegance.”
⁵

When Lieberman began working at Brown University in 1976, he turned his attention to the connection between higher levels of language and the motor system. He started with the basal ganglia. These neural structures, the striatum and the globus pallidus, lie beneath the cortex, the brain’s outermost rind. The basal ganglia are responsible for learning patterns of motor activity—playing tennis, dancing, picking up a cup of tea. They also control the way different physical movements or mental operations are ordered, one dance step after another, and they are crucial in responding to a change in the direction of movement or thought.

Lieberman compared the basal ganglia of neurologically normal people with patients who had Parkinson’s disease. In Parkinson’s the brain progressively degenerates, and among the first and hardest-hit structures are the basal ganglia. The cortex is generally one of the last parts of the brain to be damaged, but when it is, the patient falls victim to dementia. People suffering from Parkinson’s have tremors and rigidity and repeated patterns of movement. What intrigued Lieberman about these people was that they also had trouble comprehending and producing syntax. In addition to showing their physical symptoms, they tended to produce sentences that were particularly short, with only simple syntax.

Lieberman carried out a study of Parkinson’s patients in which they were asked to say “one,” “two,” or “three” in order to identify which of three pictures best corresponded to a sentence they had heard. People who are neurologically normal generally make no errors when taking this test, but a number of the Parkinson’s patients with damage to the basal ganglia struggled with sentences with slightly complicated syntax and with long, conjoined sentences of simple syntax.

In another study many Parkinson’s patients were shown to have trouble if they first heard an active sentence (“The hawk ate the sparrow”) and then were asked a related question in the passive voice (“Who was the sparrow eaten by?”). They also had difficulty when the original sentence was passive and the subsequent question was active. The patients experienced no problems in working out the meaning of sentences; it was just the syntax that tripped them up.

The fact that damage to a brain area that controlled motor skills also affected syntax was a smoking gun for a biological relationship between language and motor control. The basic idea, Lieberman argued, is that there is a dependent relationship “between the syntax of motor control and the syntax of language.”

Interestingly, these findings overlapped with some of Steven Pinker’s experimental results. Even though the two researchers began with opposite ideas about language and the mind-brain, they agreed on the subject of the basal ganglia and syntax. “Lieberman long ago predicted that the basal ganglia should have an important role in syntax,” said Pinker. “And I found corroborative data that shows it.” He continued:

 

A lot of my work on language uses a comparison between regular and irregular verbs as a way of tapping into the combinatorial, recursive part of language and the memory component of language. In particular, when we use “walked” as the past tense of “walk,” you don’t have to memorize that because you can just crank it out using the rule “add ‘ed’ to a verb.” Whereas if you use “broke” as the past tense of “break,” there you can’t use a rule, because there is no rule. You have “break/ broke,” but you have “take/took” and you have “fake/faked.” So that relies on memory.

So comparing regular and irregular forms is a way of studying this recursive-combinatorial component in the simplest possible way—sticking an “ed” onto a verb is the smallest operation that anyone would be willing to call combinatorial or recursive grammar. The reason that the irregular is a nice comparison is that it doesn’t involve a recursive-combinatorial component, but it means the same thing. It’s just another way of expressing the past tense at the same length and same complexity.

We found that patients with Parkinson’s disease have more trouble with regular than with irregular verbs, and they have more trouble with novel verbs. Like, when a new word enters the language, like, “to spam,” everyone knows that the past tense is “spammed.” I don’t think you’d look that up in a dictionary or memorize it, but you can just deduce it from your world of recursive grammar. That’s something that patients with Parkinson’s disease have more trouble with than irregular forms, and that fits into Lieberman’s theory that the basal ganglia are implicated in recursive syntax.

 

Lieberman has gone on to explore the basal ganglia in a completely different group of subjects. Starting in 1993, he began to compare the linguistic and motor performance of Parkinson’s patients with that of individuals who were climbing Mount Everest. Both sets of people incur brain damage, specifically to the basal ganglia, though the basic cause is very different. Parkinson’s is a progressive and fatal disease, whereas the basal ganglia damage suffered by climbers on Everest results from the lack of oxygen. In most cases it is temporary. Nevertheless, the climbers exhibit a lot of the same deficits experienced by Parkinson’s patients.

Lieberman set up a monitoring unit at Everest’s Base Camp, fifty-three hundred meters above sea level. His research team administered baseline cognitive tests to the climbers and took samples of their speech. As the climbers ascended the mountain and stopped at the next four camps, further tests and speech samples were obtained by radio link.

One of the abilities that Lieberman examined was how the climbers assembled the bits that make up distinctive sounds of speech. For example, when you pronounce
b,
you must coordinate at least two movements. At some point, you open your lips and release air while simultaneously vibrating the vocal cords deep in your throat. Timing the onset of voicing in speech sounds is yet another complicated motor skill at which every normal speaker is expert, though few are consciously aware of it. It is also another kind of movement sequence that gets affected in Parkinson’s disease.

For example, the only difference between a
b
and a
p
is that you vibrate your vocal cords much sooner for the former than for the latter. With a
b,
voicing occurs within twenty-five milliseconds of opening your lips; with a
p,
your vocal cords start vibrating more than twenty-five milliseconds after you open your lips. Because Parkinson’s patients experience a breakdown in the onset timing of voicing in speech sounds, some of their
b
’s sound like
p
’s, and vice versa. (The same applies to
d
and
t
and to
g
and
k
.) This deficit occurs alongside an increase in syntactic errors and a delay in the comprehension of simple sentences.

Lieberman showed that the higher the climbers went up the mountain, the more trouble they had with the timing of their voicing and the more their comprehension of syntax degraded. The farther up they went, the less oxygen they breathed, and just like Parkinson’s patients, they became less adept at distinctly pronouncing sounds like
b
and
p,
and they took longer to understand test sentences.

It’s clear from this evidence, according to Lieberman, that the basal ganglia are crucial in regulating speech and language, making the motor system one of the starting points for our ability not only to coordinate the larynx and lips in talking but to use abstract syntax to create meaningful and complicated expressions.

One of the important functions of the basal ganglia is their ability to interrupt certain motor or thought sequences and switch to a different motor or thought sequence. Climbers on Everest become increasingly inflexible in their thinking as they ascend the mountain—stories about bad decision making in adverse circumstances abound. Accordingly, Lieberman’s climbers showed basic trouble with their thinking.

One mountaineer monitored by Lieberman scored well at base camp but demonstrated extreme anomalies in his speech and a dramatic decline in thinking as he ascended. The researchers told him that he wasn’t functioning normally and advised him to descend, but he refused, insisting he was fine. When the weather took a turn for the worse and his companions descended, he persevered in going forward. A few days later he fell to his death.

It was later discovered that at the time of his death, a harness the climber needed to secure himself to fixed ropes was not properly attached. There was nothing wrong with the harness itself; the problem was in how it had been used. In order to secure the harness, a correct sequence of steps had to be carried out. It appears that the lack of oxygen supply to the basal ganglia affected the climber’s ability to follow the basic sequence of clipping and unclipping.

Basal ganglia motor control is something we have in common with many, many animals. Millions of years ago, an animal that had basal ganglia and a motor system existed, and this creature is the ancestor of many different species alive today, including us. When we deploy syntax, Lieberman argued, we are using the neural bases for a system that evolved a long time ago for reasons other than stringing words together.

Chimpanzees, obviously, have basal ganglia. Birds have basal ganglia. So do rats. When rats carry out genetically preprogrammed sequences of grooming steps, they are using the basal ganglia. If their basal ganglia are damaged, then their separate grooming moves are left intact, but their ability to execute a sequence of them is disrupted. (Lieberman calls their grooming pattern UGG, universal grooming grammar.)

The fact that a number of different animals use the basal ganglia for sequencing, whether it involves grooming or words, said Lieberman, suggests that there is no innately human specialization for simple syntax. Instead of being a contained and recent innovation in the human lineage, the foundation of syntactic ability is an adaptation of our motor system, a primitive part of our anatomy.

Lieberman’s contrarian (at least prior to 1990) take on language and its history offers an entirely different way of thinking about language evolution. When he started engaging with the subject of language, he wrote of it as not so much a new thing that humans
have
as a new thing we
do,
and we do it with a collection of neural parts that has long been available to us. Moreover, when you think about language this way, it is not really a “thing” at all but a suite of abilities and predispositions, some recently evolved and some primitive. The many parts of the brain and body that make up the language suite allow us to program into our own heads how our parents speak. When Lieberman calls language part-primitive and part-derived, he echoes Charles Darwin, who wrote in
The Descent of Man
that language was half art and half instinct.

The nineteenth-century German philosopher Arthur Schopenhauer said: “All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.”

The study of language evolution from the nineteenth century onward has rather neatly followed the same course as Schopenhauer’s aphorism. Linguists once considered pursuing the topic an absurd endeavor. Then it was banned. After that, the official ban developed fairly seamlessly into a virtual ban. Now, where most researchers once glibly proclaimed that you can’t study it, many say you can, including the scholar best known for saying you can’t (or at least, you shouldn’t bother).

We are at a strange now-you-see-it-now-you-don’t moment in the history of language and mind where it seems that everyone is taking possession of the same new attitude. It’s remarkable, now that the rhetoric about language evolution has shifted, how quickly what was once heretical has become received wisdom. Within a few years, students in Linguistics 101 will probably assume that asking about language evolution was always this easy and obvious.

In a relatively short time, academics like Savage-Rumbaugh, Lieberman, and Pinker, in their different ways, have had enough influence to make the subject no longer controversial or taboo but a legitimate line of inquiry—an endeavor about which reasonable people could disagree.
⁶
When questioned about the investigation of language evolution at the 2005 Morris Symposium on the Evolution of Language, Chomsky himself shrugged his shoulders and said, “I wouldn’t have guessed it could go so far.”

Of course, there are still profound disagreements among the researchers. Even though Chomsky published a paper that discussed language evolution in 2002, he remains immensely discouraging about the subject. In addition, he argues that it is possible to engage with language evolution for purely logical reasons that are internal to linguistic analysis. Pinker and Lieberman, on the other hand, build their respective cases with findings from genetics, psycholinguistic studies, and experiments that compare the cognition and communication of various animals and humans. However, they disagree completely about the nature of syntax. In 2003 Sue Savage-Rumbaugh announced that Kanzi had uttered his first spoken word, but of Chomsky, Pinker, and Lieberman, only Lieberman considers her work to have crucial insights for language evolution.

Nevertheless, the findings of all these scientists are important touchstones, and thanks to their disagreements, engagement, and even disengagement, the field has widened considerably. A great multidisciplinary conversation is now taking place. American biologists, Italian physicists, Australian neuroscientists, British anthropologists, and a variety of linguists and computer scientists are but a few of the academics investigating the origins of language. Researchers like Marc Hauser and Tecumseh Fitch, who co-wrote Chomsky’s 2002 paper on language and evolution, are proposing an entirely new field of study—evolutionary linguistics. The consensus among these researchers resonates with one of Savage-Rumbaugh’s and Lieberman’s main points: that what evolved was not a single thing. Language is not a monolith.