ASU Research E-Magazine: Can We Talk?

The brain of modern human ancestors had evolved the capability for language as early as 2 million years ago. That is the theory two ASU researchers reported in the March 1995 issue of the Journal of Behavioral and Brain Sciences. The theory is sure to stir controversy.

The conventional interpretation of the evidence is that language capacity may have first evolved in the Neanderthals about 100,000 years ago. Experts still debate whether they were vocally equipped for speech.

“We didn’t talk about speech as such. That’s another interesting area to look at,” says Wendy Wilkins, an ASU English professor who specializes in linguistics. She and co-author Jennie Wakefield, a graduate student in speech and hearing science, looked instead at when the human brain had developed sufficiently for structural aspects of language.

Wilkins and Wakefield think that the human ancestor Homo habilis had attained that level of brain development 2 million years ago. The first stone tools appear in the fossil record at about the same time.

“Things were going on to improve control of the hand and throwing—that is, hitting a moving target from a distance,” Wilkins explains. “It turned out that the parts of the brain that are important for making those things work right are where the language areas are in current human neuroanatomy.”

One of those areas is located at the back of the brain, specifically, where three different lobes of the brain come together. The lobes involved are the parietal, occipital, and temporal. Wakefield has termed it the POT region. The region includes parts of the language area known as Wernicke’s area.

Another key region is Broca’s area, located at the front of the brain. A track of fibers connects Broca’s area with the POT area. Fossil evidence indicates that all three portions of the brain—the POT region, Broca’s area, and the connecting fiber track—existed in Homo habilis.

Wilkins and Wakefield assert that these parts of the brain could have supported language skills even though they actually developed for other purposes. This leads to another controversial finding.

Some experts argue that language evolved gradually from simpler forms of communication. Apes have different calls for various types of danger. Could early human ancestors have slowly built language from similar calls?

Linguists doubt it. “It’s not easy to see how you can adapt danger calls and territory calls and things like that into a system with the complicated mathematical properties that seem to characterize only language and nothing else,” Wilkins says.

The odds are stacked against the alternative: that a genetic mutation suddenly and accidentally brought about the capacity for language.

The ASU researchers label the gradual-abrupt argument “a non-issue.” They say that the supporting brain structures evolved gradually, according to Darwinian principles.

“Language was made possible, however, only at the moment that the brain achieved the appropriate internal configuration,” they wrote in their report.

Language researchers largely have avoided the issue of its evolution, or have pursued unproductive lines of inquiry. Many linguists have not pursued questions of evolution because they appreciate the complexity of language.

“They feel like, ‘Where in the world would we start?’” Wakefield says. “It seems much easier for people in other fields to pursue it because they don’t have to adhere to what linguists would say has to be the case about brain-language relationships.”

Wilkins notes that discussions about language evolution, like those about evolution in general, can become quite heated. In 1886, the Linguistic Society of Paris actually banned the topic from debate for that very reason.

“Language relates so closely to our human essence that it’s very hard to talk about the origin of language without talking religion and theology,” she says.

The researchers hope that their work will spark linguists and scientists in allied fields to look more closely at language origins.

“We have for too long considered the origin of the linguistic capacity a mystery; it is time to treat it as a problem amenable to serious intellectual inquiry,” they wrote.