Psychology professor Iris Berent and Provost James Bean

Take 5: What makes human language so special?

by Jason Kornwitz

North­eastern Uni­ver­sity psy­chology pro­fessor Iris Berent deliv­ered the 52nd annual Robert D. Klein Lec­ture on Tuesday after­noon in the Raytheon Amphithe­ater. In her talk—titled “How do human brains give rise to language?”—Berent argued that human lan­guage is a product of a spe­cial­ized bio­log­ical system, that we are innately equipped with a lan­guage instinct.

People know how to talk in more or less the sense that spi­ders know how to spin webs,” she explained, quoting the cog­ni­tive sci­en­tist Steven Pinker. “Spi­ders spin webs because they have spider brains, which give them the urge to spin and the com­pe­tence to succeed.”

Here are five take­aways from the lec­ture, which was estab­lished in 1964 and renamed in 1979 in tribute to the late Robert D. Klein, pro­fessor of math­e­matics and vice chairman of the Faculty Senate.

What makes human lan­guage so special?

We humans are good at lan­guage,” Berent explained on Tuesday. “We acquire lan­guage rapidly and spon­ta­neously, and we are appar­ently unique in our ability to do so.”

For more than a decade, her research has focused on why, probing into one cen­tral ques­tion: What makes human lan­guage so spe­cial? As an expert in the phono­log­ical struc­ture of lan­guage, she has tackled the inquiry from a broad inter­dis­ci­pli­nary per­spec­tive, using a diverse set of methods, lan­guages, and research pop­u­la­tions, including infants and children.

Her find­ings have been pub­lished in top sci­en­tific journals—including Lan­guage, Cog­ni­tion, and the Pro­ceed­ings of the National Academy of Sci­ence—and her work has been funded by both the National Insti­tutes of Health and the National Sci­ence Foundation.

A big brain

At the begin­ning of her lec­ture, Berent sum­ma­rized the stan­dard answer to why humans can acquire lan­guage while other non­human ani­mals cannot, appealing to three generic yet dis­tin­guishing prop­er­ties of our species.

One is our brain size. Another is our capacity to engage in social inter­ac­tions. And the third is our highly refined audi­tory and artic­u­la­tory motor con­trol systems.

None of these capac­i­ties are spe­cific to knowledge—a large brain, for example, also allows you to solve math problems—and Berent argued that they’re entirely insuf­fi­cient to explain the lan­guage gap between a human and, say, a dog.

For her, it’s more plau­sible to posit that lan­guage is a spe­cial­ized bio­log­ical system, to argue that we are innately equipped with a “chip” specif­i­cally designed for language.

After ruling out two promi­nent objec­tions to this theory—including the so-​​called blank state hypoth­esis, which sug­gests that all knowl­edge derives from expe­ri­ence and perception—Berent went on to show that the brain seems to behave like a spe­cial­ized organ.

‘Blif v. lbif’

If lan­guage is a spe­cial­ized bio­log­ical system,” she told the audi­ence, “then dis­tinct lan­guages should like­wise share aspects of their design.” And that’s exactly what her research has found.

Regard­less of our mother tongue, she said, we prefer cer­tain lin­guistic struc­tures to others. Despite sig­nif­i­cant dif­fer­ences between lan­guages as unre­lated as Korean and Spanish, all of them seem to share the same set of unwritten rules that dic­tate how sounds can be arranged to form words.

In a study pub­lished in 2007, her team showed that all spoken lan­guages favor cer­tain syl­la­bles. For instance, syl­la­bles such as “lbif” are much less common across lan­guages than syl­la­bles such as “blif.” A later study showed that people are sen­si­tive to this rule even if nei­ther of those syl­la­bles occurs in their language.

In this view, the lan­guage system in the brain of every speaker is equipped with abstract uni­versal prin­ci­ples that favor ‘bla’ to ‘bna’ and so on,” she explained. “Crit­i­cally, these prin­ci­ples are active even if you have never heard either.”

What babies can tell us about language

Later in her talk, Berent pointed to her 2014 study of new­born babies to show that the human brain forms lan­guages based on an innate set of linguistic rules.

One-​​day-​​old neonates were pre­sented with blocks of audi­tory syllables—either well-​​formed ones like “blif” or ill-​​formed ones like “lbif”—while their brain activity was mon­i­tored using near-​​infrared spec­trom­etry.

Berent found that ill-​​formed syl­la­bles elicited higher acti­va­tion com­pared to well-​​formed syl­la­bles, sug­gesting that the brain has to work harder to iden­tify syl­la­bles that are worse along the hier­archy. “These results do not tell us pre­cisely why ‘lbif’ is dis­liked,” she explained, “but the fact that you find it basi­cally at birth sug­gests that this pref­er­ence is likely innate, rather than one that is acquired by learning.”

Dyslexia and the brain

Under­standing how the brain com­putes language—how neural activity gives rise to cog­ni­tive structure—could have big impli­ca­tions for language-​​based disorders.

Dyslexia is a prime example. Although it is most often clas­si­fied as a reading dis­order, it is also well known to affect how indi­vid­uals process spoken language.

In a 2013 study of both skilled and dyslexic readers, Berent and her col­leagues were sur­prised to find that the dyslexic readers’ phono­log­ical system was con­sid­er­ably stronger than their pho­netic system.

If lan­guage and speech are one and the same, then deficit to speech would surely com­pro­mise the lan­guage system as well,” she explained on Thursday. “But if the sys­tems are dis­tinct, then it is con­ceiv­able that despite the prob­lems to speech pro­cessing, the core of the lan­guage system is intact.”

She added: “I think these results show how a detailed inter­dis­ci­pli­nary approach to the lan­guage system can help illu­mi­nate the ori­gins of speech and lan­guage disorders.”

Originally published in news@Northeastern on March 24, 2016.

Rebert D. Klein Lecture - Iris Berent

Iris Berent, Professor of Psychology, gives the 52nd Annual Robert D. Klein Lecture on March 22, 2016. Photo by Matthew Modoono/Northeastern University

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