Say what? How the brain separates our ability to talk and write

May 5, 2015
Credit: Johns Hopkins University

Out loud, someone says, "The man is catching a fish." The same person then takes pen to paper and writes, "The men is catches a fish."

Although the human ability to write evolved from our ability to speak, and talking are now such independent systems in the brain that someone who can't write a grammatically correct sentence may be able say it aloud flawlessly, discovered a team led by Johns Hopkins University cognitive scientist Brenda Rapp.

In a paper published this week in the journal Psychological Science, Rapp's team found it's possible to damage the speaking part of the brain but leave the writing part unaffected—and vice versa—even when dealing with morphemes, the tiniest meaningful components of the language system including suffixes like "er," "ing" and "ed."

"Actually seeing people say one thing and—at the same time—write another is startling and surprising. We don't expect that we would produce different words in speech and writing," said Rapp, a professor in the Department of Cognitive Science in the university's Krieger School of Arts and Sciences. "It's as though there were two quasi-independent language systems in the brain."

The team wanted to understand how the brain organizes knowledge of written language—reading and spelling—since that there is a genetic blueprint for spoken language but not written. More specifically, they wanted to know if written language was dependent on spoken language in literate adults. If it was, then one would expect to see similar errors in speech and writing. If it wasn't, one might see that people don't necessarily write what they say.

The team, which included Simon Fischer-Baum of Rice University and Michele Miozzo of Columbia University, both cognitive scientists, studied five stroke victims with aphasia, or difficulty communicating. Four of them had difficulties writing sentences with the proper suffixes, but had few problems speaking the same sentences. The last individual had the opposite problem—trouble with speaking but unaffected writing.

The researchers showed the individuals pictures and asked them to describe the action. One person would say, "The boy is walking," but write, "the boy is walked." Or another would say, "Dave is eating an apple" and then write, "Dave is eats an apple."

The findings reveal that writing and speaking are supported by different parts of the brain—and not just in terms of motor control in the hand and mouth, but in the high-level aspects of word construction.

"We found that the brain is not just a 'dumb' machine that knows about letters and their order, but that it is 'smart' and sophisticated and knows about word parts and how they fit together," Rapp said. "When you damage the brain, you might damage certain morphemes but not others in writing but not speaking, or vice versa."

This understanding of how the adult differentiates word parts could help educators as they teach children to read and write, Rapp said. It could lead to better therapies for those suffering aphasia.

Explore further: Kids' oral language skills can predict future writing difficulties

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SciTechdude
not rated yet May 05, 2015
I've often thought that typed communication comes from another part of the brain, because if I had read this article in person, and you had asked me to give you feedback, I would have a hard time responding. But put a keyboard in front of me, and my fingers do all the work. I barely even know what I'm saying, fortunately that part of my brain seems to have absorbed all the vocabulary and good stuff. I wouldn't say that other people treat the written part of their brain quite as well, not feeding it a regular diet of intelligent content. Thus when they open that part of their brain nothing but bile spews out.
RobertKarlStonjek
not rated yet May 06, 2015
The assumption that we communicate by spoken word alone is flawed and this study confirms that flaw. It is only the insistence on holding to a flawed assumption that is mysterious in this study report.

Humans communicate with words (true), prosody, gesture, behaviour and context (they ignore these). In writing down words we channel all of these forms of communication into just one form. If one of these forms is left out then the others are still present.

Prosody is the tonal pitch change, intonation, inflection and sing-song nature of spoken words. This is why people who can speak only English, for instance, still enjoy opera sung in languages they do not understand. Why would one even want to know what is said in a Puccini opera aria?
RobertKarlStonjek
not rated yet May 06, 2015
Context alters the meaning of spoken words and effects the selection of words. If the house we are in is on fire then comments will have quite a different meaning to the same words spoken during a walk in the park. But in conversation, we do not describe the presence of the fire or the park we are walking through to someone beside us, but if we are communicating in text then we need to mention these things, thus in order to communicate all of the various channels of communication that we normally use in conversation, additional streams of information must be incorporated into text when that is the only medium or channel.

Linguists and language researchers generally have ignored non-spoken communication as an inconvenience and this has caused tremendous difficulties in researching the evolution of language from animal calls simply because language never did evolve from animal calls, communication evolved from all forms of communication which is why the deaf-dumb spontaneously start

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