Brain does not work the way a computer does when it comes to recognizing speech sounds, instead it determines whether or not a sound combination is allowed based on words that are already known, a new study has found. (Agencies)
When it comes to the processing of spoken language the common theory has been that the brain applies a set of rules to determine whether combinations are permissible.
Now the work of a Massachusetts General Hospital (MGH) investigator and his team supports a different explanation – that the brain decides whether or not a combination is allowable based on words that are already known.
The findings may lead to better understanding of how brain processes are disrupted in stroke patients with aphasia and also address theories about the overall operation of the brain.
"Our findings have implications for the idea that the brain acts as a computer, which would mean that it uses rules - the equivalent of software commands - to manipulate information," said David Gow of the MGH Department of Neurology.
"Instead it looks like at least some of the processes that cognitive psychologists and linguists have historically attributed to the application of rules may instead emerge from the association of speech sounds with words we already know," Gow said.
Human beings speak more than 6,000 distinct language, and each language allows some ways to combine speech sounds into sequences but prohibits others.
Although individuals are not usually conscious of these restrictions, native speakers have a strong sense of whether or not a combination is acceptable.
"Most English speakers could accept "doke" as a reasonable English word, but not "lgef," Gow said.
"When we hear a word that does not sound reasonable, we often mishear or repeat it in a way that makes it sound more acceptable.
"For example, the English language does not permit words that begin with the sounds "sr-," but that combination is allowed in several languages including Russian.
"As a result, most English speakers pronounce the Sanskrit word 'sri' - as in the name of the island nation Sri Lanka - as 'shri', a combination of sounds found in English words like shriek and shred," Gow added.
Brain does not work the way a computer does when it comes to recognizing speech sounds, instead it determines whether or not a sound combination is allowed based on words that are already known, a new study has found.