Friday, April 30, 2010

Multiple brain areas for different parts of language

Rule 2 is everything is more complicated than you think it is.* In a really cool study, it turns out
there is no single advanced area of the human brain that gives it language capabilities above and beyond those of any other animal species. Instead, humans rely on several regions of the brain, each designed to accomplish different primitive tasks, in order to make sense of a sentence. Depending on the type of grammar used in forming a given sentence, the brain will activate a certain set of regions to process it, like a carpenter digging through a toolbox to pick a group of tools to accomplish the various basic components that comprise a complex task. ...
To determine whether different brain regions were used to decipher sentences with different types of grammar, the scientists turned to American Sign Language for a rare quality it has.
Some languages (English, for example) rely on the order of words in a sentence to convey the relationships between the sentence elements. When an English speaker hears the sentence "Sally greets Bob," it's clear from the word order that Sally is the subject doing the greeting and Bob is the object being greeted, not vice versa.
Other languages (Spanish, for example) rely on inflections, such as suffixes tacked on to the ends of words, to convey subject-object relationships, and the word order can be interchangeable.
American Sign Language has the helpful characteristic that subject-object relationships can be expressed in either of the two ways – using word order or inflection. Either a signer can sign the word "Sally" followed by the words "greets" and "Bob" (a construction in which word order dictates meaning), or the signer can use physical inflections such as moving hands through space or signing on one side of the body to convey the relationship between elements. For the study, the team formed 24 sentences and expressed each of those sentences using both methods.
Videos of the sentences being signed were then played for the subjects of the experiment, native signers who were lying on their backs in MRI (magnetic resonance imaging) machines with coils around their heads to monitor which areas of the brain were activated when processing the different types of sentences.
The study found that there are, in fact, distinct regions of the brain that are used to process the two types of sentences: those in which word order determined the relationships between the sentence elements, and those in which inflection was providing the information. 
Sorry for the long quote, but they said it so well.

I have a probably unfounded attraction to a weak version of the Sapir-Whorf hypothesis which makes me hope somebody takes this study and looks at whether the parts of the brain that are activated when speaking one language rather than another have any influences on thought or behavior.

*Rule 1 is people vary. Rule 3 is everything takes longer than you think it will.

No comments:

Post a Comment