Sunday, February 10, 2008

Baby Math Geeks

ResearchBlogging.orgThere are certain abilities that humans develop with such universality it seems as if our brains might be specifically designed to acquire them. One example is language. About fifty years ago, most psychologists believed children learned language by imitating the adults around them, then refined it by receiving feedback about the accuracy of their utterances. Famous linguist Noam Chomsky was the first to point out, however, that children have an ingenious ability to create sentences they’ve never heard before, and the speed with which they pick up their native language is much quicker than any realistic learning curve. Chomsky posited there must be something inherent in the architecture of our brains that expedites learning language at a young age. Since Chomsky’s contributions to what became the cognitive revolution in psychology, a great deal of research has been done that supports the theory that people have a natural inclination toward acquiring language. Children will develop language abilities along the same general timeline regardless of the opportunities they have to learn from adult examples (excluding cases of severe isolation or abuse).

Some believe the concept of number also has an innate origin. Neuroimaging studies have indicated there are specific brain areas, primarily in the parietal lobe, that are associated with counting objects. These areas have been shown to be active during counting tasks in children as young as four years old. Behavioral experiments have demonstrated that even 6-9 month old infants have some basic understanding of numerical concepts (such as knowing if you have one object and add another you should end up with two objects, not one). This proclivity to understand numbers at such a young age might indicate that the human brain is organized to facilitate the learning of numerical concepts, just as it is with language.

The imaging evidence for a numerical region in the parietal lobe comes primarily from adults and children four or older. A group of researchers, Veronique Izard, Ghislaine Dehaene-Lambertz, and Stanislas Dehaene, wanted to determine if this localization of numerical function existed in three-month-old infants. They used electroencephalography (EEG), which measures electrical activity of the brain through electrodes placed on the scalp, to ascertain which areas of the infants’ brains were active while they watched animal-like objects on a black background. Sometimes the objects would change in appearance, other times they would differ in number.

The group found a clear distinction in brain activity between viewing object appearance and object number. When the type of the objects was changed, activity was recorded in the temporal cortex. This corresponds to regions associated with object differentiation in adults and older children. When the number of the objects was changed, however, there was activity in a network that spread from the parietal to the prefrontal lobe. This network is similar to that seen in object number recognition in adults and older children.

These results indicate there may be an inborn mechanism in the brain for understanding numerical concepts. This shouldn’t be too shocking, as it seems an understanding of numbers would be crucial to evolutionary survival (what’s more dangerous: one predator or four?). Nevertheless, it is important to remember that the concept of being born with a mind like a tabula rasa maintained its popularity throughout most of the last century. Experiments like this one suggest there are at least some basic guidelines for us to follow on that slate we are born with.


Reference:

Izard, V., Dehaene-Lambertz, G., Dehaene, S. (2008). Distinct Cerebral Pathways for Object Identity and Number in Human Infants . PLoS Biology, 6(2), e11. DOI: 10.1371/journal.pbio.0060011


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