Exploring the Mathematical Brain

ByABC News
July 31, 2001, 12:04 PM

Sept. 4 -- The new school year looms ominously for many who claim to lack a "mathematical brain," and so it may be a good time to review the findings of Brian Butterworth and Stanislaus Dehaene, two cognitive psychologists who have done much work on the neural basis of mathematical thinking.

Both their books, Butterworth's What Counts: How Every Brain Is Hardwired for Math and Dehaene's The Number Sense: How the Mind Creates Mathematics maintain that there are in the left parietal lobe of the brain certain specialized circuits that enable us to do arithmetic.

These circuits, which Butterworth terms the Number Module, ensure that all of us can automatically recognize very small numbers, match up the objects in small collections, and tell which of two small collections is larger. We do these tasks unthinkingly the way we note colors without trying to do so.Furthermore, any numerical achievements beyond this are a result of our slowly mastering various representations of numbers supplied by the surrounding culture. These include body-parts (fingers primarily), external aids such as tallies and abaci, and written symbols such as Roman or Arabic numerals.

Other cultural tools, laboriously discovered over the centuries and presented in classrooms this fall, enable us to master more advanced mathematical notions such as algebra, probability, and differential equations.

We certainly differ in the extent to which we master these tools, but we all start with the same basic mathematical brain, the authors argue.

Experimental Support for Innate Ability

To support their thesis that numerical notions are a part of our innate neural hardware, Butterworth and Dehaene describe experiments in which researchers present babies with white cards that have two black dots on them.

They place the cards a few inches from the babies' eyes and note how long the babies stare at them. The babies soon lose interest but resume staring when the researchers show them cards with three black dots.