Now we can identify the number the brain is identifying!

An article in Science News reports on how neuroscientists are able to determine the quantity of dots a person is looking at by looking at their brain activity patterns using an MRI. The study also revealed that the patterns that correspond to some number of dots, and the ones that correspond to the same number represented by a digit, were related but not the same. Computer analyses used to evaluate the patterns showed their relationship.

An interesting detail of the study’s findings was that an individual’s signature pattern for the digits could be used to determine the number of dots that person saw, but their signature pattern for the dots could not be used to determine what digit they had viewed. If the source of the digit pattern is the dot pattern, it would be easier to trace back to the originating dot pattern than it would to predict a digit pattern’s variation from that dot pattern. The researchers suggested that this was evidence that the brain’s action with respect to the non-symbolic quantities is, in some way, stronger. The patterns in brain activity when dots are viewed are more distinct and invariant.

Stanislas Dehaene is well known for his work on the neurological foundations of number and arithmetic and he is one of the authors of the paper in Current Biology on which this article is based. He has also found that non-symbolic quantities have a spatial aspect where larger numbers are associated with movement to the right and smaller ones with movement to the left. All of this suggests to me that our *symbolic* representations in mathematics are tied tightly to things the brain is already wired to do, albeit mathematics may be making significantly different use of it.

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