Brian Butterworth is on a crusade to understand the number deficit called dyscalculia — and to help those who have it. Researchers estimate that as much as 7% of the population has dyscalculia, which is marked by severe difficulties in dealing with numbers despite otherwise normal. The disorder illuminates the inner workings of the brain's number sense — the ability to understand and manipulate quantities. This sense is every bit as innate as vision or hearing, yet scientists disagree over its cognitive and neural basis, a debate that dyscalculics may help to settle.
Via Dr. Stefan Gruenwald