People need language to fully understand numbers. This discovery
– long suspected, and now backed by strong evidence – may shed
light on the way children acquire their number sense. Image via
CJ Burton/Corbis Previous studies of Amazon tribes who lack
words for numbers greater than three – or, in the case of the
Pirahã, for any numbers at all – had shown that they struggle to
understand precise quantities, when numbers are relatively
large. However, it wasn't clear whether this is because they
lacked words for larger numbers, or because they came from a
culture that viewed precise numbers as unimportant. Now Elizabet
Spaepen, a psychologist at the University of Chicago, and her
colleagues may have settled the question. The team studied
profoundly deaf people from Nicaragua who had created their own
sign language to communicate. These "homesigners" live in a
numerate culture, holding jobs and using money, yet lack any
vocabulary for numbers. So the researchers reasoned that any
difference in their numeracy mus