An enrerteining paper in the NY Times:
SCIENCE | April 22, 2008
When Language Can Hold the Answer
By CHRISTINE KENNEALLY
Does language shape what we perceive or are our perceptions pure sensory impressions?
Elizabet Spaepen, a doctoral student at the University of Chicago, examined the ability of home-signing adults in Nicaragua to use numbers. Ms. Spaepen emphasized that although the subjects had never been taught a formal sign language, including counting, they were fully integrated in society. They have jobs and they are paid as much as hearing or signing adults.
Ms. Spaepen asked the home-signers to match an array of objects laid out before them. For example, she placed plastic discs on a table and encouraged the subjects to lay out the same number of discs. If the number was small, as in one, two or three, the home-signers got it right all the time.
If the number was larger, the home-signers got it right just approximately. If Ms. Spaepen laid out four discs, the subjects might lay out five or six. Although they were never quite right, they were never completely wrong. The home-signers would not lay out one or 15 discs in response to four.
Scientists have shown that the understanding of small, specific numbers is a trait with long evolutionary history. Monkeys and other animals can compute the exact number of a small set of objects at a glance without explicitly counting. The ability is called subitization.
Ms. Spaepen suggests that when home-signers correctly use small numbers, they are relying on this innate trait. The count list we learn with most languages (some languages do not have a count list or words for specific numbers greater than three) has enabled humans to build on this heritage, taking the specific and uniform gap between “one” and “two” and “two” and “three,” and extending it out through four and higher, theoretically to infinity.