Infants Have Math Ability at 5 Months, Study Shows : Psychology: Scientists say evidence of rudimentary counting helps resolve debate over babies’ intellectual capacity.
Children as young as 5 months can perform rudimentary addition and subtraction, indicating that humans are born with an inherent mathematical ability that is functioning well before they are taught arithmetic, an Arizona researcher has found.
The results, reported today in the British journal Nature, appear to resolve a long-running debate over whether children distinguish among small numbers of items by consciously counting or by purely perceptual, non-numerical means.
The new research shows that they do count, said psychologist Karen Wynn of the University of Arizona, the paper’s author. “Infants are not just passive recipients that take in the world passively, but they can actively make inferences and reason about some aspects of the world,” she said. “This is another instance of infants having a more surprising understanding of the world than we had known.”
The findings provide “apparently cast-iron evidence . . . that young babies’ intellectual skills may go a good deal further” than scientists had previously believed, said psychologist Peter E. Bryant of Oxford University in England. The paper “is a notable event in the history of developmental psychology,” he added.
“This is a very exciting paper,” said UCLA psychologist Randy Gallistel. “The assumption used to be that there was practically nothing going on in the heads of these infants. Now we can see that many of the foundations of adult thinking are present at a very early age. . . . This represents a very dramatic change in our picture of what you can assume at the onset of cognitive development.”
But psychologist Mark Strauss of the University of Pittsburgh cautioned that more work is necessary before any firm conclusions can be reached. “It’s clear that the infants are aware of quantities and changes in quantities, and that’s an important skill . . . but they may just have some type of evidence simply that something is added or taken” that is independent of arithmetic.
During the last 20 years, researchers have found that infants display a remarkable variety of intuitive skills. Well before they are 6 months old, infants can tell objects apart by their size, shape and color. They can tell when objects are solid. They know that objects continue to exist when they are hidden. They can even tell if a speaking person’s lip movements are appropriate for the speech they are hearing.
“These are striking skills to find in a creature which used to be thought of as utterly incompetent and ineffective, but they could all in one way or another be described--even dismissed--as perceptual,” Bryant said. Researchers have long argued whether infants can directly recognize differences in the number of items or simply see that one group is larger or smaller than another. Wynn’s results, he said, indicate that the infants have a real numerical skill.
Wynn used a “looking-time” procedure that is widely employed in studying infants. In essence, the technique relies on the fact that infants will stare at something that is surprising or unexpected longer than they will at something that is predicted.
The researcher uses a display that is something like a puppet stage. To conduct an experiment for 1 plus 1, for example, the child is positioned in front of the display. A hand places a Mickey Mouse doll on the stage and it is subsequently hidden behind a small screen.
In view of the infant, the hand comes on stage and places a second doll behind the screen. The investigators can then leave the two dolls behind the screen to provide the “correct” answer (2) or secretly remove one to represent the “wrong” answer (1). When the screen is removed, an observer times how long the infant looks at the doll or dolls. In six trials, each of 32 infants was given the correct answer three times and the incorrect answer three times.
Wynn found that, on average, the infants looked at the “surprising or unexpected” incorrect answer about 20% longer than they did at the correct answer. The same results were obtained when the problem was subtraction: 2 minus 1.
Wynn is now performing the experiment using slightly larger problems, such as 2 plus 1, but does not have any results yet. She will not be able to go to larger numbers, however, because other studies indicate that infants cannot perceive numbers larger than four.
“What this shows,” she said, “is that infants truly have numerical concepts and are capable of understanding relationships between the numbers. Infants have a much richer understanding of the physical world than we give them credit for.”
The study has no practical implications, but “it is extremely important to the whole field of psychology because it is an attempt to understand how the mind works,” Gallistel said. “Our view of cognitive development was shaped by the philosophy of British empiricists that attributed an absolute minimum of structure to the undeveloped mind.” Wynn’s results, and other studies on perception, “are radically transforming that view. There is a lot more structure there than had previously been assumed.”
