While barely out of toddler years, a child's ability to intuitively estimate and compare the number of objects in a group can predict how well she will perform under formal math instruction, according to a new study by researchers at the Kennedy Krieger Institute in Baltimore.
You might recall that in June, Michèle M. M. Mazzocco, the director of Kennedy Krieger's Math Skills Development Project, released a decade-long study that found 9th-graders considered dyscalculic—those who performed in the bottom 10 percent of math ability on multiple tests—had substantially lower ability to grasp basic number quantities. The current study, published in this week's edition of the journal PLoS ONE, shows that the gaps in children's approximate number sense start well before school and can have a direct effect on their early math education.
Researchers led by Mazzocco tested 17 3- and 4-year-olds' precision in identifying the larger of two groups of objects. Throughout the tests, children saw pairs increasingly hard to guess; an easy pair might have one crayon in the first pile for every two in the second, while a difficult pair might have eight blocks in the first group for every nine in the second group. Then, two years later, the researchers retested the children—now in kindergarten, 1st, or 2nd grades—on their formal math skills, general intelligence, and verbal and number processing.
The study found that students who, at age 4, had been better at estimating and comparing the number of objects in a group, particularly in closer ratios, had no higher general intelligence or verbal skills than children with poor estimation ability, but they were faster at number processing and better in formal math skills at age 6. Early precision in number estimating accounted for more than a third of the score difference among the children on the third edition of the Test of Early Mathematics Ability, a common test of elementary math performance.
The study sample is tiny, and Mazzocco is already planning a follow-up with a larger cohort of youngsters, but she told me the results point to an approximate number sense that starts early and differs from a child's general intelligence and language skills, which are already used in preschool screening.
"I could see [number estimation] becoming part of the screening battery" for early school readiness, Mazzocco told me. "This study shows even before kindergarten, this screening might show not only those students who might have difficulty with math, but also those students who potentially might be very good at math."