A new study says that the more linear a child's mental number line becomes with time, the better he or she is at remembering numbers.
As kids grow, they learn to place numbers on a mental number line, with smaller numbers to the left and spaced further apart than the larger numbers on the right.
Then the number line changes to become more linear, with small and large numbers the same distance apart.
The new study suggests that kids whose number line has made this change are better at remembering numbers.
For the study, Clarissa A. Thompson of the University of Oklahoma and Robert S. Siegler of Carnegie Mellon University looked at how children's memory for numbers relates to the way they represent numbers in their heads.
"Young children's knowledge sometimes seems impressive, because they can count, 'one two three four five six seven eight nine ten,' but often they just learn by rote. Their counting doesn't have much to do with their understanding of how big the numbers are," said Thompson.
But eventually these words get associated with the size of the numbers.
Children normally start out with a logarithmic number line, which has more space between smaller numbers and crunches the larger numbers together at the top.
Eventually they progress to a linear number line.
In three experiments, Thompson and Siegler found that the more linear a child's number line, the better the child was at remembering numbers.
This was true for preschoolers for numbers from 1-20 and for elementary school children for numbers from 1-1000.
"We really do live in a world of numbers," said Thompson.
"Some we only need to approximate, and others we need to remember exactly. Ability to estimate the sizes of numbers influences the ability to remember the numbers exactly," he added.
The study has been published in Psychological Science, a journal of the Association for Psychological Science.