Toddlers know when the tally is right: study

Previous research has shown that children begin to enumerate as early as age two, but do not generally master counting until around age four.

But a new study of 36 Australian infants suggests that early signs of familiarity with counting can be seen when a toddler is as young as 18 months.

Published in the British Royal Society's journal Proceedings B, the study also finds that time spent helping a child work her or his way from one to five and beyond boosts an infant's early recognition of counting principles.

To gauge familiarity with numbers, researchers showed infants a video of six fish being counted, out loud, in order.

A second video showed fish "incorrectly" counted, with a researcher pointing back-and-forth between only two of the images while tallying to six.

While 15-month olds showed no preference for either video, 18-month olds tended to watch the correct sequence longer.

More sustained attention can demonstrate an infant's greater interest in -- and familiarity with -- counting, the researchers said.

When the tally was done -- correctly and incorrectly -- in Japanese, the one-and-a-half year olds didn't favour one version over the other.

Counting adheres to three abstract principles that children must grasp: a one-to-one correspondence between count words and the objects being counted, the consistent ordering of count words, and an understanding that the final number in a count sequence representing the total number of items.

(c) 2011 AFP