Scientists believe babies understand the concept of counting years before they can use numerals.
Babies know the act is related to quantity, according to research published in the journal Developmental Science.
Researchers at Johns Hopkins University recruited a group of 16 infants aged between 14 and 18 months to participate in five experiments, to test if they could recognize that counting is linked to numbers.
They watched to see how the babies would react to toys, including cars and dogs, being placed inside an opaque box with a fabric slit which a hand could pass through.
The team swapped between counting the objects before placing them inside the box and referring to the toys as "this" and "these." This appeared to change how the babies responded to the objects.
After the toys were counted, the babies seemed to expect a certain number of objects to be removed from the box. But when numbers weren't used, the infants appeared to lose interest after the first toy was taken out. In another test, the children were allowed to take the toys out of the container for 10 seconds before being asked if they'd like to play again.
If the experimenters hid two of the items, the babies would keep searching for four objects if they had previously been counted.
Jenny Wang, who co-authored the study as a graduate student at Johns Hopkins, commented in a statement: "When we counted the toys for the babies before we hid them, the babies were much better at remembering how many toys there were.
Wang told Newsweek: "Our finding shows an early sensitivity to counting that is present in infants that are years away from fully understand the meanings of count words.
"However, it does not suggest that infants understand any specific count words earlier than we thought. Instead, we believe that this early sensitivity we found in infants serves as the foundation for children's later learning of the exact use of counting in figuring out quantities in the world," she said.
Wang argued the study questions the commonly held idea that children don't start to think abstractly until they hit 7 years of age.
"Together with a growing body of infant research, our study challenges this classical view, and contributes to our understanding of the powerful learning capacities early in infancy," she said.
Lisa Feigenson, senior author of the study and professor of psychological and brain sciences at Johns Hopkins University, said in a statement: "Research like ours shows that babies actually have a pretty sophisticated understanding of the world—they're already trying to make sense of what adults around them are saying, and that includes this domain of counting and numbers."
The take-home message for parents, Wang told Newsweek, "is to keep talking to your baby lots and lots, even if you do not expect them to understand you yet."
Earlier this year, a separate study looked at children's cognition from a different angle.
The authors of the study published in the Journal of Educational Psychology debunked the idea that children have different learning styles: in other words, that some children retain information better when it is presented visually, and others physically or by listening.
Shaylene Nancekivell, a visiting scholar at the University of Michigan and study co-author, told Newsweek at the time: "I am very concerned that parents and educators may be wasting money and time using ineffective learning tools."
This article has been updated with comment from Jenny Wang.
