Babies can’t say the words “one”, “two” and “three”, but they probably know that they refer to quantities, US research suggests.
In other words, while they don’t understand the full meaning of number words until they’re about four years old, they get the basic concept before they’re two.
And that, says Lisa Feigenson, a cognitive scientist at Johns Hopkins University, shows that they have a “pretty sophisticated understanding of the world” and already are trying to make sense of what adults are saying.
To a certain extent, though, she’s not surprised. “We buy counting books for babies and we count aloud with toddlers. All of that raises the question: Are kids really clueless about what counting means until they’re in the preschool years?”
To try to find out, she and colleague Jenny Wang hid a range of small toys inside a box while infants aged 14 and 18 months watched. They couldn’t see inside the box, but they could reach into it.
Sometimes the researchers counted each toy aloud as they dropped it into the box (one, two, three, four – four cars) but at others didn’t use numbers (this, this, this, this – these cars).
They found that when they didn’t count, the babies had a hard time remembering that the box contained a number of things, often becoming distracted after they had pulled out the first one, as if there was nothing else to see.
However, when the toys were counted, they clearly expected more than one was there to be pulled from the box. They didn’t remember the exact number, the researchers say, but they did remember the approximate number.
“The counting experience that many infants receive from early in life may provide an opportunity to notice that counting often occurs in the presence of quantities – a co‐occurrence that could lead infants to link the two,” the researchers write in the journal Developmental Science.
“For such a link to form, infants must recognise instances of counting as distinct from other utterances.”
They acknowledge that the link they demonstrate is a “primitive” one, but they believe their results “provide evidence for the earliest known link between non-verbal approximate numerical representations and counting – an important component of symbolic mathematics”.
It’s a complex issue. A recent study, for example, suggested that before children learn the exact meanings for number words they “first acquire noisy preliminary meanings for these words”, but also found no reliable evidence of preliminary meanings for larger meanings.