When it comes to language, babies could know a lot more than we think they do.
A new study published online in the journal Proceedings of the National Academy of Sciences finds that 1-year-olds understand speech isn't used only to refer to things and people, but also to communicate intentions. That opens up the possibility that babies can learn about the world beyond what is directly in front of them at very young ages.
"This is the first time that we've found evidence that infants understand that speech can communicate about things we can't see," said study co-author Athena Vouloumanos, an assistant professor in the department of psychology at New York University. She recently published a study in the journal Developmental Psychology suggesting that at just 9 months old, babies can distinguish between speech and other sounds in animals and adults.
"For learning, it shows that infants aren't limited to what's in the here and now," Vouloumanos added. "They can learn about people's internal state. They can learn about things that may happen in the future or happened in the past."
To look at babies' understanding of speech, 1-year-olds watched several scenarios acted out by adults. An actor tried, but failed, to stack a ring on a funnel that was out of reach; another was able to reach all of the objects. The actor who couldn't reach the funnel then turned, looked at the second and either spoke a made-up word -- "koba" -- or coughed. Sometimes, the second actor had enough information about what the first wanted, conveyed via speech, and completed the task. Other times, that actor didn't have enough information and failed to accomplish the task.
The babies looked longer when the second actor failed to do what the first actor expressed using speech, suggesting they recognized something incongruent had happened and that they understood speech communicated something about intention that coughing could not.
"If infants understand that speech can communicate intentions, when the first person used speech and the second actor fulfilled intentions, that should be how the story ends. It shouldn't be that interesting, so they shouldn't look too long," Vouloumanos said. "But when the story doesn't have a congruent ending, the infants think that it's wrong, and they look longer."
Though experts agree that there is great variation among babies when it comes to language development, there are a few basic milestones that parents can expect by around 12 months. According to the Mayo Clinic, those may include things like imitating words, and understanding simple directions or words like "Drink your milk" or "no."
Vouloumanos said the new research, though preliminary, opens the possibility that babies can not only understand that language conveys intentions, but that it also can express broader, abstract concepts that have nothing to do with their immediate environment.
"Parents point to things in the environment, and they say, 'That's a dog. Dog, dog, dog.'" she said. "But maybe they can talk about things that aren't [there]. They can say, 'Grandma has a dog. Yesterday, you saw a dog.' And maybe the infants can also understand."