Everyone knows that language is a great tool for communication, but scholars have debated for centuries whether it also plays an important role in learning. A new study supports this notion by showing that linguistic information boosts people’s ability to sort objects.

A team led by Gary Lupyan, then at Carnegie Mellon University, asked volunteers to categorize 16 “aliens” that appeared on a computer screen as good guys or bad guys. All the aliens looked different, but half of them shared subtle features that distinguished them from the other half. Participants heard either a bell or a buzz to indicate whether their choice was correct or incorrect. But half of the volunteers received extra information: they also saw the word “leebish” or “grecious” appear on the screen, depending on which group the aliens belonged to. Those who received the linguistic cues learned to tell the difference between friend and foe much faster even though the nonsense words provided unnecessary information. And to rule out the idea that any additional cue might speed up learning, the researchers also tried giving the subjects nonlingual information about where the aliens lived; this hint had no effect. The results indicate that the words acted “as a glue,” connecting the objects in each category, says Lupyan, who is now at Cornell University.

Related work by Lupyan and others has shown that language also affects visual processing. For example, when people are asked to rapidly find a 5 among 2s on a computer screen, they are able to pick out the target number more quickly when they hear the words “find the five” than when they hear static.

These findings reveal clues about how language might have evolved in our ancestors, Lupyan says. If language were only good for communication, then it would have value to users only if it were understood by others and, therefore, would have had to evolve as a group trait. “But if language also helps individuals think,” he says, “then we can entertain other possibilities about its evolution, because people didn’t actually have to understand each other fully for language to be a useful trait.”

This story was originally printed with the title, "Learning with Language".