Neuroscience just discovered a weird way to tell when someone is really listening to you

Is there an easy way to tell when someone is really listening to what you say? New research just uncovered one unexpected sign: They may blink less. That’s the finding of a study by researchers at Concordia University in Montreal.

Most research on blinking has focused on vision, the researchers explain. But they thought blinking might also provide clues to what’s going on in people’s brains. For example, do we blink less when we are concentrating hard on listening to someone or something?

To find out, the researchers recruited 49 adults and provided them with special glasses that tracked every blink. Then they played recordings of 20 sentences for the subjects with some interfering background noise. They varied the volume of the sentences. The lower the volume, the harder it was to hear over the background sounds, and the more subjects had to concentrate. As participants listened extra hard to make out those quieter sentences, their blinking slowed down.

“We don’t just blink randomly.”

“We don’t just blink randomly. In fact, we blink systematically less when salient information is presented,” Pénélope Coupal, an honors student in Concordia’s  Laboratory for Hearing and Cognition and the lead author on the research, said in a statement from Concordia.

The researchers also wondered whether a change in visual conditions, such as lighting, would affect how often people blinked. So they repeated the experiment, but this time, they also randomly varied the lighting between dark, medium, and bright. They found the same pattern as in the first experiment. Changes in lighting made no difference. People blinked less when their brains were working harder.

Should you assume that if you’re speaking to someone, and they’re blinking frequently, they aren’t really listening to you? Not necessarily. The researchers noted that there is a wide range in people’s normal baseline blink rate, with some naturally blinking as often as 70 times per minute, and others only blinking 10 times per minute. But within those variations, the trend held. However much people naturally blink, their blinking slows when they are listening closely.

As a leader, you need to know when people are listening carefully to what you have to say, and when their attention has wandered away. That may tell you that whatever you’re saying is something they already know, or something they don’t find useful. If you’re a smart communicator, you already know to watch other people’s body language closely. It can help you tell whether what you’re saying is resonating, or whether you should move on to something else. This new research on blinking gives you one more tool to help you figure that out.

—Minda Zetlin

This article originally appeared on Fast Company‘s sister publication, Inc. 

Inc. is the voice of the American entrepreneur. We inspire, inform, and document the most fascinating people in business: the risk-takers, the innovators, and the ultra-driven go-getters that represent the most dynamic force in the American economy.