You probably didn’t notice but the last time you talked with a colleague or chatted with a friend, you blinked. A lot. Blinks are a conversational cue akin to nodding one’s head, according to a new study published today in the journal PLOS One.

As such, the unconscious reflex changes how people talk to each other. Even the subtlest non-verbal clues impact our conversations, the finding suggests.

“Our findings indicate that even visually subtle behavior such as listener blinking is anyt