Do you feel embarrassed when someone catches you yawning? Most people do. We think of yawning as a sign of being sleepy, but it’s also a signal for our bodies and brains to wake up, be alert, or come back to the moment—a kind of gentle course correction. And yes, we yawn when we’re bored, but we also yawn when we anticipate something happening. Robert Provine, an American researcher, describes yawning as a bridge between mental states – from awake to sleeping, from sleeping to wakefulness, from attentive to bored, as a threshold to aggression or sexual arousal – simply to lead us from one activity to another. From “The Sleep Revolution” by Arianna Huffington.