Yawning isn't just about helping you focus or get the nerves out. It's also something that happens when you're winding down to go to sleep. In the evening, our brain and body temperature are at their highest point throughout the 24 hours cycle. So yawning at night could be facilitating this change. But then we also know that we yawn in the mornings after we wake up. That transition from sleeping to waking is associated with the most accelerated increases in brain and body temperatures. Yawning may be multi functional. It may help promote arousal and alertness and activity in certain contects, while facilitating down regulation in those states and other contexts.