7 Simple Questions That Scientists Still Can't Answer

2. Why Is Yawning Contagious?

So, researcher have finally answered the question we've all been asking: Yawning is not contagious amongst red-footed tortoises. Phew. Okay, stupid as that seems, it does raise the question why it is contagious in humans? It's clearly not a universal phenomenon. There's something specifically human about replicating a yawn. Brain scans have shown that the parts of the human brain associated with theory of mind (that's the bit that lets you understand what others might be thinking or feeling) light up when we see other people yawning. It has also been observed that people with an underdeveloped theory of mind are less likely to find yawning contagious, so the ability to "catch" a yawn must somehow be tied up with our ability for empathy. That's all well and good, but why yawning? For a start, we don't really know why we yawn in the first place, let alone why it would be the kind of thing that would be socially advantageous to copy. It's more contagious that smiling or crying, two things that you would imagine are much more likely to evolve to be contagious. Often, even just the thought of yawning is contagious. I bet you've yawned at least once whilst reading this.