It’s ancient, unstoppable and strangely contagious. Here’s what science now knows about the humble yawn, and why evolution never got rid of it. You’re reading this sentence, and there’s a reasonable ...

Is it true that we yawn when our brains are deprived of oxygen? Most of us can feel a yawn coming on. The muscles in our jaw begin to tighten, our nostrils might flare, and our eyes might tear up as ...