This has bugged me forever and it still bugs me every time I do it. What is the biological function of a yawn? And why are yawns contagious? For many, especially me, I need only to conceive the idea of a yawn in order to be biologically compelled to yawn. If I see someone yawn, hear the word "yawn", think the word "yawn", see an animal yawn or anything like that I am forced to yawn. Why is that? Has there been any research to find out why?