I took animal behavior and neuropsychology at the college level and the word on yawning, as far as I’ve been taught, is that it is “contagious” in the sense that when you see someone yawn, you will instinctively feel the urge to yawn, though the yawn itself is not always executed. Pictures, videos and even animals yawning can trigger this same effect. Yawning was probably developed as a survival tool (as many other human behaviors were) and was probably some kind of communication device, similar to other visual, chemical, and auditory clues produced by humans and animals alike, possibly to warn others of danger. The danger theory takes its logic from the fact that the yawn is a means of getting more oxygen to the body when it needs it; if you were in danger, yawning would get more oxygen to your muscles, making you more alert, more awake, and probably harder, better, faster, stronger, etc (haha, there’s a joke in my science), which would be to your advantage in survival, which would afford you more opportunities to mate and reproduce and spread your wonderful yawning gene on to the next generation (hey look, it’s darwinian survival of the fittest!). So yes, it is “contagious.”