I’ve not found any explanations for this response.
Even before it is born, a baby yawns as early as the first trimester of prenatal development. Ultrasonic scanners reveal that a fetus yawns and hiccuping at 11 weeks.
Chimpanzees and apes yawn infectiously, just as we.
At one time, it was thought that people yawn to take in more oxygen. But in 1987, Dr. Provine proved this to be false. He gave test groups different amounts of oxygen and carbon dioxide to breathe. He found no difference in the number of yarns by each group.
Discover For Yourself
Just for fun, see how contagious your yawn can be. Without making your experiment known, pretend to yawn and notice how many people around you yawn.
Experiment again, only this time talk about yawning. How many yawn just by talking about it. Did the conversation cause you to yawn? I yawned several times while writing this post.