In one respect this would make sense, as there has been research conducted that suggests yawning is contagious: that is to say, when 1 person yawns and someone else sees it, they are more likely to yawn, suggesting that it is some kind of subconscious social reaction. And seeing as though those of us on the spectrum usually have a hard time with social ques, we might have an "immunity," to yawning out of reaction to others around us yawning?
Me personally, I yawn more than normal, but I'm just one data point...
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"The only way to live in an un-free world is to become so absolutely free that your very existance is an act of rebelian." - Albert Camus