It’s disturbing on a biological level because humans only open their eyes fully in moments of great fear or wonder and fear is way more common than wonder. It’s a bit of facial body language that says “I’m fucking terrified and maybe you should be too.” During times when they feel threatened humans open up their eyes wide to scan their surroundings for possible routes of escape or anything else that might help them against whatever it is they’re fearing at that moment. Fear is very contagious in most species including humans so seeing another human in this state even in a video or picture can trigger a panic response at some level.
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