I wasn't sure where to start this thread, sorry. Here are some ramblings. Someone fact check...
1. Has anyone noticed Ni types sort of gently gnashing their teeth together? Conversely, those with Ne high in the stack seem to have more recessed jaws.
2. I was wondering is the muscular tension seen in Se-Ni types is less Ni and more Se being active. (On a side note, it's good for the eyes to use small movements rather than lock into place).
3. I heard a physical therapist one tell his trainees in a doctorate program that moving with the head while the eyes stay behind is a sign of trauma. The eyes should lead. Should we, then, be P types by birth? I realize this is a stretch, but it makes sense to me that trauma and stress would cause people to judge more quickly.
That's all for now. None of this has been checked empirically, but I notice these things.
#1. Can't say I've noticed... but I think that'd be more related to anxiety/nervousness, maybe?
#2. In a way, yes. Ne and Se are the ones that "perk up" the eyes. Ni and Si sort of relax them in different ways. Si makes them dull and blank, while Ni makes them 'sleepy' for lack of a better word. The same applies to all the introverted functions in general, which seem to subtract activity rather than add it. That said, the scowling also counts as Ni/Si, and that's a type of tension. But it isn't directly around the eyes, per se.
#3. I'm dubious of that, lol. I've seen many people with both head vs eyes leading, who are perfectly sane. Well, as sane as people get. Haven't had the pleasure of observing many babies, so I can't say, but it may be that children in general are heavier in Perception (Pe, in particular) due to the sheer absence of perception at that age, and the catch-up they need to do.