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Why is this psychologically? It cannot be JUST preference...[...]
That's because one's physical biological sex and perception (ie You seeing other people and noticing their secondary sex characteristics) is NOT the only variable in interacting with other people, or in your context, aversion behavior because of similarities. Primary importance goes to the person, and their context,
especially their context, because this includes their local culture, what they're familiar with, how others approach them or communicate verbally or non-verbally [which covers the difference of same-sex/opposite-sex you're mentioning], alongside their own perception. It's really not a preference set inherently.
And that those 'traits' are very indistinct when applied to reality.
You can't justly compare people based on their 'traits' if the baseline is biological sex.
Keynotes to Familiarity, and Context, underlying all those you mentioned in that post.
Does anyone know the term that describes this? I'll try to detail it in a personal story.
Before sleeping (as in you're still consciously awake but trying to sleep), I've been pretty aware of my thoughts, and this is the second time in my life where I've felt this sensation--like an ascending tone and power of 'voice' (thought) in mind, that while your eyes are closed and you being alone in the room, it feels louder and louder and you feel as if being compressed even if your blanket/covering isn't tight at all, and it takes conscious effort to 'break' from the thought. Afterwards, your mind is calmed, your thoughts aren't felt as distinctly controlling, but your feelings get translated into "
not alone in your room, as if there's something else there". (even if you know there isn't any)
Felt it long ago as a first when I was around 7 or 8. My eyes were open, I was huddled on my bed, staring at a wall and an alphabet poster in thought, then I had that intensifying thought in mind and I felt in shock--broke off from it, then felt like there was someone right behind me. I didn't want to turn my back so I rolled against the wall after a very tense while and looked extremely vigilant as I searched the room for nobody.