Thanks. Very interesting with the whole "doing it wrong" and thus feeling shame and guilt as a result (two feelings I associate with superego). 5 anxiety can appear similar to 6 anxiety since both of us are head types and beside each other and we both search for truth and answers. I can't speak for 6s since I'm not one and as a whole while I can see some 6 behavior/think/motivations due to weak wing influence I have a hard time relating to and understanding how 6 operates besides the superficial things I can logicalize. Anyway, to me, anxiety is just a feeling that occurs whenever I'm in a situation where I feel incapable and overall incompetent because I have no knowledge and understanding of how to deal with it. It can be triggered by many small things like just seeing things out of the ordinary. I think claiming that 5s are actually scared of the unknown isn't too far off to explain 5 anxiety since the basis of the 5 neurosis stems from feeling disconnected from holy omniscience. This means that being disconnected from all knowledge results in a feeling of not knowing and understanding anything. I'm a stranger in a strange land.
Oh yeah. I actually mistyped as a 6 for a while.
I can't answer this for sp 1s, but my anxiety is generally a fear of getting things wrong. Even when I'm afraid of the unknown, it's because I'm afraid that I won't succeed at dealing with the unknown, because I won't be prepared -- and not succeeding will mean Doing It Wrong and embarrassing myself. As I understand it, 6/5 anxiety is more of a general "survival" thing -- something that I don't relate to at all.
As a result, the 5 must rebuild this knowledge base they were disconnected from in order to reconnect to omniscience, so naturally, all things unknown and unexperienced trigger anxiety and needs to be researched. So yes, survival-based in such a sense I guess. I need to know in order to survive. When I think about it this way, I realize how godamn irrational this actually is despite thinking of myself as a very rational person overall but meh, enneagram motivations aren't rational... Regardless of how difficult that is for me to admit. I always seek a rational explanation even if this explanation/understanding occurs intuitively and is not something I can clearly verbalize to other people. As long as I personally know/understand, it's sufficient.