[shard]

I'm not sure it's possible to not be in anyone's tribe. People are automatically in the same tribe as others in terms of age, income, social class, gender, race, nationality, education, religious and political affiliations, and not all of these can be hidden.

[rtikulit]

In my model, "tribal membership" is associated to a subconscious response we have to others when we recognize "sameness" at some level, and we subconsciously lower our social transaction cost expectations with respect to them. This is very closely related to "trust", which is largely a belief, towards a person, that we can predict their behaviour in a variety of risk situations, and it will be aligned to our own interests.

It covers a lot that other commenters have mentioned.

So with respect to the properties you've listed, it is rare for me to find someone where there's a mutual recognition of "sameness".