In a separate post on language vs conscious, I related some cases where a human is raised past the language plastic period without learning a human language; there is a deficit in symbolic learning and reasoning. This strongly suggests that symbolic reasoning is a byproduct of learning to name things in language.
It would also point to language as an elaboration of somatosensory learning.
I don’t see this in any of the linked papers, in fact, the symbolic reasoning seems to be an expected inherent behavior.