I shouldn’t say theory, per se, as much as ideas, like, what would the psychology of a group mind be like, and how would it react to different stressors and influences, including potential annihilation? (that’s one of my species).
A different species in my work: what if a culture/people, stressed by PTSD-inducing trauma, possessed a telepathic ability that could link them in various ways–would they strengthen each other? Would they heal one another? Would they transfer their trauma to one another? How would such a culture deal with uncertainty? How would an inability to communicate telepathically isolate someone born to that culture? At birth? As an adult?
And so on. I have eight species, and I’m kind of exploring questions like that with each of them (all these questions are character development background).