While we may be able to speculate that some aspects developed in response to social/interpersonal or personal need, there is also the possibility that some elements are just unintended "side effects" or consequence of natural mutation.
The concept of spandrels is that there are some biological features that are not necessarily the result of giving the animal a survival advantage. Some mutations are just passed on in the genetic heritage because they do not hinder an animal in its survival, but that does not mean that it helps them either (appendix). We cannot know for sure if a feature is helpful or just a side effect of a non harmful mutation.