"Religion" is actually a pretty neutral term and retains a little of its Latin ambiguity in that it means something like to do (something) carefully or intensely.
From my old friend
etymonline:
religion
c.1200, "state of life bound by monastic vows," also "conduct indicating a belief in a divine power," from Anglo-Fr.
religiun (11c.), from O.Fr.
religion "religious community," from L.
religionem (nom.
religio) "respect for what is sacred, reverence for the gods," in L.L. "monastic life" (5c.); according to Cicero, derived from
relegare "go through again, read again," from
re- "again" +
legere "read" (see
lecture). However, popular etymology among the later ancients (and many modern writers) connects it with
religare "to bind fast" (see
rely), via notion of "place an obligation on," or "bond between humans and gods." Another possible origin is
religiens "careful," opposite of
negligens. Meaning "particular system of faith" is recorded from c.1300.
"To hold, therefore, that there is no difference in matters of religion between forms that are unlike each other, and even contrary to each other, most clearly leads in the end to the rejection of all religion in both theory and practice. And this is the same thing as atheism, however it may differ from it in name." [Pope Leo XIII, Immortale Dei, 1885]
Modern sense of "recognition of, obedience to, and worship of a higher, unseen power" is from 1535. Religious is first recorded c.1225. Transfered sense of "scrupulous, exact" is recorded from 1599.
Many secular ceremonies are performed carefully, so it's not rite that identifies religion. Moreover, many modern people identify as religious who perform virtually no rites. Their identification seems to devolve from shared beliefs and a sense of belonging, hence my claim that the term is now more tribal than anything else.
If you try to lump all superstition under religion you'll get bizarre effects at the margins too. For instance, Italian men often surreptitiously touch their penises for luck. If you asked them is this part of their religion, many will tell you that no, the Roman Catholic tradition recommends
against such practices. But they still do it. So it's part of their body of superstition but not part of their religion.
Penis-touching should certainly fall in the scope of your thesis (e.g. stimulating testosterone for fight or flight). On the other hand, I'd suggest that the moral and ethical reflections embedded in many religions would not. "Don't lie", for instance, runs contrary to survival when deceit can make a big predator avoid you. Then again, the blood-fetish embraced by some forms of Christianity, say, might.
I think that this is about superstition and may touch on some religious beliefs and practices. I don't think it's about religion itself.