The course “Soul Beliefs” talks about how tribalism and identity function in religion. I have written about this extensively on this blog. As an example of the effect of identity and investment, let me give an anecdotal example of a former commentor here.
I met him on-line when he was still in a very liberal Christian seminary. Conversations were fun. Just before he graduated to take on a pastorship of a church, I told him to try and watch as he changes as he gets more and more invested in his church. And indeed, over the years his comment on my blog became more strident. He was more offended by what I wrote — though prior he found my posts interesting and something to think about. Several other commentors here agreed with me (through private emails) that the open-minded student, had now become a much more defensive, aggressive shepherd of his sheep.
I warn medical students that their 25 year-old self will be a radically different 35 year-old self not just by aging and having a family, but as a result of the specialty of medicine they chose. Jobs, spouse, friends and those with whom we surround ourselves, change us even though we usually deluded to think we are in control.
My contention: we are often blind to the influences of our investments and identities. We are all self-deluded. But of course, that is a matter of degree.