Here is a list of psychological phenomena connected to religion I have come up with so far. (Of course, as any psychology article on this topic always notes, showing a psychological phenomenon related to religious belief neither proves nor disproves the belief itself.) Am I missing any? Connection to orthopraxy below.
-Anthropomorphizing of the universe. 1) Partly as error. Humans have a tendency to over-apply agency to things that aren't really agents. Kids do this as they are learning to apply concepts of agency (e.g. saying goodnight to their stuffed animals and meaning it), and adults yell at their cars and computers when they malfunction, see faces in the clouds, etc. In ancient times, people had pretty intense anthropomorphisms (like whipping the sea for misbehavior). 2) Partly as motivated approach to the world. Anthropomorphizing happens when people need social contact and feel lonely, or need to explain something unexplainable. Interestingly, one social psych study (Barrett & Keil, 1996) suggested that religious people were more likely to use an anthropomorphic concept of God than a classic theological one in daily life.
-Just World Hypothesis (referenced in a previous post). People have a need to believe the world is a just and ordered place, to the extent that if something bad happens to someone and we cannot help them, we will often assume it is in some way the victim's fault (either for causing it or having some flaw that "brought it upon them").
-Illusions of External Agency (Gilbert et al, 2000): We have psychological defense mechanisms that make us happy with what we have. However, they work unconsciously, so people often assume that what they have received is objectively good for them, rather than realizing that they their minds have subjectively made it seem good. Consequently, they assume there is an agent looking out for them, since they are getting all these good things.
-Fear of death. This one sort of speaks for itself.
-Supersense. I haven't read the book of that name yet--though it's on my list--but it shows how we develop a sense for the supernatural.
So the question for me now is, can orthopraxy relate to any of these psychological needs and principles? (Not really, as far as I can tell, which is why it seems pretty untenable as a movement to me.) It often feels to me as though being in the skeptic vein pits one's automatic psychological system against one's rationally-determined beliefs. From this lens, orthopraxy comes with the costs of religion without providing any of the core psychological benefits. One lives in constant intellectual dissonance, instead of gaining the relief the lifestyle should provide (in one ideal sense).
On the other hand, though, you can justify it by appeal to practical consequences, and--in theory--other psychological/emotional gains. You get a sense of community, some nice values and traditions, it's what you're comfortable with, etc. And maybe you've got it better than the full believers--you don't accept all the beliefs and whatnot, and get to do more of your own thing, but you get to gain the community (something a la this post).
I guess the point is, orthopraxy: a double-edged sword. Sometimes I love it, sometimes I hate it.