I forgot who formulated the idea that difficult-to-understand and difficult-to-believe doctrines tend to have a unifying force for religious communities because they tend to require members of those communities to be more serious about their commitments, or a way for them to show how seriously they take them, by asserting to doctrines that are difficult.
This article says that Nicene Christianity is more difficult to believe and more illogical than some of the heresies. If so, that difficulty may have been a challenge for orthodox Christian believers that allowed them to feel, or demonstrate, more unity with their fellow believers! It may have created a firmer distinction between Christians and non-Christians or near-Christians, for one thing.
Edit: one search found the theory of Laurence R. Iannaccone (which is about different churches within Christianity) who argued that churches that impose more or stronger doctrinal requirements tend to receive more loyalty and commitment from their members. I'm not sure if that was the version that I was originally thinking of, but it seems closely related.
Henrich is a little more focused on the idea of actions that are demonstrations of one's commitment to the unifying beliefs of a group, but I think he may think that making public declarations that are confusing or embarrassing or unpopular from the point of view of outsiders can be one form of that.
This article says that Nicene Christianity is more difficult to believe and more illogical than some of the heresies. If so, that difficulty may have been a challenge for orthodox Christian believers that allowed them to feel, or demonstrate, more unity with their fellow believers! It may have created a firmer distinction between Christians and non-Christians or near-Christians, for one thing.
Edit: one search found the theory of Laurence R. Iannaccone (which is about different churches within Christianity) who argued that churches that impose more or stronger doctrinal requirements tend to receive more loyalty and commitment from their members. I'm not sure if that was the version that I was originally thinking of, but it seems closely related.