Thank you for the references. Whilst switching may indeed be relatively common among people who have had their tulpas for a long while, the actual numbers are still small − 44 according to a recent census .
Ah, so merging is some sort of forming a gestalt personality? I’ve no evidence to offer, only stuff I’ve read that I find the authors somewhat questionable sources.
Very few people have actually managed switching, from what I have read. I personally do not recommend it, but I am somewhat biased on that topic.
Merging is a term I’ve rarely heard. Perhaps it is favored by the more metaphysically minded? I’ve not heard good reports of this, and all I have heard of “merging” was a very few individuals well known to be internet trolls on 4chan.