User blog comment:Ktrfgfg/Chapter 53 Predictions + Volume12Special/@comment-64.237.230.129-20131214211207/@comment-179280-20131216182047

@Neo I guess all of this speculation comes from when the Ape Titan asks Mike about how he knows about "what's in the nape of their necks". So, at that time, it was kinda assumed that every Titan had their "pilot" there, which resulted to be the case with Titan Shifters only.