Recently, in discussions of a few key variants at the KJV Debate blog, Dr. Robinson has restated his position on the role of errors in the evolution of the textual variants:
" The further blanket claim that I “ascribe error and scribal slips to all the errors of Aleph & B” is simply incorrect. While I do maintain (on the basis of a careful examination of scribal habits) that scribal error is a primary cause of textual variation, I also clearly presume deliberate alteration and recensional activity to have occurred among the Alexandrian manuscripts (as per my 1993 article, “The Recensional Nature of the Alexandrian Texttype”). The leading principle in this regard is to presume scribal error as an initial factor so long as transcriptional probabilities suggest such, then to presume intentional change at whatever points transcriptional probabilities seem to be transcended for what appear to be stylistic or content-based “improvement” concepts in the eyes of particular scribes.I trust this will clarify the matter."
A .pdf version of Dr. Robinson's article can be found also here: The Recensional Nature of the Alexandrian Texttype.