Second, psychology does indeed make a distinction between explicit learning in which the subject actively responds to the stimuli, and implicit learning, in which executive and strategic processes play little or no part The latter term often characterises the acquisition of procedural knowledge, even though skills can be acquired both with and without conscious awareness . However, none of this implies that transfer comes easy for what is learned implicitly; evidently, Locke's , who presumably learned at least partly implicitly, had the transfer problem In summation, it seems safe to claim that(a) some knowledge is more prone to the transfer problem and some less, and(b) we will not know whether a particular kind of knowledge is prone or not until we explicitly test it. This idea actually is not new in general educational literature, but has not been emphasised much in the context of DGBL.