Conscious thought is not necessary for knowledge of results to have its effect. Research on implicit learning shows that complex information can be got by humans without their awareness. This is also shown by experiments on animal learning which show the effects of knowledge of results on later behaviour. It seems likely that unconscious learning by results evolved first in early metazoa, and conscious thought very much later. This is what Reber calls the "primacy of the implicit", meaning implicit (unconscious) learning came first in evolution.