Is iteration really easier to learn than recursion for CS1 students?

There is general consensus that recursion is difficult to learn, which may be meant to imply that novice students are more at ease with iteration --- probably a widespread perception of students themselves. However, three years of investigation in a context where recursion is introduced earlier than iteration, as well as control experiments for a standard imperative-first introduction to programming, have provided no evidence that students make more progress with iteration than they do with recursion. More specifically, by means of a pair of questionnaires devised for this purpose, two research questions have been addressed. First, do the students who learned recursion before iteration actually exhibit a stronger ability to deal with the latter? Second, do the students of the imperative-first path master iteration better than those of the recursion-earlier path