Oh, useful anecdote time! I was talking to a professor a while back about this, and he reckoned that when the University of Canterbury (in NZ) switched from Ja

Oh, useful anecdote time! I was talking to a professor a while back about this, and he reckoned that when the University of Canterbury (in NZ) switched from Java to Python for their 100 level papers, the grades went from bimodal to single-modal. Not sure why that is, and I don't remember him giving me a reason, but I guess it's fair to assume that a lot of students were really struggling with the initial learning curve of Java (boilerplate, static typing, more difficult array and string manipulation) compared to Python, and either just not getting it, or getting frustrated and giving up. Now I didn't see any numbers to back up his claims, as it was a casual conversation, but I'd be inclined to believe him that they were bimodal. Anyway, the point I'm making is that the study here references only one university, different universities have different curriculum and different teaching styles, which could affect whether the distribution is bimodal or not.