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Comment by danellis | Hacker News Reader

He appears to answer a slightly different question to the one that was asked, but I agree with what he said in his answer. To be a really good programmer, you need to have a particular kind of brain, and if you do, you will pick everything up very quickly. If you don't, you will always have a weak grasp of some concepts no matter how much you are taught.

There are university lecturers who agree that it's clear within the first couple of weeks whether someone has the aptitude to study CS. I remember a paper that was talked about a few years ago that described a "double hump" in aptitude, clearly separating the two groups. They wrote a very short test that was a good predictor of success. There's an article on Coding Horror about it: http://www.codinghorror.com/blog/2006/07/separating-programm...

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That is a fascinating paper referred to in the blog post.

I teach introductory chemistry, and for a long time, I've felt that there are students who are just incapable of making relatively simple mental models of the concepts that we discuss. To give an example, there are students who don't have a mental model of what density is.

I imagine that most people here have a good grasp of density and each of us has some mental model where the 'matter' in dense materials is "tightly packed" when compared to less dense materials. This isn't a perfect mental model, but it's reasonably accurate.

The students who don't/can't make these models view the entire course as a collection of arbitrary formulas that make absolutely no sense and require painstaking memorization. As a rule, they do poorly, unless they are exceptionally good at memorizing.

I've felt that there are students who are just incapable of making relatively simple mental models of the concepts that we discuss.

Just because this seems to be the case, I would only ask that you don't let this become a limiting belief that you project on your "incapable" students.

I only say so because I know I've taken various courses over the years (HS or college) where that sort of analogous big-picture communication you're talking about didn't really click for a few months or even years. When one is overwhelmed - or at least feeling overwhelmed - with the volume of new fundamental concepts to be grasped, it's akin to having 1,000 jigsaw pieces dumped on your coffee table. Oh and by the way, we're going to apply time pressure and grade you on your ability to figure out the big picture.

In that case, learning can turn into a fear-based "tread water because I'm drowning" activity where rote memorization is the fallback tool to get the learner to shore alive. The outcome is no longer the joy of understanding and meditating on those analogies/models to get the fundamentals to click, but trying to avoid death (err, a failing grade).

It wasn't until I revisited those certain topics later without the time-sensitive pressure of exams/grades that the broader models for understanding would "click" and all those rotely memorized fundamentals would fall into place - which is an indescribable joy.

So while your incapable students may not seem to grasp the big picture now, it's likely you are still making a difference by implanting those fundamentals which will snap together later on in life.

You make a fair point and my generalization was certainly too sweeping.

One of the things that I tell my students is that sometimes, if they stick around long enough, things will make sense.

That being said, I'm still at a loss on how to help the students who aren't making mental models that (to me) seem relatively fundamental. I try to use visuals and videos when applicable and when possible, but I would use other approaches if I could think of something that would be helpful.

Finally, I think/speculate there is a continuum of skill with mental model building. When I was a postdoc, I worked with people who had deep mental models of statistical mechanics that I just didn't have. So...I know what it feels like, but I don't know how to fix it.

The Camel Has Two Humps was not successfully replicated. The authors presented http://crpit.com/confpapers/CRPITV78Bornat.pdf in 2008:

"Two years ago we appeared to have discovered an exciting and enigmatic new predictor of success in a first programming course. We now report that after six experiments, involving more than 500 students at six institutions in three countries, the predictive effect of our test has failed to live up to that early promise."

The predictive test wasn't replicated - that doesn't sat anything about the original observation.

Right, programming is just very, very hard to teach. From the paper:

> And even in the most encouraging of our results, we ﬁnd a 50% success rate in those who don’t score C0 or CM2.

Do you have any idea if there's any way for someone to find and take that test?

If you look at the bottom of Dehnadi's page (http://www.eis.mdx.ac.uk/research/PhDArea/saeed/), there are links to the test script, answer sheet, marking guide etc.

Is it just me or are the answers to the first five questions wrong on the answer key?

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