Mark Guzdial, in The 10K Hour Rule: Deliberate Practice leads to Expertise, and Teaching can trump Genetics | Computing Education Blog, responds to a Slate article claiming that genetics is more important than practice:
Here’s my argument summarized. The Slate authors and Macnamara et al. dismiss the 10K hour rule too lightly, and their explanation of genetic/innate basis for expertise is too simple. Practice is not the same as deliberate practice, or practice with a teacher. Expertise is learned, and we start learning at birth with expertise developing sometimes in ways not directly connected to the later activity. The important part is that we are able to learn to overcome some genetic/innate disparities with good teaching. We shouldn’t be giving up on developing expertise because we don’t have the genes. We should be thinking about how we can teach in order to develop expertise.
Mark’s blog is read (or at least commented on) mainly by teachers of computer science, so he is largely preaching to the choir here. I would like to believe that my teaching makes a difference—I spend almost all my time teaching, grading, or preparing to teach.
I do believe that most students in my classes leave the class with better skills than they came in with. Whether that is due to my teaching or just to the students being forced to practice is somewhat difficult to determine—to a large extent my teaching style consists of forcing students to practice skills that they’ve generally ignored in the past (like in-program documentation) and providing them detailed feedback on their practice. I’d like to believe that the feedback (both individual and group) matters, since I give up my weekends to provide the feedback. If only the practice matters, then I could do as many of my colleagues do and just do I/O testing or delegate the feedback to untrained undergraduate graders.
So I have a bias towards believing Mark’s claim that teaching matters, and that there is a difference between different sorts of practice by students.
But the outcomes for individual students seem to depend more on the students coming in than on what I do. Those students who come in better prepared or “innately” smarter progress faster than those who come in behind, so the end result of the teaching is that differences among the students are amplified, not reduced. Whether the differences in the students coming in are due to prior practice, prior teaching, or genetics is not really knowable, but also not really relevant.
Mark claims that “Genetics/innate starts at birth, no later”, which is somewhat of a simplification. Although innate differences are present at birth (by definition), they may not be expressed until much later, either due to the developmental program that coordinates gene expression or due to environmental triggers. So phenotypic differences may not appear until much later (genes for patterns of facial hair among men generally make no difference until puberty, for example).
He claims that
If you’re going to make the genetics/innate argument, you have to start tracking participants at birth. Otherwise, there’s an awful lot that might add to expertise that’s not going to get counted in any practice logs.
I’ve only had one child that I have taught from birth on (and lots of others also taught him), and we all know the uselessness of sample size=1, so it is not possible for me (and probably for anyone) to track participants from birth for a significant sample size. But there are certainly ways to estimate the heritability of talent without tracking all activity since birth—the twin studies that he dismisses attempt to do precisely that. (Some of the twin studies are well done and some are useless anecdotal reports—but there is substantial evidence that some talents have a substantial heritable component.)
Of course, it is always hard to pick apart whether “nature” or “nurture” is responsible for a particular difference in talents, since there is a large feedback loop. Small differences in initial results can result in differences in how much pleasure practice provides and how much support is given, which can in turn affect how much practice is done and how valuable the practice is. So small differences in “innate” talent can be amplified to large differences in outcomes.
I’d like to believe Mark’s claim that “Hours spent in practice with a good teacher are going to contribute more to expertise than hours spent without a teacher,” and that I’m a good enough teacher to make that difference. But I fear that there is a lot of confirmation bias here—I want to believe that what I do matters, so I accept articles and studies that confirm that belief.
Looking back over my own education, I had a few teachers who helped me progress, and a few who probably delayed my learning by convincing me that the subject they were teaching was unutterably tedious, but a lot of my learning was on my own without a teacher. Sometimes the initial learning was with a teacher (often my Dad, when I was child, see Thanks, Dad), but subsequent learning was pretty much entirely from books and solo practice. It is hard to say whether I would have achieved more expertise with teachers—some of the stuff I learned was esoteric enough that there were no teachers and I had to teach myself. Other material was more commonly available, but I came at it from an unusual direction, so that the conventional ways of teaching the material would have been a very bad match for me.
Having an expert mentor around can make difference, and structured practice (such as I assign to my students) can make a difference—even just having an externally imposed reading schedule can make a difference. But most of my learning in the past couple of decades has been without a teacher and without an externally imposed course structure.
So my own experience is that teachers are not the secret sauce to developing expertise. Good teaching helps, but good learning can take place even in the absence of teachers.
Look back at that definition of “deliberate practice”—who’s going to pick the activities that most address your needs or provide the immediate feedback? The definition of deliberate practice almost assumes that there’s going to be teacher in the loop.
I think Mark is wrong here. For example, when I was teaching myself electronics design, I picked the activities based on what I wanted to design. The feedback came from building and testing the circuits—from the real world, not from the opinions of teachers. I found that some of the simplified models used in the text books and religiously repeated in intro courses were not very useful, while others were very handy and gave good results. Having a teacher steering me would have probably resulted in less learning, because I would not have been as invested in the examples (so less willing to explore) and the examples would have been chosen to give the conventional results, rather than showing where the conventional models break down.
For example, my post Capacitance depends on DC bias in ceramic capacitors explains how I found out about how ceramic capacitors change their capacitance with DC bias. The knowledge was out there in various industrial application notes, but it is not generally taught in beginning electronics courses—capacitors are treated as ideal devices. A teacher would probably have led me to a circuit that did not have a large DC bias on the capacitors, so that they would have acted much like the ideal devices, and I would not have learned a very important (and often overlooked) flaw in the models. I may be less expert in the conventional models than someone who spent the same amount of time studying electronics with a teacher, but I have picked up odd bits of learning that I would have missed with most teachers.
Similarly, my posts Diode-connected nFET characteristics, More mess in the FET modeling lab, and Mic modeling rethought showed my learning about the characteristics of nFET transistors, where I ended up with a different model from the textbook ones. Teachers would have almost certainly directed me to learn the conventional model first, and then much more complicated models to patch the conventional model (that’s all I could find in any of the textbooks). Not having a teacher let me find a useful simple model for the I-vs-V curve that models the entire curve fairly well, without having to switch between models. (Incidentally, I never did come up with an explanation for the negative resistance in the first nFETs measured in the “more mess” post—that part has been discontinued and other nFETs I’ve measured don’t exhibit the phenomenon.)
Mark might argue that I had good teachers in the past, which allowed me to develop more expertise at self-teaching. I won’t dispute that, but I think his main point “the definition of deliberate practice almost assumes that there’s going to be teacher in the loop” is refuted by self-teaching with real-world feedback.