Implicit and Explicit Instruction

Having discussed a two-axis model on research-in-teaching in my previous post, I would like to take a look at another two-axis model. This one is from a blog post by Greg Ashman titled, not surprisingly, “A two-axis model of approaches to learning”. I’m now a regular reader of Ashman’s blog because I find his musings both thoughtful and provocative. (I discuss another of his posts here.)

The main point of this post is to add a second dimension to the discussion often surrounding implicit versus explicit instruction. I hear about this most often in the context of promoting inquiry learning (implicit) over the lecture format (explicit) with a clear bias towards inquiry being the preferred mode, particularly in the sciences. I’ve even run a multi-disciplinary multi-instructor Scientific Inquiry course that emphasized active learning in small class meetings.

Here is Ashman’s two-axis model. (Graphic is from Ashman’s blog.) The horizontal axis features explicit instruction on the right and implicit on the left.

We need to define the vertical axis (“situational accountability”). Here’s what Ashman says. “When we think of teacher-student interactivity, we tend to perceive it as a mechanism for gaining and giving feedback. However, it also serves another function; it promotes situational accountability. It is ‘situational’ in the sense that the accountability exists in the same learning episode as the instruction rather than after some delay. For instance, if there is a chance that you will be called upon to interact at some point in a lesson then you are more likely to pay attention to the instruction in that lesson. Situational accountability can be increased in a number of ways and to differing degrees. A simple approach might be to intersperse instruction with questions to randomly chosen students. However, it is also worth noting that Slavin’s two conditions for successful group work both act to increase situational accountability. So this is a more general idea.” (Read Ashman’s article if you want to know more about Slavin’s two conditions. He provides a link.)

Let’s take a look at each quadrant. Ashman has usefully categorized the types of students who would benefit from each method.

In the bottom right, you have Lecturing. This isn’t a bad method once you think about the target audience: self-motivated novices. When I want to learn something new, I enjoy going to a lecture. (Okay, maybe I’m weird.) One nice thing about being in a university is there are plenty of interesting lectures throughout the year. Or perhaps I watch a video, and thanks to the internet I have choices galore. But the crucial part is that I am self-motivated. Ashman’s example is first year university students studying an elective, i.e., something the student isn’t required to take but chooses purely out of interest. Presumably this means self-motivation. I have practically met no one in my first year chemistry courses (both the one for science majors and for non-science majors) who was taking it simply for the fun of it as an elective. They were either fulfilling the “science” requirement (if not a science major) or taking it as part of their major (true for biology, chemistry, physics, and engineering majors). Perhaps a traditional lecture (one that’s not so interactive) is not a good method for introductory college-level chemistry courses. I’m inclined to agree, but practically no one in my department drones on without substantial interaction with the students. Then again, I’m part of a liberal arts college with small class sizes. But if you were teaching at a large research university with 400 students in your class, that might be different.

The top left (Accountable Inquiry) is where I would place most (but not all) of the popular Active Learning pedagogies you hear about. Notice that these are geared to students with high prior knowledge who are not self-motivated. Many of the students in my chemistry classes have had some chemistry before they came to college (although they may have forgotten much of what they attempted to learn by rote) so I’m not starting completely from scratch. I think this partially explains why at degree-granting institutions, this approach works well. It is much harder to pull off when the student is a complete novice. Even when the student isn’t a complete novice, if you pitch the Inquiry activity at two high a level, the students just flounder. (Sadly, I speak from experience – and have learned to calibrate a little better by mixing in some explicit instruction, the next category.) One may quibble with the definition of what it means to be self-motivated. I’m going to say that grades, GPA and getting into medical school are not what I would classify as self-motivators. They are motivators, but of a different sort. (This is another can of worms that requires its own blog post so I won’t elaborate.)

The top right is where you have Explicit Instruction. This is where Ashman is as a math teacher at the grade school level. Students are novices and not necessarily self-motivated. I would argue that even at the university level, it would be important to mix in Explicit Instruction with Accountable Inquiry. In chemistry, while the students have been exposed to some of the material, they often don’t have the conceptual framework well-established and therefore they are seeing the material afresh in a different context at the college level. This approach is my preferred mode, i.e., there is a fair amount of my “lecturing” but it’s not like the lectures I would attend to learn something new. I see my lectures as being set pieces for Explicit Instruction. There needs to be Q&A and interactions with students throughout the class meeting. We also sometimes break into smaller groups to work on more “inquiry” based activities. This at least seems to work well for the types of students I get in my classes at my institution.

The bottom left (Self-determined inquiry) is what I do as a practicing scientist. While undergraduate education may have benefited from this approach way back when (and you still see it in the Oxbridge approach), by and large the massification of higher education means this is not going to work in most colleges or universities. There will be outliers, but we’re talking about the mass of students here. Graduate education works in this way to some extent, and so do small upper-division electives with highly motivated students. A capstone or independent research experience could also fall into this category.

What I like about Ashman’s model is that by just adding one more dimension, he opens up the pedagogical discussion that would otherwise be summarized as inquiry-based versus lecture, the guide-by-the-side versus the sage-on-the-stage, or many other caricatures that try to put two things in opposition to each other. It makes a nice media sound-bite, but like most important issues one needs some nuance and a little more complexity to move forward. Secondly, Ashman’s examples of learners in each quadrant is a challenge to me not to see my students in static groups but to see if I can move students from one quadrant into another. I’d like to move them from novice to expert, and from less motivated to more motivated. Different students will be at different stages, but there is some benefit to students helping each other and learning as a community that group work active-learning scenarios may leverage.