Monday, October 29, 2007

Learning styles

I've been puzzled by the fact that the IEP of one of my students describes the student as a "visual learner," while I would have said that visual information is what she has the most trouble with. This student is pretty good at algebraic manipulations, but understanding graphs has been a challenge. In particular, she quickly learned how to compute the slope of a line given the coordinates of two points, but learning to find the slope by inspecting the graph - by counting the units of vertical and horizontal change - required a lot of effort and repetition. And even then it seemed to be easier for her to first determine the coordinates of a couple points on the graph and then to plug these into the slope formula, rather than to just read the rise and the run off the graph. Also, she apparently really struggled with Geometry last year.

Her IEP recommends that she be placed near the front of the classroom so that she, being a visual learner, can see the board well, and all of that seems perfectly sensible and easy to accommodate. However, I am wondering about what exactly is meant by these learning styles categories: Are we talking about the mode of input - about which senses are used - or rather about the character of the information processed? I'll admit from the start that I have not done my homework in terms of reading the academic literature on learning styles - just those bullet-pointed short versions used in alternative credentialing programs - and maybe the most appropriate response to my questions would just be a reference to some standard text on these matters. Which would be fine.

In trying to distinguish 'mode of input' from 'character of information' (or whatever; if anyone knows any official terminology in this area, let me know) I'm reminded of Bach-y-Rita's little devices for transmitting visual information by tactile means. Starting in the 60s, he experimented with optical sensors attached to arrays of tiny electrodes attached to blind subjects' backs. Initially, candidates just experienced random tingling sensations from the electrodes, but with some time and practice this gave way to an immediate experience of rudimentary vision, enough to find their way while walking. They could, for example, "see" if an object was placed in front of another, blocking the latter from "view." When a candidate equipped with such an apparatus learns about his or her world by using information transmitted through tiny electrodes attached to the skin, is this candidate acting a as a "visual" learner or rather as a "kinesthetic" learner? I'd say the former, even though the mode of input is tactile.

Presumably the information needed to navigate a sidewalk could instead be given in verbal form, as a list of instructions about when to move and when to stop, and this language-based information could be accessed aurally, from directions read aloud, or the mode of input could be tactile, as when reading the list of steps in Braille. However, if the information were provided as a list of instructions about how to walk, reading these instructions would hardly make the information "visual" even though the mode of input were now visual, and reading them in Braille presumably would not make it more suitable for kinesthetic learners. Similarly, I would think that if a student learns most readily by a visual approach, then the student's needs are hardly met by the information being available as words on a screen or board, because even though the mode of input is certainly visual, the character of the information is verbal - and being able to see well is quite compatible with having a language-based learning disability.

In teaching my students about the number line I have come to wonder whether I am over-emphasizing a visual approach because such an approach happens to be mine. I guess I compare numbers by mentally placing them on the number line, and that is how I have always made sense of the rules for negative numbers. However, my (mathematically adept) husband insists that he does not think of numbers this way - and certainly the magnitude of a number and its position on a line are not the same thing. After all, the Ruler Postulate, which tells us that we can define a one-to-one correspondence between numbers on the one hand and positions on a line on the other, and in such a way that differences between numbers correspond to distances between points, is not a trivial statement. Besides, I have this unclear notion that Geometry developed for centuries without numbers attached in any important way, while Algebra did without Coordinate Geometry and number lines for the longest time (but I've never actually studied History of Mathematics, and don't really know). Anyway, students who have trouble distinguishing left and right might conceivably be more confused by the number line approach while still being perfectly capable of reasoning with signed numbers. It might be interesting to try and think of approaches to the material that are less visually oriented, instead of just assuming that this approach pretty much defines understanding, since that is the way I, um, see it!

Not that it matters that much in practical terms. I'm sure that in terms of learning outcomes for my students, they'd have been better served by my spending this time on getting their papers back to them quickly instead of writing all these words. But, whatever.

Thursday, October 25, 2007

The electric eraser cleaner

My classroom has old fashioned black blackboards on three walls, and the chalk dust has been getting out of hand. A couple days ago I took two erasers to the bathroom and beat them against the sink for a while, sending up clouds of dust and choking on it, and the morning after I wiped the board with a wet cloth instead. Upon which a student gave out the inside information: C-dog*, there's a machine for cleaning those erasers!

I had never heard of such a thing, and was fully prepared for this to be a little joke on the part of the student (she is funny). But a colleague confirmed that there was indeed an eraser cleaner, and pointed out where it was located, in a tiny, tiny closet containing this machine on a shelf and nothing else. It's this powerful little vacuum cleaner with a rotating brush, and it sucks the chalk dust into a ballooning green bag as it works. And it makes some noise while it's on!

My erasers are very clean now. Here's a picture of the machine. Isn't it the neatest thing?

*No idea where that came from - again, she is a funny student.

Saturday, October 6, 2007

Learning linearity from scratch

I'm teaching Algebra I for the first time this year, and having occasion to take a closer look at possible sources of great confusion and misunderstanding in later courses. Teaching Algebra II, I've often resorted to the number line to work with negative numbers and with fractions, always presupposing that the students would have a basic grasp of the very idea of a number line. Now I'm seeing what it looks like when students don't quite understand how a number line works.

In graphing scatter plots, it turned out a number of students - a significant fraction in a talented class - were 1) varying the distance between the numbers, and 2) placing the numbers according to their order in the table rather than sorting them in increasing order. I returned the homework assignments with a new deadline for redoing the plots, directing students to keep the spacing between the numbers on the number line constant. Several conscientious students redid the graphs, dutifully keeping a constant spacing of, say, 4 graph paper squares between the numbers - but the numbers thus placed would still be, say, 41, 37, 58 - the order would not be strictly increasing, and the differences between the numbers were not constant.

So the "simple" task of creating a scatter plot in the beginning of Algebra I actually presupposes some grasp of the Ruler Postulate, which they won't see for a year - the postulate that it is possible to assign numbers to the points on a line in such a way that number differences measure distance. After reiterating again and again that a certain distance on the axes must correspond to a fixed number difference, and copying student graphs onto transparencies and critiquing them in class, and conferring with students one-on-one - the graphs are finally looking pretty good.

I was initially surprised by what I saw as a puzzling deficiency in PreAlgebra skills. But my husband, a theoretical Physics grad student, pointed out that I was expecting students to understand linearity as a prerequisite for this unit on linear relations. The idea of a correspondence between distance and number difference contains what I am supposed to teach them.

After this lesson learned I am wondering about the Algebra II students I taught last year, whether many of them also never really knew how number lines worked either, and I just didn't get it - or whether a bit of Geometry taken in the meanwhile at least takes care of that issue.