Sunday, 19 October 2008

Why we simplify

Simplifying (oversimplifying) is good for teaching, not-so-good for learning.

While walking back home from Safeway just now, a guitar bag in one hand and shopping bags on the other, plus a bag of lecture notes on my back, this new thought came upon me.

This morning, a friend of mine sent me an SMS: Hey. Tell me, which enzyme is involved in glycogenolysis again? Starts from p. The answer is glycogen phosphorylase.
Now, I can perhaps tell any person - who does not yet know - the correct answer, in one or two words (teaching), but it wouldn't necessarily be something meaningful to him/her (learning). Like, come on, how much time does it take to say out the name of the enzyme? It's only 4-7 syllables.

Teaching looks at the transmitting end. For high school leavers, a lecture covering glycogenolysis and its counterpart glycogenesis, plus some glycolysis and gluconeogenesis could probably be done in 1 hour. One hour.

Learning focuses on the learning end. "You only really understand the material when you can teach it to someone else," so goes the saying. Learning glycogenolysis from a Biochemistry textbook can take hours or days, depending on the purpose of learning it and the level of detail required.

And honestly, to me - as I'm learning this stuff now, for this semester - I think memorizing isolated bits of knowledge is not very useful. It's good for the initial bit of learning, but not when we have hundreds and thousands of facts to deal with in our heads. Once we form more links between yesterday's new knowledge and today's new knowledge, what we learn eventually makes more sense. It no longer comes through (futile) rote memorisation (although it may initially did), but through solid understanding of the matter being discussed.

For example, I think the knowledge of "glucagon increases blood glucose" bears more meaning if the question of "How?" is addressed - at least for students studying some Biochemistry. I can easily mention that the hormone glucagon triggers a cascade of reactions that eventually activates the enzyme glycogen phosphorylase (and deactivates glycogen synthase), but it is only because I've looked and re-looked at the diagram in Lehninger too many times. And because I've learned in high school about chemical equations, enzymes and hormones. It involves the use of a 7-helix G-protein coupled (membrane) receptor, adenylyl cyclase, cytosolic cAMP, PKA, and phosphorylase kinase.
But for a moment, imagine a world without simplification... That would be unimaginable! The way that humans learn is by spending time doing/reading/writing/thinking about something. We don't learn to speak a language in perfect grammar in one day! It's like churning time into something that's learned.

And in any case, if a biochemist read this post, I reckon s/he'd say that I myself am simplifying stuff by referring to glycogen phosphorylase as if it's one, single distinct thing. (I am aware that there's the inactive phosphorylase b and active phosphorylase a, but that's all I know about it...and then of course there's much more detail about the active site, affinity, inhibition, etc.)

So simplification has its place in teaching (especially for teachers, because time here in this world is limited). But for the purpose of solid understanding (on the learner's part), let's not just take it at face value. Ask questions, especially the assumptions made in making the simplified statement.

And how I wish everyone in our study group could really grasp the essence of this semester: Nutrition, Digestion and Metabolism. It really is a well-crafted academic programme. Now time for exam preparation.

Picture credit:mcb.web.psi.ch