May 24, 2009
Most propositional knowledge (knowledge of facts) is pretty easy to come by (at least in principle). There is only one capital of Venezuela, and if you wish to learn the capital of Venezuela, Wikipedia will cooperatively inform you that it is Caracas. For propositional knowledge that Wikipedia knoweth not, there is the scientific method. Procedural knowledge - the knowledge of how to do something - is a different animal entirely. This is true not only with regard to the question of whether Wikipedia will be helpful, but also in the brain architecture at work: anterograde amnesiacs can often pick up new procedural skills while remaining unable to learn new propositional information.
One complication in learning new procedures is that there are usually dozens, if not hundreds, of ways to do something. Little details - the sorts of things that sink into the subconscious with practice but are crucial to know for a beginner - are frequently omitted in casual descriptions. Often, it can be very difficult to break into a new procedurally-oriented field of knowledge because so much background information is required. While there may be acknowledged masters of the procedure, it is rarely the case that their methods are ideal for every situation and potential user, because the success of a procedure depends on a vast array of circumstantial factors.
I propose below a general strategy for acquiring new procedural knowledge. First, saturate by getting a diverse set of instructions from different sources. Then, distill by identifying what all or most of them have in common. Finally, improvise within the remaining search space to find something that works reliably for you and your circumstances.
The strategy is not fully general: I expect it would only work properly for procedures that are widely attempted and shared; that you can afford to try multiple times; that have at least partially independent steps so you can mix and match; and that are in fields you have at least a passing familiarity with. The sort of procedural knowledge that I seek with the most regularity is how to make new kinds of food, so I will illustrate my strategy with a description of how I used it to learn to make meringues. If you find cookies a dreadfully boring subject of discourse, you may not wish to read the rest of this post.
The first step is to collect procedural instructions for the object of your search from many different people, saturating your field of search with a variety of recommendations. A Google search did it in my case; for more esoteric knowledge, it might be necessary to look harder. Half a dozen of the more popular sets of instructions tends to be plenty for recipes, but the ideal number could easily be higher for procedures with a wider variance of detail or an unusually high number of people who have no clue what they are talking about. Here are four recipes for meringues that I referred to and one recipe for meringue pie topping that also informed my learning. I also got one recipe from a friend.
All of the recipes purported to teach me to do the same thing: turn some eggwhites and sugar (and varying other ingredients) into puffy little cookies. They varied in such details as: ingredient ratios, type of sugar, other ingredients called for besides eggwhites and sugar, oven temperature, what to line the cookie sheet with, and mentions of other factors such as having a clean mixing bowl or humid weather.
The second step is to extract what all of the procedures have in common, and decide which non-ubiquitous steps to include. In this case, I first had to multiply all the recipes to make them call for the same number of eggwhites (since those are very difficult to halve or otherwise adjust, I chose them instead of sugar as my starting point). All five of the recipes (after this revision) called for four eggwhites; all of the recipes call for either caster/superfine sugar or unspecified sugar1; all of them call for vanilla; all of them instruct me to beat the eggwhites to peaks first and then add the sugar and beat it in. Four of them call for salt. Four of them call for cream of tartar. Most of them call for components like candy and nuts, but since I know that meringues come in a wide variety of flavors (by, for example, reading these recipes) I treat these all as optional. Proposed oven temperatures/baking times are (200/1.5 hours), (250/30 minutes), (300/25 minutes), and (325/15 minutes). They vary in whether the cookies are to be baked on a greased cookie sheet, a greased and floured cookie sheet, on baking parchment, on paper towels, or on tinfoil.
A good place to start is to go with the majority: I decided to include both salt and cream of tartar. Next, I eliminated the impractical: I could not find superfine sugar at the store and I don't own a food processor, so I went with granulated sugar. As for the rest of the instructions, it was a free-for-all. No two recipes agreed about the cookie sheet arrangement; the two of them that mentioned "cracking" disagreed on whether it was a desireable outcome; and worst, none of them explained why every time I tried to make these cookies, they refused to foam up and form peaks2. Time for the last step.
A close reading of the more verbose recipes turns up urgent cautions about not letting any grease into the batter, be it a smear from a prior cooking adventure left on the mixing bowl, a bit of yolk, or - in one recipe - the oils that are naturally on skin. This last, it turned out, was the key: I was separating eggs by hand, and was not very neat about it. I switched to a technique recommended by a friend involving spoons, and presto, I could get the meringue batter to hold peaks...
But how long to cook them, at what temperature, and sitting on what? There, it was necessary to experiment (fortunately, after having narrowed the search space somewhat). This stage depended as much on my personal taste, the local weather, and the behavior of my oven as on the accuracy of the original recipes; it seems that my oven runs hot, so I need to bake them at 250 degrees or cooler and babysit them after the first ten minutes, or they will burn. Additionally, parchment paper and tinfoil3 wound up burning the bottoms of the cookies before the tops were even dry; paper towels worked.
1Caster and superfine sugar are the same thing, and you can make a reasonable facsimile using a food processor. When the type of sugar is not specified in a recipe, it means to use granulated white sugar; other kinds are named (e.g. light or dark brown sugar, turbinado sugar, confectioner's sugar, etc.). This is one of the examples of a situation where background knowledge of the field comes in handy.
2Not that this stopped me from baking the batter anyway. It just turned into round, flat cookies instead of puffy, light ones.
3I didn't get around to trying greased nor greased and floured bare cookie sheets - I prioritized these tests last because they involve more dishes to wash.