Jigging and Expertise

Jigging and Expertise April 7, 2016

In an essay on “The Intelligent Use of Space,” David Kirsh observed that since we have bodies, “we are spatially located creatures: we must always be facing some direction, have only certain objects in view, be within reach of certain others. How we manage the space around us, then, is not an afterthought; it is an integral part of the way we think, plan and behave, a central element in the way we shape the very world that constrains and guides our behavior.” Thus “human agents make use of resources in the situation to help draw conclusions and solve problems rather than use abstract, symbolic computations. People make mental tools of things in the environment.

This puts Hirsh firmly in the “interactionist” camp regarding human beings and their environment: “to understand human behavior, and to design robots that scale up to complex dynamic environments, we must explore the interaction between agent and environment. Humans, to a significant degree, shape and even create the environment, that in turn, influences their behavior and development.

Not only do we shape the environment that shapes us, but we shape the environment toward particular tasks. Hirsh watched videos of people cooking, bagging groceries, working, playing Tetris, to explore how we arrange tools and materials spatially in order to improve our performance of tasks, to leave cues and clues to what comes next, to streamline, to limit the number of basic choices we might have to make in the course of the task. Experts don’t do much planning, and don’t do much deciding in the course of their task. They set the environment to complete the task with as much excellence, and as little mid-stream decision-making as possible.

“Jigging” is one method: “A jig is a device for stabilizing a process: it is a mechanism for reducing the degrees of freedom of a target object. A vice is a jig, a table top can serve as a jig, but so can a ‘pick’ in basketball, or the slides on a cabinet drawer which determine the direction of free movement, or compliance. Jigging is one way of preparing or structuring the environment. The more completely prepared an environment is, the easier it is to accomplish one’s task.

Hirsh distinguishes “informational” from “physical” jigs; the former hides certain possibilities, certain allowances, that would otherwise be available in the environment; a physical jig physically blocks us from performing certain tasks. A “cue” is a kind of informational jig: “Agents ‘seed’ the environment with attention getting objects or structures. These can be harnessed to not only reduce perceived choice but to bias the order in which actions are undertaken. When I put a roll of film by the doorway, for example, I am using space to create a reminder to prevent me from just marching out the door without remembering my earlier intention to get the film developed today.

A spatial arrangement isn’t random, but speaks of what must has been and what must be done. Hirsh uses an example from his own home: “in my kitchen at home, a task as simple as preparing a plain garden salad, reveals a latent production line because I wash vegetables by the sink and cut them on a chopping board. . . . When we examine this task we note two uses of space: The equipment and surfaces of a station effectively trigger an action frame or task context in which only a fraction of all actions are considered. Once a context of action has been triggered, the local affordances make clear what can and must be done. If a tomato were viewed in isolation, a cook in search of a salad might consider chopping it, washing it, placing it directly in a salad bowl or plate, or even eating it on the spot. To perform most of these tasks the cook would have to first find the relevant equipment – knives, sink, bowl etc. Exactly which task the cook would do would depend on where in the plan he was. The virtue of spatially decomposing the task is that one need not have to consult a plan, except at the very highest level, to know what to do. Each task context affords only certain possibilities for action. You don’t think of washing vegetables when they are sitting beside a knife and a cutting board, unless their unwashed state stands out and alerts you to a problem. Similarly, if an item is unwet and beside the sink, for all intents and purposes, it carries a ‘wash me’ label.”

The spatial arrangement is information rich: “A cook entering the room can read off what is to be done, for there is enough information available in the set-up. The reason production line layouts are examples of hiding affordances rather than highlighting affordances is that the context of action delimits the range of immediately available actions to the ones that are ‘ready to go’. When a knife and board are present, cutting actions are ready to go, and washing is not.”


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