Broadly speaking, there are three classes of scriptlets:
1. cognitive
2. physical
3. perceptual
Cognitive scriptlets have a physical component (if they didn't, nothing would ever happen). Thus the VCR scriptlet is mostly a prescription about what to do in a cognitive sense (the physical aspect being no more than button pushing). Similarly, the e-mail scriptlet involves only mouse clicks and keyboard strokes at the physical level.
Purely physical scriptlets do occur: typing and button pushing are two examples. More interesting ones are bicycle riding, brake pedal pushing on a car, tooth brushing, and so on. Perceptual scriptlets involve the recognition of things, such as recognizing individual people, noticing dangerous situations, or the perceptual part of hitting a baseball.
A cognitive scriptlet refers to knowledge about use. This knowledge is usually consciously available. That is, a person in possession of that knowledge can talk about it. If the sentence "John knows how to use X" makes sense for a given X, then X is a cognitive scriptlet.
A physical scriptlet refers to knowledge about operations. This knowledge is not usually consciously available. That is, a person in possession of a physical scriptlet may not be able to talk about it. If the sentence "John knows how to operate an X" makes sense for a given X, then X is a physical scriptlet.
A perceptual scriptlet refers to knowledge about observations. This knowledge is not usually consciously available; a person in possession of a perceptual scriptlet may not be able to talk about it. If the sentence "John knows how to recognize an X" makes sense for a given X, then X is a perceptual scriptlet.
Take me to the outline for the book
