Chris Johnson, Index

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Rasmussen: Skill, Rules and Knowledge

• Signals:
  - sensory data from environment;
  - continuous variables;
  - cf Gibson's direct perception.
  
  
• Signs:
  - indicate state of the environment;
  - with conventions for action;
  - activate stored pattern or action.
  
  
• Symbols:
  - can be formally processed;
  - related by convention to state.

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