2.4: Efficiency

• Input from eyes and ears is first stored in the short-term sensory store.
• The perceptual processor takes the stored sensory input and attempts to recognize symbols.
• The cognitive processor takes the symbols recognized by the perceptual processor and makes comparisons & decisions.
• The motor processor receives an action from the cognitive processor & instructs the muscles to execute it.
• Cycle Time: the main property of a processor
• Fusion strongly affects our perceptions of causality.
• Skill: a procedure that has been learned thoroughly from practice
• Skill-based decisions: automatic responses that require little to no attention.
• Types of decision making:

  • Skill-based
  • Rule-based
  • Knowledge-based
• Rule-based decisions: decisions in which the human is consciously processing a set of rules of the form "if X, then do Y"
• Knowledge-based decisions: used to handle unfamiliar or unexpected problems
• Hick-Hyman Law of Reaction Time:

  shows that the number of cycles required by the cognitive processor is proportional to the amount of information in the stimulus
• Fitt's Law:

  • specifies how fast you can move your hand to a target of a certain size at a certain distance away
• Fitt's Law relies on closed-loop control.
• Gesture: a particular movement of the mouse (or stylus or finger) that triggers a command
• Hick-Hyman Law:

  • named after British & American Psychologist team

  1. William Edumund Hickman
  2. Ray Hayman
• Hick-Hyman Law:

  • the more stimuli to choose from, the longer it takes the user to make a decision on which one to interact with
• Use Hick-Hyman Law to:

  • examine how many functions you should offer at any part of your website
  • how these functions will affect your users' overall approach to decision-making
• Reduce the number of stimuli and get a faster decision-making process.
• K.I.S.S (Keep It Short & Simple)

  • states that "Simplicity is the key for a system to work in the best way"
• The objective of Hick-Hyman Law is to:

  • try and simplify the decision-making process, not eliminate it entirely
• The aim of UI design:

  • reduce the distance from one point to the next & make the target object large enough to enable prompt detection & selection of interactive elements without sacrificing accuracy
• Categorizing Choice:

  • enabling users to find items from higher categories, as if looking under sections in a library
• Obscuring Complexity:

  • breaking up long or complex processes into screens with fewer options