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LEC 5- Theories, Models and Principles of Usability - Coggle Diagram

- - - - Systems and people become social actors.
  - - - selective attention
      - divided attention
    - - direct manipulation
  - - - Gestalt's law
        
        grouping- items that appear close to each other appear as one group
        
        principles within Gestalts Law
        
        Good continuation
        
        Symmetry
        
        Proximity
        
        Periodicity
        
        Similarlity
      - Von Restoroff Effect
        
        Isolation effect
        
        when there are similar objects, the one that differs from the rest is likely to be remembered
      - Fitts Law
        
        Amount of time taken to move a pointer to a target area
        
        depends on the size of the target
        
        depends on distance between pointer and the target
        
        MT= a+b*log2(D/W+1)
      - Hicks Law
        
        As the number of choices increases the decision time also increases
        
        don't put too many options in a menu
        
        RT= MT +processing speed*log2(n)
      - Peak End Rule
        
        people judge an experience largely based on how they felt at its peak and at its end, rather than the total sum or average of every moment of the EXP
        
        moments which are intense- peak and when the exp ends- end
        
        rollercoaster
- - - - 1.
        
        Goals (Desire)
        
        world
        
        Cycle of evaluation
        
        Perceive results
        
        Gulf of Evaluation
        
        Difference between system representation and user expectations
        
        scan myki card and it says card is not read
        
        Evaluate against what we wanted to happen(expectation
        
        Interpret results
      - 2.
        
        Form the intention (to act!!)
      - 4.
        
        Execute
      - Gulf of Execution
        
        difference between user intention and supported actions
        
        action you want to take is not supported by the system
      - 3.
        
        specify steps of action!
- - - - Consistency
        
        matching user expectations/mental model
        
        Consistency refers to having similar operations and similar elements for achieving similar tasks.
        
        users get comfortable to the landscape of the webiste
        
        using style guides can help + guidelines
      - Affordance
        
        a feature of the object that tells the user how to use it.
        
        to afford means to give a clue
        
        objects invite action
        
        an object affords an action or functionality
        
        the affordance of an object can be poor
        
        looks like an button but it isn't a button. not clear how to user it
        
        strong affordances= clear to how to use it
        
        blue underline= hyperlink=can be clicked on
      - Signifier
        
        perceived affordance
        
        what is the proper use of this object
        
        “The term signifier refers to any mark or sound, any perceivable indicator that communicates appropriate behaviour to a person
      - Mapping
        
        Mapping is the relationship between controls and the effect they have on the world
        
        should be natural
      - Feedback
        
        communicate frequently with user especially after actions
        
        timely and informative feedback
        
        empathetic and its two way
        
        acknowledge successful interactions
      - Constraints
        
        limitations
        
        Constraints can restrict the kind of interactions that can take place and therefore help reduce the amount of information we process
        
        physical, logical, semantic, and cultural constraints guide actions and ease interpretation
      - Discoverability/Visibility
        
        Visibility is the basic principle that the more visible an element is, the more likely users will know about them and how to use them
        
        you should be able to find the function and understand quickly and easily.