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					including Model Human Processor
           design tool
• A description of a mental model and how they
  can be applied to the design of a user
  interface.

• The importance of designing a system model
  that matches closely to the user’s mental
  model.

• Model Human Processor design tool.
• In the previous lesson we learnt how different
  design principles are applied to the design of a
  GUI.

• You could break down these design principles
  into categories of:
   –   Perception
   –   Attention
   –   Memory
   –   Learning
• How does the user perceive the signals from a
  computer?

  – Red text or warning signs indicate stop.
  – Green text or no problems indicate go.

• Perception can also change based on sound
  signals.
  – Happy DING might mean something saved correctly.
  – Sharp CLUNK might mean something didn’t save
    properly.
• Designing an interface to hold a user’s attention.

• Cluttered = bad!

• Important information needs to be clear and
  obvious so the user doesn’t get fed up looking for
  it!

• Looking at layout and aesthetics.
• Thinking about pre-existing knowledge of the
  user.

• Thinking about consistency between system
  screens to make it easy to use the system.

• Less familiar screens should be design to make
  the transition as easy as possible!
• Looking at previous experiences to design an
  interface that was easy to use.

   – Going from Windows 3.1 to Windows 7 would be a
     huge jump.

   – But Windows Vista to Windows 7 is much less of a
     jump!


• Providing useful help screens is essential too.
• You can break down the users who use computers into
  two categories.

• Those who:
   – Have lots to some understanding of the operation of a
     computer.
   – Have little to no understanding of the operation of a
     computer.

• Those in the first category are tend to be able to
  complete tasks at a faster rate compared to those in
  the second category.
• The way in which we interact with a computer
  is based on what we know...

  – Our:
     •   Perception
     •   Attention
     •   Memory
     •   Learning ability
• The way in we interact with a computer could
  be defined by our mental model.

• A designer will have to design an interface
  taking into account our mental models.

• And it can be quite tricky as everyone has a
  unique mental model.
• What is useful is that we all have similarities in
  our mental models and, as a designer, we can
  control the development of the mental model.

• For instance...
   –   A user wants to save a word processed file.
   –   They learn how to do it in MS Word.
   –   The user starts a new document in MS Excel.
   –   The user saves the file using the same method using
       what they have learnt in the previous application.
• By mimicking the methods used across applications.

• Consistency is often the key.

• It is also important to think about user experiences.
  For example:
   – Many people grow up learning about the green cross code.
   – Green man means walk; Red man means stop.
   – This could be translated into systems to help users interact
     with the system.
   – The use of image and sound are critical.
• A user’s mental model should allow them to
  envisage the results of an action.

• They will then use this mental model to help
  them to predict the actions that need to take
  place to complete another task.
• An effective user interface takes into consideration:
   – The fact that all mental models are different.
   – Mental models are effected by user experience.

• The designer must:
   – Ensure that the interface translates the intention of the
     user onto the interface.
   – The action of the computer should match that anticipated
     by the user.

• The actions of the computer could be translated
  through visual clues or by sound.
• The system model must match as closely as
  possible to the user’s mental model.

• If the system model is too far removed from the
  user’s mental model then the system will not be
  used efficiently.

• The system model must build upon user
  experience as much as possible to ensure smooth
  transitions.
• All users bring misconceptions to all systems.

• By designing a system that predicts these
  misconceptions and addresses them will help
  boost confidence in the user.

• For instance, this means using the same
  shortcut keys across applications and systems.
• Two men go camping.

• One man marks a can of powered milk with
  M and powered mash potato with P.

• The next morning the other man puts
  cereal in his bowl. He picks up can P and
  pours it on his cereal and adds water.

• He believed P stood for Powdered Milk and
  M stood for Mash.

• Different users have different misconceptions based on previous
  experiences.

• The man who had Mash on his cornflakes went camping last year and
  labelled cans M for Mash and P for Powered Milk!
•   A design tool with the aim of portraying a user of a computer system as an actual
    computer!

•   A basic example:
                       Skin                                               Eye


                Touch Short-term                                    Visual Short-term
                    memory                                              memory


                 Touch Processor                                    Visual Processor

                                      Cognitive Short-Term Memory

                              Facts
      Long-Term Memory                    Cognitive Processor


      Long-Term Memory                      Motor Processor                      Muscles
•   Information is received through your skin and eyes.

•   This is the input.

                         Skin                                               Eye


                  Touch Short-term                                    Visual Short-term
                      memory                                              memory


                  Touch Processor                                     Visual Processor

                                        Cognitive Short-Term Memory

                                Facts
      Long-Term Memory                      Cognitive Processor


      Long-Term Memory                        Motor Processor                      Muscles
•   Information is passed to working memory by the perceptual processor.



                      Skin                                               Eye


                Touch Short-term                                   Visual Short-term
                    memory                                             memory


                 Touch Processor                                   Visual Processor

                                     Cognitive Short-Term Memory

                             Facts
      Long-Term Memory                   Cognitive Processor


      Long-Term Memory                     Motor Processor                      Muscles
•   The working memory includes two separate storage sections;
     –    One for visual images and one for touch feelings.
•   The working memory also includes those sections of the long-term memory that are
    currently of interest to the user.

                              Skin                                                  Eye


                      Touch Short-term                                        Visual Short-term
                          memory                                                  memory


                       Touch Processor                                        Visual Processor

                                                Cognitive Short-Term Memory

                                      Facts
         Long-Term Memory                             Cognitive Processor


         Long-Term Memory                               Motor Processor                    Muscles
•   This process can be related to the process of loading data from disk into RAM.



                      Skin                                               Eye


                Touch Short-term                                   Visual Short-term
                    memory                                             memory


                 Touch Processor                                   Visual Processor

                                     Cognitive Short-Term Memory

                             Facts
      Long-Term Memory                   Cognitive Processor


      Long-Term Memory                     Motor Processor                      Muscles
•   The motor processor then draws on the long-term memory and the cognitive processes to
    complete an action.
•   For example...if you burn yourself you pull your hand away! You look at the damage and
    assess any problems.
                       Skin                                               Eye


                 Touch Short-term                                   Visual Short-term
                     memory                                             memory


                  Touch Processor                                   Visual Processor

                                      Cognitive Short-Term Memory

                              Facts
      Long-Term Memory                    Cognitive Processor


      Long-Term Memory                      Motor Processor                      Muscles
• Now apply this to another model.

                      Ear                                               Eye


              Auditory Short-                                     Visual Short-term
               term memory                                            memory


            Auditory Processor                                    Visual Processor

                                    Cognitive Short-Term Memory

                            Facts
   Long-Term Memory                     Cognitive Processor


   Long-Term Memory                       Motor Processor                      Muscles
•   You know that right clicking on an image will bring up a menu.
•   You see the menu and you click on copy.
•   You click copy and then right click again to paste.
•   You hear a noise indicating a problem.
•   You think about the problem and realise that you are going to over-write the old file.

                            Ear                                                     Eye


                     Auditory Short-                                         Visual Short-term
                      term memory                                                memory


                    Auditory Processor                                       Visual Processor

                                           Cognitive Short-Term Memory

                                  Facts
       Long-Term Memory                         Cognitive Processor


       Long-Term Memory                          Motor Processor                             Muscles
• A model can be applied to the design of a user
  interface by:

  – Logically ordering inputs, possibly by those required
    from the user.

  – Using an on-screen flashing cursor to show where
    data is to be input.

  – Using an audible stimulus (e.g. A beep sound) to
    indicate when an error has been made by the user.
A company wants to introduce a stock
ordering system. A user interface will need
to be designed:

a) Describe the user interface too known as Model
   Human Processor (MHP).

b) Identify and explain two examples of how MHP
   could be applied to the interface.
A publishing company is updating the
accounts system that is currently in use.

a) Explain how a user’s perception and memory
   should be considered when the accounts system
   interface is being designed.

b) Explain how colour should be used when
   designing the HCI.

				
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posted:8/9/2012
language:English
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