{"id":368,"date":"2013-06-27T16:37:44","date_gmt":"2013-06-27T20:37:44","guid":{"rendered":"http:\/\/localhost\/cs4760\/2014\/?page_id=368"},"modified":"2016-01-26T07:17:51","modified_gmt":"2016-01-26T12:17:51","slug":"normans-interaction-theory","status":"publish","type":"page","link":"http:\/\/cs4760.csl.mtu.edu\/2021\/lectures\/normans-interaction-theory\/","title":{"rendered":"Norman’s Interaction Theory"},"content":{"rendered":"

An obvious diagram of the Human-Computer Interface interaction:<\/p>\n

Human <—> Interface <—> Computer<\/p>\n

The diagram does not illuminate much.\u00a0 Norman\u2019s 1988 book the Design of Everyday Things<\/em> is one of the first appearance of the phase “user centered design.” \u00a0Norman’s genius was to view the interaction as a cycle with two components; execution<\/em> and evaluation<\/em>:<\/p>\n

\"Diagram<\/a>

Norman’s Interaction Cycle<\/p><\/div>\n

Viewing the HCI as cycle is an accurate representation with respect to both the user and the system (computer and program) point of views.\u00a0 Execution and evaluation are words the user understands. According to Norman the execution<\/strong> component can be further divided into:<\/p>\n

    \n
  1. Establishing the goal<\/li>\n
  2. Forming the intention<\/li>\n
  3. Specifying the action sequence<\/li>\n
  4. Executing the action<\/li>\n<\/ol>\n
    \"Gulfs<\/a>

    Gulfs between System and UI<\/p><\/div>\n

    The evaluation<\/strong> component is divided into:<\/p>\n

      \n
    1. Perceiving the system state<\/li>\n
    2. Interpreting the system state<\/li>\n
    3. Evaluating the system state<\/li>\n<\/ol>\n

      From the user’s perspective, the user first establishes a vague goal which the user specifies by forming an intent.<\/em> Then the user can determine a sequence of actions that the user executes.\u00a0 After the system responds (or maybe before if the system is slow), the user perceives the new system state which the user interprets and evaluates with respect to the user’s intended goal.\u00a0 The cycle repeats.\u00a0 The user forms the execution and evaluation in a task domain, called the task language<\/em>.\u00a0\u00a0 The system responses to the user’s action in a different language, called the core language<\/em>.\u00a0 A major cause of HCI failure is the differences between the two languages. Norman defines to kinds of errors due to the gulf of execution<\/em> and the gulf of evaluation<\/em>.\u00a0\u00a0A problem with Norman\u2019s model is that it does not make the UI explicit. Abowd and Beale (1991) extended making the UI explicit. There are still two languages, task and core, but the UI is responsible for translation between languages, so the gulfs exist in the UI. The UI is involved in 4 mappings:<\/p>\n

        \n
      1. \u00a0Articulation<\/li>\n
      2. Performance<\/li>\n
      3. Presentation<\/li>\n
      4. Observation<\/li>\n<\/ol>\n

        The picture I like to draw is two horse shoes, one representing the system and the other the user. The gap between the horse shoes representing the gulfs in the UI.<\/p>\n

        \"Gulfs<\/a>

        Gulfs represented by magnets<\/p><\/div>\n

        I like to think that an expert (experienced in the task) using a well designed HCI resembles two horse shoe magnets <\/strong>properly aligned; the horse shoes are strongly bonded together and the gaps disappear. Have you ever watched an expert user of VI editing?\u00a0 The document editions appear automatically like magic.\u00a0 Or how about a good system administrator using UNIX commands?\u00a0 Both of these interfaces are command line not WIMP interfaces.\u00a0 They work so well because the user has learned a task language that well matches the core language. Each horse shoe leg represents a mapping.\u00a0 The user must map the goals to a sequence of actions, articulation<\/em>.\u00a0 The system (modeled as a finite state machine) interprets the user’s actions and performs the correct internal change of state; this mapping is called performance<\/em>.\u00a0 Then the system must present the new internal state, presentation<\/em>.\u00a0 Finally the user must correctly map the presentation to task language, observation<\/em>.\u00a0 HCI errors can be associated with the four mappings<\/strong>:<\/p>\n

          \n
        1. Articulation<\/li>\n
        2. Performance<\/li>\n
        3. Presentation<\/li>\n
        4. Observation<\/li>\n<\/ol>\n

          All four mappings of the windows operating system interface are poor.\u00a0 Consider a user wanting to stop the opening of an unwanted window during booting.\u00a0 If the file is not in the start-up directory then the registry must be edited (another problem).\u00a0 The user can delete the wrong key or entry; representing an articulation error.\u00a0 If the user does not know to edit the registry then the user assumes that it is not possible to get rid of the window; a performance coverage problem. There is no indication that the registry has been edited, another poor presentation.\u00a0\u00a0 The user may not be able to interpret the keys of the registry properly; an observation problem.<\/p>\n

          OK this example is too obscure. Consider the MS Word processor.\u00a0 The user using short keys to select a command might press crtl-alt-del accidentally; definitely an articulation error.\u00a0 The user may not be able to find the correct formatting commands in the menus; performance coverage error.\u00a0 Or the user may type :) truly desiring colon and closed parenthesis but Word makes a smiley face; wrong performance.\u00a0 Comparing the printed document with the monitor displayed document the user finds discrepancies.\u00a0 This is a presentation error.\u00a0 The user does not realize that the blue background text is meant to indicate selection (and should not appear in the printed version) – this is an observation error.<\/p>\n

          Consider another example using a VCR remote control. The user is not sure if the recording is set properly. User presses the wrong button or the wrong sequence of buttons is an articulation error. The VCR can record on any channel but the remote can not access the channel is a coverage or performance error. The VCR does not indicate the channel or the recording is a presentation error. The user misinterprets the VCR symbols is an observation error. More examples of poor mapping interfaces:<\/p>\n

          Articulation:<\/p>\n

            \n
          • Clustering of light switches in a room<\/li>\n
          • Adjacent keys causing opposite state changes<\/li>\n
          • Pressing keys simultaneously<\/li>\n<\/ul>\n

            Performance:<\/p>\n

              \n
            • To shut down Windows user must click on START<\/li>\n
            • User can not find important Windows OS commands<\/li>\n
            • Applications missing important utilities<\/li>\n
            • Applications performing the command wrong<\/li>\n<\/ul>\n

              Presentation:<\/p>\n

                \n
              • Lack of indication, no visual change in the UI<\/li>\n
              • Netscape navigator status bar;\u00a0document done<\/li>\n<\/ul>\n

                Observation:<\/p>\n

                  \n
                • User falls asleep during boot up and misses important log information :)<\/li>\n
                • Can not read fonts<\/li>\n
                • Windows outside of the desktop view port or under other windows<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

                  An obvious diagram of the Human-Computer Interface interaction: Human <—> Interface <—> Computer The diagram does not illuminate much.\u00a0 Norman\u2019s 1988 book the Design of Everyday Things is one of the first appearance of the phase “user centered design.” \u00a0Norman’s genius was to view the interaction as a cycle with two components; execution and evaluation: […]<\/p>\n","protected":false},"author":61,"featured_media":0,"parent":112,"menu_order":6,"comment_status":"closed","ping_status":"closed","template":"page-templates\/front-page.php","meta":{"footnotes":""},"class_list":["post-368","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/cs4760.csl.mtu.edu\/2021\/wp-json\/wp\/v2\/pages\/368","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/cs4760.csl.mtu.edu\/2021\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/cs4760.csl.mtu.edu\/2021\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/cs4760.csl.mtu.edu\/2021\/wp-json\/wp\/v2\/users\/61"}],"replies":[{"embeddable":true,"href":"http:\/\/cs4760.csl.mtu.edu\/2021\/wp-json\/wp\/v2\/comments?post=368"}],"version-history":[{"count":16,"href":"http:\/\/cs4760.csl.mtu.edu\/2021\/wp-json\/wp\/v2\/pages\/368\/revisions"}],"predecessor-version":[{"id":1599,"href":"http:\/\/cs4760.csl.mtu.edu\/2021\/wp-json\/wp\/v2\/pages\/368\/revisions\/1599"}],"up":[{"embeddable":true,"href":"http:\/\/cs4760.csl.mtu.edu\/2021\/wp-json\/wp\/v2\/pages\/112"}],"wp:attachment":[{"href":"http:\/\/cs4760.csl.mtu.edu\/2021\/wp-json\/wp\/v2\/media?parent=368"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}