Gabriel Spitz Representation at the Interface 1 Gabriel

Gabriel Spitz Representation at the Interface 1

Gabriel Spitz What is Representation 2

Gabriel Spitz Representation Is … Representation is the choices that a designer makes when: selecting control types conceptualizing objects specifying labels composing instructions to support a function or an object at the interface 3

Gabriel Spitz 4

Gabriel Spitz Choosing Control Types Spinner Drop down + Table Scroll + Table 5

Gabriel Spitz Conceptualizing Objects Textual objects Graphical objects 6

Gabriel Spitz Specifying Labels Action label Consensus Icons 7

Gabriel Spitz Focus of Representation is concerned primarily with the nature of the choice rather then its implementation For example should a command to get out from a process be labeled Exit Close Finish OK Kill Implementation of the selected choice will be discussed later when we talk about Presentation 8

Gabriel Spitz Choosing Commands 9

Gabriel Spitz Impact Of Representation 10

Gabriel Spitz Selecting a Date Picker - 1 11

Gabriel Spitz Selecting a Date Picker - 2 12

Gabriel Spitz Selecting Representation The controls in the previous examples all supported the same task – Date Picking However they differed in how the user specified the date, and in turn: The type and intensity of cognitive demands placed on the users, or workload Speed of task performance The likelihood of making an error 13

Gabriel Spitz Representation - Example Read Select Click Read Select 14

Gabriel Spitz Effective Representation 15

Gabriel Spitz To be Effective A representation needs to be: Compatible with users characteristics Suitable for a specific task and usability goals within a given context and culture Compliant with standards, guidelines, and expectation There is significant overlap among the above elements 16

Gabriel Spitz Domain Compatibility Icons Analysis Icons Cyber Security Medical Mechanical 17

Gabriel Spitz Selection Criteria for Representation From a Usability perspective effective representations are those that are: Easy to remember Easy to interpret Easy to use 18

Gabriel Spitz Easy to Remember Best commands, icons, and actions sequences are those that are easy to remember For example Using the cursor to highlight a row Vs Recalling a sequence of keyboard commands 19

Gabriel Spitz Ease of Remembering The ease with which a new item can be remembered depends on its meaningfulness (Craik & Lockhart 72) The reason is that meaningful items are processed at a deeper level 20

Gabriel Spitz Deep Processing - Example Stroop Effect Blue Yellow Green The color of the font competes with the meaning of the word because both are meaningful A non-English native can ignore the meaning of the word 21

Gabriel Spitz Meaningful Items Meaningfulness of an item is effected by: Familiarity with the item In a case of a word it relates to the frequency with which it occurs in everyday life – E. g. , Expunge vs. Delete Its associated imagery In the case of a word it is the extent to which the word can elicit images in our mind 22

Gabriel Spitz Familiarity of words - Example Familiar words Door Read Stop Unfamiliar words Compile Substitute Scan 23

Gabriel Spitz Associated Imagery -Example High imagery words Ride Sleep Eat Low imagery words Begin Increase Evaluate 24

Gabriel Spitz Selecting Labels such as command names or object names used at the interface should be meaningful – well understood Meaningfulness should be considered within The context in which the item is to be used The culture Users’ characteristics 25

Gabriel Spitz Labels - Example Some Unix commands have names that are difficult to remember by novice users For example CAT – List content of a file GREP – Search for a string MV – Move LPR – Print file 26

Gabriel Spitz Representation of Icons are another common form of designating commands, objects, or tools Meaningfulness of an icon is determined by: Context Task The underlying concept that we try to represent 27

Gabriel Spitz Using Icons Easy to interpret For Example: VS. F 5 For Slideshow Power Point 28

Gabriel Spitz Icons example 29

Gabriel Spitz Summary When selecting a label for a command Use terms that are already known to users rather than invent new words/labels Use terms that are frequently used by the end users Use terms that elicit imagery Capitalize on good graphics Use recognition rather than recall 30