Chapter 2: Understanding and conceptualizing interaction

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Chapter 2 Understanding and conceptualizing
interaction
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Understanding the problem space

• What do you want to create?
• What are your assumptions?
• What are your claims?

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A framework for analyzing the problem space

• Are there problems with an existing product or
  user experience?
• Why do you think there are problems?
• How do you think your proposed design ideas might
  overcome these?
• When designing for a new user experience how will
  the proposed design extend or change current ways
  of doing things?

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Conceptual model

• a high-level description of how a system is
  organized and operates. (Johnson and Henderson,
  2002, p. 26)

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Main components

• Metaphors and Analogies.
• Concepts
• Relationships
• Concept ?? User Experience Goals.

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Benefits

• How do users understand the interaction model?
• Not to become narrowly focused early on
• Establish a set of common terms they all
  understand and agree upon
• Reduce the chance of misunderstandings and
  confusion arising later on

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A classic conceptual model the spreadsheet

• Analogous to ledger sheet
• Interactive and computational
• Easy to understand
• Greatly extending what accountants and others
  could do

www.bricklin.com/history/refcards.htm
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The Star interface
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Interface metaphors

• Designed to be similar to a physical entity but
  also has own properties
• e.g. desktop metaphor, search engine

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Benefits of interface metaphors

• Makes learning new systems easier
• Helps users understand the underlying conceptual
  model

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Problems with interface metaphors (Nelson, 1990)

• Break conventional and cultural rules
• e.g., recycle bin placed on desktop
• Can constrain designers in the way they
  conceptualize a problem space
• Conflict with design principles
• Forces users to only understand the system in
  terms of the metaphor
• Designers can inadvertently use bad existing
  designs and transfer the bad parts over

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Interaction types

• Instructing
• Conversing
• Manipulating
• Exploring

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Instructing

• Where users instruct a system by telling it what
  to do
• e.g., tell the time, print a file, find a photo
• Very common interaction type underlying a range
  of devices and systems

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Conversing

• Like having a conversation with another human
• Examples include search engines, advice-giving
  systems and help systems

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Manipulating

• Exploits users knowledge of how they move and
  manipulate in the physical world
• Virtual objects can be manipulated by moving,
  selecting, opening, and closing them

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Direct manipulation

• Proposes that digital objects be designed so they
  can be interacted with analogous to how physical
  objects are manipulated

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Core principles of DM

• Continuous representation of objects and actions
  of interest
• Physical actions and button pressing instead of
  issuing commands with complex syntax
• Rapid reversible actions with immediate feedback
  on object of interest

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Why are DM interfaces so enjoyable?

• Novices can learn the basic functionality quickly
• Experienced users can work extremely rapidly to
  carry out a wide range of tasks, even defining
  new functions
• Intermittent users can retain operational
  concepts over time
• Error messages rarely needed
• Immediate feedback
• Users gain confidence and mastery and feel in
  control

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What are the disadvantages with DM?

• Not all tasks can be described by objects and not
  all actions can be done directly
• Some tasks are better achieved through delegating
  rather than manipulating
• e.g., spell checking
• Moving a mouse around the screen can be slower
  than pressing function keys to do same actions

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Exploring

• Involves users moving through virtual or physical
  environments

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A virtual world
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A CAVE