CS459559 HumanComputer Interaction

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CS459/559Human-Computer Interaction

• Usability of Handheld Products
• 9-10-2007
• Prof. Searleman, jets_at_clarkson.edu

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Outline

• Presentation HW1 Handheld products
• usability user experience
• design usability principles
• Reading assignment start Chapter 3
• HW2 posted, due Friday 9/14
• Activity2 posted, also due Friday 9/14
• write a brief description for your HCI project,
  including your team members
• PR1 posted, due Friday 10/05

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Usability of handheld electronic devices

• To date we have seen presentations on
• 4G iPod
• Chinese/English dictionary
• Motorola cell phone
• TI89 titanium graphing calculator
• Olympus 770 SW digital camera
• iPhone
• wiimote
• Label maker
• RCA TV remote control

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Summary points

• Need to have a good understanding of the problem
  space
• specifying what it is you are doing, why, and how
  it will support users in the way intended
• A conceptual model is a high-level description of
  a product
• what users can do with it and the concepts they
  need to understand how to interact with it
• Decisions about conceptual design should be made
  before commencing any physical design

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Summary points

• Interface metaphors are commonly used as part of
  a conceptual model
• Interaction types (e.g., conversing, instructing)
  provide a way of thinking about how best to
  support the activities users will be doing when
  using a product or service

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Theories, models and frameworks

• Are used to inform and inspire design
• A theory is a well-substantiated explanation of
  some aspect of a phenomenon
• A model is a simplification of some aspect of
  humancomputer interaction intended to make it
  easier for designers to predict and evaluate
  alternative designs
• A framework is a set of interrelated concepts
  and/or a set of specific questions

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Main differences

• Theories tend to be comprehensive, explaining
  humancomputer interactions
• Models tend to simplify some aspect of
  humancomputer interaction
• Frameworks tend to be prescriptive, providing
  designers with concepts, questions, and
  principles to consider

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Chapter 3 Understanding users
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Overview

• What is cognition?
• What are users good and bad at?
• Describe how cognition has been applied to
  interaction design
• Theories of cognition
• Mental models, theory of action
• Information processing
• External cognition, distributed cognition

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Why do we need to understand users?

• Interacting with technology is cognitive
• We need to take into account cognitive processes
  involved and cognitive limitations of users
• We can provide knowledge about what users can and
  cannot be expected to do
• Identify and explain the nature and causes of
  problems users encounter
• Supply theories, modelling tools, guidance and
  methods that can lead to the design of better
  interactive products

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What goes on in the mind?
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Core cognitive aspects

• Attention
• Perception and recognition
• Memory
• Reading, speaking and listening
• Problem-solving, planning, reasoning and
  decision-making, learning
• Most relevant to interaction design are
  attention, perception and recognition, and memory

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Attention

• Selecting things to concentrate on at a point in
  time from the mass of stimuli around us
• Allows us to to focus on information that is
  relevant to what we are doing
• Involves audio and/or visual senses
• Focussed and divided attention enables us to be
  selective in terms of the mass of competing
  stimuli but limits our ability to keep track of
  all events
• Information at the interface should be structured
  to capture users attention, e.g. use perceptual
  boundaries (windows), color, reverse video, sound
  and flashing lights

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Activity Find the price of a double room at the
Holiday Inn in Bradley
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Activity Find the price for a double room at the
Quality Inn in Columbia
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Activity

• Tullis (1987) found that the two screens produced
  quite different results
• 1st screen - took an average of 5.5 seconds to
  search
• 2nd screen - took 3.2 seconds to search
• Why, since both displays have the same density of
  information (31)?
• Spacing
• In the 1st screen the information is bunched up
  together, making it hard to search
• In the 2nd screen the characters are grouped into
  vertical categories of information making it
  easier

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Design implications for attention

• Make information salient when it needs attending
  to
• Use techniques that make things stand out like
  color, ordering, spacing, underlining, sequencing
  and animation
• Avoid cluttering the interface - follow the
  google.com example of crisp, simple design
• Avoid using too much because the software allows
  it

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An example of over-use of graphics
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Perception and recognition

• How information is acquired from the world and
  transformed into experiences
• Obvious implication is to design representations
  that are readily perceivable, e.g.
• Text should be legible
• Icons should be easy to distinguish and read

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Is color contrast good? Find italian
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Are borders and white space better? Find french
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Activity

• Weller (2004) found people took less time to
  locate items for information that was grouped
• using a border (2nd screen) compared with using
  color contrast (1st screen)
• Some argue that too much white space on web pages
  is detrimental to search
• Makes it hard to find information
• Do you agree?