UserCentered Website Development A HumanComputer Interaction Approach

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User-Centered Website DevelopmentA
Human-Computer Interaction Approach
UCD - Capabilities of Human beings
By Gustavo Alatta
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Capabilities of Human beings

• Anyone who is developing websites needs to know
  some basics about limits of human perceptions,
  cognition, and memory. We dont have to be
  involved in the latest research, but some basics
  are essential.
• Goals of this presentation.- Learn about
• Human sense, perception, memory and
  interruptions.
• Some Guidelines based on these topics.

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Capabilities of Human beings

• Senses
• 1.- Ours senses feed our perceptions.
• 2.- Most of us have at least 5 senses, primary
  among which are sight, hearing, touch, taste, and
  smell. As a whole. We are primary visual beings.
• 3.- STATS When a number of students were asked
  which sense they would most hate to lose, 75
  replied sight (Synnot 1993).
• 4.- Design good web materials requires Knowledge
  of how people see.

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Capabilities of Human beings

• Perceptions
• 1.- Among different schools of thought, we will
  borrow from the school of constructivism (Agnew
  1987).
• 2.- Central ides of constructivism is that our
  brains dont create pixel by pixel recording of a
  scene like a digital camera. Instead, our minds
  create or construct intervening models that
  abstract and summarize what comes out of the
  optic nerve, and these model influence what we
  perceive.
• 3.- Constructivism theory contends that when we
  see something we dont remember all the
  information in the scene. We retains only pieces
  that have meaning for us.

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Capabilities of Human beings

• Gestalt Psychology (shape) We organize what we
  see into meaningful whole by using five
  principles
• 1. Proximity Group by distance or location.
• 2. Similarity Group by type.
• 3. Symmetry by meaning.
• 4. Continuity by flow of lines or alignment.
• 5. Closure We perceive shapes that are not
  complete.

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Proximity
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How can we apply the principle of proximity here?
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Look Location give you a better idea about you
menu
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Similarity
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How can we apply the principle of similarity here?
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Better. What else.?
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More similarity.. fonts
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Continuity
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Can apply the principle of continuity here?
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Continuity by alignment (horizontal)What else?
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Vertical alignment.
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Capabilities of Human beings

• Memory
• 1.- The Hierarchical Model

Sensor Memory
Short-term Memory
Long-term Memory
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Capabilities of Human beings

• Model of Memory
• 1.- Sensor Memory.- Buffer that store sensory
  input.
• 2.- Short-term memory.- Holds limited amount of
  data for a period of time ranging from 30 seconds
  to 2 minutes. As new info is coming the old one
  is forgotten. How much data can short-term memory
  can hold? The answer is given in the title of a
  landmark 1956 paper by psychologist George Miller
  The Magic number seven, plus or minus two
  (Miller 1956)
• 3.- Long-term memory a virtually unlimited
  memory.

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Capabilities of Human beings

• CHUNKING George Miller in his article discussed
  his number seven in seven terms of chunks. A
  chunk might be a digit, such a single digit in a
  phone number.
• EX. Consider www.betbooksbuys.com. This URL has
  20 characters in it. At the first time seem that
  Miller is stating that this URL is too big to fit
  in short-term memory. In actually, however,
  people group the characters into the following
  chunks
• 1.- www. 2.- best 3.- book 4.- buys 5.- .com
• As five chunks. The URL fits nicely into a
  short-term memory.

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Capabilities of Human beings

• Interruptions.- Two phenomena, focusing of
  attention and handling of interruptions, are
  closely linked to Memory.
• For web designers. Its important to give people
  clues or memory aids for resuming interrupted
  tasks.
• Also What else is an interruption let ask this
  questions. How fast does a system have to respond
  before the users attention becomes diverted from
  the task at hand?

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Capabilities of Human beings

• Let see this answer (Robert Miller 1968).
• Response Time User reaction
• less than 0.1 sec User perceives this is
  instantaneous
• Less than 1.0 sec User notices the delay, but
  has no break in thought stream
• Less than 10.0 sec user switches to another
  task.

When delay occurred you should give a feedback to
the user to wait. User need and acknowledgement
that a mouse click or other input has been
received
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Capabilities of Human beings
Questions?