Attention and Memory Constraints

1
Attention and Memory Constraints
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Focus attention

• Focusing attention
• grouping
• creating a meaningful order
• using perceptual laws
• coloring

3
June 2 3 St. Louis, Mo NSA QualifierMotel
6 [phone] 41.95June 9 10 Springfield,
Mo ASA National QualifierRodeway Inn (417)
866-5255 49.00June 16 17 Springfield, Mo.
MCI TournamentFairfield Inn 219/738/2840
69.95June 23 24 Kokomo, IN NSA National
QualifierRamada Inn 317-459-8001 55.00June 30-
July 3 Kansas City Blue SpringsRamada Ltd.
816-229-6363 45July 7 8Geneseo, Il. Geneseo
Tournament Deck Plaza Motel [phone]
46.95July 14 15 Lafayette, IN Field of Dreams
ClassicDays Inn [phone] 4 9.00July
19-22 Moline, Il. State Tournament Hampton
Inn [phone] 57.00July 28 - 30 Moline,
Il. Regional Tournament LaQuinta (30)
762-900854.00July 31 - Aug. 4 W. PalmBeach,
FLNSA National TournamentHampton
407-471-8700 42.00
How much was the hotel at Kansas City?
4
How much was the hotel at Kokomo, In?
Date City Tournament Hotel Phone
Number Cost June 2 3 St. Louis, Mo NSA
Qualifier Motel 6 [phone] 41.95 June 9
10 Springfield, Mo ASA National Qualifier Rodeway
Inn [phone] 49.00 June 16
17 Springfield, Mo. MCI Tournament Fairfield
Inn 219/738/2840 69.95 June 23 24 Kokomo,
IN NSA National Qualifier Ramada
Inn 317-459-8001 55.00 June 30- July 3 Kansas
City Blue Springs Ramada Ltd. 816-229-6363 45.00
July 7 8 Geneseo, Il. Geneseo Tournament Deck
Plaza Motel [phone] 46.95 July 14
15 Lafayette, IN Field of Dreams Classic Days
Inn [phone] 49.00 July 19-22 Moline,
Il. State Tournament Hampton Inn (309)
762-1711 57.00 July 28 - 30 Moline, Il.
Regional Tournament LaQuinta (309)
762-9008 54.00 July 31 - Aug. 4 W. PalmBeach,
FL NSA Nat. Tournament Hampton
407-471-8700 42.00
5
Cognitive Aids

• Norman (1992)
• external representations that are intended to
  gain our attention at a time relevant to the task
  that needs to be performed.
• examples
• Systems should be designed to provide information
  systematically.

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Automatic processing

• fast
• demanding minimal attention
• unavailable to consciousness
• Examples
• Ctrl - C
• Ctrl - Z

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Stoop Effect (Automatic processing)Name the
colors of the items.
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Stoop effect (Gleitman, 1991)
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What are the implications of automatic processing
for interface design?

• automatic processes are not affected by the
  limited capacity of the brain and do not require
  attention
• controlled processes have limited capacity and
  require attention and conscious control.
• give examples

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What is this? What is its function?
10" x 24" twisted wire with a wooden handle
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What is the function of the antique?

• What processing step do you use to figure out the
  function?
• What are the affordances of this object?
• What are the constraints?

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Memory constraints

• Level of processing theory
• Extent to which new material can be remembered
  depends on it meaningfulness.
• more meaningful a piece of information, the
  deeper the level at which it is processed.
• Familiarity
• Imagery

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Icons

• are small pictorial images that are used to
  represent system objects.
• Why?
• people are instinctively drawn to pictures
• icons prove to be an ideal shorthand.

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Picture is worth a thousand words, but an icon
often isnt.

• research shows text and icon combination have
  best response times.
• reading is a slower cognitive process than visual
  recognition.
• icons are often harder to recognize than objects
  in our visual environment.
• icons can be learned.

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A good icon must do two things

• effect quick initial recognition of the image
• fast recall of the image.

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Successful icons.

• In usability studies of icons conducted at
  Microsoft, an icon was considered very successful
  when 80 percent of those tested recognized it.
• Show your icon to lots of people - test it!
• recognition?
• like it?

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Excess of detail and bright colors impede quick
recognition.
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• These small icons add meaning to the words in
  this dialog and help convey the function.

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• The large graphic in this wizard dialog from
  Window 95 helps convey the concept of connection
  across telephone lines.

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What is happening?
Animations have to be designed to focus on the
key aspect of the function.
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Color
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Two kinds of light receptors in the eye.

• Rods register light and dark or the relative
  brightness of objects.
• Cones perceive color. They respond to
• red light
• green light
• primarily to blue

Same number of red and green cones but fewer
blue cones.
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Color blindness

• True red-green color blindness is rare, affecting
  less than 1 percent of the human population.
• About 9 percent of males have some form of color
  deficiency or color confusion, color deficiencies
  in women are very rare.

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Color is Emotional

• Red excites the eye.
• Blue calms it.
• Be careful with color.
• The more colors that users can set for
  themselves, the happier they will be.

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Color Has Cultural Associations

• red - danger
• yellow - caution
• green - go, okay, money
• Purple - regal

• Black is mourning
• White is mourning (Japan)

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Based on the principle of

• color being a useful coding mechanism for
  grouping, use different colors to distinguish
  layers.
• color makes things stand out, use color to make
  features prominent.
• of figure/background, dark or dim backgrounds
  should be used, such as deep blue, and bright
  colors for the foreground.

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Color suggestions

• Color draws attention.
• Use color for grouping or relating things to each
  other.
• effective when there arent too many of them
• used repetitively
• associate with a common cultural use of color
• Use dark or dim colors for backgrounds, such as
  deep blue, and bright colors for the foreground

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Color cont.

• Blue is hard to focus
• Blue is hard to focus
• fewer cones in the human eye
• great background color
• does not work in small areas, thin fonts, or
  narrow lines.

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Color cont.

• Colors influence other colors.

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Color cont.

• colors that are very similar in both hue and
  value will also cause visual discomfort when seen
  next to each other (eye strain).

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Recommended colors for alarm and status words
active green alarm red clear white critical red d
isable red emergency red enable green failure red
major red minor yellow normal green off black on g
reen on-line green power red run green standby yel
low stop red