1. Human information processing: Chapters 4-9
Attentional resources
Receptors
Perception
Response selection
Response
execution
Decision making
Long-term memory
Working memory
Controlled
system

2. Cognition Object and pattern perception Working memory
Long-term memory
Attention and mental resources

3. Description of the elements of cognition
Role in information processing
Process/Theory
Design implications

4. Object and pattern perception: Feature analysis
Role: bottom up process of extracting information from sensory stimuli
Process:
Break stimulus into features that are mapped onto stored patterns
geons are the basic feature of 3-D objects
Unitization=transformation from feature analysis to more global processing

5. Object and pattern perception: Feature analysis
Design implications:
Feature compatibility: Preserve curve and diagonal lines in displaying text
Upper and lowercase: Upper case for letter features, lower case for words (unitization)
Gaps between letter or number strings enhance perception
Line drawings may be superior to photo renderings for shape perception

6. Object and pattern perception
Top-down and Bottom-up processing
Task, context, and design defines role of each
Design to enhance each (e.g., make visible, use redundancy)
Icons vs. Text
Legibility, discrimination, and interpretation
Pro: Universal, space efficient, effective
Con: No clear understanding of how to design “good” icons

7. Working memory Role: Keeps information active while in use Process:
Visuospatial sketchpad and phonological loop maintain two types of information
Limited by capacity (7±2 chunks)
USA, FBI, CIA (3 chunks not 9)
Constant rehearsal is needed to retain
Limited by time: half life=7 secs for 3 chunks, 70 seconds for 1 chunk

8. Working memory Design implications
Minimize working memory load (timeXchunks)
Use redundant sources (text+speech)
Exploit chunking
Size of item clusters OR ?
Use meaningful sequences
Letters rather than numbers (1-800-GET-HELP)
Separate numbers and letters
Minimize confusion
Use different memory codes
Order text/instructions carefully

9. Long-term memory
Role: Keeps event information and knowledge available for recall over long periods of time
Process:
Item strength (frequency, recency)
Number of associations (associations between items form chunks, which are available for easy recall)
Networks of associations (schemas, mental models)
Forgetting (weak strength, few associations, interfering associations)
Procedural/implicit vs declarative

10. Long-term memory
“We paint the remote past, as it were, upon a canvas in our memory, yet often imagine that we have direct vision of its depths” (W. James) ??
Multiple people - same event
Iowa vs. Michigan (1991)
Motor Vehicle Accidents
Tragedies
Regan being shot
Shuttle Challenger
Sept. 11th

11. Long-term memory Design implications
Encourage regular use (frequency, recency)
Standardize (frequency, recency)
Memory aids (supplement LTM)
Carefully designed information (limit LTM dependence, support associations)
Develop correct mental models (Information processing model for designers, Rankine cycle for NPP controllers)

12. Attention and mental resources
Role: Attention is required to support most cognitive activities (not LTM or sensory registers)
Process:
Selective, Focussed, and Divided attention (e.g., cocktail party phenomenon, search light)
Automatic and controlled processing (e.g.,manual transmission and learning to drive)

13. Attention and mental resources
Process: Multiple Resources
Modality (auditory vs. visual, verbal vs. motor)
Code (spatial vs. verbal)
Stages (perceptual/cognitive vs response)

14. Modes, codes, and stages in cognitive processing

15. Attention and mental resources
Design implications
Design to engage different attentional resources
(e.g, voice dial rather manual on car phone)
Facilitate timesharing by making tasks automatic
(e.g., consistent mapping such as red for stop in driving)
Provide information regarding importance to guide people in allocating resources to tasks
(e.g., design tone urgency to match message urgency)

17. Key concepts
Cognition can be divided into processes each of which has implications for design
Effective perception depends on bottom-up and top-down processing
Working memory is limited and volatile
Chucking makes working memory effective
Long-term memory depends on associations and schema
Attention is composed of multiple resources