1. Comp 15 - Usability and Human Factors
Unit 3b - Cognition and Human Performance
This material was developed by Columbia University, funded by the Department of Health and Human Services, Office of the National Coordinator for Health Information Technology under Award Number 1U24OC

2. Memory Short term sensory storage Working Memory Long Term Memory
Component 15/Unit 3b
Health IT Workforce Curriculum Version 2.0/Spring 2011

3. Memory Processes Encoding: process of putting things into memory
Storage: how information is maintained in memory
Retrieval: accessing information from memory
Encoding: process of putting things into memory
Storage: how information is maintained in memory
Retrieval: accessing information from memory
Component 15/Unit 3b
Health IT Workforce Curriculum Version 2.0/Spring 2011

4. Health IT Workforce Curriculum Version 2.0/Spring 2011
Working memory (WM)
WM is the short-term memory or temporary store that keeps information “active”
When processing in WM, we bring information from the sensory register and long-term memory (LTM) into WM
Information is encoded
WM has limitations
The limitations of WM have major implications for system design
Component 15/Unit 3b
Health IT Workforce Curriculum Version 2.0/Spring 2011

5. WM Capacity Constraints
The upper limit of capacity is 7 +/- 2 chunks of information
A “chunk” is the unit of WM space, defined jointly by the physical and cognitive properties that bind items within the chunk together
The upper limit of capacity is 7 +/- 2 chunks of information
A “chunk” is the unit of WM space, defined jointly by the physical and cognitive properties that bind items within the chunk together
Component 15/Unit 3b
Health IT Workforce Curriculum Version 2.0/Spring 2011

6. Long-term memory (LTM)
LTM provides a mechanism for storing information and retrieving it at a later time
Relatively permanent storage system
Highly organized knowledge structures
Different types of information
LTM provides a mechanism for storing information and retrieving it at a later time
Relatively permanent storage system
Highly organized knowledge structures
Different types of information
Component 15/Unit 3b
Health IT Workforce Curriculum Version 2.0/Spring 2011

7. Health IT Workforce Curriculum Version 2.0/Spring 2011
Carving Up Knowledge
Factual Knowledge
Risk factors for coronary artery disease
Declarative or Conceptual Knowledge
Deeper level of understanding
Part of a network of knowledge and beliefs
Procedural Knowledge
How to perform various actions
Decision rules in guidelines
Collaborative Knowledge (people and artifacts)
Individual and collective
Component 15/Unit 3b
Health IT Workforce Curriculum Version 2.0/Spring 2011

8. Cognitive Constructs for Mental Representation
Schema
Mental Images
Representation of perceiving some object, event, or scene
Propositions
Capture the meaning of linguistic and other symbolic forms
Mental models
Schema
Representation of perceiving some object, event, or scene
Mental Images
Capture the meaning of linguistic and other symbolic forms
Propositions
Mental models
Component 15/Unit 3b
Health IT Workforce Curriculum Version 2.0/Spring 2011

9. Schemata Represent a higher level kind of knowledge structure
Representing the generic concepts stored in memory (e.g., fruits, chairs, geometric shapes, and vertebrates)
Schemata for concepts underlying situations, events, sequences of actions and so forth
Models of the external world
Represent a higher level kind of knowledge structure
Representing the generic concepts stored in memory (e.g., fruits, chairs, geometric shapes, and vertebrates)
Schemata for concepts underlying situations, events, sequences of actions and so forth
Models of the external world
Component 15/Unit 3b
Health IT Workforce Curriculum Version 2.0/Spring 2011

10. Schemata (cont.)
To process information with the use of a schema is to determine which model best fits the incoming information
Features of schemata
Constants (all birds have wings)
Variables (chairs can have between 1 and 4 legs)
Active recognition devices aimed at evaluating how well they fit to the data being processed
Component 15/Unit 3b
Health IT Workforce Curriculum Version 2.0/Spring 2011

11. Health IT Workforce Curriculum Version 2.0/Spring 2011
Bird Schema
Type:
animal
Locomotion:
flies* (default value)
walks
swims
Communication:
sings*
squawks
Size:
small*
medium
large
Habitat:
trees*
lands
waters
Food:
insects*
seeds
fish
Colors:
Variable
Image of 2 types of birds.
Component 15/Unit 3b
Health IT Workforce Curriculum Version 2.0/Spring 2011

12. Scripts
Eating in a Restaurant, Attending a Lecture, The Visit to the Dentist’s Office
Knowledge structure captures general information about routine events
Customers, waiter, cook
Professor, GSIs, students
Dentist, assistant, patient, and the drill
Scripts have typical roles
Customers are hungry
Students are thirsty for knowledge
Patient needs 6 cavities filled, some root canal work and a bridge installed
Scripts have entry conditions
We can fill in or infer the scenes and actions that are not explicitly mentioned
Scripts elicit elaborated knowledge of an event type
Component 15/Unit 3b
Health IT Workforce Curriculum Version 2.0/Spring 2011