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ISE 670- Cognitive Engineering
Midterm 1
58
Engineering
Undergraduate 4
02/20/2011

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Cards

Term
What is the goal of cognitive systems engineering?
Definition
To influence how people react to your particular design
Term
Visibility
Definition
The correct parts must be visible and they must convey the right message; indicates crucial directions; example- hinges on a door
Term
Mappings
Definition
What you want to do, and what appears possible; natural relationships = good mappings; example- car controls
Term
Affordances
Definition
The perceived and actual properties of the thing, primarily those fundamental properties that determine how that thing could be used; example- a chair affords sitting
Term
Conceptual models
Definition
used to form "mental simulations of devices" to simulate their operations; good ones allow us to predict the effect of our actions
Term
Feedback
Definition
Sending back to the user information about what action has actually been done; example- sound can tell us when things are/ aren't working properly
Term
Gulf of execution
Definition
The difference between intentions and allowable actions. Does the system provide actions that correspond to the intentions of the user?
Term
Gulf of evaluation
Definition
Reflects the amount of effort the person must exert to interpret the physical state of the system and determine how well expectations have been met.  Does the system do what you expected it to do?
Term
Cognitive affordances
Definition
suggests/indicates/gives clues to its use
Term
Selective attention
Definition
How narrowly people typically focus their attention
Term
Hicks- Hyman Law
Definition
suggests humans process information at a constant rate; reaction time is linear to the log of decisions to be made
Term
Stimulus-response compatibility
Definition
expected relationship between the location of a control or movement of a control response and location or movement of the stmulus display to which the control is related
Term
Speed-accuracy tradeoff
Definition
if we try to execute actions very rapidly, we are more likely to make errors; also, if we must be cautious because of error consequences, we will work slow--> these are negative correlations caused by user strategies
Term
Fitt's Law
Definition
calculation of movement time based on how far/ how difficult the movement (based on amplitude of movement and precision of target required)
Term
Proprioceptive feedback
Definition
aka tactile feedback; sensationsof touch, feel, pressure, and resistance that provide feedback
Term
Knowledge in the world
Definition
information people externally reference that triggers knowledge in the head--> it is retrievable whenever it is visible or audible--> visual cue
Term
Knowledge in the head
Definition
information stored in your brain that often requires the trigger of an external source; not readily retrievable, requires memory search, reminding, or learning
Term
Power of constraints
Definition
external constraints reduce the amount of information that must be learned to a reasonable quantity; example- constraints of rhyme and meaning reduce information necessary to remember a word in a long poem
Term
natural mappings
Definition
help reduce the need for information in memory by having things arranged/ organized in a sensical manner; example- placement of controls for burners on a stove
Term
Perception principle 1- What factors contribute to legibility?
Definition
Size (visual angle), font (style), contrast (i.e. color contrast), spacing, relative location, luminance
Term
Cognitive narrowing
Definition
fixating on the solution before you fully understand the problem
Term
Gestalt laws
Definition

the way in which the mind groups things that are relatively close together

 

example-how many objects below? 4 or 16?

 

xx   xx

xx   xx

 

xx   xx

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Term
Waterfall method of design
Definition
Start w/ requirements document--> passed off to designer--> passed off to software architects...etc (only first group meets w/ user so last group is constrained by decisions already made)
Term
representative tasks
Definition
tasks that users have actually described to designers; should be detailed, real tasks users have faced; described in words
Term
Task-oriented design (as opposed to waterfall)
Definition
Using task-analysis to design in each phase- understand what the user is trying to do with several iterations
Term
Usability objectives
Definition
specific numbers that quantify usability; targets for motivation to beat competition or meet functional needs of tasks
Term
participatory design
Definition
designing WITH rather than designing FOR; designers and users working in collaboration; goal should be to improve somebody else's work, not make $
Term
Requirements analysis
Definition
Defining what user needs to do, not how it will be done
Term
What are the 6 elements of conceptual analysis?
Definition
user analysis, development of use cases, identification of objectives and constraints, study of competitors, business plan, functional requirements document
Term
What are the 3 elements of a use case?
Definition

Persona- personal characteristics/ background

Goal/Task- what do you want to accomplish?

Context- Where are they?  What resources do they have?

Term
What are some examples of objectives and constraints?
Definition
Speed, accuracy, training time, market appeal, cost, development time and expertise, standards and regulations, software and hardware requirements
Term
Physical power of constraints
Definition

constrain possible operations

example- large peg cannot fit into small hole

Term
Semantic power of constraints
Definition
constraint relying on the meaning of a situation; example- windshield goes in front of a riders face, so we know which way to face
Term
Cultural constraint
Definition
constraint relying on cultural conventions; example- red, white and blue lights = police car; cultures have different conventions which make humans uncomfortable
Term
Logical constraint
Definition
relationships between spatial and functional layouts- example- 2 switches (left controls left light and right controls light on the right)
Term
Negative space
Definition
gives eyes a resting point; separates content and calls attention to content; without it, the user becomes overwhelmed and confused
Term
Measure with your eyes
Definition
optical illusions account for 90% of visual logic of composition; things are what they look like--> circles look smaller than squares; design is visual
Term
Figure-ground relationships
Definition
people's minds automatically perceive certain objects as foreground and others as background; example- when looking out at the class, teacher's mind parses people's faces as foreground, walls as background
Term
mental model vs. conceptual model
Definition

mental model- user's understanding

conceptual model- designer's understanding

Term
human error- slips vs. mistakes
Definition

slip- goal is right, execution is wrong (example- typed the letter o instead of number 0)

mistake- do not haveright goal in mind/ do not know the goal

Term
Yerkes- Dodson Law
Definition
Design influences workload- too little or too much stimulation in a design is not effective.  Performance is shaped like an upside-down U when graphed vs. level of arousal
Term
stimulus-response capability
Definition
based on natural mappings; example- buttons should be placed close to things they are related to; fun fact- vibration causes quickest human response if hands are already on buttons
Term
Population stereotype
Definition
People have preconceived knowledge they rely on being consistent; example- color coding- red = bad and green = good
Term
salience
Definition
how strongly something jumps out (size, constrast, flashing, etc..); it is challenging to make designs salient for many types of users
Term
loss of skill
Definition
design with the mentality "people need to use it or they will lose it"- balancing automation with human control
Term
risk compensation
Definition
you might think you have designed a safety system, but people will compensate/ adapt to make the situation worse; example- anti-skid brakes, people follow the car in front of them closer now
Term
Swiss cheese model
Definition
People design on a number of levels (latent and active) in order to prevent accidents from happening; each of these levels may have holes in them that could allow the accident to happen, but the goal is to minimize/ eliminate the holes to decrease the probability of a hazard
Term
rapid prototyping
Definition
allows you to get a sense of what the design "feels" like; HAZARD- tendency towards cognitive narrowing- need to understand the problem before designing solutions
Term
cognitive task analysis
Definition
characterize what is happening in someone's mind- 3 types- descriptive, normative, and predictive
Term
descriptive task analysis
Definition
description of what people are doing in current environment
Term
normative task analysis
Definition
what should people do in a given environment
Term
Predictive task analysis
Definition
What will people really do? Different alternatives to accomplish 1 task.
Term
Heuristic analysis
Definition
constructive way to analytically/ judgementally determine if a system is working properly
Term
Design for adaptation and evolution
Definition
people are bound to do things you did not intend; design with safety hazards in mind; try to reduce design- induced errors; example- lawn mower blade guard
Term
Design from the outside in
Definition
Answer the question- what experience should the user have when they try to do a certain task?
Term
Ego-driven design
Definition
want people to be excited about designing, but do not want to design to the point where designer is designing for himself as opposed to the customer; NEED to design for user usability, not personal satisfaction!
Term
5 perceptual principles of display design
Definition

1. Make displays legible

2. Avoid absolute judgement limits (judgement based on a SINGLE sensory variable)

3. Top down processing- what people expect to see

4. Redundancy Gain- alternative physical forms like voice, print, and pictures to convey single message

5. Discriminability- avoid unnecessary features

Term
4 Principles of effective labels
Definition

1. visibility/ legibility

2. discriminability

3. meaningfulness

4. location

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