Final Exam Flashcards
(109 cards)
1
Q
What are the types of long term memory? (please provide definitions)
A
(1) Episodic: represents our memory of events and experiences in serial form like a diary (example: you went to the store yesterday)
(2) semantic: represents more general concepts, possibly generalized from episodes (example: the concept of “a server” rather than yesterday’s server)
2
Q
What is a schema?
A
Mixed form representation of the two types of long term memory (episodic and schematic). Describes sequences that occur in everyday events
3
Q
What are the three levels of control (for memory)? don’t provide defs.
A
(1) Skill-based daughter schema
(2) Rule-based mother schema
(3) Knowledge-Based situations
4
Q
What is a skill-based situation? (the first level of memory control)
A
(daughter schema)
routine tasks, preprogrammed scripts that can be triggered, no execution feedback required
5
Q
What is a rule-based situation? (the second level of memory control)
A
(mother-schema)
general rules to be applied in different situations, task consist of repetitive skills, activated after rule selection, stimuli are used in determining rule to trigger
6
Q
What are knowledge based situations? (the third level of memory control)
A
no fixed rule set, use abstract knowledge to solve problems, choose between alternative solutions and their consequences
7
Q
What is the swiss cheese model?
A
It’s a model of of accident causation. Each cheese slice represents a defensive layer of a system.
Each layer has holes - they open/ close continuously.
8
Q
Consider the crash of the boat looked at in class? What type of mistake/ slip is the following cause?
Bow doors were open
- relatively normal procedure, no problems at low speed
- negative working system, no news is good news
- no working light on bridge or (sleeping) attendance reports
A
Rule-based mistake
9
Q
Consider the crash of the boat looked at in class? What type of mistake/ slip is the following cause?
Sleeping attendance
- shift work
- attendance did not get meal on time because ferry was late
- high peaks, long stretches of inactivity
- no daylight in cargo bay, so no synching of biological clock
A
Skill-based slip
10
Q
Consider the crash of the boat looked at in class? What type of mistake/ slip is the following cause?
No warning light on bridge
- ship was designed for more personnel
- management did not investigate before lay-offs
A
knowledge mistake
11
Q
Consider the crash of the boat looked at in class? What type of mistake/ slip is the following cause?
Not enough personnel
- ship was designed for shorter route, with shorter hours
- ship was therefore designed for lower personnel cost
A
knowledge mistake
12
Q
Consider the crash of the boat looked at in class? What type of mistake/ slip is the following cause?
ship was not designed for route
- doors were too low
- pumps were too small
A
rule-based mistake
13
Q
According to Wagenaar, per disaster there are how many human errors?
A
3 to 4
14
Q
How do you prevent skill-based slips?
A
- introduce conscious checkpoints in design
- consistent design
15
Q
How do you prevent rule-based mistakes?
A
(more difficult)
- automated signalling of procedure selection error (aircrafts)
(signal automatically when an error occurs during a procedure)
16
Q
How do you prevent knowledge-based mistakes?
A
- bounded rationality principle: people choose simplest solution
- containment so that errors do not become disasters
Bounded rationality is the idea that in decision-making, rationality of individuals is limited by the information they have, the cognitive limitations of their minds, and the finite amount of time they have to make a decisions
17
Q
What does task analysis give you?
A
- an early focus on the user
- early identification of problems and real-world analysis
- more accurate idea of the user’s goals
- better fit of new system into current system
- early information about training and documentation
18
Q
What is the fountain model used in task analysis?
A
1) analysts (user current task world knowledge)
2) design (redesign task model, user interface & system func, protoyping & implementation)
3) evaluation (after each step, redo pary of analysis or design as necessary)
19
Q
What is the Hierarchical Task Analysis?
A
A procedural decomposition using a tree to describe the task world of the user.
20
Q
What are the components of task modelling?
A
Goal (external task): state of system desired by user
Task (internal task): activities needed to reach goal
- unit task (lowers verbalized task)
- basic task (highest task construct executable by system command)
Action: task that does not require knowledge or rule based control
21
Q
A general task model typically has -?- levels?
What does a four level model typically look like?
A
3-5
abstract level
expert level
highest common level
lowerst common levlel
22
Q
When to stop a task models?
A
In complex systems, the unit task can be a good place to stop
in simple general applicance design, detail motor actions
23
Q
Obtaining a task model depends on the type of user knowledge. What are the two main categories of methods to collect user data?
A
- Knowledge acquisition: you ask the user
2. ethnographical studies: you become the user
24
Q
What is
The process involved in knowing, or the act of knowing. Includes perception and judgment. Includes every mental process that can be described as an experience of knowing as distinguished from an experience of feeling or of willing. Includes, all processes of consciousness by which knowledge is built up, including perceiving, recognizing, conceiving and reasoning”
A
human cognition
25
What is perception?
vision
26
What are the two types of visual representation?
1. Stimulus-driven perception (recognition of visual properties, no labels required)
2. Cognition-driven perception (recognition of concepts, knowledge influences perception, meaningful labels and groupings)
27
What provides colour vision in the eye ?
Cones
28
What are rods and cones?
provide visual acuite and colour vision to the eye.
Rods (sensitive to dim and achromatic light (night)
Cones (respond to brighter, chromatic light (day))
29
Eye movements resposition the -?-
fovea
30
What are the five main classes of eye movements?
1. smooth pursuit (smooth tracking movements)
2. Convergence/ divergence (focus movements)
3. Nystagmus ("sawtooth" movements while tracking
4. Saccadic (fast, ballistic jumps)
5. Fixations (almost no movement)
31
What are the Gestalt principles and laws? (6)
- Law of Closure (incomplete figures are perceived as complete or whole)
- Low of Proximity (objects near in space are perceived as belonging together)
- Law of similarity (objects with similar attributes are perceived as belonging together)
- Law of continuity (objects aligned along a line or curve are perceived as belonging together)
- Law of symmetry (perceive symmetrical objects as figures over ground, and symmetric around central axis)
- Law of common Fate (Objects moving together perceived as belonging together)
32
What is Weber's Law?
The size of the just noticeable difference (Delta I) is a constant proportion.
Just noticeable difference/ size = constant.
TO make differences noticeable should be at least 16% different
(Webers constant is 0.16)
- can be used for various sensory modalities in GUIs (brightness, loudness, line length, font weight etc.)
- governs some thresholds of noticeable different (line thickness,colour shades)
33
What is Weber-Fechner's law?
Webers law broken into two parts:
- Two stimuli will be discriminable if they generate a visual response that exceeds some threshold
- The visual response R to an intensity I is given by the equation R = log(I)
34
What laws revealed the relationship between the absolute stimuli increase and the perceived increment?
Fechner's - Weber's Law
35
What is the power law of practice?
The time RT to perform a task on the Nth trial follows a power law
- people get better with practice, but will asymptote at a certain performance level
(you are an expert once you can only improve by < 10%)
36
What are the 3 quantifiable laws of HCI?
1. Power Law of Practice
2. Hicks Law
3. Fitts' Law
37
What is Hicks Law?
Decision time T increases with uncertainty about a judgement (yes/no decision)
38
How does Hicks law explain the following two physical properties of a surface that increase the probability of being hit?:
1. distance from the hand to the surface (when distance larger, probability lower)
2. Size of the surface (surface larger, prob larger)
Hicks law explains this:
- The further away/ small the surface, the more decisions made
- the faster the feedback loop, the smaller time per decision
39
What is Fitts' Law?
Movement time MT to a surface is a linear function of the index of difficulty (ID).
Further from the surface the more difficult it is to hit and therefore longer it will take to hit it. If you want the amount of time moving to be the same from a further distance you need to make the size of the surface larger. ---> For you Tanel
40
Fitts' Law and Hick's Lae are both -?- laws.
What is the key takeaway?
What can the law be used to evaluate
information
Larger surfances require larger distance to obtain the same movement time.
Can be used to evaluate:
- efficiency of input devices
- design of display objects
41
What are the three levels of processing for word recognition?
1. Feature level (line elements within letters)
2. Letters level (letter elemenets)
3. Word Level (word elements)
42
What is the interactive Activation Model for Reading?
| McClelland & Rumelhart
```
Each element (line, letter, and word) has a counter also known as an activation level. Tracks evidence for matching that element. Counters provide evidence (or a lack of it) to other counters)
Diagram***
```
43
What is Miller's Magic Number?
7 (because we can only code 7 (+/- 2) chunks of information in short-term memory
44
Why can you have more menu items if you group items together meaningfully? (short term memory)
Chunks are meaningful seperations
45
How do we solve short-term memory bottleneck?
- simple designs
| - good chunking
46
What is the information processing model?
Pipeline model - (atkinson & shiffrin)
| models characterized by sequential nature
47
What is the human processor model?
The human processor model uses the sum of the following principles to calculate overall response time:
- perceptual processor cycle time
- cognitive processor cycle time
- movement processor cycle time
RT = Tp + Tc + Tm
48
What are the usability principles?
Learnability: time and effort it takes to reach a certain level of task performance (interactive systems should be easy to learn)
Ease of use: Interactive systems should be effective in allowing user to reach goal. Interactive systems should allow the user to do this in an efficient manner
Flexibility: Interactive systems should be adaptable to circumstances
Satisfaction: Interactive systems should lead to user satisfaction
49
What ensures a system is flexible?
- dialog initiative
- parallelism
- task migratability
- substitutivity
- customizability
- measuring flexibility
50
How do you ensure user satisfaction?
- emotional value
- aesthetics
- environmental factors
51
What is the user centred design process?
1) Analysis
- create and evaluate user models with users
- identify user/ technology/ budget constraints
2) Design
- set usability/ technology/ budget design goals where possible
- create design models
- evaluate design models in real contexts with real users
- build prototypes with limited backend functionality
3) Evaluation
- test prototype and real users along design goals
- iterate at every step
52
What are the three different models users & designers communication through?
Designer's model: a conceptual model of the system
User's model: mental model developed through interaction with the system
(should be same as designer's model but usually isn't)
Design Model: all things that make up knowledge of the design
53
What should be used to create good design models?
should match user mental model
- use affordances
- use metaphors
- use spatial mappings
- use direct manipulation
54
What is the problem with user mental models?
How user actually understands user interface often incorrect or incomplete
55
What do task models and performance models model?
Task models model knowledge and rules
Performance models model skills: action schemas
56
What are GOMS?
Task performance models
- typically used to describe the user's new task design
Goals + Operators + Methods + Selection
- Goals: describe the highest task level
- Methods: provide different ways of dividing goals into sub-goals
- Selections: rules on when to select which sub-goal method
- Operators: low-level actions that require no rule-based control
57
What are the different ways to quantify task models?
Mental Effort
Learning time
Consistency
Performance
58
What are detailed versions of GOMS used for? and what are they called?
Used to predict low-level task performance in early evaluations
These more detailed models are known as Keystroke Level Modelling (KLM)
59
KLM shows the time to perform a task is -?- and time to execute is equal to:
linear
= time for keystrokes + pointing + homing + drawing + mental + system response time
60
What are the different types of visual design models?
Sketches
Story boards
Early prototypes
61
What are storyboards? used for?
- visual scenarios
- provide platform for early evaluation by providing concrete examples of possible solutions
- typically contain number of images depicting your interaction syles in action
62
Scenarios and storyboards provide one linear path through the system. What are the pros and cons of this?
Pros:
- life and time are linear
- easy to understand
- concrete
Cons:
- no choice
- miss the unintended
63
How does Fitt's law model pointing tasks
Fitt's Law states that larger targets require larger distance to obtain the same movement time
This law can be used to evaluate the efficiency of input devices
64
What is the theorem of information capacity?
tells the maximum rate at which information can be transmitted over a communications channel of a specified bandwidth in the presence of noise
C = B log2(1+ S/N)
```
C = Channel capacity in bits/ s
B = bandwidth of the channel
S/N = signal-to-noise ratio
```
65
What did the keyboard layout study show? (regarding Fitt's law)
- mouse fastest on all counts and has lowest error rates
- variations in positioning time with the mouse and joystick are accounted for by Fitt's law
- -- mouse: measured Fitts's Law slope constant is close to that found in other eye-hand tasks leading to the conlcusion that positioning time with this device is almost the minimal achievable
- -- positioning time for the key devices is shown to be proportional to the number of keystrokes which must be typed
66
Comparing input devices with Fitts' Law. Measures for IP, or bandwidth, can motivate performance comparisons across...?
Device
Limb
Task
67
What are issues with speech input?
1. Efficiency of speech input correction is low
2. while speech may seem intuitive, users need to know the lexicon
3. there is no good solution for deixis
other issues:
4. privacy issues
5. limited world knowledge
68
What are the different types of input for VR?
- Speech
- Gestural (datagloves, optical, skeletal,..)
- Isotonic (magnetic trackers, depth capera,...)
- Rotational (inertia measurement unit, eyetraker, depth camera....)
- Isometric (springlike joysticks, spaceball...)
69
What are Bertin's visual design variables?
```
Position
Size
Shape
Value
Orientation
Colour
Testure
Motion
```
70
What are Bertin's visual variables characteristics?
Distinctive (change in variable enough to select from group?)
Associative (change in variable enough to perceive as a group?)
Quantitative (numerical reading obtainable from changes in this variable?)
Ordinal (changes in this variable perceived as ranked?)
Resolution (think of as variation - how many changes in this variable are perceivable?)
71
What are the colour attributes?
Hue: the wavelength of the light reflected or emitted by the surface (colour changes)
Luminance (lightness): the total amount of light reflected or emitted by the surface in comparison to a white surface under the same illumination (shade of colour changes)
Saturation (Chroma): The intensity of the spectral colour in relation to total energy (goes from dim purple to harsh red)
72
What are the mathematics of layout?
```
Make the ration of every element the same
Magic number (φ) = 1.618
(a + b)/a = a+b (When a = 1 and b = 0.618)
```
73
What is the Golden Ratio?
φ-based layout (found in nature and in famous paintings/ architectures)
- ratio of every element the same
74
What fond should be used for body text? (serif vs sans-serif)
Serif
75
What are things to consider regarding font?
Size and Weight
Colour
Positioning
Spacing (should have a ratio of ~ 1.6)
76
What are properties of good typography?
Legibility: how easily individual characters can be distinguished from one another
Readability: how easy it is to read the text as a whole, as opposed to the individual character recognition described by legibility
Saccadic Rhythm: ability to recognize meaning of approximately three words at once
No eye strain: the eye tires if the line required more than 3 or 4 saccadic jumps
77
Basic (big) data visualization
| What is a representation?
a formal system or mapping by which the information can be specified
ex: 34
decimal: 34
binary: 100010
roman: XXXIV
78
What is a good representation?
Allow people to find relevant information (easy to find)
| Allow people to compute desired conclusion (computations may be difficult of "for free" depending on representations)
79
What are the following?
1. show the data
2. not get in the way of the message
3. avoid distortion
4. present many numbers in a small space
5. make large data sets coherent
6. encourage comparison between data
7. supply both a broad overview and fine detail
8. serve a clear purpose
Tufte's principles for information visualization
80
What is chart junk?
content-free decoration -> should be avoided
81
What is rapid prototyping? and what does it allow you to do?
- Creates limited versions of a working system that can be tested with real users
- facilitates iterative design and formative evaluation
- allows you to think about usability problems hands-on
- allows you to simulate or quickly implement alternative user interface designs
- allows you to gather early user feedback
82
What are the rapid prototyping dimensions?
1. representation
2. scope (mock-up of the interface or does it include some computational component?)
3. Executability (can it be "run"?)
4. Maturity (stage of the product as it is developed?)
83
What are the types of rapid prototypes?
Low-Fidelity Prototypes: sketchy design models for early evaluation
Mid/High-Fidelity Prototypes: provide a look and feel of part of an application, more mature version of the design models, can be more thoroughly evaluated in real user tests
84
What are Lo-Fi Prototype advantages and disadvantages?
Advantages:
- fast/ cheap to implement/ throw away
- can be used early in design process
- can be based directly on your visual design models
- highlight inconsistencies in the design of the interface
- highlight areas under specified
- illustrate complexity of interface
- users can evaluate many representations
Disadvantages:
- visual prototypes may in fact limit creativity and thus limit interface design
- don't allow representation of the entire interface
- even complex representations may provide a limited understanding of the interface
- difficult as programming
- limited tools for evaluation
85
The lifetime of a prototype can be broadly categorized as -?- and -?-
evolutionary
| throw-away
86
What is an evolutionary prototype?
an initial version of a system that can be refined into production-quality software
87
What are Hi-Fi prototype advantages and disadvantages?
adv:
- easier to study
- data collected from user studies more likely trustworthy
- often supports the early design of user help system and tutorials
Dis:
- can take a signif amount of time to set up and learn
- be expensive to purchase
- limit interface design to known conventions
- compile very slow code
- throw-away tools can't always be used for implementation
- usually take longer to create and modify
88
What are the goals of evaluation?
1. Effectiveness. Does the system have the right functionality?
2. Learnability. How easy is it to learn that functionality?
3. Efficiency. How fast would the current design be?
4. Satisfaction. Do you users like the design?
5. Error. How many and what are the causes?
89
What are the evaluation heuristics: ten core principles?
1. Visibility of system status: sys should always keep users informed about what is going on through appropriate feedback within reasonable time
2. Match between system and the real world: should speak the users' language, with words, phrases and concepts familiar to the user
3. User control and freedom: support undo and redo
4. Consistency and standards: follow platform conventions
5. Error prevention: prevents problems
6. recognition rather than recall: make objects, actions, and options visible
7. Flexibility and efficiency of use: allow users to tailor frequent actions
8. Aesthetic and minimalist design
9. Help users recognize, diagnose, and recover from errors: error messages should be expressed in plain language
10. help and documentation
90
What is the protocol analysis?
in any observational method, much depends on the recording technique
There are a number of techniques to record user actions:
- paper and pencil
- audio recording
- video recording
- computer logging
- user logs
91
Questionnaire design
what are the four steps
1. Define what you want to measure
2. Write questions and design the questionnaire
3. Administer the questionnaire
4. Analyze the data
92
What can questionnaires be used to measure and not measure?
measure:
- user satisfaction
- prior knowledge about the domain
- mental load after task execution
- subjective performance rating
- personality traits
- cognitive abilities
not measure:
- what command names to use
- how to organize items in a menu
- which colours enhance visibility
- how a user learns a command
- where the user will make errors
93
What are the types of response errors?
1. Motivated Errors (respondent tries to keep interviewer from discovering something)
2. Memory Errors (respondents can't remember how or when something happened)
3. Communication errors (questionnaire/ interviewer does not make it clear what is being asked OR respondent does not make the answer clear)
4. Response Set (respondent simply always fills out the right/ most agreeble answer)
94
What are observational and qualitative studies?
- system is studied in user's work context
- main advantage is that you observe interactions you would have missed in a clinical lab environment
- main disadvantage is that measurements can be difficult to obtain because of noise, interruption etc.
95
What are Empirical studies? (usability tests)
- system is studied in a controlled environment
- the main advantage is that you can strictly control the situation to carefully measure effects
- the main disadvantage is that you loose some of the real-world richness in your data
96
What is an experimental method?
one of the most powerful methods of evaluating a design or aspect of design
it provides scientific empirical evidence to support a particular claim or hypothesis such that you can generalize it
97
What are the basic experimental procedure?
1. Evaluator chooses a hypothesis to test, stated in terms of a cause and an observable effect
2. hypothesis is tested by measuring some attribute of subject behaviour
3. behaviour is measured in conditions that differ only in the values of some controlled variable
4. any changes in behavioural measures is attributed to the difference in the controlled variable
5. a statistical test is conducted to the observed cause-effect relationship was not due to chance
6. the hypothesis is accepted or rejected
98
What are the two basic types of variables in experiments?
1. Independent Variables (Factors)
- - these are the causes that you control in order to create an effect on measured behaviour
- - Levels of the independent variable produce different conditions for comparison of effects
```
Dependent Variables (Measurements)
-- these are the variables that measure the effect on behaviour
```
99
What are the two main methods you can use to organize the application of your factors on subjects: (experimental design)
1. Within-subjects design
- -> Number of subjects required equals number of subjects per condition (usually 15 per condition, typ 30)
- only the difference in performance of subjects between conditions are measured
2. Between-subjects design
- --> each subject experiences only one level of the factor (number of subjects required equals number of conditions times number of subjects per condition, groups need to perform equal on secondary variables)
- differ in their approach to the control of confounding secondary variables
100
What are the pros and cons of the within-subjects type of experiment design?
- cheap (minimal subjects)
- personal variables such as IQ are no problem (they have the same influence on every condition)
- situational variables are no problem (the conditions succeed rapidly)
- positional variables are a problem
101
What are Between Subjects experiment design pros and cons?
- Expensive (many subjects are required)
- Personal variables such as IQ are a problem
- situational variables are a problem
- positional variables aren't a problem
102
What are the five things on the evaluation checklist?
1. Design process stage
2. Evaluation style: lab or field?
3. Objective vs subjective
4. quantitative vs qualitative
5. resources
103
What are the types of VR Experiences?
Immersive spaces
- 2D 360 panorama/movie
- high visual quality
- limited interactivity
Immersive Experiences
- 3D graphics (lower visual quality)
- high interactivity (movement in space, interact with objects)
104
VR vs 2D GUI
For most tasks a 2D GUI is the better choise (more efficient and effective - 2D navigation is faster)
- 3D not good for things like email, calender info
105
What is VAC?
Vergence Accommodation Conflict: occurs when your brain receives mismatching cues between the distance of a virtual 3D object and the focusing distance required for the eyes to focus on that object
106
What is a community of practice?
A. group responsible for setting policies and procedures
B. a team responsible for task analysis
C. a group of people with different roles and experiences working together
C. a group of people with different roles and experiences working together
107
Haptic feedback uses the sense of touch. True or False?
true
108
WHich is not a visual variable in design?
A. size
B. Orientaion
C. Angle
D. Colour
C. angle
109
True/ False
| Evolutionary prototyping tools offer non-standard forms of user input and avoid compilation
False
| It's going to be a produce therefore you need production level code
