Quizlet Flashcards
Model Human Processor
Framework for understanding human information processing. Human analog of a microprocessor. Models sensory processing + cognition + motor processing and their interctions.
Gestalt Theory
Argues organization is a fundamental building block of perception. Law of Proximity, Law of Similarity, Law of Closure, Law of Figure/Ground, Law of Continuity
Encoding Specificity
Memory better when context available at encoding is also available at retrieval
Semantic Memory
Long Term Memory about facts, concepts, and skills
Episodic Memory
Long Term Memory; orders events and experiences in time
Spread of Activation
Current thought activates a pattern (or concept) which activates associated concepts
Discrimination Principle
Recall is determined by candidates that exist in LTM relative to cues. Too many candidates: false memory, too few cues: cannot recall
Uncertainty Principle
Decision time increases with level of uncertainty
Variable Rate Principle
Cycle time is shorter for increased task demands
Gulf of Execution
Difference between user’s perceived execution actions and required actions
Gulf of Evaluation
Difficulty of assessing the state of the system and how well the artifact supports the discovery and interpretation of that state
Conceptual Model
Mental representation of how an object works and why it works that way. Approximate, incomplete, and evolving.
Affordance
Exhibits the possibility of some action. Perceived and actual properties that determine just how the thing could possibly be used
Natural Mapping
Proper and natural/spatial arrangements for the relation between controls and their movements to the outcome from such action into the world
Feedback
Conveying what action has been done and what the result was. Visible, Obvious, Immediate, Persistent
Types of Errors
Slips - errors in skilled, routine behavior. Mistakes - errors in intention
Designing for Error
Enable “undo” or place obstacles. Design useful error messages. Place Physical Constraints, Semantic Constraints, Cultural Constraints, Logical Constraints
Metaphors
Facilitate transfer of mental models. Borrow vocabulary and actions from physical world to describe abstract concepts
Seven Stages of Action
Forming the goal, forming the intention, specifying an action, executing the action, perceiving the state of the world, interpreting the state of the world, evaluating the outcome
Stakeholders
People affected by your software, not necessarily users. People who get the facebook notification from Nike running app
Profile
Represents one user
Persona
Represents a prototypical user. Benefits: Persistent reminder that you are designing for someone, aids design discussions, provides context for task scenarios
Task
Tells a complete story of an action that a specific user performs. Independent of interface detail. Characteristics: Frequency, difficulty, time to complete, criticality
Contextual Inquiry
Apprentice/Master model, contextual interview. Aspire to see their world as they do. Understand what was done and why. Look for tasks, artifacts, workflow, communications constraints Advantage: Learn tacit data, constraints, and build rapport.
Interviews
Purpose: learn about attitudes, motivations, desires, case examples. Ask questions that can be answered from their own experience.
Work Models
Graphical way of representing the result of Contextual Inquiry. Generated during group interpretation session after data collection.
Affinity Diagram
Work Model. Cluster similar ideas together, e.g. post-it notes.
Sequence Model
Work Model. Step by step work grouped by intent.
Flow Model
Work Model. Focus on how people communicate and inflows and outflows of documentation.
Artifact Model
Work Model. Sketch their physical artifacts, e.g. how a scheduler is used.
Physical Model
Work Model. Documents physical environment where work happens. Includes organization, grouping, and movement.
Purpose of Prototyping
Explore alternatives, test with users, get feedback, anchor communication, show commitment. The best prototype is one that in the simplest and most efficient way makes the possibilities and limitations of a design idea visible and measurable. Inexpensive, disposable, fosters creative thinking
Developing a Prototype
Use iterative design. Problems: local maximum, when to stop.
Why Evaluate a Prototype
Identify big issues. Only effective if you want to improve the design.
User Walkthrough
Evaluation Technique. Evaluate how well users can perform tasks with your paper prototype. Need user, task descriptions, and prototype with functionality.
Wizard of Oz
Lo-fi prototype. Must require less effort than real thing. Enables fast iterations, more real than paper, designers learn by controlling prototype in background. However may distort technology and some features cannot easily be simulated.
Paper Prototype
Lo-fi prototype. Easy to throw out. Invites higher level feedback. Disposable, plentiful, emphasizes big picture.
Video Prototype
Lo-fi prototype. Short film depicting future experience. More difficult to create, non-interactive.
Hierarchical Task Analysis
Observe desired tasks. collect list of actions, organize and apply model or heuristics to predict task performance based on model of human cognition
GOMS
Goals, Operators, Methods, Selection Rules. Method of task decomposition used to describe tasks and how a user performs those tasks with a design. Expert, error-free, goal-directed, rational. Resulting model is abstract, approximate, quantitative.
Use of GOMS
Predict task completion times, analyze interaction paths, predict likelihood of errors, test functional coverage, predict time to learn tasks, develop task-centered documentation.
When to Use GOMS
Want to make a task more efficient or want a formal method of writing tasks.
How to Use GOMS
List all actions of a task by imagining you are instructing someone else to do it. Group actions into hierarchy. Decompose lowest actions until a quantifiable action is reached.
Why GOMS
Cost of modelling is less than cost of prototyping. No special skills required, predict performance before committing to a design. But, assumes error-free expert behavior and many aspects it cannot predict.
KLM
Keystroke Level Model = GOMS - Goals. Walk through task, list operators, use heuristics to insert M operators (mental). Can be used to evaluate interaction methods and trade-offs.
Action Analysis
List the actions for performing a task (write down how you would describe performing a task to a friend). Multiply number of steps by [2,3] secs for range of [best, worst] performance. Pros: Fast and cheap. Cons: Only estimates completion time, less accurate.
Empirical Evaluation Methods
Having to do with end user. Example: User Walkthrough
Analytic Evaluation Methods
Using a model. Example: GOMS, KLM
Inspection Evaluation Methods
Cognitive Walkthrough, Heuristic Evaluation
Cognitive Walkthrough Pros and Cons
Easy to learn and apply, helps identify controls obvious to designer but not user.
Cons: Focuses mostly on novice users, does not provide quantitative results.
What you need for Cognitive Walkthrough
Prototype, task scenarios, user personas, evaluation team, walkthrough questions.
Heuristic Evaluation
Inspection-based technique for identifying usability problem in UIs. Teach heuristics to evaluators, several evaluators apply heuristics to describe problems (what, why, severity, fix), rate severity of problems, aggregate and devise solutions.
Number of Heuristic Evaluators
Single evaluator: 35% of problems that can be found through a Heuristic Evaluation. 3 - 5: 60-75% of problems that can be found through a Heuristic Evaluation. Diminishing returns after.
Heuristic Evaluation Heuristics
Visibility of system status, match between system and real world, user control and freedom, consistency and standards, error prevention, recognition rather than recall, flexibility and efficiency of use, aesthetic and minimalist design, help users recover from errors, help and documentation
Heuristic Evaluation Pros and Cons
Cost effective, valid, no experience necessary.
Relies on interpretation, heuristics are generic, won’t lead to breakthroughs
High Fidelity Prototype
Makes everyone happy since there’s working implementation.
Requires large investment, slow iteration, can inhibit creativity.
Floor and Ceiling
floor: the learning curve or ease of learning and use
ceiling: the output, what the user can do
Design (general)
(v): the process of making
artifacts that solve human problems
(n): the artifacts made
Dieter Rams
Chief Design Officer at Braun from 1961 to 1995, huge influence in the field including ipod, calculator, camera
TCUID
Process (and philosophy) for building usable interactive systems with a continual focus on users and tasks
TCUID Process
Understand, explore, refine, implement, deploy.
Low Fidelity Prototype
Class of prototype methods that trade realism for investment. Adheres to economic principle so as not to be susceptible to false progress. Quick. inexpensive, disposable, big picture, fosters creative thinking.
UI Tools
Prototyping and development tools that encompass a layer between toolkits and applications. The right tool makes it easier to build certain types of applications.
Mash-up
Create applications by combining data and services from existing web sites, transform web from informational to computational platform. Yahoo Pipes.
Signifiers
Refers to any perceivable indicator that communicates approximate behavior (affordances) to a person.
Working Memory
Fast access, limited capacity, stores intermediate thought.
Perceptual Processor
Discrete and limited. Two stimuli within a cycle appear instantaneous, fused. Top down (constructivist) relies on experience and knowledge; bottom up (eceological) relies on info stored in environment.
Perceptual Memory
Visuo-spatial, phonological (linguistic), can be used simultaneously with separate senses.
Back-of-the-Envelope Action Analysis
Get a quick look at the big picture. Every actions takes at least 2 or 3 seconds. Does not give you precision, low cost in terms of time, no mental operations.
HP Solutions Center
Multiple HP logos, my cartridges vs all cartridges, inconsistent ink level information.
UMATI
Obtain snacks by grading CS exam problems.
Resilience Engineering
Designing with errors in mind, error-conscious.
Double Diamond Model of Design
Branch from core idea, diverge and converge in the lo-fi stage. First diamond is to narrow down the idea, the second is for the UI.
Iterative Design vs Linear Stages
Linear stages progress in one direction, also called the waterfall method. No progress is made until the current stage is complete. Iterative design focuses on continual refinement.
Don Norman’s Law of Product Development
“The day a product development process starts, it is behind schedule and above budget”
The Stigma Problem
People don’t like admitting to their infirmities. Products may be well developed and solve the problem but rejected by their intended audience.
Competitive Force
How competition in the market place influences your design.
Incremental and Radical Design
Incremental emphasizes on gradual progression whereas radical design implies a breakthrough.
Moral Obligations of Design
Design to better the human condition as opposed to focusing solely on capital gain.
Growth of the Small
It’s easy to get into design, prototype, put your idea into effect now as opposed to in the past. Tools and resources are easier to access, etc.
Problem Space Theory/Model
Problem states exist: initial and goal Heuristics are employed to select appropriate operators to reach the goal. Knowledge-level system contains an agent that changes itself and its environment to their own knowledge to reach goals.
Golden Rule of Design
Understand computers (limitations, capacities, tools, platforms) and understand people (psychological, social aspects, human error).
Local Structure
Interaction dealing with goal-seeking behavior.
Summative Evaluation
Performed at the end of an iteration to verify whether the product is good enough or not.
Software Life Cycle
An attempt to identify the activities that occur in software development.
Waterfall model
Requirement specification, architectural design (decomposition of services), detailed design (decomposition of separate components), coding and unit testing, integration and testing, maintenance.
Usability Engineering
User-centered design where the product’s usability is based on users’ experiences. Asserts usability metrics to be judged upon delivery.
Design Rationale
Information that explains why a computer system is the way it is, including its structural and architectural description and its functional or behavioral description.
Goals of Evaluation
Assess the extent and accessibility of the system’s functionality, users’ experience of the interaction, and to identify specific problems within the system.
Participatory Design
Users part of your design team. Pros: readily available feedback, brianstorm ideas, deeper insights, diverse perspectives, communicates seriousness of building UI for users. Cons: users gain group bias, sometimes too conciliatory or impede development altogether, more difficult to come to a consensus, may limit focus to specific users instead of wider audience.
Protocol Analysis
Methods for recording user actions: paper and pencil, audio recording, video recording, computer logging, user notebooks
Interviews and Questionnaires
The former more free-style, can be adapted to suit particular user and context, effective for high-level evaluation. The latter is more structured, questions fixed in advance, able to reach a wider audience, less time to administer, can be analyzed rigorously.
Universal Design
Process of designing products so that they can be used by as many people as possible in as many situations as possible.
Types of Cognitive Models
Hierarchical representation of the user’s task and goal structure, linguistic and grammatical models, physical and device-level models.
Cognitive Complexity Theory
Assumes distinction between long term and short term memory; 2 parallel descriptions: user’s goal and computer system. User’s goal in based on GOMS-like goal hierarchy, expressed using production rules: if condition then action
Linguistic Models
Grammar of articulation translation and how it is understood by the user. User’s interaction with a computer is often viewed in terms of a language.
Physical and Device Models
Articulation at the human-motor level. Keystroke-level model: uses understanding of human motor system for performance prediction, aimed at execution of simple command tasks. Three-state model: model for input devices, each having different sensory-motor characteristics.
Knowledge-based Analysis
Look at what users need to know about the objects and actions involved in a task and how that knowledge is organized, building taxonomies.
Entity-relation-based Analysis
An object-based approach where the emphasis is on identifying the actors and objects, the relationships between them and the actions they perform. Associated with database design and OOP.
Cognitive Walkthrough
For each action in a task, tell a story asking: will the user be trying to produce the effect the action has? Will the user see the control for the action? Will the user recognize the control produces the desired effect? After the action is taken, will the user understand the feedback and be able to proceed?
Radius of Activation
Does not have to be the exact size of the virtual button in the case of touch-screens. Benefit to those with large hands.
Global Structure
Overall structure of application with various screens, pages, or device states.
