Human-Computer Interaction and Usability Engineering

Comprehensive practice flashcards defining core terms, heuristics, cognitive concepts, and design methodologies covered across the lecture series.

Usability

The property of the relationship between humans with goal-driven tasks and an artifact, measured by the speed and success with which goals can be accomplished (task performance).

Needfinding

A qualitative design research method where an existing artifact and humans performing tasks are studied to determine user goals and identify usability issues that decrease task performance.

User-Centered Design

A design methodology where designers focus on humans, their specific goals, and their tasks to design an artifact that supports real human interactions.

Iterative User-Centered Design

A process of repeatedly redesigning an existing artifact based on user studies and testing to help users accomplish their tasks faster and more successfully.

Heuristic Evaluation

A discount usability engineering method involving a small team of evaluators who independently inspect an interface based on recognized usability principles or rules of thumb.

Visibility of System Status

Nielsen heuristic stating that the interface must always keep users informed about what input was received, current processing, and processing results through prompt and appropriate feedback.

Match Between System and Real World

Nielsen heuristic stating that the system should speak the user's language using words, phrases, and concepts familiar to the user, adhering to real-world conventions rather than internal system-oriented terms.

User Control and Freedom

Nielsen heuristic requiring clearly marked exits such as undo and redo to help users recover from mistaken choices without being forced down fixed paths.

Consistency and Standards

Nielsen heuristic stating that the same words, situations, and actions should mean the same thing across an application, ensuring elements that do the same thing look the same and appear in the same place.

Error Prevention

Nielsen heuristic advocating for careful design that prevents problems from occurring in the first place, such as using structured calendar pickers instead of freeform text to eliminate illegal date entries.

Recognition Rather Than Recall

Nielsen heuristic stating that objects, actions, and options should be visible or easily retrievable so that the user does not have to remember information from one part of the dialogue to another.

Flexibility and Efficiency of Use

Nielsen heuristic stating that the system should accommodate both inexperienced and experienced users by offering accelerators such as keyboard shortcuts, gestures, and macros.

System 1 (Type 1 Cognition)

An automatic, unconscious, effortless, fast, associative, and heuristic mode of human thinking that cannot be turned off.

System 2 (Type 2 Cognition)

A voluntary, conscious, effortful, slow, logical, and planning mode of human thinking that is inherently lazy and typically operates only partly engaged.

Chunking

The cognitive mechanism of grouping individual items into meaningful patterns or chunks, enabling more total information to be held within the fixed short-term memory limit of approximately $4$ items.

Automaticity

The cognitive phenomenon where repetitive practice of an action sequence or script allows it to execute rapidly with minimal conscious attention, shifting operational responsibility from System 2 to System 1.

Yerkes-Dodson Law

An empirical law stating that increased emotional arousal improves performance continuously on simple (System 1) tasks, but only enhances performance on difficult (System 2) tasks up to a moderate threshold, after which performance sharply declines.

Mental Model

An internal cognitive representation in a user's mind of how a physical or digital artifact works in the real world.

Gulf of Execution

The psychological gap between a user's goal and the physical system, centered around the questions 'How do I work this?' and 'What can I do?' to translate intentions into physical actions.

Gulf of Evaluation

The psychological gap between the physical state of the system and the user's perception, centered around the questions 'What happened?' and 'Is this what I wanted?' to assess whether goals were satisfied.

Norman's 7 Stages of Action

A framework describing human task execution and evaluation comprising seven distinct stages: Goal, Plan, Specify, Perform, Perceive, Interpret, and Compare.

Affordance

The relationship between an object and a human user that determines the physical or digital interactions that are possible with that object.

Signifier

Any perceivable mark, indicator, or visual cue that communicates an object's affordances and signals how a control or artifact should be operated.

Natural Mapping

A control mapping layout where controls are mounted directly adjacent to the item being controlled, as close as possible, or arranged in the identical spatial configuration as the target objects.

Consistent Mapping

An interface design principle where a specific control consistently and reliably causes the exact same action, supporting System 1 automaticity.

Physical Constraint

A constraint that relies on the physical properties, geometry, or boundaries of an artifact to restrict improper operations without requiring user instructions.

Lock-In

A constraint design pattern that keeps an ongoing operation active to prevent a user from prematurely terminating or stopping it.

Lock-Out

A constraint design pattern that prevents an undesirable action or system event from occurring until prerequisite conditions are met.

Inter-Lock

A constraint design pattern that enforces a specific, mandatory sequence of operations before subsequent actions can take place.

Double Diamond Model of Design

A design model structured around two divergent and convergent cycles: first finding the right problem through divergence and convergence, followed by finding the right solution through divergence and convergence.

Flexibility-Usability Tradeoff

The design principle stating that as an artifact's flexibility is increased to accommodate more broad functions, its usability and optimization for specific common tasks decrease.

Reachability Question

A control flow question asked during code investigation and debugging that involves searching along feasible paths downstream or upstream from a statement for target statements matching specific search criteria.

Contextual Design

A user-centered design methodology that uses direct customer workplace observations, work modeling, and work redesign to determine system requirements and UI specifications.

Contextual Inquiry

A field research technique combining open-ended conversational interviews and workplace observation to gather concrete data on what users actually do in their natural environments.

Partnership (Contextual Inquiry Principle)

A core principle of contextual inquiry emphasizing an equitable collaborative relationship between researcher and participant as co-investigators, actively avoiding traditional interviewer-interviewee or expert-novice hierarchies.

Affinity Diagram

A collaborative analysis method in contextual inquiry where brainstormed questions, assumptions, and field observations are recorded on sticky notes and clustered into thematic groupings to establish project focus.

Storyboard

A comic-book style sequence of visual frames and annotations illustrating the interplay, context, user actions, and screen transitions of an envisioned interaction scenario.

Wireframe

A schematic, low-to-medium fidelity design layout using boxes and lines to define screen layout, visual hierarchy, and structural workflow without finished typography, color, or graphic details.

Horizontal Prototype

A prototype providing broad feature coverage with minimal functional depth, designed to explore high-level system concepts rather than detailed workflows.

Vertical Prototype

A prototype providing comprehensive functional depth for only a narrow selection of features to conduct realistic, in-depth user evaluations.

Wizard of Oz Study

A prototyping technique where a human operator covertly intercepts inputs and manually simulates system responses to evaluate user interactions with an ostensibly automated system.

Think-Aloud Usability Study

An empirical usability evaluation method where participants perform designated tasks on a system while verbalizing their ongoing thoughts, intentions, and reactions.

Critical Incident

Any user action during a usability evaluation that fails to make progress toward completing the assigned task, typically indicating an underlying gulf of execution or evaluation.