Glossary

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AI Companion(also: Chatbot Companion, AI Companionship)

An AI companion is an artificial-intelligence system - typically a text, voice or avatar-based chatbot built on a large language model - explicitly designed to offer users a sense of social presence, intimacy or relational support, marketed as a friend, confidant, mentor or…

AI Mental Model(also: Mental Model of AI, User Mental Model of AI)

A user's conceptual representation of how an artificial intelligence system works, including beliefs about its information sources, processing methods, capabilities, and limitations. Mental models of AI are often incomplete, oversimplified, or erroneous, which can lead to…

AI-Mediated Dialogue

A paradigm in which a large language model (or similar conversational agent) stands between a user and a task, simulated social situation, or another user — either producing the conversational partner's turns, coaching the user's next turn, or both. AI-mediated dialogue is…

Ability requirement(also: Ability demand, Interaction prerequisite)

A capability that a person must possess in order to use a technology system, created implicitly by the system's design. AI systems generate new ability requirements: voice assistants require recognizable speech production, autonomous vehicles require pedestrians to look and move…

Ability-Based Design(also: ABD)

A design philosophy that focuses on what users can do rather than what they cannot, adapting systems to leverage each individual's specific abilities. Instead of designing for a "typical" user and then adding accessibility accommodations, ability-based design starts from the…

Affordance(also: Perceived affordance)

A property of an object or environment that suggests how it can be used, originally defined by psychologist James J. Gibson in 1977 as the actionable possibilities between an actor and their environment. In design, Donald Norman popularised the concept to describe how visual and…

Agency(also: User Agency, Sense of Agency)

The capacity to act, make choices, and exert control over one's own life and environment. In disability studies, agency is distinguished from independence — a person can have agency (the ability to make decisions and direct actions) while still relying on others for support,…

Always-On Computing(also: Always-available computing, Continuous computing)

A model of interaction in which computing devices — particularly wearables such as smartwatches, AR glasses, and fitness trackers — remain continuously active and accessible throughout the day rather than being engaged only for discrete tasks. Always-on computing shifts design…

Ambisonics(also: Ambisonic audio, Ambisonic sound)

A full-sphere surround sound technique that captures and reproduces audio from all directions — including above and below the listener — using a spherical harmonic representation of the sound field. Originally developed by Michael Gerzon in the 1970s, ambisonics differs from…

Anthropomorphism(also: Humanization, Anthropomorphization)

The attribution of human characteristics, emotions, intentions, or behaviors to non-human entities such as technology, animals, or objects. In assistive technology and conversational AI design, anthropomorphism raises important questions about how human-like an interface should…

Area of Interest(also: AOI, Region of Interest, ROI)

A defined region within a visual stimulus (such as a screen, webpage, or video frame) that researchers designate for analysis in an eye-tracking study. AOIs allow researchers to quantify how much visual attention participants direct toward specific elements — for example, the…

Articulation Work(also: Care Articulation, Need Articulation)

The often invisible labor of putting thoughts, needs, and feelings into words, particularly in care relationships. Articulation work involves expressing what support is needed, coordinating care activities, and communicating between care partners. This concept, originating from…

Assent(also: Informed assent, Child assent)

A participant's affirmative agreement to take part in research, used when the individual cannot legally provide informed consent — most commonly children or people with certain cognitive disabilities. Unlike informed consent, assent does not carry the same legal weight but…

Automatic UI Generation(also: Auto-Generated Interface, Model-Based UI Generation)

The process of computationally producing a graphical user interface from an abstract specification of its functionality, rather than having designers manually create the visual layout. In accessibility, automatic UI generation is significant because it can produce interfaces…

Big Five Personality Traits(also: Big Five, Five-Factor Model, OCEAN Model)

A widely used psychological model that describes human personality along five trait dimensions: Openness to Experience, Conscientiousness, Extroversion, Agreeableness, and Neuroticism. Originally developed in personality psychology, it has been adopted in human-robot interaction…

Bimanual Exploration(also: Two-handed exploration, Bimanual tactile exploration)

The use of both hands in coordinated roles to perceive an object or space by touch. In blind and low-vision users, bimanual exploration is typically asymmetric: one hand (often the non-dominant) serves as a spatial anchor holding a frame of reference while the other hand (often…

Bimodal Feedback(also: Dual-Modality Feedback)

A form of interface feedback that communicates information to the user through two simultaneous sensory channels, such as auditory and haptic, visual and haptic, or auditory and visual. Bimodal feedback is significant for accessibility because it provides redundancy — if a user…

Binaural audio(also: Binaural sound, Binaural recording, 3D audio)

An audio reproduction method that uses two channels to create a three-dimensional sound experience when listened to through headphones. Binaural recordings capture or simulate the way human ears naturally perceive sound, using differences in timing, level, and frequency between…

Bio-Signal(also: Biosignal, Biological Signal)

Any measurable electrical, chemical, or mechanical signal produced by the human body that can be detected by sensors and used as input for computer systems. In assistive technology, bio-signals are used to create alternative input methods for people with severe motor impairments…

Biosignal Interface(also: Physiological Interface, Biometric Input)

An input interface that detects and interprets biological signals from the human body — such as muscle contractions (EMG), brain electrical activity (EEG), eye movements (EOG), or galvanic skin response — to generate computer commands. Biosignal interfaces are particularly…

Chunking

In cognitive science and human-computer interaction, chunking refers to the mental strategy of grouping individual items of information into larger, unified units (chunks) to reduce working memory load. Because human working memory can hold approximately four to seven items at a…

Clicking Error(also: Click Slip, Selection Error)

An unintended mouse input that occurs during the clicking phase of target selection, distinct from errors in cursor positioning. Common clicking errors include slipping off the target (the cursor moves between button press and release), accidental clicks made while the mouse is…

Closed-Loop Adaptation(also: Closed-Loop System, Adaptive Loop)

A system design approach where real-time feedback from sensors or user behavior is continuously monitored and used to automatically adjust the system's response. In accessibility technology, closed-loop adaptation enables interfaces to respond dynamically to users' physiological…

Co-Embodiment(also: Shared Embodiment, Collaborative Embodiment)

A design concept where multiple users jointly control or inhabit a single virtual body or avatar, each contributing different aspects of the character's movements or actions. In CoSignPlay, co-embodiment allows one player to control non-manual signs (facial expressions, head…

Co-Located Collaboration(also: Co-Located Cooperation)

Co-located collaboration is the shared activity of people working or playing together while physically present in the same space, as distinct from remote or distributed collaboration. In HCI and accessibility research, co-located collaboration is studied because it adds embodied…

CogTool

A cognitive modeling tool developed at Carnegie Mellon University that generates quantitative predictions of human task performance times based on the Keystroke-Level Model (KLM) and the ACT-R cognitive architecture. Designers create storyboards of user interface screens and…

Cognitive Cycle(also: Cognitive Processing Time, Cognitive Response Time)

In the Model Human Processor framework, the cognitive cycle represents the time required for a person to process perceived information and make a decision about how to respond. A single cognitive cycle is approximately 70-110 milliseconds. Research with motion-impaired users has…

Cognitive Strategy Prompting(also: Cognitive Scaffolding, Strategy Prompting)

A design technique that provides cues or prompts within an interface to help users employ effective cognitive strategies for completing tasks, particularly benefiting users experiencing age-related cognitive decline or cognitive disabilities. Examples include framing tasks using…

Cognitive load(also: Mental load, Cognitive burden, Cognitive demand)

The total amount of mental effort required to complete a task, encompassing the processing of information, decision-making, remembering instructions, and managing attention. Cognitive load theory, developed by John Sweller in the 1980s, distinguishes between intrinsic load…

Command Recognition(also: Command Classification, Input Recognition)

The process by which a computer system interprets and classifies a user's input action — such as a gesture, voice command, or key press — as a specific intended command from a predefined vocabulary of possible commands. The accuracy of command recognition is characterised by the…

Common Ground(also: Grounding, Mutual Understanding)

The shared knowledge, beliefs, and assumptions that conversation participants use to understand each other. In communication theory, grounding is the process by which speakers establish and maintain this mutual understanding through strategies such as referencing shared context,…

Communicability

A quality property of interactive systems proposed by Semiotic Engineering theory, referring to the system's ability to effectively and efficiently convey to users the designer's communicative intentions, logic, and underlying interaction principles. High communicability means…

Computer-Supported Cooperative Work(also: CSCW, Collaborative Computing)

A field of research and practice focused on how technology can support people working together, encompassing tools for communication, coordination, and collaboration such as chat systems, shared documents, video conferencing, and project management platforms. In accessibility,…

Conceptual Model(also: Mental Model)

A user's internal understanding of how a system works, including what actions are possible, what the current state is, and what the consequences of actions will be. Conceptual models are critical in accessibility because users who cannot build an accurate mental representation…

Cone Tree(also: Cone Trees, Cone Tree Visualization)

A 3D or 2D information visualization technique for displaying hierarchical data structures, where child nodes are arranged in a cone or fan shape around their parent node. When a user selects a child, the parent shrinks into the background and the selected item's children expand…

Confirmation Message(also: Positive Feedback, On-track Feedback, Progress Confirmation)

A system message that reassures users they are performing a task correctly or are on the right path, as opposed to only providing error messages or corrective instructions. In assistive technology and cognitive accessibility, confirmation messages have been shown to be…

Context-Aware Computing(also: Context Awareness, Situational Awareness Computing)

Computing systems that can sense and adapt their behavior based on the user's current context, including location, activity, environment, and task state. In accessibility, context-aware systems go beyond static information delivery to provide real-time, situation-appropriate…

Context-Aware Interface(also: Context-Sensitive Interface, Adaptive Interface)

A user interface that dynamically adapts its content, features, or behavior based on the user's current context, such as their location, current task, time of day, or the website they are visiting. In cognitive accessibility, context-aware interfaces are particularly valuable…

Conversational Scaffolding(also: Scaffolded Interaction)

Human or technology-provided support, prompts, or guidance that helps individuals accomplish communication tasks they might struggle with independently. In voice assistant contexts, scaffolding includes features like setting up calendars, providing reminders, and offering…

Critical Design(also: Critical Design Framework, Design Through Critique)

A research through design methodology that foregrounds the ethics of design practice, reveals potentially hidden agendas and values, and explores alternative design values. In accessibility research, critical design is used to create provocative prototypes not primarily intended…

Cursor Assistance(also: Pointer Assistance, Mouse Assistance)

Software techniques that modify cursor behavior to make pointing and clicking easier for users with motor impairments. Cursor assistance encompasses a range of approaches including enlarging the effective target area (area cursors, bubble cursors), making targets "sticky" so the…

Cursor Control(also: Pointer Control, Cursor Navigation)

The ability to direct and position an on-screen cursor or pointer using an input device such as a mouse, trackball, touchpad, joystick, or eye tracker. Cursor control is a fundamental requirement for interacting with graphical user interfaces and involves both gross movements…

Cursor Freeze(also: Pointer Freeze, Steady Clicks)

An assistive technology technique that locks the cursor position in place during mouse button clicks, preventing the cursor from moving between the press and release of the button. This addresses a common source of errors for users with motor impairments who may involuntarily…

Cyborg(also: Cybernetic Organism)

A being that integrates both organic and technological components, extending human capabilities through mechanical or digital augmentation. In disability studies and accessibility research, the cyborg concept has been applied to understand how people with disabilities who use…

Design Psychology(also: Designer Cognition, Design Thinking Process)

The study of the cognitive processes, mental models, and decision-making strategies that designers employ during the product development process. In the context of accessibility, design psychology is relevant because accessibility guidelines and resources must align with how…

Design probe(also: Technology probe, Cultural probe)

A research methodology in human-computer interaction where a prototype or artefact is deployed with participants not primarily to test usability, but to provoke reflection, surface unanticipated needs, and explore a design space. Unlike usability testing, which evaluates how…

Dialogue Design(also: Interaction Dialogue, User Dialogue Design)

Dialogue design in human-computer interaction refers to the structured planning of the conversational exchange between a user and a system, defining how input is accepted, how the system responds, and how errors are handled across interaction turns. In accessible interface…

Direct Manipulation(also: Direct Manipulation Interface, DMI)

An interaction style in human-computer interfaces where users directly act on visible objects rather than issuing commands. Key characteristics include continuous representation of objects, physical actions instead of complex syntax, and immediately visible results. Examples…

Dramaturgical framework(also: Dramaturgy, Goffman's dramaturgy, Impression management)

A sociological framework developed by Erving Goffman in The Presentation of Self in Everyday Life (1956) that analyses social interaction as a theatrical performance. The framework distinguishes between the frontstage (the public performance where people present a desired…

Dyadic Interaction(also: Dyad Interaction, Paired Interaction)

Social interaction between two individuals, studied as the fundamental unit of social exchange. In accessibility and intervention research, dyadic interaction is often examined in contexts such as child-caregiver pairs, student-peer partnerships, or client-therapist…