Glossary

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Corrective feedback(also: Error correction feedback, Instructional feedback)

Specific information provided to a user after an action that identifies what was done incorrectly and how to improve on the next attempt. In accessible interaction design, corrective feedback for blind users is typically delivered through text-to-speech (e.g., "make it longer,"…

Cross-Filtering(also: Interactive Filtering, Linked Filtering)

A dashboard interaction technique where applying a filter in one component (such as selecting a category in a chart or using a dropdown widget) automatically updates the data displayed in other related components throughout the dashboard. Cross-filtering enables users to explore…

Cross-Modal Consistency(also: Multimodal Consistency, Cross-Modal Alignment)

The alignment and coherence of information presented simultaneously through different sensory channels — such as touch and hearing, or vision and sound. In accessible education, cross-modal consistency ensures that what a blind user feels through tactile graphics matches what…

Crossing-Based Interaction(also: Goal Crossing)

An alternative to traditional point-and-click interaction where users select a target by dragging across its boundary rather than tapping or clicking on it. Instead of requiring a precise tap within a target area, crossing-based interaction registers a selection when the user's…

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…

Customizability(also: Customization, Personalization)

The ability for users to modify and configure a system's interface, interaction methods, and behavior to match their individual needs and preferences. In accessibility contexts, customizability is a core design principle that acknowledges the diversity of disabled users'…

Customizable Interface(also: Configurable Interface, User-Customizable UI)

A user interface that allows individuals to modify its appearance, behavior, or content display according to their preferences and needs. In accessibility contexts, customizable interfaces enable users to adjust parameters like font size, color scheme, content density, filtering…

Customization Paradox(also: Paradox of Choice in Customization)

The phenomenon where providing more customization options to reduce barriers paradoxically creates new barriers through increased cognitive load, decision fatigue, and distraction from the customization interface itself. The customization paradox is particularly acute for ADHD…

Dead Time(also: Wait Time, Idle Time)

In scanning-based assistive technology interfaces, the period during which a user must passively wait before they can make their next input action. In row-column scanning, dead time occurs while waiting for the desired row or column to be highlighted. Longer dead times reduce…

Degrees of Freedom(also: DoF, 3DoF, 6DoF)

In virtual and extended reality, degrees of freedom refers to the number of independent movement axes available to a user within a virtual environment. Three degrees of freedom (3DoF) allows rotational head tracking only — looking up/down, left/right, and tilting — which is…

Deictic Gesture(also: Pointing Gesture)

A deictic gesture is a pointing or indicating motion (typically with a finger, but also with gaze, head, or tool) that directs another person's attention to a specific referent in the shared environment. In face-to-face tutoring, deictic gestures are central to effective…

Design Sprint(also: Google Design Sprint)

A structured, time-constrained design methodology originally developed at Google Ventures that guides teams through five phases — Map, Sketch, Decide, Prototype, and Test — to rapidly solve design problems and validate ideas with real users. In accessibility contexts, design…

Designing with Friction(also: Friction by Design)

An HCI design stance, associated with Matthias Korn and Amy Voida, that argues for deliberately introducing friction into interactive systems to surface politics, provoke reflection, and enable democratic contention — rather than pursuing frictionless user experience as a…

Device Independence(also: Device-Independent Design, Input Agnostic Design)

A web design principle that ensures content and functionality are accessible regardless of the input device or interaction method used to access them. Device-independent design avoids assumptions about how users will interact with content — not relying solely on mouse events,…

Device-Dependent Event Handler(also: Device-Dependent Event, Mouse-Dependent Event Handler)

An event handler in web development that is triggered only by a specific input device, such as a mouse click or touch gesture, rather than being accessible through multiple input methods. Device-dependent event handlers create significant accessibility barriers because users who…

Dialog Act(also: Dialogue Act, Speech Act)

A classification label representing the communicative intention behind a spoken or written utterance in a conversational system. In the context of accessible technology, dialog acts are used to interpret what a user wants to accomplish when issuing voice commands — for example,…

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 Touch Mapping(also: DTM, Touch-to-Audio Mapping)

An interaction technique in accessible touchscreen interfaces where the physical position of a user's finger on the screen corresponds directly to a position within the underlying content, such as a data visualization. When applied to chart accessibility, direct touch mapping…

Disambiguation(also: Target Disambiguation, Touch Disambiguation)

In accessible interface design, disambiguation is the process of resolving ambiguity when a user's input could correspond to more than one interactive target. This commonly occurs on touchscreens where small, densely packed elements make precise selection difficult, particularly…

Discrete Specification(also: Discrete Positioning, Grid-Based Positioning)

In cursor control interfaces, a positioning method where the user selects from a finite set of predefined locations to move the cursor to an approximate position quickly. Examples include grid-based systems where the screen is divided into numbered cells, or ghost cursor systems…

Distraction Reduction(also: Distraction Removal, Distraction Minimization)

Design strategies and technologies that minimize or eliminate elements that divert attention from primary content or tasks. In video accessibility for ADHD, distraction reduction involves identifying and removing or de-emphasizing visual elements (overlays, busy backgrounds,…

Drag and Drop(also: DnD)

An interaction pattern in which users select an on-screen object by pressing and holding, then move it to a new location before releasing. Drag and drop is widely used in visual programming environments, file management, and content editing. It presents significant accessibility…

Drone Accessibility(also: UAV Accessibility, Accessible Drone Piloting)

The design and adaptation of unmanned aerial vehicles (drones) and their control interfaces to be usable by people with disabilities. This includes providing alternative input methods such as voice commands, adapted controllers, and tangible interfaces, as well as multimodal…

Dwell Activation(also: Dwell Click, Dwell Selection)

An input method where an action is triggered by maintaining focus on a target for a specified period of time (the dwell time). Commonly used with eye tracking and head tracking systems, dwell activation allows users to select items without needing to physically click. While…

Dwell Selection(also: Dwell Click, Dwell Time Selection, Hover Click)

An interaction technique where a user activates or selects an on-screen element by keeping a cursor, gaze point, or pointer within the target area for a specified duration (the dwell time), rather than clicking or tapping. Dwell selection is essential for people with motor…

Elicitation Study(also: Gesture Elicitation Study)

An elicitation study is a user research method in which participants are shown the effect of an action (called a referent) and asked to propose the input or gesture (called a sign) that should cause it. This approach generates user-defined interaction techniques rather than…

Embodied Communication(also: Embodied Interaction)

Communication that involves the whole body as a resource for meaning-making, including gestures, posture, facial expressions, gaze, touch, and physical movement through space. Embodied communication recognizes that meaning is not solely transmitted through words but is…

Embodied Experience(also: Embodied Interaction, Embodiment (UX))

The dimension of user experience that arises from the body's sensory and kinaesthetic encounter with a system or environment — motion, vibration, balance, proprioception, ambient sound, and felt pace — rather than from explicit information channels. In autonomous transport,…

Embodied Interaction(also: Embodied Cognition in HCI)

An approach to human-computer interaction that emphasizes the role of the physical body in how people engage with and understand technology. Embodied interaction recognizes that cognition is not purely mental but shaped by physical experience, movement, and sensory engagement.…

End-User Elicitation(also: Elicitation Study, User-Defined Gestures)

A participatory research method where end users are asked to propose or create their own interaction techniques, gestures, or commands for a given system function, rather than having researchers prescribe interactions in advance. In accessibility research, elicitation studies…

Enhanced Area Touch(also: Area Touch, Expanded Touch Area)

A touchscreen interaction technique that enlarges the effective touch point from a single pixel to a larger circular area, expanding both the motor space (the physical area the user needs to target) and the visual space (the on-screen representation of targets). When multiple…

Error Recovery(also: Error Correction, Error Handling)

The process and mechanisms by which users can identify, understand, and correct errors that occur during interaction with a system. In accessibility contexts, error recovery is particularly important because errors can be harder to detect with assistive technologies—a screen…

Error correction strategy(also: Text correction, Input error recovery)

The methods and behaviours users employ to detect and fix errors during text input, including backspace deletion, cursor repositioning, autocorrect, and retyping. For blind and visually impaired users, error correction is disproportionately costly because detecting errors…

Execution Gap(also: Gulf of Execution)

From Don Norman's model of human-computer interaction, the distance between a user's goals and the physical actions required to achieve them using a given system. A system with a wide execution gap forces users to translate what they want into technical commands, parameters, or…

Expert User(also: Advanced User, Power User)

A user who has substantial experience with a system and has internalised its structure, commands, and idioms. Expert users typically prefer direct, efficient interaction — keyboard shortcuts, command-line syntax, scripting, and customised workflows — over step-by-step menus.…

Explore by Touch(also: Touch Exploration)

A screen reader interaction mode on touchscreen devices in which users drag their finger across the screen to discover and hear descriptions of interface elements beneath their fingertip. When Explore by Touch is active, a single tap does not activate a control — instead, the…

Eyes-Free Interaction(also: Eyes-Free Computing)

Interaction with digital devices and interfaces without requiring visual attention to a screen. Eyes-free interaction is essential for blind users but also benefits sighted users in contexts where looking at a screen is unsafe (driving), impractical (exercising), or socially…

Eyes-Free Interaction(also: Eyes-Free, Eyes-Free Gaming, Eyes-Free Interface)

Eyes-free interaction refers to the use of digital systems and interfaces without relying on visual output, using alternative modalities such as audio, haptic feedback, or speech. In gaming contexts, eyes-free games use 3D spatial audio, sound cues, and non-visual feedback to…

Eyes-free Interaction(also: Eyes-free Input, Nonvisual Interaction, Eyes-free Interface)

Interaction techniques that allow users to operate devices without looking at the screen or interface. Eyes-free interaction is essential for people who are blind, but also benefits sighted users in contexts where visual attention is unavailable or dangerous, such as while…

Eyes-free interaction(also: Eyes-free interface, Non-visual interaction)

An interaction paradigm in which users operate technology without relying on visual feedback, instead receiving information through auditory, haptic, or other non-visual channels. Eyes-free interfaces are essential for people who are blind or have low vision, but also benefit…

Feedback Design(also: System Feedback, User Feedback Design)

The design of system responses that communicate to users what is happening, what the system understood, and what actions are needed. Effective feedback design is critical in assistive technology, where users may have limited sensory, motor, or cognitive channels for receiving…

Feedforward(also: Anticipatory Feedback)

Design information that tells users what to expect before they take an action, guiding them toward intended functionality by communicating expected results. Unlike feedback (which confirms what happened after an action), feedforward helps users form correct expectations and make…

Finger Reading(also: Touch Scanning, Tactile Scanning)

A touch interaction technique used on accessible touchscreen interfaces where users continuously pan or slide their finger across the screen to explore content, receiving feedback for every position touched without encountering blank or unresponsive areas. In accessible data…

Fisheye View(also: Fisheye Lens, Graphical Fisheye)

A focus+context visualization technique, introduced by Furnas, that magnifies a region of interest while progressively compressing surrounding context — analogous to a fisheye camera lens. Used in tree visualizations, menus, and graphs to help users see detail and structure…

Fitts' Law(also: Fitts Law)

A predictive model of human movement in human-computer interaction that states the time required to move to a target area is a function of the distance to the target and the size of the target. Specifically, larger and closer targets are faster to acquire than smaller and more…

Fitts' Law(also: Fitts Law)

A predictive model of human movement that describes the time required to move to a target as a function of the target's size and distance from the starting point. Formulated by Paul Fitts in 1954, the law states that smaller and more distant targets take longer to acquire. In…

Fitts's Law(also: Fitts Law, Fitts' Law)

A predictive model of human movement that describes the time required to rapidly move to a target area as a function of the distance to the target and the target's size. Smaller and more distant targets take longer to reach and are more prone to errors. In accessibility, Fitts's…

Fluid Traversal(also: Fluid Navigation)

A navigation design principle for screen reader interfaces that aims to mirror the flexibility of sighted visual attention. Fluid traversal has two key properties: it should be concise (requiring minimal key presses or actions to move between parts of a representation) and…

Focus Management(also: Focus Control, Programmatic Focus)

The practice of controlling which element on a web page or application receives keyboard focus, and ensuring that focus moves in a logical and predictable manner as users interact with the interface. Focus management is one of the most challenging aspects of web accessibility…

Focus and Context(also: Focus+Context, Detail in Context)

An information visualization and interaction design principle that simultaneously presents detailed information about a specific item of interest (focus) alongside an overview of the surrounding structure or environment (context). In accessibility, the focus+context approach is…