Glossary

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Human Intelligence Task(also: HIT)

A unit of work on a crowdsourcing platform, particularly Amazon Mechanical Turk, that requires human judgment to complete. HITs typically involve tasks that are difficult for computers but straightforward for humans, such as image labeling, transcription, content moderation, or…

Human Interaction Proof(also: HIP, Human Interactive Proof)

A challenge-response test designed to distinguish human users from automated software (bots). Human Interaction Proofs are the technical term for CAPTCHAs and similar verification systems. While effective against automated attacks, HIPs present significant accessibility…

Human Interface Device(also: HID, Input Device, Peripheral)

Any device used to facilitate interaction between a human and a computer, including keyboards, mice, trackballs, joysticks, touchscreens, switches, and eye-tracking systems. The USB HID standard defines a protocol for these devices that enables plug-and-play compatibility. For…

Human Machine Interface(also: HMI, Human-Computer Interface)

The point of interaction between a human user and a machine, encompassing all hardware and software through which users control and receive feedback from a system. In accessible design, HMIs must support multiple modalities—visual, auditory, and haptic—to accommodate users with…

Human Rights Model of Disability(also: Rights-Based Model of Disability)

A framework for understanding disability that builds on and extends the social model by emphasising the inherent dignity and rights of people with disabilities. Grounded in the UN Convention on the Rights of Persons with Disabilities (CRPD), this model goes beyond identifying…

Human-AI Alignment(also: AI Alignment, Value Alignment)

The design and training of AI systems to exhibit behaviours consistent with human values, intentions, and goals. In accessibility, human-AI alignment requires that AI systems accurately represent and respond to the diverse values and experiences of disabled and neurodivergent…

Human-AI Co-Creation(also: Human-AI Co-Creative, Co-Creative AI, Mixed-Initiative Co-Creation)

Human-AI co-creation refers to creative work in which a person and an AI system iteratively contribute to the same artifact, with each shaping the other's next move rather than the AI acting as a one-shot tool. In accessibility contexts, co-creative systems are used to scaffold…

Human-AI Collaboration(also: Human-AI Teaming, AI-Assisted Authoring)

An interaction paradigm where humans and artificial intelligence systems work together, each contributing their complementary strengths to achieve outcomes neither could produce as effectively alone. In accessibility contexts, human-AI collaboration combines AI efficiency in…

Human-AI Interaction(also: HAI, Human-AI Collaboration, AI Interaction Design)

The study and design of how people interact with artificial intelligence systems, including how AI communicates its outputs, uncertainty, and limitations to users. Key principles include making AI behavior transparent, supporting user correction of errors, acknowledging…

Human-Centered AI(also: HCAI, Human-Centered Artificial Intelligence, HCXAI)

Human-Centered AI (HCAI) is a design and research orientation that places human experience, context, agency, and values at the center of how AI systems are built and evaluated, rather than optimizing only for model performance. In accessibility contexts, HCAI emphasizes that AI…

Human-Centered Computing(also: Human-Centred Computing, People-Centered Computing)

Human-centered computing is an approach to technology design and development that places human needs, capabilities, and experiences at the center of the design process. It emphasizes understanding the full diversity of human physical, sensory, and cognitive abilities, and…

Human-Centered Design(also: HCD, User-Centered Design, UCD)

A design approach that prioritizes the needs, capabilities, and experiences of end users throughout the design process. Popularized by IDEO and formalized in ISO 9241-210, human-centered design involves iterative cycles of understanding user context, specifying requirements,…

Human-Centered Threat Modeling

A methodology borrowed from security and privacy research that identifies the people and institutions who intend to cause harm to a specific population, the threats they pose, and the defensive strategies the population uses. In accessibility research, human-centered threat…

Human-Machine Interface(also: HMI, Human-Computer Interface)

The point of interaction between a human user and a machine, system, or device, encompassing the hardware and software through which users communicate with and control technology. In the context of accessible design, HMIs include physical controls (buttons, levers, keypads),…

Human-Nature Interaction(also: HNI)

A research area within human-computer interaction concerned with how people perceive, access, and engage with natural environments, and how technology can mediate that relationship. HNI draws on environmental psychology, biophilia, and posthumanist design to study experiences…

Human-Powered Accessibility(also: Human Computation for Accessibility, Crowd-Powered Assistive Technology)

An approach to assistive technology that uses remote human workers — whether paid crowdworkers, volunteers, or trained agents — to provide accessibility services that automated systems cannot yet deliver reliably. Examples include providing real-time visual descriptions for…

Human-Robot Interaction(also: HRI)

The interdisciplinary field studying how humans and robots communicate, collaborate, and coexist. In accessibility contexts, HRI research explores how robots can be designed to support people with disabilities in workplaces, homes, and public spaces — including collaborative…

Human-Vehicle Interaction(also: HVI, Vehicle-pedestrian interaction)

The field studying how people communicate, negotiate, and coordinate with vehicles and their occupants — including drivers, passengers, and, increasingly, automated systems. Human-vehicle interaction encompasses internal interfaces (dashboards, voice assistants,…

Human-computer interaction(also: HCI, Human-machine interaction)

The interdisciplinary study of the design, evaluation, and use of interactive computing systems by humans, drawing on computer science, psychology, design, and social science. HCI research encompasses how people use technology, how interfaces should be designed for usability and…

Human-in-the-Loop(also: HITL)

An approach to AI system design and evaluation that incorporates human judgment, feedback, and oversight at critical points in automated processes. In accessibility contexts, human-in-the-loop methodologies involve people with disabilities and other affected communities in…

Human-like trust in AI(also: Anthropomorphic trust)

The phenomenon where users develop trust in AI systems based on their human-like qualities — such as natural voice, conversational style, emotional expressiveness, and social behaviors — rather than the system's actual functional reliability. In accessibility contexts, this…

Humanoid Robot(also: Humanoid)

A robot whose physical form approximates a human body, typically with a head, torso, two arms, and (in bipedal designs) two legs. Humanoid robots are studied in accessibility research as embodied demonstrators that can present gestures, postures, and movement sequences in ways…

Humming Interface(also: Control-by-Humming, Hum-Based Interface)

A human-computer interaction method that uses hummed pitch patterns as control signals for operating devices. In a humming interface, a pitch detection algorithm analyses the user's hummed input, segments it into discrete notes based on pitch contour (rising, falling, or flat),…

HyDE(also: Hypothetical Document Embeddings)

A query-expansion technique for retrieval-augmented generation in which an LLM is first asked to generate a hypothetical answer to the user's question, and that hypothetical answer — rather than (or alongside) the raw query — is embedded and used to search the document index.…

Hybrid Captioning(also: AI-Augmented Captioning, Blended Captioning)

A captioning approach that combines human-generated captions with AI-powered correction or enhancement to achieve higher accuracy than either method alone. Hybrid systems leverage the reliability and contextual awareness of trained human captioners while using automatic speech…

Hybrid Craft(also: Digital Craft, Computational Craft)

A making practice that combines traditional hand-craft techniques (embroidery, weaving, quilting, ceramics, woodworking) with digital fabrication tools such as computerised embroidery machines, laser cutters, or 3D printers. In accessibility and HCI research, hybrid craft is…

Hybrid Interaction(also: Multimodal Hybrid Approach)

An interaction design approach that combines multiple input and output modalities, allowing users to switch between them based on task requirements, context, and personal preferences. In accessibility research, the "voice for speed, screen for verification" principle exemplifies…

Hybrid Search(also: Hybrid sign-language search)

A sign-language dictionary search pattern that combines search-by-video (a user performs the sign into a camera for sign recognition to match) with search-by-feature (manual filtering of the candidate list by linguistic properties such as handshape and location). Introduced as a…

Hybrid Space(also: Blended Space, Hybrid Community Space)

A community or program environment that combines both in-person and online elements, not necessarily simultaneously, to create a more accessible and inclusive experience. In accessibility contexts, hybrid spaces address barriers such as geographic distance, mobility limitations,…

Hybrid automaton(also: Hybrid state machine)

A computational model that combines discrete state transitions with continuous dynamics, used in interactive systems to govern object behaviours based on multiple users's simultaneous inputs. In collaborative virtual environments for autism intervention, hybrid automata control…

Hydrocephalus(also: Hydrocephaly, Water on the Brain)

A condition characterized by an abnormal accumulation of cerebrospinal fluid within the ventricles of the brain, causing increased intracranial pressure and enlargement of the head. Hydrocephalus can be congenital or acquired, and if untreated can lead to developmental delays,…

Hyper-aged Society(also: Super-aged Society)

A country or region where people aged 65 and over make up more than 21% of the total population. The term distinguishes extreme demographic aging from merely "aging" (7%+) or "aged" (14%+) societies. Japan became the world's first hyper-aged society around 2007 and is widely…

Hyperactivity

A core symptom of ADHD characterized by excessive movement, restlessness, difficulty remaining seated or still, and feeling driven as if by a motor. In adults, hyperactivity often manifests as internal restlessness rather than obvious physical activity. For digital…

Hyperacusis(also: Decreased sound tolerance)

A hearing condition in which everyday sounds are perceived as uncomfortably or painfully loud, even at volume levels that are tolerable for most people. Hyperacusis involves a reduced tolerance for the overall volume of sound rather than sensitivity to specific sound types…

Hyperarticulation(also: Clear Speech, Over-Articulation)

A speaking style in which a person exaggerates the clarity of their pronunciation by moving their tongue and mouth to more extreme positions, producing more distinct vowel and consonant sounds. Hyperarticulation occurs naturally when speakers perceive that their listener is…

Hyperfixation

Hyperfixation is an intense, prolonged focus on a single activity, topic or interest to the exclusion of other tasks and bodily needs, commonly associated with ADHD and autism. Unlike hyperfocus, which is often channelled toward a productive task, hyperfixation can latch onto…

Hyperfocus(also: Hyper-Focus, Flow State)

A state of intense, sustained concentration on a task or activity, commonly experienced by people with ADHD and other neurodivergent conditions. During hyperfocus, individuals may become deeply absorbed in work for extended periods, achieving exceptional productivity and depth…

Hypergraph

A mathematical structure that generalises both trees and graphs by allowing edges (called hyperedges) to connect any number of nodes rather than being limited to exactly two. In the context of accessible graphical representations, hypergraphs are used to model the visual…

Hypermedia

An extension of hypertext that incorporates multimedia content — audio, video, images, and animation — alongside text, all linked in a non-linear structure. What distinguishes hypermedia from hypertext is the implied sequencing required for time-based media: a video contains…

Hyperopia(also: Farsightedness, Long-Sightedness, Hypermetropia)

A refractive error in which the eye focuses light behind the retina rather than on it, causing near objects to appear blurred while distant objects may remain relatively clear. Hyperopia occurs when the eyeball is too short or the cornea is insufficiently curved. It is…

Hyperstory(also: Interactive Story, Branching Narrative, Hypertext Story)

A hyperstory is an interactive, non-linear narrative structure in which users make choices that influence the direction and outcome of the story. Adapted from hypertext concepts, hyperstories combine storytelling with interactive exploration, allowing users to navigate through…

Hypertext

A way of organising and presenting textual content in a non-linear manner by breaking it into fragments and describing the relationships between them. A book has chapters in a fixed order, but hypertext allows content to be navigated in multiple paths through links between…

Hypervigilance

A state of heightened alertness and sensitivity to potential threats in one's environment, commonly associated with PTSD, anxiety disorders, and trauma. Hypervigilant individuals may constantly scan for danger, feel uncomfortable with people behind them, need clear exit routes,…

Hypotonia(also: Low Muscle Tone, Muscle Hypotonia, Floppy Muscle Syndrome)

A condition characterized by decreased muscle tone, resulting in reduced resistance to passive movement and often affecting posture and motor control. Hypotonia is common in many developmental disabilities including Down syndrome, cerebral palsy, and various genetic conditions.…