Glossary

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Functional Illiteracy(also: Low Literacy, Limited Literacy)

A condition in which a person has basic reading and writing skills but cannot effectively understand or use written text for everyday tasks such as reading instructions, filling out forms, or comprehending web content beyond simple sentences. UNESCO defines functional illiteracy…

Functional Literacy(also: Functional illiteracy)

The level of reading and writing skill needed to handle everyday tasks — filling out forms, reading medication instructions, understanding a utility bill, using a web service. Adults below this threshold are described as functionally illiterate, which in the United States is…

GAIA(also: Guidelines for Accessible Interfaces for people with Autism, Guidelines for Accessible Interfaces for Autism)

A set of design guidelines specifically developed to make digital interfaces more accessible for autistic users. GAIA addresses common barriers that autistic people face when using technology, including sensory overload from animations and complex layouts, difficulty with…

GPS Tracking(also: GPS Monitoring, Electronic Tracking, Location Tracking)

The use of Global Positioning System technology to monitor and record the geographic location of a person or device in real time. In accessibility and dementia care contexts, GPS tracking is used in safe walking aids and wearable devices to help caregivers locate people who may…

Game-Based Assessment(also: Gamified assessment, Serious-game assessment)

The use of purpose-built games or playful interactive experiences to measure cognitive, behavioral, or skill-based constructs that would traditionally be assessed through structured tests or questionnaires. Game-based assessments embed validated task parameters (e.g.,…

Generalized Anxiety Disorder(also: GAD)

A mental-health condition characterized by persistent, excessive, and often uncontrollable worry about a range of everyday situations, accompanied by physical and cognitive symptoms such as restlessness, fatigue, difficulty concentrating, muscle tension, and sleep disturbance.…

Generative Thinking(also: Generative Cognition, Creative Problem Solving)

Generative thinking is the cognitive ability to spontaneously produce novel ideas, solutions, or approaches to problems without external prompting. In the context of autism and cognitive accessibility, generative thinking is significant because it is often considered impaired in…

Germane Cognitive Load(also: Germane Load)

One of three types of cognitive load identified by cognitive load theory, referring to the mental effort devoted to processing, constructing, and automating knowledge schemas — the productive cognitive work that leads to actual learning. Unlike extraneous load (which is…

Gist Summary(also: Gist, Page Gist, Web Page Summary)

A gist summary is a brief, automatically or manually generated overview of a document or web page that captures its central theme or focus, enabling a reader to quickly assess the content's relevance without reading the entire text. In accessibility contexts, gist summaries are…

Global Symbols

A community-interest company and open symbol platform that hosts multiple pictogram libraries for AAC and Easy Read, supports translation into many languages, and provides an AI-assisted SymbolBuilder tool for generating new symbols. Global Symbols is widely used in projects…

Grapheme

The smallest unit of a writing system, typically a letter or group of letters that represents a single phoneme (sound). For example, the word "ship" contains three graphemes: <sh>, <i>, and <p>. Understanding grapheme-phoneme correspondence — how written letters map to spoken…

Graphicacy(also: Graph Literacy, Visual Literacy)

The ability to read, interpret, and communicate information presented in graphs, charts, maps, and other visual representations of data. Graphicacy is considered a foundational literacy alongside reading, writing, and numeracy. It involves three progressive stages: reading the…

Graphical Model(also: Visual Model, Graphical Representation)

In educational and accessibility contexts, a visual representation system that uses shapes, colours, spatial relationships, and physical manipulation to convey abstract concepts. Graphical models for mathematics represent numbers as groups of objects whose size corresponds to…

Grounding(also: Grounding Techniques, Grounding Exercises, Self-Regulation)

A set of therapeutic and coping techniques used to help a person reconnect with the present moment and their physical surroundings during periods of emotional distress, anxiety, or trauma response. Grounding activities aim to strengthen the connection between mind and body and…

Guided Error Training(also: Error-Based Training, Productive Failure)

An instructional method where learners observe or experience common errors along with their corrections, rather than only seeing error-free demonstrations. Research shows this approach helps build more robust mental models of how systems work, improving knowledge transfer to new…

Guided Incremental Search(also: Step-by-Step Search, Faceted Browsing)

A web navigation pattern in which users are led through a series of small, sequential choices — such as selecting categories, subcategories, and filters — to progressively narrow search results toward a target. While this approach reduces the cognitive demand of each individual…

Gulf of Execution

A concept from Don Norman's theory of action describing the gap between a user's intention and the actions available to achieve that goal through an interface. When the gulf of execution is large, users struggle to figure out how to operate a system to accomplish their…

Gunning Fog Index(also: Gunning FOG, FOG Index)

A traditional readability formula developed by Robert Gunning in 1952 that estimates the years of formal education a reader needs to understand a text on first reading. It is calculated from average sentence length plus the percentage of "complex" words — words with three or…

Hemi-Attention(also: Hemispatial Neglect, Unilateral Neglect, Visual Neglect)

A neurological condition in which a person has reduced attention or awareness to one side of space, typically the side opposite to a brain injury. Unlike hemianopsia (where visual input is lost), hemi-attention involves a failure to attend to or process stimuli on the affected…

Hick-Hyman Law(also: Hick's Law)

A principle from experimental psychology stating that the time it takes a person to make a decision increases logarithmically with the number of available choices. In accessibility and interface design, Hick-Hyman Law informs the practice of limiting the number of options…

Hierarchical Task Analysis(also: HTA)

A structured method for describing and analyzing tasks by breaking them down into goals, sub-goals, and operations in a hierarchical tree structure. Originally developed for industrial and safety-critical domains, HTA has been adopted in accessibility research to identify where…

Home Button(also: Home Key, Home Screen Button)

The home button is a persistent, consistently-placed control on a device that returns the user to a known starting state — typically the home screen or main menu — from anywhere in the interface. From an accessibility standpoint, the value of a reliable home button is cognitive:…

Human Failure Modes and Effects Analysis(also: HFMEA, Human FMEA)

An adaptation of Failure Modes and Effects Analysis (FMEA) that focuses specifically on human performance and error. HFMEA systematically examines each step in a process to identify how humans might fail, why they might fail, and what effects those failures would have. In…

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…

Iconography(also: Icon Design, Icon System)

The design and systematic use of visual symbols to convey meaning in an interface. Good iconography balances recognisability, consistency, and cultural appropriateness so that users can interpret symbols quickly without reading text. For accessibility, icons alone are rarely…

Illiteracy(also: Functional Illiteracy, Low Literacy)

The inability to read or write, or having reading and writing skills below a functional level needed for everyday tasks. In the context of digital accessibility, illiteracy and low literacy present significant barriers to using text-based interfaces, navigating websites,…

Image-Based Interface(also: Photo-Based Interface, Picture-Based Interface)

A user interface design approach that uses photographs, icons, or other visual images as the primary means of interaction and identification, minimizing or eliminating the need for text. Image-based interfaces are particularly valuable for users with cognitive disabilities, low…

Immersive Analytics(also: 3D Data Visualisation, Spatial Analytics, Immersive Visualisation)

Immersive analytics is the application of interactive 3D, virtual reality (VR), or augmented reality (AR) technologies to support data exploration, analysis, and decision-making. By leveraging spatial context, immersive analytics aims to overcome the limitations of flat 2D…

Immersive Storytelling(also: Interactive Narrative, VR Storytelling)

A narrative approach that places users inside a story environment, allowing them to experience and interact with the narrative through spatial presence, sensory engagement, and active participation. In therapeutic and accessibility contexts, immersive storytelling can scaffold…

Impostor Syndrome(also: Impostor Phenomenon, Impostorism)

A psychological pattern in which individuals doubt their accomplishments and fear being exposed as fraudulent despite evidence of competence. For people with disabilities, impostor syndrome is often intensified by ableist institutional structures: accommodations may be…

In-situ Highlighting(also: In-situ Guidance, In-situ Instruction, On-screen Highlighting)

In-situ highlighting is a tutorial technique that overlays visual indicators directly on the live application interface to show the user exactly where to tap, look, or interact next - rather than describing the action in a separate text or video tutorial. Common implementations…

Inattentional Blindness(also: Perceptual Blindness)

Inattentional blindness is the failure to notice a fully visible but unexpected object or feature when attention is directed elsewhere. It is distinct from change blindness (failure to notice a change between two views): inattentional blindness is about missing something that…

Independent Living(also: Autonomous Living)

A philosophy and practical goal emphasizing that people with disabilities should have the same opportunities and control over their daily lives as people without disabilities, including making choices about where and how they live. In accessibility practice, independent living…

Information Appliance(also: Smart Appliance, Dedicated Device)

A computing device designed for a specific, well-defined purpose that is communication-oriented and easy to use, in contrast to a general-purpose computer. Information appliances typically have reduced functionality and complexity compared to desktop or laptop computers, making…

Information Foraging(also: Information Foraging Theory)

A theoretical framework from cognitive science that models how people search for and navigate to information, drawing an analogy to animal foraging behaviour. Users assess "information scent" — cues like link text, headings, and page structure — to decide whether to continue…

Information Overload(also: Cognitive Overload, Information Overwhelm)

The state of being overwhelmed by the volume of information presented, making it difficult to identify relevant content, make decisions, or complete tasks effectively. In web accessibility contexts, information overload disproportionately affects screen reader users who must…

Information Scent(also: Information Smell)

A concept from information foraging theory that describes the strength of cues in a user interface that indicate whether a particular path (link, button, menu item) will lead to desired information or functionality. Strong information scent means users can easily predict what…

Information Seeking(also: Information Retrieval Behavior, Information Search)

The process of actively looking for specific information to answer a question, complete a task, or satisfy an information need. Information seeking on the web involves formulating queries, navigating search results, scanning pages for relevant content, and synthesizing…

Information chunking(also: Chunking)

The practice of organizing information into smaller, manageable groups or segments to reduce cognitive load and improve comprehension and retention. Rooted in cognitive psychology research on working memory limitations, chunking is essential for accessible content design —…

Inhibitory Control(also: Response Inhibition, Impulse Control)

The executive function that enables a person to suppress automatic or impulsive responses in favor of more appropriate, goal-directed behavior. Inhibitory control is essential for tasks requiring sustained focus, turn-taking, and resisting distractions. It is commonly affected…

Instructional design(also: Learning design)

The systematic process of creating educational or instructional materials and experiences that facilitate effective learning and task completion. In accessibility, instructional design principles ensure that tutorials, product manuals, help documentation, and learning materials…

Instrumental Activities of Daily Living(also: IADL, IADLs)

Complex daily tasks that require higher-order cognitive and organizational skills beyond basic self-care. IADLs include managing finances, shopping, preparing meals, housekeeping, using transportation, managing medications, and using communication devices. The Lawton IADL Scale…

Intellectual Disability(also: ID, Intellectual Development Disorder)

A disability characterized by significant limitations in intellectual functioning (reasoning, learning, problem-solving) and adaptive behavior (everyday social and practical skills), originating during the developmental period. Intellectual disability exists along a continuum…

Intellectual Disability(also: ID, Cognitive Disability, Learning Disability (UK))

A disability characterized by significant limitations in intellectual functioning (reasoning, learning, problem-solving) and adaptive behavior (conceptual, social, and practical skills) that originates before age 22. Intellectual disabilities exist on a spectrum from mild to…

Intellectual Disability(also: ID, Learning Disability (UK), Cognitive Disability)

A condition characterized by significant limitations in both intellectual functioning (reasoning, learning, problem-solving) and adaptive behavior (conceptual, social, and practical skills) that originates before age 22. The DSM-5 and ICD-11 classify severity levels based on…

Intentional Sensory Stimulation

A design approach for technology that deliberately leverages optimal sensory modes — visual, auditory, haptic, or multimodal — to facilitate comprehension and engagement, rather than simply reducing interface complexity. Introduced in the context of dementia accessibility…

Interaction Framing(also: Narrative Framing, Framing (Interaction Design))

Interaction framing refers to the way a system positions the user's role and the meaning of their input, independent of the underlying mechanics. The same choice can be framed as completing a task ("select the appropriate response") or as taking a meaningful action inside a…

Interactive Task Guidance(also: Task Guidance System, Step-by-Step Task Support, Task Prompting)

Interactive task guidance is a form of cognitive assistive technology that provides real-time, step-by-step instructions to help individuals with cognitive impairments complete multi-step daily activities. Unlike simple reminder systems that only alert users to start a task,…

Intrinsic Cognitive Load(also: Intrinsic Load)

One of three types of cognitive load identified by cognitive load theory, referring to the inherent difficulty of the material being learned based on its complexity and the learner’s prior knowledge. Intrinsic cognitive load is determined by the number of elements that must be…