Glossary

Search results

Pronominal Reference(also: Pronoun Reference, Anaphoric Reference)

The use of pronouns or pronoun-like expressions to refer back to entities previously introduced in a discourse. In spoken and written languages this is typically achieved with words such as "he," "she," "it," or "they"; in American Sign Language and other signed languages,…

Proportional Font(also: variable-width font)

A typeface in which characters have varying widths based on their natural proportions—a narrow "i" takes less space than a wide "m". Most fonts used in everyday reading are proportional, including Arial, Times New Roman, and Verdana. While proportional fonts create a more…

Proprioception(also: Proprioceptive Sense, Body Position Sense)

The body's ability to sense its own position, movement, and orientation in space without relying on vision. Proprioceptive information comes from sensory receptors in muscles, tendons, and joints that detect stretch, tension, and pressure. For people who are blind or have low…

Prosociality(also: Prosocial Behavior, Prosocial Behaviour)

Prosociality refers to voluntary behaviour intended to benefit others, including helping, sharing, comforting, and cooperating. In accessibility and dementia research, prosocial acts observed during group activities - passing a card so a peer can see it, a reassuring touch on…

Prosodic Breaks(also: Prosodic Pauses, Prosodic Boundaries)

Pauses or breaks in the flow of communication that convey grammatical, syntactic, or emphatic meaning. In sign language, prosodic breaks occur between signs and serve functions similar to intonation and pausing in spoken language — marking sentence boundaries, separating clauses…

Prosody(also: Speech Prosody, Intonation Patterns)

The patterns of stress, rhythm, intonation, and timing in speech that convey meaning beyond the literal words. Prosody communicates emotions, emphasis, questions versus statements, sarcasm, and conversational cues like turn-taking signals. For AAC users relying on text-to-speech…

Prosopagnosia(also: Face Blindness)

A neurological condition characterised by the inability to recognise familiar faces, despite otherwise intact visual and cognitive abilities. People with prosopagnosia may fail to recognise family members, friends, or colleagues by face alone, instead relying on alternative cues…

Prospective Memory

The ability to remember to carry out intended actions in the future, such as taking medication at a specific time, attending an appointment, or completing a task when a particular cue arises. Prospective memory is distinct from retrospective memory (remembering past events) and…

Prosthesis(also: Prosthetic, Prosthetic Device, Artificial Limb)

A prosthesis is an artificial device that replaces a missing body part, which may be lost through congenital conditions, injury, or disease. Prostheses range from purely cosmetic devices designed to replicate natural appearance, to functional devices that restore some degree of…

Prosthesis(also: Prosthetic, Prosthetic device, Artificial limb)

A prosthesis is an artificial device that replaces a missing body part, most commonly a limb. Prosthetics range from cosmetic devices that restore appearance to functional devices that enable specific activities. Modern prosthetics may include mechanical components, myoelectric…

Prosthetics(also: Prostheses, Prosthetic Devices, Artificial Limbs)

Artificial devices designed to replace missing body parts, most commonly limbs lost through amputation, congenital absence, or trauma. Modern prosthetics range from basic cosmetic devices to highly functional myoelectric arms controlled by muscle signals and…

Prosumer(also: Producer-Consumer, Prosumer Content Creator)

A person who both produces and consumes content, particularly on the web. Prosumers are not formally trained in web design or development but are responsible for creating and managing user-generated content shared online — such as blog posts, newsletters, community websites, and…

Protactile Language(also: Pro-Tactile, PT)

A fully touch-based language developed by the DeafBlind community that redefines communication through physical contact, including taps, squeezes, and shared contact space. Protactile Language represents a striking example of a communication micro-culture, where a community…

Protanomaly(also: Protan Anomalous Trichromacy)

A type of colour vision deficiency where the long-wavelength (red) cone cells have a shifted sensitivity range rather than being absent entirely. Protanomaly is a milder form of protan CVD compared to protanopia, resulting in reduced but not absent ability to distinguish reds…

Protanopia(also: Protan Dichromacy, Red-Blind)

A type of colour vision deficiency caused by the complete absence of long-wavelength (red) cone cells in the retina. People with protanopia cannot distinguish between red and green and perceive reds as significantly darker than people with typical colour vision. This darkening…

Protected Characteristic(also: Protected Class, Protected Ground)

A personal attribute that is protected from discrimination under equality legislation. Under the UK Equality Act 2010, the nine protected characteristics are: age, disability, gender reassignment, marriage and civil partnership, pregnancy and maternity, race, religion or belief,…

Proteus Effect

The Proteus Effect is a phenomenon, first described by Yee and Bailenson (2007), in which the appearance of a person's avatar influences how they think, behave and interact in virtual or augmented environments. For example, users assigned taller or more attractive avatars tend…

Prototyping(also: Prototype)

The iterative creation of tangible, interactive representations of a design - ranging from paper sketches and cardboard mock-ups to functional software builds - used to explore ideas, elicit feedback, and test assumptions before committing to a final product. In accessibility…

Provenance Indicator(also: Source Attribution)

Information that identifies which AI model, trial, or prompt produced a particular piece of content in a multi-model comparison. Provenance indicators help users understand which models generate which claims, enabling them to build mental models of individual model strengths and…

Provocation (HCI)(also: Design provocation, Provotype)

In human-computer interaction, a designed artifact whose purpose is to unsettle assumptions, provoke debate, or surface hidden values rather than to solve a defined problem. Provocations draw on traditions of critical design (Dunne and Raby), adversarial design (DiSalvo),…

Proxemic Interaction(also: Proximity-Based Interaction, Proxemics)

An interaction design approach that uses the spatial relationship between users, devices, and objects in the environment — including distance, orientation, and movement — to trigger contextual actions and content delivery. Derived from Edward T. Hall's theory of proxemics (the…

Proxemics(also: Interpersonal distance, Personal space)

The study of how people use and perceive physical space in social interactions, originally defined by anthropologist Edward T. Hall in 1966. Hall identified four distance zones: intimate (0–45 cm), personal (45 cm–1.2 m), social (1.2–3.6 m), and public (beyond 3.6 m). In…

Proximity Detection(also: Proximity Sensing, Proximity-Based Localization)

A method of determining a user's approximate location by measuring their closeness to known reference points, such as BLE beacons or Wi-Fi access points, based on signal strength. In accessible indoor navigation systems, proximity detection is used to localize users at specific…

Proxy(also: Support Person, Intermediary User)

In accessibility contexts, a person who assists someone with a disability in using technology or accessing services. Proxies may include family members, caregivers, support workers, or friends who help with tasks ranging from physical operation of devices to interpretation of…

Proxy Account(also: Delegate Account)

A formal mechanism within a digital system that allows an authorized person to perform tasks on behalf of another user with defined permissions and accountability. In financial technology, proxy accounts enable financial delegates to help older adults or people with disabilities…

Proxy Feedback(also: Proxy User Testing, Surrogate Feedback)

A user research method in which feedback on designs or prototypes is gathered from people who are close to the target users — such as carers, therapists, family members, or support workers — rather than from the users themselves. This approach is used when direct communication…

Proxy Interface(also: Accessibility Proxy, Alternative Interface)

An intermediary user interface that sits between the user and the original content, re-presenting information in a more accessible format without modifying the underlying source. In accessibility contexts, proxy interfaces are used to transform visually-encoded content (like…

Proxy User(also: Proxy Participant, Surrogate User)

A person without a disability who participates in research or usability testing as a stand-in for the intended end user with a disability. Proxies are commonly used in AAC and assistive technology research to circumvent challenges in recruiting and communicating with…

Proxy stakeholder(also: Proxy informant, Proxy respondent)

In requirements engineering and participatory design, a proxy stakeholder is a person—such as a caregiver, support worker, family member, or healthcare professional—who actively mediates, interprets, and scaffolds technology use on behalf of a primary user who faces barriers to…

Pseudo-Attraction Force

A haptic illusion technique that creates the sensation of being pulled or pushed in a specific direction by exploiting the nonlinear relationship between physical and perceived acceleration. The technique uses asymmetric oscillation: a strong, brief acceleration in the intended…

Pseudo-participation(also: Pseudo-participation by Design)

A term coined by Palacin et al. (2020) to describe forms of user involvement in design that appear participatory on the surface but grant participants limited power to shape outcomes. In accessibility and AI contexts, pseudo-participation occurs when disabled people are invited…

Pseudobulbar Affect(also: PBA, Emotional Incontinence, Involuntary Emotional Expression Disorder)

A neurological condition characterized by episodes of involuntary, exaggerated, or inappropriate emotional expression — such as uncontrollable laughing or crying — that may not match the person's actual emotional state. Pseudobulbar affect occurs after damage to the neural…

Pseudonymization(also: Pseudonymisation, De-identification)

A privacy technique in which personally identifying fields are replaced with artificial identifiers — typically hashes, tokens, or randomly assigned IDs — so that the data can no longer be attributed to a specific person without additional information kept separately. Recognised…

Psychoacoustics

The branch of perceptual psychology that studies how humans subjectively perceive sound - loudness, pitch, timbre, spatial location, foreground/background segregation, and masking. Psychoacoustic principles underpin accessible audio design: screen reader pacing, earcon and…

Psychoeducation

The process of providing education about a mental health condition, its symptoms, treatment options, and management strategies to individuals with the condition and their support networks. For OCD, psychoeducation helps people understand the nature of obsessions and compulsions,…

Psycholinguistics

The scientific study of the cognitive and neural processes that underlie the production, comprehension, and acquisition of language. Psycholinguistic research measures phenomena such as reading and signing rate, comprehension under time pressure, lexical access, and the role of…

Psychological Accessibility

A dimension of accessibility concerned with whether users find a product or service useful, appropriate, and satisfying, beyond being merely technically operable. Psychological accessibility addresses factors such as user confidence, willingness to engage with technology, and…

Psychometric Evaluation(also: Psychometric Validation, Psychometric Analysis)

The process of assessing whether a measurement instrument (such as a questionnaire or survey) possesses desirable statistical properties including validity, reliability, and consistency. In accessibility and usability research, psychometric evaluation is used to determine…

Psychometric Test(also: Psychometric Assessment, Psychometric Evaluation)

A standardised measurement instrument designed to assess an individual's cognitive abilities, motor skills, perceptual speed, or other psychological attributes. In accessibility research and usability evaluation, psychometric tests such as the Mini-Mental State Examination…

Psychometric validation(also: Psychometric evaluation, Instrument validation)

The process of establishing that a measurement instrument (such as a questionnaire or scale) possesses adequate reliability (consistency of measurement), criterion validity (correlation with established measures), and construct validity (measuring the intended theoretical…

Psychomotor testing(also: Psychomotor assessment, Motor performance testing)

The measurement of cognitive-motor integration — how quickly and accurately a person can translate mental intentions into physical actions such as reaching, pointing, grasping, or tapping. Psychomotor tests assess reaction time, movement speed, accuracy, coordination, and…

Psychophysics

Psychophysics is the scientific study of the quantitative relationship between physical stimuli and the sensations and perceptions they produce. Founded in the 19th century, it uses rigorous experimental methods to measure how humans detect, discriminate, and scale sensory…

Psychosocial Disability(also: Psychosocial Impairment)

A disability that stems from diverse mental, cognitive, or emotional experiences that lead to impairment and experienced barriers in social participation. Psychosocial disabilities include conditions such as ADHD, anxiety, depression, bipolar disorder, and other mental health…

Psychosocial Impact of Assistive Devices Scale(also: PIADS)

A 26-item self-report questionnaire designed to measure the psychosocial impact of an assistive technology device on a person's functional independence, well-being, and quality of life. PIADS assesses three subscales: competence (subjective feelings of competence, productivity,…

Public Access System(also: Kiosk, Self-Service Terminal, Public Information Kiosk)

Interactive computer terminals placed in public locations for use by the general population, including ticket vending machines, ATMs, check-in kiosks, and information displays. These systems present unique accessibility challenges because users cannot customize them, may have…

Public Access Terminal(also: Public Kiosk, Public Information Terminal)

A Public Access Terminal is an interactive computing device installed in public spaces for use by the general population, including information kiosks, ticketing machines, check-in terminals, voting machines, and ATMs. Accessibility of public access terminals is particularly…

Public Digital Terminal(also: PDT, Self-Service Terminal, Self-Service Kiosk)

A publicly available interactive electronic device that provides services or information to users, such as ATMs, ticket vending machines, check-in kiosks, and information points. Public digital terminals present significant accessibility challenges because users cannot install…

Public Transport Accessibility(also: Transit Accessibility, Accessible Public Transportation)

The design of buses, trains, stations, stops, timetables, and associated services to be usable by people with all types of disabilities. This includes physical features (ramps, lifts, tactile paving, audio announcements), information accessibility (large print, screen reader…

Pull Notification(also: On-Demand Notification, User-Initiated Notification)

A notification or information delivery model where content is provided only when explicitly requested by the user, in contrast to push notifications which are delivered automatically. In assistive navigation contexts, pull notifications allow blind users to request specific…

Pulmonary Rehabilitation(also: PR, Respiratory Rehabilitation)

A supervised, multidisciplinary program for people with chronic respiratory diseases that combines patient education, exercise training, and self-management skills to reduce symptoms, improve quality of life, and increase physical activity. During pulmonary rehabilitation,…