Glossary
Searchable terminology from accessibility, web standards, and related fields.
6660 terms — page 217 of 333
- Perceptual Bandwidth (Sensory Bandwidth, Information Bandwidth)
- Perceptual bandwidth refers to the rate at which a sensory channel can transmit information to the brain. In accessibility contexts, the concept highlights the fundamental asymmetry between vision and…
- Perceptual Computing (Perceptual Intelligence)
- A computing paradigm in which systems use sensors such as cameras, microphones, and motion detectors to perceive and interpret human behaviour, including gestures, facial expressions, speech, and body…
- Perceptual Congruence (Perceptually Congruent Structure)
- A design principle for accessible representations that requires the structure of a non-visual interface (such as a screen reader navigation tree) to mirror the visual structure of the original graphic…
- Perceptual Cycle (Perceptual Response Time, Perceptual Processing)
- In the Model Human Processor framework, the perceptual cycle is the time required for a person to perceive and register a stimulus from their environment, such as seeing a visual change on screen. The…
- Perceptual Gap
- A design failure identified by Choudhury (2026) in which an AI system's explanation is delivered through exactly the sensory channel that its user cannot access. For example, a Grad-CAM heat map overl…
- Perceptual Guidance
- An instructional technique that directs a user’s attention to specific perceptual features of a target — most commonly color and on-screen location — to help them detect or disambiguate it. In accessi…
- Perceptual Hashing (Image Hashing, pHash)
- A technique that generates a compact fingerprint (hash) of an image based on its visual content rather than its raw data. Unlike cryptographic hashes that change completely with any modification, perc…
- Perceptual Integration (Perceptual Binding)
- The process by which the brain combines information arriving through different sensory channels — vision, hearing, touch, proprioception — into a single coherent percept of an object or event. Percept…
- Perceptual Learning (Visual Perceptual Learning, PL)
- A long-studied phenomenon in vision science in which repeated exposure to, or training on, specific perceptual features — color, orientation, spatial location, shape — produces durable improvements in…
- Perceptual Linear Prediction (PLP, PLP Coefficients)
- Perceptual Linear Prediction (PLP) is an acoustic feature extraction technique used in speech processing that models human auditory perception. PLP analysis applies psychoacoustic principles including…
- Perceptual Span (Reading Span, Visual Span)
- The area of text around a fixation point from which useful information can be extracted during reading. Research using eye-tracking has shown that skilled deaf readers have a larger perceptual span th…
- Perceptual User Interface (PUI, Natural User Interface)
- A human-computer interaction paradigm that uses natural human capabilities such as vision, speech, gestures, and body movement as input modalities rather than relying on traditional devices like keybo…
- Perceptual speed (Processing speed, Cognitive processing speed)
- The speed at which an individual can accurately perceive, compare, and respond to visual or auditory stimuli, typically measured through timed tasks requiring rapid symbol comparison or pattern matchi…
- Perceptualisation (Perceptualization)
- A multi-sensory display of abstract information, inferred by Nesbitt to be a fundamentally human quality. Where visualisation presents abstract data through the visual design space (charts, graphs, ma…
- Perfect Pitch (Absolute Pitch, AP)
- The innate ability to identify or reproduce musical pitches without the aid of a reference note. People with perfect pitch can recognize and name any musical note by its pitch alone. For blind and low…
- Perinatal depression (PND, Perinatal mood disorder)
- Perinatal depression (PND) refers to major depressive episodes that occur during pregnancy (antenatal depression) or in the weeks following childbirth (postpartum depression). It affects up to 10% of …
- Peripersonal Space (Near space, Reaching space)
- The area immediately surrounding the body that is within arm's reach, typically extending about 60-70 cm from the body. Peripersonal space is significant in accessibility because blind and visually im…
- Peripheral Awareness (Peripheral Perception, Ambient Awareness)
- The innate ability to unconsciously maintain and constantly update a sense of one's social and physical surroundings without actively directing attention to them. In accessibility contexts, peripheral…
- Peripheral Neuropathy (Neuropathy)
- Peripheral neuropathy is a condition resulting from damage to the peripheral nerves, which carry signals between the brain, spinal cord, and the rest of the body. Symptoms typically include numbness, …
- Peripheral Vision (Side Vision)
- Vision that occurs outside the center of gaze, encompassing the ability to see objects and movement to the sides, above, and below the point of fixation. Peripheral vision is important for spatial awa…