Sensory, Attentional and Perceptual Processes – Key Vocabulary

Comprehensive vocabulary list covering sensation, attention, perceptual organisation, depth cues, constancies, illusions, and cultural influences from Chapter 4 of Psychology (Sensory, Attentional and Perceptual Processes).

Sensation

The immediate, basic experience produced when a stimulus activates a sensory receptor.

Stimulus

Any physical energy or event that can activate a sense organ and evoke a response.

Sense Modality

A specialised sensory system (e.g., vision, hearing) that registers a particular kind of stimulus.

Sensory Receptor

A structure (external or internal) that detects and encodes specific forms of physical energy.

Kinesthetic Sense

Deep sense that provides information about the position and movement of body parts.

Vestibular Sense

Deep sense located in the inner ear that informs us about balance and body orientation.

Absolute Threshold (Absolute Limen)

The minimum intensity of a stimulus detectable 50 % of the time.

Difference Threshold (Difference Limen)

The smallest change in stimulus intensity required to detect a difference 50 % of the time.

Psychophysics

The study of relationships between physical stimuli and the sensations and perceptions they produce.

Functional Limitation of Sense Organs

The restricted range within which human sensory systems can detect stimuli (e.g., eyes cannot see very dim or very bright light).

Attention

The process of selectively concentrating on certain stimuli while ignoring others; includes alertness, concentration, and search.

Selective Attention

Focusing on a limited number of stimuli out of many simultaneously impinging on the senses.

Divided Attention

Allocating mental effort to two or more tasks or stimuli at the same time, usually possible with highly practised activities.

Sustained Attention (Vigilance)

Maintaining concentration on a task or stimulus for prolonged periods.

Span of Attention

The amount of information that can be grasped in a single brief exposure; typically 7 ± 2 items.

Attention Deficit Hyperactivity Disorder (ADHD)

A childhood disorder marked by impulsivity, excessive motor activity, and difficulty sustaining attention.

Bottom-up Processing

Perceptual analysis that begins with sensory input, building up to the perception of a whole object.

Top-down Processing

Perception driven by knowledge, expectations, and experience, working from the whole to recognition of parts.

Perceptual Set (Expectancy)

A readiness to perceive stimuli in a particular way based on expectations.

Field-Dependent Cognitive Style

Global perception of the environment; difficulty separating details from surrounding context.

Field-Independent Cognitive Style

Analytic perception that easily separates parts from the surrounding field.

Figure-Ground Segregation

The organisation of the visual field into a central figure that stands out against a background.

Gestalt

A structured whole in perception that is more than the sum of its parts.

Principle of Proximity

Gestalt rule stating that elements near each other are perceived as belonging together.

Principle of Similarity

Gestalt rule that similar items are grouped together perceptually.

Principle of Continuity

Tendency to perceive smooth, continuous patterns rather than discontinuous ones.

Principle of Smallness

Smaller areas are seen as figures against a larger background.

Principle of Symmetry

Symmetrical regions are perceived as figures against asymmetrical backgrounds.

Principle of Surroundedness

Regions enclosed by others are seen as figures.

Principle of Closure

Tendency to fill in gaps and perceive incomplete figures as complete.

Prägnanz (Good Form)

The tendency for perceptual organisation to be as simple, regular, and symmetrical as possible.

Form Perception

Recognition of organised visual patterns as meaningful wholes.

Depth Perception

Ability to perceive the world in three dimensions and judge distance.

Monocular Cues

Depth cues available to each eye alone (e.g., relative size, interposition, linear perspective).

Binocular Cues

Depth cues that require both eyes (e.g., retinal disparity, convergence).

Relative Size

Monocular cue where smaller retinal images are perceived as farther away.

Interposition (Overlapping)

Monocular cue where a closer object blocks part of a more distant one.

Linear Perspective

Monocular cue in which parallel lines appear to converge with increasing distance.

Aerial Perspective

Monocular cue whereby distant objects appear hazier due to atmospheric particles.

Texture Gradient

Monocular cue; denser texture signals greater distance.

Motion Parallax

Monocular kinetic cue where nearer objects seem to move faster than distant ones as we move.

Accommodation (Ocular)

Depth cue from the eye-lens changing thickness to focus on objects at different distances.

Retinal (Binocular) Disparity

Slightly different images on each retina that the brain compares to gauge distance.

Convergence

Muscular cue produced by inward turning of the eyes for near objects.

Perceptual Constancy

Tendency to perceive objects as stable (in size, shape, brightness) despite changes in sensory input.

Size Constancy

Perceiving an object’s size as unchanging despite variations in retinal image size.

Shape Constancy

Perceiving familiar objects as having constant form regardless of viewing angle.

Brightness Constancy

Perceiving an object’s brightness as constant even when illumination changes.

Illusion

A misperception or misinterpretation of a real external stimulus.

Müller-Lyer Illusion

Geometrical illusion in which lines of equal length appear unequal due to arrowhead fins.

Vertical-Horizontal Illusion

Illusion where a vertical line appears longer than an identical horizontal line.

Phi-Phenomenon

Illusion of movement created when stationary lights are flashed in rapid succession.

Sociocultural Influence on Perception

The effect of cultural experience and social environment on the ways people interpret sensory information.