Sensory, Attentional and Perceptual Processes

Vocabulary flashcards covering key terms and concepts in sensory, attentional, and perceptual processes from Chapter 4.

Cognition

The interrelated set of mental processes—including sensation, attention, and perception—that work together to generate knowledge of the world.

Sensory Receptors

Specialised information-gathering systems that receive and gather information from internal and external environmental sources.

Kinesthetic System

A deep sense organ system that provides feedback regarding body position and the movement of individual body parts relative to one another.

Vestibular System

A deep sense organ system responsible for providing information about body position and movement.

Sensation

The initial detection and neural encoding of physical stimuli by a sense organ, providing basic sensory attributes such as loudness, warmth, or colour.

Sense Modality

A specialized sense organ system adapted for processing a specific type of sensory information.

Psychophysics

The discipline that studies the quantitative relationship between physical stimuli and the sensations they evoke.

Absolute Threshold (Absolute Limen, AL)

The minimum intensity or value of a stimulus required to activate a sensory system and evoke a sensation on $50\%$ of trials.

Difference Threshold (Difference Limen, DL)

The smallest detectable difference in value between two physical stimuli necessary to perceive them as different on $50\%$ of trials.

Attention

The cognitive process of selectively focusing awareness on specific environmental stimuli while filtering out competing stimuli.

Alertness

An individual's state of readiness to deal with stimuli as they appear in the environment.

Concentration

The sustained focusing of conscious awareness on a specific object or task while excluding surrounding distractions.

Search

An attentional activity involving active scanning to locate a specified target or subset of objects among a larger array.

Focus of Attention

The center or focal point of conscious awareness where stimuli are attended to clearly and sharply.

Fringe of Attention

The peripheral area of awareness surrounding the focus, containing stimuli that an individual is only vaguely conscious of.

Divided Attention

The allocation of attentional effort to perform two or more activities simultaneously, made possible through automatic processing of highly practiced tasks.

Automatic Processing

Information processing that occurs without intention, operates unconsciously, and requires minimal cognitive effort.

Selective Attention

The process of selecting a limited subset of sensory inputs for further processing from a vast array of available stimuli.

Filter Theory

Broadbent's (1956) model proposing that a selective filter screens out competing sensory inputs in short-term memory, allowing only one stimulus through a bottleneck for higher-level processing.

Filter-Attenuation Theory

Triesman's (1962) model proposing that unattended stimuli are weakened (attenuated) rather than completely blocked, allowing highly relevant stimuli like one's name to reach awareness.

Multimode Theory

Johnston and Heinz's (1978) model conceptualizing attention as a flexible system allowing selection at sensory, semantic, or conscious stages, with later selection demanding greater mental effort.

Sustained Attention (Vigilance)

The ability to maintain focused concentration on an object or event over an extended period of time.

Span of Attention (Perceptual Span)

The maximum number of items an observer can grasp in a single momentary exposure, identified by Miller as $7 \pm 2$ items.

Tachistoscope

A laboratory instrument used to present visual stimuli for brief fraction-of-a-second exposures to measure the span of attention.

Attention Deficit Hyperactivity Disorder (ADHD)

A common primary school-age behavioural disorder characterized by impulsivity, excessive motor activity, and significant impairment in sustaining attention.

Ritalin

A medication commonly prescribed for ADHD that decreases over-activity and distractibility while increasing focus and concentration.

Perception

The process of interpreting, constructing, and assigning meaning to sensory information using memory, motivation, learning, and cognitive context.

Bottom-Up Processing

Perceptual processing that begins with analyzing sensory features or individual parts to construct a recognized whole object.

Top-Down Processing

Perceptual processing where expectations, prior knowledge, or the whole context guide the identification and interpretation of component parts.

Perceptual Set

A mental readiness or expectancy to perceive a stimulus in a particular way based on familiarization, context, or prior experience.

Cognitive Style

An individual's consistent and characteristic way of organizing, processing, and perceiving environmental information.

Field Dependent Cognitive Style

A cognitive style characterized by perceiving the visual environment globally and holistically, experiencing difficulty isolating embedded parts from their context.

Field Independent Cognitive Style

A cognitive style characterized by an analytical perceptual approach, enabling individuals to easily isolate smaller component parts or hidden figures from a surrounding context.

Form Perception

The perceptual process of organizing raw visual elements into structured, meaningful, and identifiable whole shapes or objects.

Gestalt

A German term meaning form or regular figure, representing the principle that perception consists of organized wholes rather than the sum of discrete sensory parts.

Pragnanz

The Gestalt law stating that brain processes are oriented toward perceiving the simplest, most stable, and best possible figure ('good figure').

Figure-Ground Segregation

The fundamental perceptual organization process wherein a visual scene is separated into a distinct object with contours (figure) and a formless background (ground).

Rubin's Vase

A classic visual figure illustrating figure-ground segregation, where viewers alternate between perceiving a central white vase and two black facing profiles.

Principle of Proximity

The Gestalt organization principle stating that visual elements positioned close together in space or time tend to be perceived as a unified group.

Principle of Similarity

The Gestalt organization principle stating that stimuli sharing similar physical properties (such as shape or color) are grouped together.

Principle of Continuity

The Gestalt principle stating that elements aligned in a smooth, continuous pattern or line are perceived as belonging together.

Principle of Smallness

The Gestalt principle stating that smaller enclosed areas are preferentially perceived as figures against a larger surrounding background.

Principle of Symmetry

The Gestalt principle stating that symmetrical visual areas tend to be perceived as figures against asymmetrical backgrounds.

Principle of Surroundedness

The Gestalt principle stating that regions completely surrounded by other areas are consistently perceived as distinct figures.

Principle of Closure

The Gestalt principle describing the perceptual tendency to mentally fill in gaps in incomplete sensory inputs to perceive a complete object.

Depth Perception

The ability to perceive the world in three dimensions and judge the distance of objects, converting two-dimensional retinal images into three-dimensional experiences.

Monocular Cues

Depth perception cues effective when viewing a scene with only one eye, frequently utilized by artists as pictorial cues.

Relative Size

A monocular depth cue where smaller retinal images of familiar objects are interpreted as being farther away, while larger images appear closer.

Interposition (Overlapping)

A monocular depth cue where an object that partially covers another object is perceived as being closer to the observer.

Linear Perspective

A monocular pictorial cue where parallel lines appear to converge as they recede into the distance toward a vanishing point on the horizon.

Aerial Perspective

A monocular cue where distant objects appear blurry or bluish due to atmospheric dust and moisture scattering light.

Texture Gradient

A monocular depth cue where a surface texture appears denser and finer as distance increases.

Accommodation

A monocular physiological cue where ciliary muscles alter the thickness of the eye lens to focus images of near or distant objects onto the retina.

Motion Parallax

A kinetic monocular depth cue where objects at different distances move across the visual field at varying relative speeds when the observer moves.

Binocular Cues

Depth and distance cues that rely on simultaneous visual input from both eyes.

Retinal Disparity

A binocular depth cue resulting from the horizontal separation ($6.5\,\text{cm}$) between the eyes, producing slightly different images on each retina that the brain interprets as depth.

Convergence

A binocular depth cue in which eye muscles turn the eyes inward to focus on close objects, sending signals to the brain to estimate proximity.

Perceptual Constancy

The tendency to perceive physical objects as stable in size, shape, and brightness despite continuous changes in sensory stimulation.

Size Constancy

The tendency for an object's perceived size to remain relatively constant regardless of changes in distance and retinal image size.

Shape Constancy

The perceptual tendency to view familiar objects as retaining their true shape regardless of orientation or changes in the retinal image shape.

Brightness Constancy

The tendency to perceive an object's lightness or darkness as constant despite changes in the amount of light reflected from it.

Illusions

Misperceptions resulting from incorrect interpretation of sensory information, creating a mismatch between physical reality and perception.

Muller-Lyer Illusion

A geometrical illusion where two equal-length lines appear different in length due to inward- or outward-pointing arrowheads at their ends.

Vertical-Horizontal Illusion

A visual illusion where a vertical line is perceived as longer than an intersecting horizontal line of identical length.

Phi-Phenomenon

An apparent movement illusion created when stationary visual stimuli are presented in rapid succession at an appropriate rate.