U3 Topic 2 - Perception

Flashcards covering visual and auditory sensation, perception processes, Gestalt principles, depth cues, constancies, and cultural influences based on senior psychology lecture notes.

Sensation

The process of detecting physical energy or stimuli from the external environment. Involving three stages; reception, transduction, and transmission.

Perception

The active process where the brain selects, organizes, and interprets raw sensory information to create meaningful experiences.

Reception

First stage of sensation, involving receiving and detecting external stimuli.

Transduction

The second stage of sensation, involving the process which receptors convert the stimulus’s energy into electrochemical signals (nerve impulses).

Transmission

The third stage of sensation, in which electrochemical nerve impulses are sent to the central nervous system for processing.

Selection

The first stage of perception where the brain filters out irrelevant stimuli to attend to important visual or auditory information.

The thalamus assists with this before relaying the info to appropriate regions for further processing.

Organisation

The second stage of perception in which sensory information is grouped into a coherent patterns.

Interpretation

The final stage of perception where the brain assigns meaning to sensory input based on prior knowledge, expectations, motives and emotions.

Absolute Threshold

The minimum level of stimulus energy required for a stimulus to be detected $50\%$ of the time under ideal conditions.

Signal Detection Theory

A theory proposing that stimulus detection involves both sensory processes and psychological decision-making processes influenced by attention, fatigue, and motivation.

Thalamus

A subcortical structure located between the cerebral cortex and midbrain that acts as a sensory relay station, filtering irrelevant stimuli and directing signals to appropriate primary sensory cortices.

Electromagnetic Energy

The physical energy source for vision that travels in waves of varying sizes across the electromagnetic spectrum.

Visible Light Spectrum

The narrow range of electromagnetic energy wavelengths that photoreceptors in the human eye are sensitive to.

Photoreceptors

Light-sensitive sensory receptor cells located in the retina, comprising rods and cones.

Rods

Photoreceptors located mainly in the peripheral retina that function well in dim light, detect black, white, and shades of grey, and outnumber cones by $20:1$.

Cones

Photoreceptors concentrated in the central retina responsible for colour vision, high visual acuity, and fine detail under bright light conditions.

Optic Chiasm

The X-shaped point where half of the nerve fibers from each retina cross over to the opposite side of the brain, directing visual field information contralaterally.

Feature Detectors

Specialised neurons in the visual cortex that respond individually to specific elements of a visual stimulus, such as lines of specific orientation, angles, or motion.

Anatomy of the Eye

The sensory structure for vision comprising the cornea (A), iris (B), pupil (C), lens (D), retina (E), and optic nerve (F).

Sound Wave

A longitudinal wave consisting of alternating compressions and rarefactions that propagates physical energy through a medium such as air, water, or solids.

Amplitude (Sound)

The maximum displacement of particles in a medium from equilibrium during a sound wave, determining perceived volume or loudness.

Wavelength (Sound)

The distance between two consecutive peaks or troughs in a sound wave, which is inversely related to wave frequency.

Frequency

The number of sound wave cycles per second measured in hertz ($\text{Hz}$), which determines perceived pitch.

McGurk Effect

A perceptual illusion demonstrating visual-auditory integration where conflicting lip movements and auditory speech blend into a completely new perceived sound.

Pinna

The visible outer part of the ear that collects and funnels sound waves into the auditory canal.

Ossicles

Three tiny bones in the middle ear—the malleus (hammer), incus (anvil), and stapes (stirrup)—that amplify eardrum vibrations before sending them to the cochlea.

Cochlea

A spiral-shaped, fluid-filled inner ear structure containing the basilar membrane and hair cells where auditory transduction takes place.

Hair Cells

Specialised sensory receptors for hearing situated along the basilar membrane inside the cochlea that convert mechanical fluid vibrations into electrochemical signals.

Binaural Cues

Auditory cues that use slight differences in the arrival timing and intensity of sound reaching each ear to determine sound location.

Anatomy of the Ear

The auditory organ composed of the outer ear (pinna, auditory canal), middle ear (eardrum, malleus, incus, stapes), and inner ear (cochlea, basilar membrane, hair cells, auditory nerve).

Bottom-Up Processing

Perceptual processing that constructs a whole perception directly from incoming sensory data without influence from prior knowledge or expectations.

Top-Down Processing

Perceptual processing driven by higher-level cognitive factors, using prior experience, stored memories, expectations, and context to assign meaning to stimuli.

Primary Sensory Cortex

A specialised region of the brain where raw sensory information from receptors is initially processed (such as the primary visual or primary auditory cortex).

Association Cortex

A specialized region of the cerebral cortex where multiple streams of sensory data are integrated for higher-level mental functions.

Perceptual Set

A predisposition or mental readiness to perceive a stimulus in a particular manner based on past experience, context, motivation, and emotional state.

Gestalt Principles

Visual perception rules used during the organisation stage based on the principle that the brain perceives holistic configurations where 'the whole is greater than the sum of its parts'.

Proximity

A Gestalt principle stating that individual elements positioned close to one another are naturally grouped together into a unified pattern or whole.

Similarity

A Gestalt principle stating that visual elements sharing physical attributes such as shape, size, or colour are grouped together as a single unit.

Continuity

A Gestalt principle describing the brain's tendency to organize visual elements that lie along a smooth, continuous path into unified lines or curves.

Figure-Ground Organisation

A Gestalt principle describing how a visual scene is organised by distinguishing a central object of focus (the figure) from its surrounding background (the ground).

Closure

A Gestalt principle describing the brain's tendency to fill in gaps or missing parts in incomplete figures to perceive a complete, whole object.

Camouflage

An application of figure-ground organisation where contours are broken up or contrast is reduced, causing the figure to blend in with its background.

Symmetry

A Gestalt principle where visually balanced elements arranged around a central axis are perceived as unified structures due to proximity and alignment.

Depth Perception

The ability to accurately estimate distance and three-dimensional space using visual cues, despite retinas receiving only two-dimensional images.

Binocular Depth Cues

Visual depth cues that require sensory input from both eyes working together to estimate distance.

Retinal Disparity

A binocular depth cue arising because eyes are set $6\text{ to }7\text{ cm}$ apart, causing slightly different retinal images that the brain compares to judge distance (operates up to $20\text{ m}$, strongest within $7\text{ m}$).

Convergence

A binocular depth cue operating within about $7\text{ cm}$ where eyes turn inward to focus on approaching objects, with the brain gauging distance from extraocular muscle tension.

Monocular Depth Cues

Visual depth cues that enable the perception of depth and distance using input from one eye alone.

Pictorial Depth Cues

Monocular depth cues used on two-dimensional surfaces to create an impression of three-dimensional depth.

Linear Perspective

A pictorial depth cue where parallel lines appear to converge as they extend toward an imaginary vanishing point on the horizon.

Interposition

A pictorial depth cue where an object that partially overlaps or obscures another is perceived as being closer.

Texture Gradient

A pictorial depth cue where surface details are fine and distinct up close, but become gradually less detailed and denser as distance increases.

Relative Size

A pictorial depth cue where the object producing the larger image on the retina is perceived as closer, provided the true sizes of the objects are known.

Height in the Visual Field

A pictorial depth cue where ground objects higher in the field (closer to horizon) or sky objects lower in the field (closer to horizon) are perceived as farther away.

Perceptual Constancy

The tendency to maintain a stable perception of an object's physical characteristics despite changes in the image cast on the retina.

Size Constancy

The ability to perceive an object as maintaining its actual size regardless of changes in the retinal image size caused by changing distance.

Shape Constancy

The ability to perceive an object's true shape as remaining constant even when changes in viewing angle alter its retinal image shape.

Colour Constancy

The ability to perceive an object as retaining its true colour despite variations in illumination or lighting conditions.

Loudness

The perceived intensity or volume of a sound, directly corresponding to the amplitude of the sound wave.

Pitch

The perceived highness or lowness of a sound, directly corresponding to the frequency of the sound wave.

Timbre

The unique quality or character of a sound determined by wave complexity, allowing distinction between different sound sources playing the same pitch and volume.

Culture

The normative rules, traditions, social behaviours, and language shared by a specific group of people that shape perception.

Phonemes

The smallest units of sound in a language capable of distinguishing words; human infants are born with universal phoneme discrimination that narrows to native language sounds by 10 to 12 months.

Music Enculturation

The lifelong process through which individuals acquire preferences, structural expectations, and pitch discrimination skills specific to their cultural musical environment.

de Bruine, Vredeveldt and van Koppen (2018)

A study demonstrating that Sub-Saharan African asylum seekers scored significantly lower than Western Europeans on pictorial depth perception ($M = 7.57$ vs $M = 15.89$) and visuospatial cube folding ($M = 1.63$ vs $M = 3.30$), but showed equal 2D and 3D vase recognition accuracy.

Hudson Pictorial Depth Perception Test

A diagnostic test using 2D line drawings (e.g., hunter, antelope, elephant) to evaluate whether participants perceive 3D spatial depth based on pictorial cues.

Visuospatial Processing

The cognitive ability to analyze, mentally transform, and manipulate two-dimensional patterns and three-dimensional spatial objects.

Acquiescence

A response style or tendency to answer 'Yes' to all test items, potentially reflecting cultural norms surrounding politeness or deference to authority.

Patel and Demorest (2013)

A meta-analytic review demonstrating that music enculturation shapes structural memory, expectations, and neural processing effort, challenging the idea that music is purely a universal language.