Chapter 5 – Sensation & Perception (Psychology 2e)

Vocabulary flashcards summarizing essential terms and definitions from Chapter 5 (Sensation & Perception) to aid exam review.

Sensory Receptors

Specialized neurons that react to specific kinds of physical energy (light, sound, chemicals, pressure, etc.).

Sensation

The process in which sensory receptors detect stimuli from the environment.

Transduction

Conversion of stimulus energy into an electrical neural signal (action potential).

Absolute Threshold

Minimum intensity of a stimulus required to be detected 50 % of the time.

Subliminal Message

Stimulus that is below conscious awareness yet still influences neural activity.

Just Noticeable Difference (JND)

Smallest change in a stimulus that can be detected; also called difference threshold.

Perception

Interpretation and conscious experience of sensory information.

Bottom-Up Processing

Perception driven by incoming sensory data rather than expectations.

Top-Down Processing

Perception shaped by knowledge, expectations, and thoughts before sensory details are fully processed.

Sensory Adaptation

Reduced awareness of a constant, unchanging stimulus over time.

Inattentional Blindness

Failure to notice a visible stimulus because attention is engaged elsewhere.

Signal Detection Theory

Framework describing how detection of stimuli is influenced by motivation, expectations, and mental state.

Müller-Lyer Illusion

Visual illusion in which identical lines appear different in length because of arrow-like endpoints.

Wave Amplitude

Height of a wave from peak to trough; in light it relates to brightness, in sound to loudness.

Wavelength

Distance between successive peaks of a wave; determines color in light and is inversely related to frequency.

Frequency

Number of waves passing a point per second, measured in hertz (Hz).

Visible Spectrum

Portion of the electromagnetic spectrum humans can see (≈ 380–740 nm).

Color–Wavelength Relation

Long wavelengths appear red, medium green, short blue/violet.

Pitch

Perceived highness or lowness of a sound, determined by frequency.

Decibel (dB)

Unit measuring sound intensity (loudness).

Photoreceptors

Light-sensitive cells (rods and cones) in the retina.

Cones

Photoreceptors for bright-light, high-acuity, color vision; concentrated in the fovea.

Rods

Photoreceptors specialized for dim-light, peripheral, and motion vision.

Fovea

Small retinal region with highest concentration of cones and sharpest vision.

Optic Nerve

Bundle of retinal ganglion cell axons carrying visual information to the brain.

Blind Spot

Retinal point where the optic nerve exits; contains no photoreceptors.

Optic Chiasm

X-shaped structure where optic nerves partially cross, routing visual fields to opposite hemispheres.

“What” (Ventral) Pathway

Visual stream specialized for object recognition and identification.

“Where/How” (Dorsal) Pathway

Visual stream specialized for spatial location and guiding actions.

Trichromatic Theory

Idea that color vision arises from three cone types sensitive to red, green, and blue light.

Opponent-Process Theory

Color coding in opposing pairs (red–green, blue–yellow, black–white) at later visual stages.

Afterimage

Lingering visual impression after stimulus removal, often in complementary colors.

Depth Perception

Ability to perceive spatial relationships in three dimensions.

Binocular Cues

Depth information requiring both eyes (e.g., binocular disparity).

Binocular Disparity

Slightly different images each eye receives, contributing to 3-D depth perception.

Monocular Cues

Depth signals usable with one eye, such as linear perspective.

Linear Perspective

Monocular cue in which parallel lines converge with distance.

Interposition

Monocular cue in which closer objects partially block more distant ones.

Pinna

External ear structure funneling sound into the auditory canal.

Tympanic Membrane

Eardrum; vibrates in response to sound waves.

Ossicles

Three middle-ear bones (malleus, incus, stapes) that amplify vibrations.

Cochlea

Spiral, fluid-filled inner-ear structure where sound transduction occurs.

Basilar Membrane

Membrane inside the cochlea that moves in response to sound and supports hair cells.

Hair Cells

Auditory receptor cells that convert mechanical movement into neural impulses.

Temporal Theory of Pitch

Pitch coded by firing rate of auditory neurons (effective up to ~4000 Hz).

Place Theory of Pitch

Pitch coded by which place on the basilar membrane is stimulated (high freq at base, low at tip).

Monaural Cues

Sound-localization information obtainable by a single ear.

Binaural Cues

Localization cues requiring both ears, based on intensity and timing differences.

Interaural Level Difference

Sound’s intensity difference between ears, aiding horizontal localization.

Interaural Timing Difference

Tiny discrepancy in arrival time of a sound at each ear.

Conductive Hearing Loss

Impaired sound conduction in outer/middle ear; often treatable with hearing aids.

Sensorineural Hearing Loss

Damage to inner ear or auditory nerve preventing signal transmission to brain.

Taste Buds

Clusters of gustatory receptor cells embedded in papillae of the tongue.

Umami

Savory taste associated with amino acid glutamate (e.g., MSG).

Olfactory Bulb

Brain structure that receives smell information from olfactory receptor neurons.

Pheromones

Chemical signals released by organisms to influence conspecifics’ behavior/physiology.

Meissner’s Corpuscles

Skin receptors sensing light touch and low-frequency vibration.

Pacinian Corpuscles

Skin receptors detecting deep pressure and high-frequency vibration.

Merkel’s Disks

Skin receptors responding to light, sustained pressure and texture.

Ruffini Corpuscles

Skin receptors sensitive to skin stretch.

Thermoception

Sense of temperature (heat and cold).

Nociception

Detection of harmful stimuli signaling potential tissue damage (pain perception).

Inflammatory Pain

Pain arising from tissue damage and inflammatory processes.

Neuropathic Pain

Pain resulting from nerve or CNS damage.

Congenital Insensitivity to Pain

Genetic disorder characterized by inability to feel physical pain.

Vestibular Sense

Sense of balance and body posture based on inner-ear fluid movement.

Otolithic Membrane

Gel layer in vestibular organs that bends hair cells during linear acceleration or head tilt.

Proprioception

Awareness of body-part position relative to one another.

Kinesthesia

Perception of body-part movement through space.

Gestalt Psychology

View that perceptions are organized wholes greater than the sum of parts.

Figure–Ground Relationship

Tendency to segment visual field into a focal figure and a background.

Gestalt Principle of Proximity

Tendency to group objects that are close together.

Gestalt Principle of Similarity

Tendency to group elements that are alike in appearance.

Gestalt Principle of Continuity

Preference for smooth, continuous patterns rather than abrupt changes.

Gestalt Principle of Closure

Inclination to perceive incomplete figures as complete wholes.

Implicit Bias in Perception

Unconscious attitudes influencing how we perceive individuals or groups (e.g., age overestimation of Black boys).