Sensation and Perception (OpenStax Psychology) — Chapters 5.1–5.6

Vocabulary flashcards covering key terms and concepts from sensation, perception, waves, vision, hearing, the other senses, and Gestalt principles in chapters 5.1–5.6.

Absolute threshold

The minimum amount of stimulus energy required for a stimulus to be detected 50% of the time.

Difference threshold (Just Noticeable Difference, JND)

The smallest detectable difference between two stimuli; varies with stimulus level.

Weber’s law

The idea that the difference threshold is a constant fraction of the original stimulus.

Subliminal messages

Stimuli presented below the threshold of conscious awareness; can be processed but have limited behavioral effects.

Sensation

Detection of a stimulus by sensory receptors, signaling that something is present.

Perception

The organization, interpretation, and conscious experience of sensory information.

Bottom-up processing

Processing that starts with sensory input and builds up to perception.

Top-down processing

Processing guided by knowledge, expectations, and prior experience.

Perceptual set

Biases in perception driven by beliefs, expectations, and culture.

Inattentional blindness

Failing to notice visible objects when attention is engaged elsewhere.

Signal detection theory

Theory that perception depends on both stimulus strength and the observer’s goals, expectations, and arousal.

Figure-ground

Gestalt principle of separating a visual scene into a figure and its background.

Proximity

Gestalt principle stating that objects close to each other tend to be grouped.

Similarity

Gestalt principle stating that alike objects are grouped together.

Good continuation (continuity)

Gestalt principle that the brain prefers smooth, continuous lines.

Closure

Gestalt principle where incomplete figures are perceived as complete objects.

Binocular cues

Depth cues that require two eyes.

Monocular cues

Depth cues that can be perceived with one eye.

Binocular disparity

The slightly different views from each eye that enable depth perception.

Linear perspective

Monocular depth cue where parallel lines appear to converge in the distance.

Interposition

Monocular cue where overlapped objects indicate depth order.

Relative size

Monocular cue where smaller image size suggests greater distance.

Cones

Photoreceptors in the retina that function best in bright light and color vision; concentrated in the fovea.

Rods

Photoreceptors in the retina that function best in low light and motion detection; noncolor.

Fovea

A small depression in the retina densely packed with cones for high acuity vision.

Retina

The light-sensitive layer at the back of the eye containing photoreceptors.

Optic nerve

The bundle of retinal ganglion cell axons that transmits visual information to the brain.

Optic chiasm

The X-shaped structure where optic nerves from the two eyes cross; info from the right field goes to the left brain and vice versa.

Trichromatic theory of color vision

Color vision theory proposing three types of cones (red, green, blue) that combine to yield all colors.

Opponent-process theory

Color vision theory proposing color is coded in opposing pairs (black-white, yellow-blue, green-red) and explains afterimages.

Negative afterimage

A visual afterimage that is the opposite color of the original stimulus, supporting opponent-process theory.

Pupil

The opening in the eye that controls light entry; size changes with light and arousal.

Cornea

The transparent, outer eye surface that helps focus light.

Iris

The colored part of the eye that controls pupil size.

Lens

Transparent structure that focuses light onto the retina and can change shape to focus.

Accommodation

The lens’ ability to change shape to focus on near or far objects.

Cochlea

A snail-shaped, fluid-filled inner ear structure containing hair cells (mechanoreceptors) for hearing.

Basilar membrane

Inner-ear membrane on which hair cells sit and that moves in response to sound.

Hair cells

Auditory receptor cells in the cochlea that transduce mechanical vibrations into neural signals.

Auditory nerve

Nerve that carries auditory information from the cochlea to the brain.

Place theory of pitch perception

Theory that different frequencies stimulate different places along the basilar membrane.

Temporal theory of pitch perception

Theory that pitch is coded by the rate of firing of auditory neurons.

Interaural level differences (ILD)

Binaural cue: difference in sound pressure level between the ears used for horizontal localization.

Interaural time differences (ITD)

Binaural cue: difference in arrival time of a sound at the two ears used for localization.

Conductive hearing loss

Hearing loss due to problems with transmitting sound to the cochlea (eardrum or ossicles).

Sensorineural hearing loss

Hearing loss due to problems in the inner ear or auditory nerve; often permanent.

Ménière’s disease

Inner-ear disorder causing hearing loss, tinnitus, vertigo, and pressure; may involve cochlear degeneration.

Cochlear implant

Electronic device that stimulates the auditory nerve to restore some hearing.)

Ossicles

Three middle-ear bones: malleus (hammer), incus (anvil), stapes (stirrup) that transmit sound.

Malleus (hammer)

One of the middle-ear bones; attached to the eardrum.

Incus (anvil)

Middle-ear bone between malleus and stapes.

Stapes (stirrup)

Small middle-ear bone that transmits vibrations to the inner ear.

Pinna

Visible outer part of the ear that helps funnel sound into the auditory canal.

Tympanic membrane

The eardrum; vibrates in response to sound, moving the ossicles.

Vestibular sense

System responsible for balance and posture; includes utricle, saccule, and semicircular canals.

Utricle

Part of the vestibular system that detects head position relative to gravity.

Saccule

Vestibular organ that senses linear acceleration and head tilt.

Semicircular canals

Three fluid-filled tubes in the inner ear that detect head rotation.

Proprioception

Sense of body position in space.

Kinesthesia

Sense of body movement and coordination.

Meissner’s corpuscles

Touch receptors that respond to light touch and low-frequency vibrations.

Pacinian corpuscles

Touch receptors that detect deep pressure and high-frequency vibrations.

Merkel’s disks

Touch receptors that respond to light pressure.

Ruffini endings

Touch receptors that detect stretch of skin.

Free nerve endings

Nerve endings that detect a variety of stimuli, including temperature and pain.

Nociception

Sensory signaling of potential harm or tissue damage (pain perception).

Thermoception

Sense of temperature.

Gustation (taste)

Sense of taste; detected by taste receptors on the tongue.

Olfaction (smell)

Sense of smell; detected by olfactory receptors in the nose.

Taste buds

Clusters of taste receptor cells with hair-like extensions that detect tastants.

Umami

Fifth basic taste associated with monosodium glutamate.

Pheromones

Chemical signals that influence social and reproductive behavior between members of the same species.

Olfactory bulb

Bulb-like structure at the tip of the frontal lobe where olfactory nerves begin.

Olfactory receptors

Receptors in the nasal mucosa that bind odor molecules.

Timbre

The quality or color of a sound that distinguishes different sources with the same pitch and loudness.

Visible spectrum

Portion of the electromagnetic spectrum visible to humans, roughly 380–740 nm.

Wavelength

Distance between successive crests of a wave; inversely related to frequency.

Frequency

Number of wave cycles that pass a point per second; measured in hertz (Hz).

Amplitude

Height of a wave; in vision relates to brightness; in hearing relates to loudness.