UNIT 2 - Sensation and Perception

Vocabulary flashcards covering key concepts, mechanisms, theories, anatomical structures, and principles from the Sensation and Perception lecture.

Sensation

The process of detecting, converting, and transmitting raw sensory information from the external and internal environments to the brain.

Perception

The process of selecting, organizing, and interpreting incoming sensory information into meaningful patterns and mental representations of the world.

Illusion

A false or misleading impression produced by errors in the perceptual process or by actual physical distortions.

Transduction

The process by which receptor cells in sense organs convert physical stimuli into neural impulses (action potentials).

Coding

The process of transmitting sensory neural messages to the brain through different routes, allowing the brain to differentiate physical stimuli.

Psychophysics

The field of psychology that studies the link between physical characteristics of stimuli and the psychological experience of them.

Difference Threshold

The minimal difference in stimulus strength that is detectable 50% of the time; also known as Weber's Law of just noticeable differences (JND).

Absolute Threshold

The minimum intensity of stimulation needed to consciously detect a stimulus 50% of the time, formulated by Gustav Fechner.

Subliminal Perception

The perception of weak sensory stimuli presented below the threshold of conscious awareness, often flashed using a tachistoscope.

Sensory Adaptation

The phenomenon in which sensory receptors become less sensitive and fire less frequently when exposed to a constant, unchanging stimulus.

Habituation

The process by which lower centers of the brain filter sensory stimulation to ignore or prevent conscious attention to unchanging stimuli.

Endorphins

The body's natural painkillers released during physical exertion to inhibit pain perception.

Gate-Control Theory

The theory stating that pain experience depends on whether neural messages pass through a gatekeeper mechanism in the spinal cord.

Phantom Limb Pain

A condition in which an amputee continues to feel sensations such as pain or tickling in a missing limb due to conflicting neural signals.

Congenital Insensitivity to Pain with Anhidrosis (CIPA)

A genetic mutation preventing the formation of nerve cells responsible for transmitting signals of pain, heat, and cold to the brain.

Multimodal Perception

The process where sensory information from one sense influences the perception of information from another sense as inputs integrate.

Blind Spot (Optic Disc)

The area on the retina where the optic nerve leaves the eye, containing no photoreceptor cells.

Fovea

The central area of the retina containing the highest density of photoreceptor cells, providing the clearest vision.

Nearsightedness

A visual acuity defect in which light rays focus in front of the retina.

Farsightedness

A visual acuity defect in which light rays focus behind the retina.

Presbyopia

A visual condition caused by age-related loss of elasticity in the eye's lens.

Astigmatism

A visual impairment caused by an irregularly shaped cornea or lens that prevents light from focusing properly on the retina.

Glaucoma

A group of eye diseases that damage the optic nerve and can lead to vision loss and blindness.

Agnosia

The loss of the ability to perceive or recognize specific sensory stimuli.

Prosopagnosia

A specific neurological condition characterized by the inability to recognize or perceive faces.

Place Theory for Hearing

The theory of pitch perception stating that hair cells at different locations along the basilar membrane respond to high-pitched sounds.

Frequency Theory for Hearing

The theory of pitch perception stating that hair cells vibrate at the same low frequency as the low-pitched sounds being detected.

Conduction Hearing Loss

Hearing loss resulting from mechanical problems in transmitting sound waves to the cochlea.

Sensorineural Hearing Loss

Hearing loss caused by damage to the hair cells or auditory nerve; also known as nerve deafness.

Olfaction

The chemical sense of smell, mediated by olfactory receptors responding to odorants, and the only sensory system not routed through the thalamus.

Gustation

The chemical sense of taste, operating via taste receptor cells in taste buds inside papillae on the tongue.

Umami

A savory taste sensation sensitive to glutamate found in meat, broth, and MSG.

Mechanoreceptors

Specialized sensory receptors in the skin that transduce tactile stimuli associated with texture, pressure, temperature, and pain.

Vestibular Sense

The body sense that informs the brain about head position and balance in 3D space using hair cells in the semicircular canals and vestibular sacs.

Kinesthesis

The sense that provides information about body posture, orientation, and movement of individual body parts via receptors in muscles, joints, and tendons.

Conflict Theory of Motion Sickness

The theory attributing motion sickness to a sensory disagreement between information from the eyes and the vestibular system.

Trichromatic Theory of Color

The theory stating that color vision depends on three color systems sensitive to red, green, and blue light.

Opponent-Process Theory

The theory postulating that color vision relies on three systems sensitive to opposing color pairs: blue/yellow, red/green, and black/white.

Selective Attention

The process of focusing conscious awareness on specific important sensory information while filtering out irrelevant stimuli.

Feature Detectors

Specialized brain neurons that respond selectively to specific features of visual stimuli, such as shape, angle, or faces.

Perceptual Set

A readiness or expectation to perceive sensory stimuli in a particular manner.

Frame of Reference

The contextual background or environment that influences how a stimulus is interpreted.

Bottom-Up Processing

Perceptual processing that begins with raw sensory data gathered from the environment and sends it up to the brain for analysis.

Top-Down Processing

Perceptual processing driven by higher-level cognitive processes, such as existing knowledge, expectations, and context.

Figure-Ground Perception

A Gestalt principle of form perception where objects (the figure) are perceived as distinct from their background (the ground).

Proximity (Nearness)

A Gestalt organizational principle stating that objects located close to each other tend to be perceived as a group.

Similarity

A Gestalt organizational principle stating that stimuli with similar features (such as color or shape) are grouped together.

Closure

A Gestalt organizational principle stating that the brain automatically fills in gaps in incomplete figures to perceive a whole object.

Perceptual Constancies

The ability to perceive objects as unchanging in size, shape, color, and brightness despite variations in sensory input.

Interposition (Overlapping)

A monocular depth cue in which an object that partially blocks another object is perceived as closer.

Extrasensory Perception (ESP)

Supposed psychic perceptual abilities, such as telepathy, clairvoyance, and precognition, that go beyond normal physical senses.