Sensation, Perception, and Learning

Comprehensive vocabulary flashcards covering sensation, sensory thresholds, visual and auditory pathways, perceptual organization, and classical and operant learning mechanisms.

Sensation

The detection of external physical stimulus by the sense organs.

Perception

The processing, organization, and interpretation of sensory information in the brain.

Transduction

The biological process in which sensory receptors translate physical stimuli into neural signals that the brain can interpret.

Thalamus

The subcortical brain structure functioning as the sensory gateway for sight, sound, touch, and taste, relaying sensory signals to cortical areas.

Absolute Threshold

The level of physical stimulus intensity at which a person correctly detects the stimulus $50\%$ of the time.

Difference Threshold

The minimum amount of physical difference required between two stimuli for a person to detect that a change has occurred.

Just-Noticeable Difference (JND)

The proportion of the original sensory input required to perceive a detectable difference between stimuli.

Sensory Adaptation

A decrease in sensory responsiveness that occurs when stimuli do not change, causing sensory receptors to fire less frequently.

Retina

The thin, light-sensitive inner surface of the back of the eyeball that contains photoreceptor cells (rods and cones).

Rods

Retinal photoreceptor cells that respond best to low levels of illumination and are primarily responsible for night vision.

Cones

Retinal photoreceptor cells that respond best to higher levels of illumination and are responsible for high-acuity color vision.

Ganglion Cells

Neurons in the retina that receive inputs from photoreceptors and generate action potentials transmitted along the optic nerve to the brain.

Visible Spectrum

The band of electromagnetic radiation detectable by human photoreceptors, ranging from approximately $400\,\text{nm}$ to $700\,\text{nm}$.

Light Amplitude

The physical height of a light wave between baseline and peak; higher amplitude creates the perception of brighter color, whereas lower amplitude produces darker color.

Light Wavelength

The physical distance between successive peaks of a light wave, which determines hue; shorter wavelengths produce blue, while longer wavelengths produce red.

Trichromatic Theory

The theory that color perception results from three distinct cone types in the retina: S cones (short wavelengths/blue), M cones (medium wavelengths/green), and L cones (long wavelengths/red).

Opponent-Process Theory

The theory that retinal ganglion cells receive excitatory input from one cone type and inhibitory input from another, producing color pairings perceived as opposites and generating afterimages.

Gestalt Psychology

A psychological movement originating in the 1900s positing that the human brain groups visual features into structured, organized wholes rather than isolated components.

Figure-Ground Organization

A fundamental Gestalt visual principle where visual perception organizes a scene into an object of focus (the figure) distinct from its backdrop (the ground).

Proximity (Gestalt)

The visual grouping principle stating that figures situated close together are perceived as belonging to a single unit or object.

Continuity (Gestalt)

The visual grouping principle asserting that intersecting, overlapping lines are interpreted as smooth and continuous.

Closure (Gestalt)

The visual grouping principle in which the visual system fills in missing visual contours or gaps to perceive a completed figure.

Illusory Contours

The perceptual phenomenon of seeing clear boundaries or outlines of shapes where no physical edges exist.

Bottom-Up Processing

Perceptual analysis initiated by sensory input based solely on an object's low-level physical features.

Top-Down Processing

Perceptual interpretation influenced by high-level cognitive factors, including previous knowledge, context, and expectations.

Perceptual Set

A mental predisposition or readiness to perceive stimuli in a particular manner dictated by context and prior experiences.

Binocular Disparity

A depth cue resulting from the approximate $65\,\text{mm}$ distance between the eyes, producing slight differences between the two retinal images.

Occlusion

A monocular pictorial depth cue in which an object that is closer blocks the view of an object situated farther away.

Linear Perspective

A monocular pictorial depth cue where lines known to be parallel appear to converge toward a common point in the distance.

Texture Gradient

A monocular pictorial cue where the texture of a receding surface progressively appears denser and finer.

Object Constancy

The brain's ability to correctly perceive an object as unchanging in size, shape, color, and lightness despite significant variations in the physical sensory input reaching the retina.

Audition

The sensory process of detecting sound waves caused by changes in air pressure within hearing distance.

Hair Cells

Auditory sensory receptors positioned on the basilar membrane within the cochlea that bend to convert fluid pressure waves into neural signals.

Hertz (Hz)

The standard physical unit of frequency representing the number of times a sound wave repeats each second.

Temporal Coding

A mechanism for encoding auditory pitch based on the firing rates and timing of action potentials in the auditory nerve, especially for lower-frequency sounds.

Place Coding

A mechanism for encoding auditory pitch based on the specific location of hair cells activated along the basilar membrane, primarily for high-frequency sounds.

Vestibular Sense

The sensory system operating through the semicircular canals of the inner ear that maintains balance and body orientation in space.

Papillae

Small rounded projections on the surface of the tongue that house clusters of taste buds.

Taste Buds

Sensory structures embedded within tongue papillae containing taste receptor cells that detect chemical molecules dissolved in saliva.

Olfactory Epithelium

A specialized mucous membrane in the upper nasal cavity containing olfactory receptors that bind odorant molecules.

Olfaction Route

The sensory pathway for smell that transmits signals directly from olfactory receptors via the olfactory nerve to the primary olfactory cortex, bypassing the thalamus.

Slow Fibers

Unmyelinated nerve fibers that slowly transmit intense sensory input to the brain, producing the perception of dull, chronic, and steady pain.

Fast Fibers

Myelinated nerve fibers that rapidly transmit intense sensory input to the brain, producing the perception of sharp, immediate pain.

Learning

A relatively enduring change in behavior resulting from environmental experiences.

Non-Associative Learning

A category of learning about a single stimulus (such as a sight or sound) encountered in the external world without associating it with another stimulus.

Habituation

A non-associative learning process characterized by a decreased behavioral response following repeated or continuous exposure to a non-threatening stimulus.

Sensitization

A non-associative learning process characterized by an increased behavioral response following repeated or threatening exposure to a stimulus.

Classical Conditioning

A form of associative learning where an originally neutral stimulus comes to elicit a conditioned response after being repeatedly paired with an unconditioned stimulus.

Unconditioned Stimulus (US)

A stimulus that inherently and reliably elicits an innate biological reflex without any prior conditioning (e.g., food causing salivation).

Unconditioned Response (UR)

An unlearned, automatic reflex triggered by the unconditioned stimulus (e.g., salivation upon presentation of food).

Conditioned Stimulus (CS)

An initially neutral stimulus that elicits a response only after it has been repeatedly paired with an unconditioned stimulus.

Conditioned Response (CR)

A learned behavioral response elicited by a conditioned stimulus after acquisition has occurred.

Acquisition

The learning phase in classical conditioning during which repeated pairings of the conditioned stimulus and unconditioned stimulus establish the conditioned response.

Extinction (Classical Conditioning)

The gradual elimination of a conditioned response that occurs when the conditioned stimulus is repeatedly presented without the unconditioned stimulus.

Spontaneous Recovery

The reappearance of a weakened conditioned response when the conditioned stimulus is presented after an interval of rest following extinction.

Stimulus Generalization

The tendency of stimuli that are physically similar to the conditioned stimulus to elicit the conditioned response.

Stimulus Discrimination

The learned ability to differentiate between two similar stimuli when only one of them has been paired with the unconditioned stimulus.

Operant Conditioning

A learning process in which the frequency of an operant behavior is determined by the consequences (reinforcement or punishment) that follow it.

Law of Effect

Edward Thorndike's principle stating that behaviors that lead to satisfying outcomes are more likely to occur again, whereas behaviors yielding unsatisfactory outcomes are less likely.

Reinforcer

Any stimulus or consequence following a behavior that increases the probability of that behavior being repeated.

Observational Learning

The acquisition or modification of a behavior resulting from watching another individual engage in that behavior.

Modeling

The direct imitation or replication of a specific behavior that was previously observed in another person.

Vicarious Conditioning

Learning to enact or avoid a behavior based on observing whether others are rewarded or punished for performing that behavior.