Key Terms in AP Psychology: Sensation and Perception

Sensation

The process by which our sensory receptors and nervous system receive and represent stimulus energies from our environment. Stimulation of the sense organs. (Raw data of experience: smells, sights, sounds, pain, etc.)S

Perception

The process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events.

Visual agnosia

A neurological condition where individuals cannot recognize objects visually despite intact vision.

Wavelength

Determines hue (color). Length of light waves.

Amplitude

Influences brightness. Height of light waves

Purity

Affects saturation.

Transduction

The conversion of physical stimuli (e.g., light, sound waves) into neural signals by sensory receptors.

Cornea

Transparent layer that bends light to help focus.

Pupil

Opening in the iris that controls light entry.

Iris

Colored part of the eye that regulates the size of the pupil.

Lens

Adjusts shape to focus light on the retina.

Retina

Light-sensitive layer containing rods and cones.

Fovea

Center of the retina with high cone density for sharp vision.

Optic nerve

Transmits visual information to the brain.

Optic disk (blind spot)

Area where the optic nerve exits; lacks photoreceptors.

Lens accommodation

The lens changes shape to focus near or far objects on the retina.

Nearsightedness

Close objects are clear; distant objects appear blurry.

Farsightedness

Distant objects are clear; close objects appear blurry.

Rods

Detect black, white, and gray; important for night vision.

Cones

Detect color and fine detail; function in daylight.

Ganglion cells

Neurons in the retina that transmit signals to the brain via the optic nerve.

Dark & light adaptation

Adjustment of the eyes to low (dark) or bright (light) lighting conditions.

Trichromatic theory of color

Proposes that the retina contains three color receptors (red, green, blue).

Dichromatism

Partial color blindness (two functioning cones).

Monochromatism

Total color blindness (one or no functioning cones).

Opponent processing theory

Visual system processes colors in opposing pairs (e.g., red-green, blue-yellow).

perceptual set

a mental predisposition to perceive one thing and not another

Feature analysis

the process of detecting specific elements in visual input and assembling them into a more complex form

Top-down processing

Using prior knowledge and expectations to interpret sensory information. (What do you see in the picture? Some said man based on previous pictures shown; some said rat).

Bottom-up processing

Building perception from sensory input without prior knowledge.

Apparent motion (Phi phenomenon)

an optical illusion where a series of still images shown in rapid succession appear to be moving, creating the perception of continuous motion even though no actual movement is present

Figure-ground

Gestalt Principle. Differentiating an object from its background.

Proximity

Gestalt Principle. Grouping nearby objects together.

Closure

Gestalt Principle. Filling in gaps to perceive a whole object.

Similarity

Gestalt Principle. Grouping similar items together.

Simplicity

Gestalt Principle. Perceiving the simplest form of a stimulus. (We perceive the top image rather than the bottom one)

Continuity

Gestalt Principle. Seeing continuous patterns.

Depth perception

The ability to judge the distance of objects.

Retinal disparity

Slight differences in images between the two eyes.

Convergence

Eyes turning inward to focus on close objects.

Linear perspective

Monocular Depth Cue. Parallel lines converging in the distance. (Like art)

Texture gradient

Monocular Depth Cue. Objects appearing denser as distance increases. (Further flowers are smaller and harder to see)

Interposition

Monocular Depth Cue. Closer objects block farther ones. (Blue is closer because it is "over/blocking" red)

Relative clarity

Monocular Depth Cue. Distant objects appear hazier.

Relative size

Monocular Depth Cue. Smaller images are perceived as farther away. (Left coke can is further away because it is smaller)

Perceptual constancy

Monocular Depth Cue. the tendency to perceive an object you are familiar with as having a constant shape, size, and brightness despite the stimuli changes that occur

Frequency

Determines pitch. Inverse of wavelength.

Timbre

Quality of sound that distinguishes it from others

Volley theory

the idea that groups of neurons in the auditory system fire in rapid succession, creating a "volley" of nerve impulses, allowing the brain to perceive higher frequencies of sound than any single neuron could fire on its own

Cochlea

Coiled structure containing auditory receptors. Recognizes sound vibrations and sends signals to the brain.

Hair cells

the sensory receptor cells located within the inner ear, specifically in the cochlea, which convert mechanical sound waves into electrical signals that the brain can interpret (Where transduction occurs fr)

Place theory

Different pitches activate specific areas of the cochlea.

Frequency theory

Pitch is determined by the rate of neural firing.

Sound localization

Determining the direction of a sound source.

Sensorineural deafness

a type of hearing loss caused by damage to the inner ear, specifically the cochlea's receptor cells or the auditory nerve, which prevents the proper transmission of sound signals to the brain

Conduction deafness

a type of hearing loss caused by damage to the outer or middle ear structures (like the eardrum or ossicles), which prevents sound waves from being effectively conducted to the inner ear, resulting in reduced hearing ability

Vestibular sense

Detects balance and body orientation via the semicircular canals.

Taste (gustatory system)

Taste buds detect chemical stimuli.

6 types of taste

Sweet, sour, salty, bitter, umami (savory), oleogustus (fat).

Supertasters/medium tasters/nontasters

Variations in taste sensitivity.

Sensory adaptation

Decreased sensitivity to constant stimulation. (Bad smell becomes less noticeable when you sit in it for hours)

Olfactory cilia

tiny, hair-like structures located in the nasal cavity that act as sensory receptors for smell, detecting odor molecules dissolved in mucus and converting them into neural signals that are sent to the brain (hair cells of the nose)

Olfactory bulb

the part of the brain that initially processes smell signals, receiving information from the nose via the olfactory nerve and sending it to other brain regions for further interpretation

Tactile system

Processes touch sensations.

Skin structures

the different layers of the skin, including the epidermis (outer layer) and dermis (inner layer), which contain specialized nerve endings that detect sensations like touch, pressure, temperature, and pain, allowing us to perceive stimuli from the environment through our skin

Gate-control theory

The spinal cord can block or allow pain signals to the brain. (acting as a gate)

Schema

Cognitive framework for interpreting information based on past experience.

Sensory interaction

The principle that one sense can influence another.

Absolute threshold

minimum amount of stimulation that an organism can detect 50% of the time

Just noticeable difference

The smallest detectable difference between stimuli.

Signal detection theory

Predicts when we will detect weak signals amid background noise.

Four possible outcomes:

Hit - Detecting signals when present.

Misses-Failing to detect signals when present

False Alarms-detecting signals when they are absent

Correct Rejection-Not detecting signals when they are absent

Weber's Law

The change in a stimulus needed for detection is proportional to the original stimulus (1/30th of size).

Pheromones

a chemical signal released by an organism that influences the behavior of other members of the same species

Synesthesia

A condition where stimulation of one sense triggers another.

Kinesthetic sense

Awareness of body position and movement.

Selective attention

Focusing on one stimulus while ignoring others.

Cocktail party phenomenon

Focusing on a specific voice in a noisy environment while recognizing noises (such as your name) from other voices.

Change blindness

Failure to notice subtle changes in the environment. (Example: Changed shirt of person speaking in a video)

Inattentional blindness

Failure to notice visible objects due to focus elsewhere. (Example: Not seeing moonwalking gorilla in basketball video because you are focusing on basketball)

Afterimage

Visual image that persists after the stimulus is removed.

Prosopagnosia

Inability to recognize faces.

Blind sight

a phenomenon where a person with damage to their primary visual cortex can unconsciously respond to visual stimuli

Phantom limb syndrome

Sensation of pain or presence in a missing limb.