Unit 1.5 Psych

Sensation

The process of detecting physical energy (stimuli) from the environment and converting it into neural signals.
Example: Feeling the warmth of a mug in your hand.

Perception

The brain’s interpretation of sensory input.
Example: Realizing the mug you're holding contains coffee.

Visual Agnosia:

A condition where someone can see but cannot recognize objects.
Example: Seeing a spoon but being unable to identify it as something used for eating.

Light & Its Physical Properties:

Light is electromagnetic radiation with properties like wavelength (color), amplitude (brightness), and purity (saturation).
Example: A red rose appears red because it reflects light with a long wavelength.

Transduction:

The conversion of physical energy into neural signals.
Example: Light hitting the retina and being turned into electrical impulses.

Cornea:

Protects the eye and bends light.

Pupil:

Opening that controls light entry.

Iris:

Muscle that adjusts the pupil.

Lens

Focuses light on the retina.

Retina

Contains receptor cells.

Fovea

Sharpest vision, central retina.

Optic Nerve

Transmits signals to the brain.

Optic Disk (Blind Spot):

No photoreceptors.
Example: Light passes through the cornea, pupil, lens, hits the fovea, then the optic nerve sends signals to the brain.

Lens Accomodation:

The lens changes shape to focus on near or far objects.
Example: Focusing on a book, then looking up at a clock across the room.

Nearsightedness:

Can see close objects clearly; distant ones are blurry.
Example: Needing glasses to read the board in class.

Farsightedness:

Can see distant objects clearly; near ones are blurry.
Example: Struggling to read a menu up close but seeing street signs clearly.

Cones:

Detect color and fine detail.
Example: Seeing in dim light with rods, noticing color details with cones.

Rods:

Detect light/dark, good for night vision.

Ganglion Cells:

Neurons in the retina that collect visual info and send it to the brain.
Example: Ganglion cells relay the edge of a shape to the brain for processing.

Dark & Light Adaptation:

The eye adjusting to different light levels.
Example: Struggling to see when walking into a dark room, then gradually adjusting.

Trichromatic Theory of Color:

Color vision is based on three cone types (red, green, blue).
Example: Seeing purple as a mix of red and blue cone activation.

Dichromatism:

Missing one color cone type.

Monochromatism

Seeing only in shades of gray.
Example: A dichromat can't distinguish red from green.

Opponent Processing Theory

Color perception controlled by opposing pairs (red-green, blue-yellow, black-white).
Example: Staring at a green image, then seeing red afterimage.

Perceptual Set:

A mental predisposition to perceive things a certain way.
Example: Seeing a cloud as a bunny after someone suggests it looks like one.

Feature Analysis:

Detecting individual elements to understand the whole.
Example: Recognizing a face by noticing the eyes, nose, and mouth.

Top-Down Processing

Perception guided by experience, expectations, or knowledge.
Example: Reading messy handwriting because you expect certain words in a sentence.

Bottom-Up Processing:

Perception starting from sensory input and building upward.
Example: Identifying a song by hearing its notes for the first time.

Apparent Motion / Phi Phenomenon:

Perception of movement from a sequence of still images.
Example: Watching an animated flipbook and perceiving motion.

Figure-Ground:

Distinguishing object from background.

Proximity

Grouping nearby items.

Closure:

Filling in gaps.

Similarity:

Grouping similar items.

Simplicity:

Perceiving the simplest pattern.

Continuity

Seeing continuous patterns.
Example: Seeing a smiley face even if it’s made with only dots.

Depth Perception:

Ability to judge distances and see in 3D.
Example: Catching a ball thrown toward you.

Binocular Depth Cue: Retinal Disparity:

Each eye sees a slightly different image, helping with depth.
Example: Holding a finger close to your face and seeing it double with one eye closed.

Convergence:

Eyes turning inward to focus on close objects.
Example: Feeling your eyes cross slightly when reading close-up.

Linear Perspective:

Parallel lines appear to meet in the distance.

Texture Gradient:

Closer objects show more detail.

Interposition:

One object blocking another appears closer.

Relative Clarity:

Clearer objects are seen as nearer.

Relative Size:

Smaller objects are perceived as farther away.
Example: A road appearing to narrow in the distance due to linear perspective.

Perceptual Constancy:

Perceiving objects as unchanging despite changes in sensory input.
Example: A door is still seen as rectangular even when it’s ajar.

Volley Theory/Principle:

Neurons take turns firing to match sound frequency.
Example: Hearing a 1000 Hz tone even though one neuron can’t fire that fast alone.

Cochlea:

Spiral structure where sound is processed.

Hair Cells:

Receptors that transduce sound waves.
Example: Hair cells in the cochlea responding to a ringing bell.

Place Theory:

Pitch depends on where hair cells are stimulated.

Frequency Theory

Pitch depends on how fast neurons fire.
Example: High-pitched sounds activate hair cells near the base of the cochlea (place theory).

Sound Localization:

Determining where a sound is coming from.
Example: Turning your head when someone calls you from behind.

Sensorineural:

Damage to inner ear or nerves.

Conduction:

Damage to outer/middle ear structures.
Example: Needing a hearing aid for conduction deafness, but a cochlear implant for sensorineural loss.

Vestibular Sense: Semicircular Canals

Sense of balance and body position, located in the inner ear.
Example: Feeling dizzy after spinning because fluid in the semicircular canals is still moving.

Taste: Gustatory System - Taste Buds

Receptors on the tongue that detect taste stimuli.
Example: Noticing a sour flavor when eating a lemon slice.

Supertasters

Extra-sensitive to taste.

Medium Tasters

Average sensitivity.

Sensory Adaptation:

Decreased sensitivity to constant stimulation.
Example: No longer noticing your clothes touching your skin after a while.

Bulb:

Brain structure that processes smells.
Example: Smelling fresh-baked cookies via olfactory cilia that send signals to the bulb.

Cilia:

Receptors for smell in the nasal cavity.

Tactile System: Touch

Sense of pressure, vibration, texture, and pain through the skin.
Example: Feeling a breeze brush against your arm.

Structures in Skin (Warm/Cold, Pain):

Specialized receptors detect temperature and pain.
Example: Feeling a burning sensation from a hot pan.

Gate-Control Theory:

Theory that the spinal cord has a “gate” that controls pain messages to the brain.
Example: Rubbing a bumped knee to reduce pain.

Schema:

A mental framework for organizing information.
Example: Expecting a restaurant to have menus, tables, and servers based on your schema of dining out.

Sensory Interactions:

Senses influence each other.
Example: Food tastes bland when you have a stuffy nose.

Absolute Threshold

The smallest level of stimulus that can be detected 50% of the time.
Example: Hearing a ticking watch in a quiet room from 20 feet away.

Signal Detection Theory:

Predicts how and when we detect a signal amid background noise, considering motivation and expectations.
Example: A mother waking up to her baby’s soft cry but sleeping through a loud storm.

Ernst Weber - Weber’s Law:

The just noticeable difference is a constant proportion of the original stimulus.
Example: Needing to add more weight to a heavy object than a light one to notice a difference.

Pheromones:

Chemical signals released by organisms to affect others’ behavior or physiology.
Example: Some animals use pheromones to signal mating readiness.

Synesthesia

A condition where one sense is involuntarily linked to another.
Example: Seeing colors when hearing music.

Kinesthetic Sense

Awareness of body position and movement.
Example: Touching your nose with your eyes closed using your finger

Selective Attention

Focusing on one specific stimulus while ignoring others.
Example: Listening to your friend in a noisy cafeteria.

Cocktail Party Phenomenon

Ability to focus attention on one voice among many and detect your name in another conversation.
Example: Perking up when you hear your name across the room at a party.

Change Blindness:

Failing to notice changes in a visual scene.
Example: Not noticing that someone changed shirts between scenes in a movie.

Inattentional Blindness:

Failing to notice something visible because your attention is elsewhere.
Example: Missing a person in a gorilla suit walk through a basketball game when counting passes.

Afterimage:

A visual image that remains after the stimulus is removed.
Example: Seeing a green spot after staring at a red dot and then looking away.

Prosopagnosia (Face Blindness):

Inability to recognize faces.
Example: Not recognizing a close friend’s face, even though you know them.

Blindsight

Ability to respond to visual stimuli without consciously seeing them, due to brain damage.
Example: Navigating a hallway without “seeing” anything after a stroke affecting the visual cortex.

Phantom Limb Syndrome:

Sensation that a missing limb is still present and often painful.
Example: Feeling an itch in a leg that was amputated.