psych

🧠

1.6A — Sensation: Basic Concepts

Key Terms

Sensation: The process by which sensory receptors and the nervous system receive and represent stimulus energies from the environment.
Perception: The process of organizing and interpreting sensory information to recognize meaningful objects and events.
Absolute Threshold: The minimum stimulation needed to detect a stimulus 50% of the time. (Ex: Mei barely hearing her cat’s purr.)
Just-Noticeable Difference (JND): The smallest change in a stimulus that can be detected 50% of the time. (Ex: Devon needing two more grains of sugar to taste a difference.)
Weber’s Law: To perceive a difference between two stimuli, they must differ by a constant minimum percentage, not a fixed amount. (Ex: Chandra’s candle being noticeable only in darkness.)
Transduction: The conversion of sensory energy (like light or sound) into neural impulses. (Ex: Retina converting light waves into signals.)
Sensory Adaptation: Diminished sensitivity as a result of constant stimulation. (Ex: Samira no longer noticing her cologne.)
Sensory Interaction: The principle that one sense may influence another. (Ex: Kai’s blocked nose making food taste bland.)
Synesthesia: A condition in which one kind of sensory input involuntarily triggers another, such as seeing colors when hearing sounds. (Ex: Elias sees red when hearing note “C.”)

👁

1.6B — The Visual System

Part 1: Eye Structures

Lens: Focuses light onto the retina. (Ex: Sofia focusing on a mountain.)
Retina: Light-sensitive layer at the back of the eye; contains rods and cones. (Ex: Chen’s retina converts image into signals.)
Fovea: Central point of sharpest vision. (Ex: Miguel focusing on tiny print.)
Optic Nerve: Carries visual info from eye to brain. (Ex: Aisha’s optic nerve sending signals.)
Blind Spot: Area where optic nerve leaves the eye — no receptor cells. (Ex: Ben not noticing missing info on his screen because brain fills it in.)

Part 2: Vision Theories & Processes

Rods: Detect black, white, and gray; work best in dim light. (Ex: Kim navigating her dark room.)
Cones: Detect color; function in daylight. (Ex: Elena distinguishing red apple from green leaves.)
Trichromatic Theory: Three cone types (red, green, blue) combine to produce color vision. (Ex: Mia seeing color through 3 receptors.)
Opponent-Process Theory: Color perception is based on opposite color pairs (red–green, blue–yellow). (Ex: Kwame seeing a green afterimage after staring at red.)
Afterimages: Visual image that remains after a stimulus is removed.
Accommodation: Process by which the lens changes shape to focus near or far objects. (Ex: David’s lens adjusting from tree to flower.)

Part 3: Vision Disorders

Nearsightedness (Myopia): Distant objects blurry (eyeball too long). (Ex: Ricardo can’t see signs far away.)
Farsightedness (Hyperopia): Close objects blurry (eyeball too short). (Ex: Tanya can’t read up close.)
Prosopagnosia: Inability to recognize faces (“face blindness”). (Ex: Marcus can’t recognize his sister.)
Dichromatism: Color blindness for one pair of colors (red-green confusion). (Ex: Sean can’t distinguish red from green.)
Monochromatism: Total color blindness; only sees black, white, gray. (Ex: Maya.)
Blindsight: Ability to respond to visual info without consciously seeing it. (Ex: Layla stepping over an obstacle despite blindness.)

👂

1.6C — The Auditory System

Key Concepts

Amplitude: Determines loudness (height of waves). (Ex: Akira perceiving motorcycle as loud.)
Wavelength: Determines pitch (distance between peaks). (Ex: Rajiv’s pitch perception.)
Frequency Theory: Whole basilar membrane vibrates with the sound’s frequency—explains low pitches. (Ex: Ben’s low tone matching vibration rate.)
Place Theory: Different pitches activate different places on the cochlea’s basilar membrane—explains high pitches. (Ex: Nina hearing a high note.)
Volley Theory: Groups of neurons fire alternately for mid-range pitches. (Ex: Sofia perceiving intermediate pitch.)
Sound Localization: Determining direction of sound using differences between ears. (Ex: Diego turning toward car sound.)
Sensorineural Deafness: Damage to inner ear (cochlea/hair cells). (Ex: Ethan can’t hear high tones.)
Conduction Deafness: Damage to outer/middle ear prevents sound from reaching inner ear. (Ex: Isabelle’s earwax blockage.)

👃👅🤸

1.6D–G — Chemical & Bodily Systems

Gustation (Taste): Sense of sweet, sour, salty, bitter, umami. (Ex: Kenji tasting meal.)
Olfaction (Smell): Sense of smell. (Ex: Maria recognizing apple pie.)
Pheromones: Chemical signals that affect behavior (like ants finding food). (Ex: Bob the ant.)
Kinesthetic Sense: Awareness of body position and movement. (Ex: David touching his nose with eyes closed.)
Vestibular Sense: Balance and spatial orientation; relies on semicircular canals in inner ear. (Ex: Priya balancing on bike.)
Phantom Limb: Sensation from a missing body part. (Ex: Rashid feeling pain in amputated arm.)
Supertaster: Person with extra taste buds—more sensitive to flavors. (Ex: Isabella finding broccoli too bitter.)
Gate Control Theory: Spinal “gate” controls pain messages; rubbing can reduce pain signals. (Ex: Alex rubbing his knee to feel less pain.)

👁‍🗨️

2.1A — Principles of Perception

Gestalt Principles

Processing Types

Bottom-Up Processing: Sensory input builds perception from raw data. (Ex: Chafika tasting lemonade for the first time.)
Top-Down Processing: Prior knowledge and expectations shape perception. (Ex: Kenji recognizing blurry image as a bike.)

👀

2.1A — Perceptual Attention & Set

Selective Attention: Focusing on one thing while ignoring others. (Ex: Javier focusing on teacher’s voice.)
Cocktail Party Effect: Ability to detect your name in a noisy room. (Ex: Mei hearing her name across the room.)
Inattentional Blindness: Failing to notice something visible when focused elsewhere. (Ex: Tanya missing the gorilla suit.)
Change Blindness: Failing to notice changes in the environment. (Ex: Jordan not noticing person swap.)
Perceptual Set: Mental predisposition to perceive something a certain way. (Ex: Sofia mistaking airplane for UFO.)
Schema: Mental framework that organizes information. (Ex: Omar’s concept of “dog.”)

🎞

2.1B — Visual Perceptual Processes

Motion & Constancy

Phi Phenomenon: Illusion of movement created by flashing lights. (Ex: Christmas lights “moving.”)
Stroboscopic Movement: Perceived motion from rapid still images. (Ex: Movie reel propeller illusion.)
Autokinetic Effect: Stationary point of light appears to move in darkness. (Ex: Lila’s moving light illusion.)
Perceptual Constancies: Objects perceived as unchanging despite changes in lighting, angle, or distance. (Ex: Javier seeing car same size and color.)

Depth Cues

Monocular (1 eye):

Binocular (2 eyes):

(