Unit 2A AP Psychology

Threshold

The minimum level of stimulation required to detect a stimulus or trigger a response.
Ex: Hearing a faint sound in a quiet room.

Transduction

The conversion of physical stimuli into neural signals.
Ex: Light hitting the retina is converted into electrical impulses for the brain to process.

Absolute Threshold

The smallest amount of stimulus energy that can be detected 50% of the time.
Ex: Seeing a candle flame from 30 miles away on a clear night.

Just-Noticeable Difference

The smallest difference in stimulus intensity that a person can detect.
Ex: Detecting a slight increase in volume on the radio.

Sensory Adaptation

Decreased sensitivity to constant and unchanging stimuli.
Ex: No longer noticing the ticking of a clock after a while.

Weber’s Law

The principle that the just-noticeable difference is proportional to the intensity of the stimulus.
Ex: Adding a small weight to an already heavy object is harder to notice.

Sensory Interaction

The principle that one sense may influence another.
Ex: Smell affects how food tastes.

Synesthesia

A condition where stimulation of one sense triggers another sense.
Ex: Seeing colors when hearing music.

Wavelength

The distance between successive peaks of a wave, determining pitch or color.
Ex: Short wavelengths correspond to high-pitched sounds.

Loudness/Volume

The perception of the amplitude of a sound wave.
Ex: Turning up the volume on your speakers increases loudness.

Pitch Perception

How the brain interprets the frequency of sound waves.
Ex: Recognizing a high note in a song.

Place Theory

The theory that pitch is determined by the specific area of the cochlea activated.
Ex: High-pitched sounds activate the base of the cochlea.

Volley Theory

Groups of auditory nerve fibers firing in rapid succession to encode high frequencies.
Ex: Detecting extremely high tones in music.

Frequency Theory

The theory that pitch is related to the frequency of neural impulses.
Ex: Low-frequency sounds result in slower neural impulses.

Sound Localization

The ability to identify the direction and distance of a sound source.
Ex: Determining where a siren is coming from.

Conduction Deafness

Hearing loss caused by damage to structures that transmit sound to the cochlea.
Ex: A ruptured eardrum.

Sensorineural Deafness

Hearing loss caused by damage to the cochlea or auditory nerve.
Ex: Age-related hearing loss.

Retina

The light-sensitive layer at the back of the eye where images are focused.
Ex: Contains rods and cones for processing visual information.

Blind Spot

The area where the optic nerve leaves the retina, creating a gap in visual perception.
Ex: A small area where no image is detected.

Visual Nerve/Optic Nerve

The nerve that transmits visual information from the retina to the brain.
Ex: Helps you process and recognize objects.

Lens

The transparent structure in the eye that focuses light onto the retina.
Ex: Changes shape to focus on near or far objects.

Accommodation

The process by which the lens changes shape to focus on objects at different distances.
Ex: Focusing on a book and then looking at a distant mountain.

Nearsightedness

A condition where close objects are clear, but distant ones are blurry.
Ex: Difficulty seeing a chalkboard in class.

Farsightedness

A condition where distant objects are clear, but close ones are blurry.
Ex: Struggling to read small print in a book.

Rods

Photoreceptor cells in the retina responsible for vision in low light.
Ex: Seeing shapes in a dark room.

Light Adaptation

The process of adjusting to bright light after being in darkness.
Ex: Stepping outside on a sunny day after being indoors.

Dark Adaptation

The process of adjusting to darkness after exposure to bright light.
Ex: Walking into a dark theater after being outside in sunlight.

Trichromatic Theory

The theory that color vision is based on three types of cones sensitive to red, green, and blue.
Ex: Combining red and green light to perceive yellow.

Opponent-Process Theory

The theory that color vision depends on opposing pairs of colors.
Ex: Red vs. green and blue vs. yellow.

Fovea

The central part of the retina with the highest concentration of cones for sharp vision.
Ex: Essential for reading fine print.

Cones

Photoreceptor cells in the retina responsible for color vision and sharpness.
Ex: Allowing you to distinguish between red and blu

Afterimages

Visual images that remain after the original stimulus is removed.
Ex: Seeing a bright spot after looking at the sun and closing your eyes.

Ganglion Cells

Neurons in the retina that transmit visual information to the brain.
Ex: Contributing to the processing of images by sending signals from the eye to the brain.

Color vision deficiency

A reduced ability to distinguish between certain colors.
Ex: Difficulty telling the difference between red and green traffic lights.

Dichromatism

A type of color blindness where one type of cone photoreceptor is absent.
Ex: Seeing the world with limited colors, such as red and green appearing similar.

Monochromatism

A condition where only one type of cone photoreceptor functions.
Ex: Seeing the world in shades of gray.

Prosopagnosia

Inability to recognize faces, also known as face blindness.
Ex: Recognizing a friend only by their voice or hairstyle.

Blindsight

Ability to respond to visual stimuli without conscious awareness of them.
Ex: Avoiding obstacles despite being blind in a particular visual field.

Olfactory System

The sensory system for detecting smells.
Ex: The nose and brain working together to identify the scent of flowers.

Gustation

The sense of taste.
Ex: Tasting the sweetness of chocolate or the sourness of lemon.

Umami

Taste sensation for savory or protein-rich substances.
Ex: Enjoying the umami flavor of soy sauce.

Oleogustus

Taste sensation for fatty acids.
Ex: Noticing the fatty taste in oils.

Taste Receptors

Cells on the tongue that detect different tastes.
Ex: Helping you distinguish between sweet and salty foods.

Supertasters

People with a high density of taste buds, sensitive to flavors.
Ex: Experiencing intense bitterness in certain vegetables.

Medium Tasters

People with an average density of taste buds.
Ex: Having a balanced perception of flavors.

Nontasters

People with a low density of taste buds, less sensitive to flavors.
Ex: Needing more salt to detect its taste.

Chemical Senses

Senses that detect chemicals, such as taste and smell.
Ex: Smelling perfume or tasting food.

Sensory interaction

The influence of one sense on another.
Ex: Food tasting bland when you have a stuffy nose.

Touch

The sense that detects pressure, texture, and temperature.
Ex: Feeling the softness of a blanket.

Pain

The sense that detects harmful stimuli or injury.
Ex: Feeling a sharp sensation when stepping on a nail.

Gate Control Theory

Theory that spinal gates control the flow of pain signals to the brain.
Ex: Rubbing a painful area to reduce the sensation.

Vestibular Sense

The sense of balance and spatial orientation.
Ex: Maintaining balance while standing on one leg.

Semicircular canals

Structures in the inner ear that detect head rotation and movement.
Ex: Helping you sense when you’re spinning.

Kinesthesis

The sense of body movement and position.
Ex: Knowing your arm’s position without looking at it.

Perception

The process of organizing and interpreting sensory information.
Ex: Recognizing a face in a crowd.

Bottom-Up Processing

Processing sensory input starting from basic features.
Ex: Assembling a puzzle without knowing the final picture.

Top-Down Processing

Using prior knowledge to interpret sensory information.
Ex: Reading messy handwriting because you expect certain words.

Schema

A mental framework for organizing information.
Ex: Knowing what to expect during a restaurant visit.

Perceptual Sets

Tendency to perceive things a certain way based on expectations.
Ex: Seeing a cloud as a face due to prior suggestions.

Attention

Focusing mental resources on specific stimuli.
Ex: Concentrating on a lecture while ignoring background noise.

Inattentional Blindness

Failing to see visible objects when attention is elsewhere.
Ex: Missing a pedestrian while texting and walking.

Change Blindness

Failing to notice changes in the environment.
Ex: Not noticing a new haircut on a friend.

Gestalt Psychology

Theory emphasizing the whole is greater than the sum of its parts.
Ex: Seeing a complete circle despite gaps in the outline.

Closure

Filling in gaps to perceive a complete image.
Ex: Seeing a full square even when parts are missing.

Proximity

Tendency to group nearby objects together.
Ex: Viewing dots close together as part of the same group.

Similarity

Tendency to group similar objects together.
Ex: Grouping objects of the same color in a design.

Binocular Depth Cues

Depth cues that require both eyes.
Ex: Using retinal disparity to judge distance.

Retinal Disparity

The difference in images between the two eyes for depth perception.
Ex: Holding a finger close to your face and seeing it double.

Convergence

Eyes turning inward to focus on a nearby object.
Ex: Crossing your eyes to look at your nose.

Monocular Depth Cues

Depth cues that require only one eye.
Ex: Judging distance using linear perspective.

Relative Clarity

Objects that are hazy appear farther away.
Ex: Distant mountains looking blurry.

Relative Size

Smaller objects are perceived as farther away.
Ex: Cars in the distance looking tiny.

Texture Gradient

Objects with less texture appear farther away.
Ex: Bricks looking smoother in the distance.

Linear Perspective

Parallel lines converging in the distance indicate depth.
Ex: Railroad tracks meeting at the horizon.

Interposition

Objects blocking others are perceived as closer.
Ex: A tree partially covering a house appears nearer.

Perceptual Constancy

Perceiving objects as unchanging despite changes in perspective.
Ex: Recognizing a door as rectangular even when open.

Apparent Movement

Perceiving motion where there is none.
Ex: Seeing movement in a flipbook animati