AP Psychology Unit 2 (Perception, Sensation, Thinking)

Mrs. Weck LHS AP Psychology 2025

Sensation

The process by which sensory receptors & the nervous system detect stimuli

Transduction

The conversion of sensory stimuli into neural impulses which can be understood by the brain

Perception

The process through which the brain organizes and interprets sensory information to turn it into meaningful events

Absolute Threshold

The minimum amount of stimulation required for a stimuli to be detected

Just-Noticeable Difference

The smallest change in a stimulus that a person can detect

Sensory Adaptation

When sensory receptors become less responsive to constant stimuli over time

Weber’s Law

The bigger a stimulus is, the more stimulation is required to notice a difference

Sensory interaction

The belief that one sense can influence another

Synesthesia

A condition where stimulation of one sensory pathway leads to automatic activation of another sensory pathway

Retina

The part of the eye which converts light into neural signals

Blindspot

An area where vision is absent

Visual Nerve

A bundle of nerve fibers that transfer visual information from the retina to the brain where it is processed into images

Lens

A structure in the eye which focuses light onto the retina

Accomodation

When the lens changes shape to focus on objects at different distances

Nearsightedness

A vision condition where close objects appear clear, but distant objects appear blurry

Farsightedness

A vision condition where distant objects appear clear, but close objects appear blurry

Photoreceptors

Specialized cells in the retina that detect light & convert it into electrical signals

Rods

Photoreceptor cells in the retina responsible for vision in low-light conditions & detecting motion

Cones

Photoreceptor cells in the retina responsible for vision in bright-light & color vision

Trichromatic Theory

Vision is based on 3 types of cone receptors sensitive to either red, green, or blue light. The brain combines signals from the cones to create a wide range of colors.

Opponent-Process Theory

Color vision is based on pairs of opposing color processes: Red & Green; Blue & Yellow; Black & White

Fovea

The central area of the retina responsible for sharp, central vision

Afterimages

Visual images that remain after the stimulus is removed (caused by temporary overstimulation of cone cells)

Ganglion Cells

Specialized cells that transmit information to the brain via the optic nerve

Dichromatism

When people have only 2 working cone cells instead of 3

Monochromatism

When people only have 1 or NO working cone cells causing them to see in black & white

Prosopagnosia

The inability to recognize familiar faces

Blindsight

Being able to detect or “see” objects in your blindspot

Wavelength

The distance between peaks of a wave

Pitch

How high or low a sound is

Amplitude

The measure of the intensity of a soundwave

• Greater amplitude = louder

• Lower amplitude = quieter

Loudness

The perception of volume on a scale from loud to quiet

Pitch Perception

The brain’s interpretation of determining if a sound has a high or low tone

• Higher frequency = higher pitch

• Lower frequency = lower pitch

Place Theory

Different parts of the inner ear detect different sound frequencies

Volley Theory

Auditory neurons fire in rapid succession (volleys) to perceive pitches above the firing rate of individual neurons

Frequency Theory

The frequency of a sound wave directly corresponds to the rate at which auditory neurons fire

Sound Localization

The brain’s ability to determine the location of a sound source

Conduction Deafness

Hearing loss caused by problems to the outer or middle ear

Sensorineural Deafness

Hearing loss caused by damage to the inner ear or auditory nerve

Olfactory System

Receptors in the nose which detect smells & send signals to the brain

Thalamus

The brain's sensory control center (except for the sense of smell) which directs messages to sensory receiving areas in other parts of the brain.

Pheromones

Chemical substances released by humans & animals that trigger social or behavioral responses

Gustation

The sense of taste involving receptors on the tongue that detect different flavors

Sweet, Sour, Salty, Bitter, Umami, Oleogustus 

Types of tastes

• Sweet: associated with sugar

• Sour: caused by acidic foods (ex: citruses)

• Salty: associated with salt

• Bitter: associated with unpleasant tastes (ex: dark chocolate)

• Umami: associated with savory tastes (ex: meat, cheese)

• Oleogustus: a proposed taste associated with fatty foods

Taste Receptors

Specialized cells on the tongue and mouth that detect different tastes

Supertasters

People who are highly sensitive to taste & experience flavors intensely

Medium Tasters

People who have an average sensitivity to taste & experience flavors moderately

Nontasters

People who are least sensitive to taste & experience flavors with minimal intensity

Warm/Cold Receptors

Specialized cells on the skin that detect changes in temperature

Pain

The emotional response to stimuli (which can vary from person-to-person)

Gate Control Theory

The theory that pain is controlled by a neural “gate” in the spinal cord which can open or close to allow or block pain.

Phantom Limb

When sensations can be “felt” in a missing body part

Vestibular Sense

The sense of orientation, balance, & movement due to inner ear receptors

Semicircular Canals

Inner ear structures that detect head movement

Kinesthesis

The awareness of your body parts’ own movement & position in space

Bottom-Up Processing

The way the brain makes sense of information by starting with small details then piecing them together to complete a perception.

Top-Down Processing

The way the brain makes sense of information based on context, prior knowledge, & expectations.

Schema

Mental frameworks that help people organize & interpret information about the world

Perceptual Set

A mental tendency to notice some aspects of sensory data & ignore others a certain way influenced by expectations, experiences, or context.

Gestalt Psychology

We tend to perceive things as “wholes” rather than just “parts”

• ex: seeing a full face rather than just eyes, noses, mouths, ears, etc..

Closure (Gestalt Principle)

Perceiving incomplete or interrupted patterns as complete, filling in the missing information to create a whole object

Proximity (Gestalt Principle)

Objects near each other are perceived as a group, rather than as individual elements

Similarity (Gestalt Principle)

Objects that look alike (color, shape, size, etc) are perceived to belong in a group.

Figure & Ground (Gestalt Principle)

The ability to distinguish an object (figure) from its surroundings (ground)

Attention

Selective Attention

Focusing on a specific task while ignoring other stimuli in the background

Cocktail Party Effect

The ability to focus on a single conversation in a noisy environment

Inattentional Blindness

When people fail to notice an unexpected stimulus in their visual field because they’re focused on something else

Change Blindness

When people fail to notice large changes in their environment when the change occurs simultaneously with a visual disruption.

Binocular Depth Cues

Visual information that requires both eyes to perceive depth & distance

Retinal Disparity

When each eye sees a slightly different view due to their positions in the skull. (Helps with depth perception)

Convergence

When the eyes move inward to focus on close objects

Monocular Depth Cues

Visual information that requires one eye to perceive depth & distance

Relative Clarity

• Closer objects appear clearer & more detailed

• Further objects appear blurry & less detailed

Relative Size

• Closer objects appear larger

• Further objects appear smaller

Texture Gradient

The amount of detail a person can perceive decreases with distance

Linear Perspective

Parallel lines seem to meet at the horizon in the distance creating the illusion of depth & distance

Interposition

When one object covers another making it appear closer

Perceptual Constancy

the brain's ability to perceive familiar objects as having stable qualities (size, shape, and color) despite changes in the sensory input, such as distance, lighting, or viewing angle

• ex: a door still being a door despite being opened or closed

Apparent Movement

Perceiving objects as being in movement despite nothing actually moving

• ex: Flashing Christmas lights appear to move, but they’re actually not

Prototype

Something that serves as the best example of a category

• ex: an apple is a great (blank) for fruits because it is edible, sweet, has seeds, and is a plant.

Schema

Metal frameworks that help organize & recognize information based on past experiences & knowledge

• ex: a girl sees a new animal for the first time

• the animal has fur, a tail, barks, floppy ears, and has 4 legs

• the girl creates a new (blank) for dogs

• Next time the child sees a dog, she’ll know quickly

Assimilation

The process of fitting new information into already existing schemas

• ex: a child sees a new breed of dog with pointy ears instead of floppy ones

• while this dog is physically different from the ones in the child’s already existing schema, it still shares many characteristics

• The new breed of dog is added to the child’s schema for dogs

Algorithms

Step by step procedures or formulas for solving problems that guarantee a correct solution

• ex: a morning routine, or an exercise routine can be considered algorithms because they involve a specific, repeatable set of steps to achieve the goal of being prepared for sleep or a workout. 

Heuristics

Mental shortcuts (rules of thumb) that simplify decision-making

• ex: when buying a new phone, many people choose the most recent iPhone because they trust the quality even though they haven’t compared the other brands’ technologies

Representativeness Heuristic

A mental shortcut where people make judgments about something based on stereotypes

• ex: You’re meeting a man on a blind date

• He’s

Availability Heuristic

A mental shortcut where people rely on immediate examples that come to mind when evaluating a decision

• ex: an airplane has recently crashed & there has been lots of media coverage

• People have been more reluctant to buy plane tickets even though flying is the safest method of travel

• The increased broadcasting has lead people to overestimate the danger

Mental Set

The tendency to approach situations in a certain way because that worked in the past

• ex: You’re struggling to open a pickle jar

• You keep twisting the lid forcefully because it worked the last time

• This (blank) might prevent you from seeking out easier solutions such as tapping the lid against the counter to break the seal

Priming

Exposure to one stimulus influences the response to another stimulus without conscious intent

• ex: A store displays fresh, vibrant flowers in its storefront

• customers are more likely to perceive the store as having fresh, high quality produce

• This (blank) can subconsciously influence customers to buy more fruits and vegetables than they would have if they hadn’t seen the flowers

Framing

The manner in which information is presented can influence decisions or perceptions

• ex: people are more likely to believe cereal that markets itself as 90% fat-free is healthier than a cereal that has 10% fat even though they mean the same thing.

Gambler’s Fallacy

The belief that past events influence future ones

• ex: “The coin has landed on tails 17 times in a row, it must land on heads on the next flip!”

• The probability of the coin landing on either side is equally as likely as the next

Executive Functions

Cognitive processes that allow people to make goal-directed behaviors & have critical thinking

• ex: preparing to apply to college by setting goals for your academic success, organizing college lists, and planning ahead

Sunk-Cost Fallacy

Continuing an activity just because you have already invested time, effort, or money even though you do not enjoy it.

Creativity

The ability to come up with new & unique ideas

Divergent Thinking

The ability to generate many different solutions to a problem.

• ex: A teacher asks “How many uses can you think of for a paperclip?”

• a student answers: making jewelry, picking a lock, creating art, or the usual holding papers

Convergent Thinking

Narrowing down options to select the single best answer to a problem

Functional Fixedness

A cognitive bias that makes a person see objects only in terms of their usual functions, which can block problem-solving

• ex: a person needs to tighten a screw, but doesn’t have a screwdriver, so they give up rather than using a coin to tighten the screw.

Testing Effect

The improved memory that results from actively retrieving information (testing yourself) rather than just rereading or reviewing material.

• ex: taking practice quizzes helps you study better for tests than simply reviewing notes

Metacognition

The awareness & understanding about your own thinking processes (thinking about thinking)