AP Psych Vocab: Sensation and Perception

Sensation

The process by which our sensory receptors and nervous system receive stimulus from the environment (5 senses)

Perception

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

Bottom-Up Processing

Information from the senses is first received, then the brain puts meaning to it

Top-Down Processing

The brain’s perception of the info brought in by the 5 senses

Psychophysics

The study of the relationship between sensations and the stimuli that produce them

Absolute Threshold

The minimum stimulation needed to detect a stimulus 50% of the time

Ex. The faintest sound you can hear in a quiet room or the dimmest light you can see in the dark

Signal Detection Theory

Detecting the presence of a faint stimulus amid background stimulus

Ex. I can hear the leaves rustle while I’m in the middle of a busy parking lot

Subliminal

The inability to detect stimuli below our absolute thresholds

Ex. I can’t hear the very quiet speaking that’s covered by loud music in my YouTube video

Difference Threshold

The least amount of stimulation needed to notice that a change has taken place

Ex. The smallest difference in volume on a radio that you can hear

Weber’s Law

The idea that to perceive a difference between two stimuli, they must differ by a constant percentage

Ex. If you're holding a 10-pound weight, you might notice a difference of 1 pound. However, if you're holding a 100-pound weight, you might need a 10-pound difference to notice a change.

Sensory Adaptation

Our sensitivity to unchanging stimuli gradually diminishes

Ex. City dwellers are no longer annoyed by the constant noise of traffic because they’ve become accustomed to it

Selective Attention

The focusing of conscious awareness on a particular stimulus (the brain only focuses on one main thing at a time)

Cocktail Party Effect

The ability to listen to one voice among many

Inattentional Blindness

Failing to see visible objects when our attention is directed elsewhere

Change Blindness

Failing to notice changes in the environment

Transduction

Transforming signals from the environment (light waves, sound waves, etc.) into neural impulses that the brain can read

Wavelength

Distance from the peak of line light or sound wave to the peak of the next

Hue

Dimension of color that is determined by wavelength of light

Intensity

Amount of energy in a light or sound wave influencing what we see as brightness

Pupil

Opening in the center of the eye where light enters

Iris

Ring of muscle tissue that form the colored part of the eye and controls the size of the pupil opening

Accommodation

Sensation and perception where the eye's lens changes shape to focus images close or far from the retina

Retina

Back inner surface of the eye with layers of neurons to begin processing visual info

Acuity

Sharpness of vision

Nearsightedness

When you can see things close, but not farther away

Farsightedness

When you can see things farther away, but not lose

Rods

Retinal receptors that detect black, white, and gray, and are sensitive to movement

Cones

Retinal receptors that are concentrated near the center of the retina and function in lit conditions. They can detect fine detail

Optic Nerve

Carries neural impulses from the eye to the brain

Blind Spot

Where the optic nerve leaves the eye, creating a "blind" spot because no receptor cells are located here.

Fovea

Central focal point in the retina, around which the eye's cones cluster

Feature Detectors

Nerve cells in the brain's visual cortex that respond to specific features of the stimulus, such as shape, angle, or movement

Young-Heimholtz Trichromatic Theory

Theory that the retina contains 3 different types of color receptors - one most sensitive to red, one to green, one to blue. When stimulated, it can produce the perception of any color

Parallel Processing

Brain’s ability to perceive several features simultaneously

Ex. Movement, color, size, direction

Color Constancy

Perceiving familiar objects as having consistent color, even if changing illumination alters the wavelengths reflected by the object.

Ex. I know the door is still brown even if the lights are on or off

Audition

The sense of hearing

Frequency

The number of complete wavelengths that pass a point in a given time

Ex. Per second or per hour

Pitch

A tone’s experienced highness or lowness; depends on frequency

Middle Ear

The chamber between the eardrum and cochlea containing 3 tiny bones that concentrate the vibrations of the ear drum on the cochlea’s oval window

Inner Ear

The innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs

Cochlea

A coiled, bony, fluid-filled tube in the inner ear; sound waves traveling through the cochlear fluid trigger nerve impulses

Place Theory

According to Heimholtz, we hear different pitches because different sound waves trigger activity at different places along the cochlea’s basilar membrane (only explains HIGH pitches)

Frequency Theory

We sense pitch by the basilar membrane vibrating at the same rate as the sound (only explains LOW pitches)

Conduction Hearing Loss

Hearing impairment caused by problems in the outer or middle ear, preventing sound waves from reaching the inner ear and cochlea (less common)

Sensorineural Hearing Loss

Hearing impairment caused by damage to the hair cells or auditory nerves in the inner ear (most common)

Gate-Control Theory

Proposes that there is a "gate" in the spinal cord that can either allow or block pain signals from reaching the brain

Sensory Interaction

The principle that one sense may influence another

Ex. When the smell of food influences its taste

Kinesthesis

Our movement sense; our system for sensing the position and movement of individual body parts

• Receptors located in muscles and joints

• Messages sent to the cerebellum

• Ex. Even though our eyes are closed, we still know that we’re sitting criss-cross

Vestibular Sense

Our balance sense; our sense of body movement and position that enables our sense of balance

• Receptors located in semicircular canals in our ears

• Messages sent to the cerebellum

Visual Capture

Our tendency to allow visual images to dominate our perception

Ex. We perceive the voice as coming from the puppet’s mouth, even though the sound is actually coming from the person (ventriloquism effect)

Gestalt

An organized whole. Gestalt psychologists emphasize our tendency to integrate pieces of information into meaningful wholes

Figure-Ground

A principle that states that we organize our perceptions into figure and background

Grouping

The perceptual tendency to organize stimuli into groups based on proximity, similarity, closure, etc.

Depth Perception

The ability to see objects in three dimensions although the images that strike the retina are two-dimensional; allows us to judge distance

Ex. Objects closer to us appear larger than objects further away

Visual Cliff

A test that determines the age at which humans perceive depth (occurs around 6 months of age)

Binocular Cues

Depth cues that depend on two eyes

Monocular Cues

Depth cues that depend on one eye

Retinal Disparity

The closer an object comes to you the greater the disparity, or difference in the angle is between the two images

Convergence

When objects are closer to you, there is more tension in the muscle of your eyes

Phi Phenomenon

An optical illusion that causes one to see several still images in a series as moving

Perceptual Constancy

Perceiving objects as unchanging (having consistent color, brightness, shape, and size)

Perceptual Adaptation

The ability to adjust to artificially displaced or inverted visual field

Ex. I feel disoriented wearing glasses with weird lenses, but eventually I’ll be able to adjust

Perceptual Set

How our expectations, contexts, and emotions influence our perception

Ex. My friend tells me this movie is hilarious. As a result, I find myself laughing more than I usually would

Human Factor Psychologists

Explores how people and machines interact and how machines and physical environments can be made safe and easy to use

Extrasensory Perception (ESP)

The ability to obtain information about the world around you without using the five senses

Ex. Superpowers like telepathy or seeing the future