1.6 Ap Psychology Meyers Key Terms

Sensation

The process by which our sensory receptors and nervous system receive information from the environment.

Sensory Receptors

Specialized neurons that detect physical energy (like light, sound, touch) and send signals to the brain.

Perception

The process of organizing and interpreting sensory information so we can recognize meaningful objects and events.

Bottom-up Processing

Processing that starts with sensory input and builds up to perception (like noticing details first).

Top-down Processing

Using past experiences, knowledge, and expectations to interpret sensory information.

Transduction

The process of converting one form of energy into another — like turning light waves into neural signals.

Psychophysics

The study of how physical energy (like light, sound, etc.) relates to our psychological experience of them.

Gustav Fechner

A psychologist who founded psychophysics and studied the relationship between physical stimuli and perception.

Absolute Threshold

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

Signal Detection Theory

Predicts how and when we detect a faint stimulus among background noise; depends on attention and experience.

Subliminal

Below your absolute threshold — you can’t consciously detect it, but it may still influence you slightly.

Priming

When exposure to one stimulus affects your response to another stimulus without conscious awareness.

Difference Threshold

The smallest difference between two stimuli that can be detected 50% of the time.

Ernst Weber

A scientist who discovered that the difference threshold depends on the proportion, not the amount of change.

Weber’s Law

To notice a difference between two stimuli, they must differ by a constant percentage, not a fixed amount.

Sensory Adaptation

When you become less sensitive to a constant, unchanging stimulus (like not noticing your perfume after a while).

Wavelength

The distance between peaks of a light wave; determines color (hue).

Hue

The color we experience, such as red or blue, determined by wavelength.

Intensity

The amount of energy in a light wave; influences brightness.

Cornea

The clear, curved part of the eye that helps focus light.

Pupil

The adjustable opening in the center of the eye that lets light in.

Iris

The colored part of the eye that controls the size of the pupil.

Lens

Focuses light on the retina by changing shape (accommodation).

Retina

The light-sensitive layer at the back of the eye that contains rods and cones.

Accommodation

The process where the lens changes shape to focus on objects at different distances.

Rods

Retinal cells that detect black, white, and gray; work well in dim light.

Cones

Retinal cells that detect color and detail; work best in bright light.

Optic Nerve

Carries visual information from the eye to the brain.

Blind Spot

The area on the retina where the optic nerve leaves — no receptor cells there.

Fovea

The central focus point in the retina with the most cones; gives sharp vision.

Young-Helmholtz Trichromatic (Three-Color) Theory

The theory that the retina has three color receptors — red, green, and blue — that combine to make all colors.

Opponent-Process Theory

The theory that color vision is controlled by opposing pairs: red–green, blue–yellow, and black–white.

David Hubel

Neuroscientist who discovered feature detectors in the visual cortex.

Torsten Wiesel

Neuroscientist who discovered feature detectors in the visual cortex with David Hubel.

Feature Detectors

Brain cells that respond to specific visual features like edges, angles, or movement.

Parallel Processing

Processing many aspects of a visual scene (color, motion, form, depth) all at once.

Audition

The sense or act of hearing.

Frequency

The number of sound wave cycles per second; determines pitch.

Pitch

How high or low a sound seems; depends on frequency.

Middle Ear

Contains the three tiny bones (hammer, anvil, stirrup) that send vibrations to the cochlea.

Cochlea

A spiral-shaped, fluid-filled structure in the inner ear where sound waves are changed into neural signals.

Inner Ear

Contains the cochlea and semicircular canals; helps with hearing and balance.

Sensorineural Hearing Loss

Hearing loss caused by damage to the cochlea’s hair cells or auditory nerve.

Conduction Hearing Loss

Hearing loss caused by damage to the mechanical system that conducts sound waves (like the eardrum or bones).

Cochlear Implant

An electronic device that converts sounds into electrical signals to help restore hearing.

Place Theory

The theory that different pitches are heard because sound waves trigger activity at different places in the cochlea.

Frequency Theory

The theory that pitch is related to how fast the entire basilar membrane vibrates.

Gate-Control Theory

The theory that the spinal cord has a “gate” that controls pain signals — it can block or allow them to reach the brain.

Gustation

The sense of taste.

Olfaction

The sense of smell.

Kinesthesis

The sense of body position and movement of body parts.

Vestibular Sense

The sense of balance and body movement, controlled by the inner ear.

Sensory Interaction

When one sense influences another, like how smell affects taste.

Embodied Cognition

The idea that our thoughts are influenced by our body sensations and actions (like holding a warm drink making you feel socially warm).