AP Psychology: Sensation and Perception

Sensation

The process of detecting physical stimuli from the environment (such as light, sound, or touch) and converting them into neural signals.

Perception

The process of organizing, interpreting, and making sense of the sensory information.

Stimulus

Any external event or object that can be detected by the senses.

Transduction

The conversion of physical energy (e.g., light, sound) into neural signals.

Absolute Threshold

The minimum intensity of a stimulus required to be detected 50% of the time.

Difference Threshold (Just Noticeable Difference, JND)

The smallest difference between two stimuli that can be detected.

Sensory Receptors

Specialized cells that detect sensory stimuli (e.g., rods and cones in the eyes, hair cells in the ears).

Sensory Adaptation

The diminished sensitivity to a stimulus after prolonged exposure.

Bottom-Up Processing

Sensory processing that begins with the raw sensory input and works up to higher-level processing (data-driven).

Top-Down Processing

Perception guided by prior knowledge, experience, and expectations (conceptually driven).

Selective Attention

Focusing on a specific aspect of the environment while ignoring others.

Perceptual Set

A mental predisposition to perceive something in a particular way based on prior experience or expectations.

Gestalt Psychology

A theory that suggests people naturally perceive objects as organized patterns and wholes, rather than the sum of their parts.

Figure-Ground Relationship

The ability to distinguish a figure from the background.

Proximity

Objects that are close together are perceived as a group.

Similarity

Similar objects are grouped together.

Continuity

We tend to perceive continuous patterns, rather than disjointed ones.

Closure

We tend to fill in gaps to create a whole object.

Depth Perception

The ability to perceive the world in three dimensions and judge distances.

Binocular Cues

Depth cues that depend on the use of both eyes, such as convergence and retinal disparity.

Monocular Cues

Depth cues that can be perceived with one eye, such as linear perspective, relative size, interposition, and light and shadow.

Perceptual Constancy

The perception that objects remain stable despite changes in sensory input.

Size Constancy

The perception that an object's size remains constant despite changes in distance.

Shape Constancy

The perception that an object's shape remains constant despite changes in perspective.

Color Constancy

The perception that an object's color remains constant despite changes in lighting.

Motion Perception

The ability to perceive movement in the environment, including phenomena like stroboscopic movement and phi phenomenon.

Retinal Disparity

The difference between the images seen by each eye, which provides a cue for depth.

Convergence

The inward movement of both eyes when focusing on a close object, which also provides depth information.

Wavelength

The distance between successive crests of a wave; related to color perception (hue).

Amplitude (Light)

The height of a wave; related to brightness of light.

Rods

Photoreceptors in the retina responsible for vision in low light and peripheral vision.

Cones

Photoreceptors responsible for color vision and sharp detail.

Fovea

The central part of the retina, responsible for sharp, detailed vision.

Optic Nerve

The nerve that transmits visual information from the retina to the brain.

Blind Spot

The point where the optic nerve exits the retina and no photoreceptors are present.

Trichromatic Theory

Proposes that color vision is based on three primary colors: red, green, and blue.

Opponent-Process Theory

Suggests that color perception is based on opposing color pairs: red-green, blue-yellow, black-white.

Frequency (Sound)

The number of waves per second; related to pitch perception.

Amplitude (Sound)

The height of sound waves; related to loudness.

Pitch

The perception of frequency, or how high or low a sound seems.

Place Theory

The theory that different parts of the cochlea respond to different frequencies of sound.

Frequency Theory

The theory that the rate of neural impulses corresponds to the frequency of sound.

Auditory Canal

The passageway that directs sound waves to the eardrum.

Cochlea

The spiral-shaped organ in the inner ear responsible for converting sound vibrations into neural signals.

Kinesthetic Sense

The sense of body position and movement of individual body parts.

Vestibular Sense

The sense of balance and spatial orientation, located in the inner ear.

Signal Detection Theory

A theory that explains how we detect signals amidst noise based on factors like motivation, expectation, and experience.

Subliminal Perception

The perception of stimuli below the threshold of conscious awareness.

Habituation

A decrease in response to a repeated stimulus over time.