Psyc 110: Chapter 5

Flashcards covering key concepts from Chapter 5 on sensation and perception.

Sensation

The detection of physical stimulus energy from the environment and the sending of that information to the brain.

Perception

The brain’s process of organizing and interpreting sensory information.

Sensory Receptors

Specialized cells that detect specific kinds of stimuli, converting them into neural signals.

Sensory Organs

Body structures that contain sensory receptors, such as the eyes, ears, skin, and tongue.

Transduction

The conversion of physical stimulus energy into neural signals that the brain can understand.

Absolute Threshold

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

Difference Threshold (JND)

The smallest difference between two stimuli that can be noticed.

Weber’s Law

The principle stating that the just noticeable difference depends on a proportion of the original stimulus, not a fixed amount.

Sensory Adaptation

Reduced sensitivity to a constant, unchanging stimulus over time; our sensory systems become less responsive.

Habituation

Decreased response to repeated or unimportant stimulation as an organism learns to ignore constant stimuli.

Cornea

The thick, transparent outer layer of the eye that helps focus incoming light.

Pupil

The dark opening in the center of the eye that regulates the amount of light entering.

Iris

The colored circular muscle that controls the size of the pupil and regulates the amount of light that enters the eye.

Lens

The transparent structure behind the pupil that focuses light onto the retina.

Retina

The thin inner surface at the back of the eye that contains sensory receptors, responsible for converting light into neural signals.

Rods

Retinal receptors primarily used for night vision and detecting light in low-light conditions.

Cones

Retinal receptors used for color vision and fine detail recognition, functioning best in bright light.

Ganglion Cells

The first neurons in the visual system that process signals from the retina and transmit visual information to the brain.

Optic Nerve

The bundle of ganglion cell axons that carries visual information from the eye to the brain.

Blind Spot

The area where the optic nerve leaves the retina; it contains no rods or cones, resulting in a lack of visual information in that spot.

Optic Chiasm

The point where the optic nerves partially cross, allowing visual information from both eyes to be processed in opposite hemispheres of the brain.

Left Visual Field

The visual field processed by the right hemisphere of the brain.

Right Visual Field

The visual field processed by the left hemisphere of the brain.

Steps from Sensation to Perception in Vision

The progression from a physical stimulus to perception: Physical stimulus → sensation → transduction → neural signals → brain processing → perception.

What Happens During Visual Transduction?

Light is converted by receptors in the retina into neural signals that the brain can interpret.

Wavelength

The distance between peaks of a light wave; it determines the hue or color perceived.

Amplitude

The height of a light wave; this influences the intensity or brightness of the color perceived.

ROY G. BIV

An acronym for the colors of the visible spectrum: Red, Orange, Yellow, Green, Blue, Indigo, Violet.

Longest Visible Wavelengths

Red light, which has the longest wavelengths in the visible spectrum.

Shortest Visible Wavelengths

Violet light, which has the shortest wavelengths in the visible spectrum.

Trichromatic Theory

The theory of color vision stating that perception of color is based on three types of cone receptors responsive to red, green, and blue.

Opponent-Process Theory

The theory that color is processed in opposing pairs such as red-green, blue-yellow, and black-white.

Why are Both Color Theories Considered Correct?

Both theories are supported because we have three cone types for color detection, and the brain processes this information in an opponent-like manner.

S Cones

Cones that are most sensitive to short wavelengths of light, primarily responsible for blue color perception.

M Cones

Cones that are most sensitive to medium wavelengths of light, primarily involved in green color perception.

L Cones

Cones that are most sensitive to long wavelengths of light, primarily responsible for red color perception.

How Does the Brain Determine Color?

By comparing the relative activity levels of S, M, and L cones in response to light.

Gestalt Psychology

The psychological perspective that emphasizes the brain's tendency to organize sensory input into meaningful wholes or patterns.

Figure-Ground

The perceptual tendency to separate objects (figures) from their backgrounds (ground).

Proximity

The principle that objects that are close to each other tend to be perceived as grouped together.

Similarity

The principle that similar objects are perceived as belonging together.

Continuity

The tendency to perceive smooth, continuous patterns rather than discontinuous ones.

Closure

The perceptual tendency to fill in gaps to perceive complete objects.

Illusory Contours

Perceived edges or shapes created by the brain when there are no actual lines or borders.

Bottom-Up Processing

Perception that starts with the sensory input; it emphasizes features of the stimulus.

Top-Down Processing

Perception that is influenced by knowledge, experiences, and expectations, affecting how sensory information is interpreted.

Depth Perception

The ability to perceive distance and three-dimensional space in the environment.

Monocular Depth Cues

Depth cues that can be perceived using only one eye, such as relative size and occlusion.

Binocular Depth Cues

Depth cues that require the use of both eyes to perceive depth and distance, such as binocular disparity.

Occlusion

A depth cue where a nearer object obstructs the view of a farther object, indicating depth.

Height in Field

The position of objects in the visual field; objects that are higher are often perceived as farther away.

Relative Size

The perception that smaller-looking objects are usually farther away than larger ones.

Linear Perspective

A depth cue that occurs when parallel lines appear to converge as they recede into the distance.

Texture Gradient

The perception of variation in texture density that indicates distance; with distance, texture appears denser and less detailed.

Familiar Size

Using known sizes of objects to estimate their distance in a visual field.

Binocular Disparity

The slight difference in the images seen by each eye that the brain uses to perceive depth.

When Does Binocular Disparity Work Best?

For nearby objects, where the difference in images from each eye is more pronounced.

Motion Aftereffect

The phenomenon where, after watching movement in one direction, a stationary object seems to move in the opposite direction.

Stroboscopic Motion

The perception of motion that occurs when still images are shown rapidly in sequence, creating the illusion of movement, as seen in films.

Object Constancy

The perception of objects as stable and unchanging despite variations in viewing conditions.

Size Constancy

The perception of an object as having a constant size regardless of changes in distance.

Shape Constancy

The perception that an object maintains the same shape despite changes in viewing angle.

Color Constancy

The perception that an object appears the same color under varying lighting conditions.

Brightness Constancy

The perception of an object as having a stable lightness despite changes in illumination.