Sensory Perception and Gestalt Principles in Psychology

one must

Sensory Adaptation

Diminished sensitivity to a constant stimulus over time. Example: You stop noticing the smell of your own perfume after a while.

Weber's Law

To detect a difference between two stimuli, the change must be by a constant proportion, not amount. Example: You can notice a 5-pound difference in a 10-pound weight, but not in a 100-pound one.

Transduction

The process of converting physical energy (light, sound, touch) into neural signals your brain can interpret. Happens in sensory organs like the retina or cochlea.

Loudness

The perception of sound intensity; determined by the amplitude (height) of sound waves. Greater amplitude = louder sound.

Kinesthesis

Your sense of body position and movement of individual body parts. Allows you to touch your nose with your eyes closed.

Vestibular Sense

Your sense of balance and body orientation, located in the inner ear (semicircular canals). Helps you stay upright and coordinated.

Cones

Color-sensitive receptors in the retina (mostly in the fovea). Work best in bright light and detect fine detail.

Rods

Light-sensitive receptors in the retina that detect black, white, and gray. Work best in dim light; important for night vision.

Signal Detection Theory

Predicts when we will detect weak signals (like faint sounds) amid background noise. Depends on signal strength, experience, expectation, motivation, and fatigue.

Fovea

The central point of the retina where cones cluster. Provides sharpest vision and detail.

Selective Attention

Focusing on one stimulus while ignoring others. Example: You can focus on one voice in a noisy classroom (the cocktail party effect).

Perceptual Set

A mental predisposition to perceive one thing and not another, based on expectations or past experiences. Example: Seeing a 'cloud' shaped like a rabbit because someone mentioned it first.

Gestalt

Means 'whole' — emphasizes that we perceive objects as organized patterns, not isolated parts. 'The whole is greater than the sum of its parts.'

Figure-Ground

The organization of the visual field into figure (the object) and ground (the background). Example: Reading words (figure) on a page (ground).

Closure

A Gestalt principle — we fill in gaps to make a complete, whole object. Example: Seeing a broken circle as a full circle.

Visual Cliff

A lab device used to test depth perception in infants and animals. Found that depth perception appears early in development.

Binocular Cues

Depth cues that require both eyes to perceive distance. Includes retinal disparity and convergence.

Retinal Disparity

The brain compares images from both eyes to judge distance — the greater the difference, the closer the object. Example: Holding your finger close and switching eyes — it 'jumps.'

Phi Phenomenon

The illusion of movement created when lights blink on and off in quick succession. Used in neon signs and movies.

Stroboscopic Movement

Perceiving continuous motion in a series of slightly varying images. Example: Flip books or animation.

Relative Height

We perceive objects higher in our field of vision as farther away.

Linear Perspective

Parallel lines appear to converge in the distance. Example: Railroad tracks meeting at a point.

Relative Clarity

Hazy or blurry objects appear farther away; clear objects appear closer.

Interposition

If one object overlaps another, we see it as closer.

Light and Shadow

Brightly lit objects appear closer, shaded or darker objects appear farther away.

Relative Size

If two objects are the same actual size, the one that casts a smaller retinal image seems farther away.

Size Constancy

We perceive objects as having a constant size, even when their distance changes. Example: A car far away still looks 'normal-sized,' not tiny.

Shape Constancy

We perceive the shape of an object as constant even when viewed from different angles. Example: A door looks rectangular even when it's half open.

Perceptual Adaptation

The ability to adjust to changed sensory input (like seeing through new glasses). Your brain adapts to flipped or shifted visual input.

Similarity (Gestalt Principle)

We group similar items together (color, shape, etc.) as part of the same pattern.

Visual Capture

Vision dominates other senses — when there's a conflict, we trust what we see over what we hear. Example: Watching a ventriloquist and thinking the puppet is talking.