AP Psychology Unit 1B: Sensation and Perception

Absolute threshold

The smallest amount of something we can sense.

Transduction

Changing something, like light or sound, into a signal our brain understands.

Just noticeable difference

The smallest change in something we can notice.

Sensory adaptation

Getting used to a constant sensation, like a smell or a sound.

Weber’s law

The idea that noticing a change depends on how big it is compared to what’s there.

Synesthesia

When senses blend, like seeing colors when hearing sounds.

Retina

The back part of the eye that detects light.

Blind spot

A part of the eye where we can't see because there are no detectors there.

Visual (optic) nerve

The nerve that sends visual information from the eye to the brain.

Photoreceptors

Cells in the eye that respond to light.

Rods

Photoreceptors that help us see in dim light and detect movement.

Lens

The part of the eye that focuses light to make images clearer.

Accommodation

The lens changing shape to focus on close or far objects.

Nearsightedness

When you can see things up close but not far away.

Farsightedness

When you can see things far away but not close up.

Trichromatic theory

The idea that we see color through three types of color detectors (red, green, and blue).

Opponent-process theory

The idea that we see colors as pairs (like red-green, blue-yellow).

Fovea

The part of the retina where we see most clearly.

Cones

Photoreceptors that help us see color and detail in bright light.

Ganglion cells

Cells in the eye that send visual information to the brain.

Dichromatism

Color blindness where two color detectors work instead of three.

Monochromatism

Total color blindness, seeing only in shades of gray.

Prosopagnosia

Difficulty recognizing faces.

Blindsight

Being able to respond to visual information without consciously seeing it.

Place theory

A theory that we hear pitch based on where sound waves hit in the inner ear.

Volley theory

The idea that groups of nerve cells work together to send sound signals for higher pitches.

Frequency theory

The idea that we hear pitch based on how fast nerves send signals.

Conduction deafness

Hearing loss due to problems with parts that carry sound to the inner ear.

Sensorineural deafness

Hearing loss due to problems in the inner ear or the nerve that connects it to the brain.

Pheromones

Chemicals animals release to communicate with others.

Gustation

The sense of taste.

Olfaction

The sense of smell.

Gate control theory

The idea that our spinal cord can block pain signals or let them through.

Phantom limb syndrome

Feeling sensations in a limb that has been removed.

Vestibular sense

Our sense of balance and body position.

Semicircular canals

Parts of the inner ear that help us balance.

Kinesthesis

Our sense of where our body parts are and how they move.

Top-down processing

Using what we already know to make sense of information.

Bottom-up processing

Starting with details to understand the whole picture.

Perceptual sets

Expectations that shape how we perceive things.

Gestalt psychology

The idea that we see things as whole forms, not just parts.

Figure/ground

Distinguishing a shape from its background.

Selective attention

Focusing on one thing and ignoring others.

Cocktail party effect

Focusing on one voice among many.

Inattentional blindness

Missing something in plain sight because you're focused elsewhere.

Change blindness

Not noticing changes in a scene when you're focused elsewhere.

Binocular depth cues

Clues about depth that require both eyes.

Monocular depth cues

Clues about depth that can be seen with one eye.

Retinal disparity

The slight difference between what each eye sees, which helps us see depth.

Interposition

When one object blocks another, we see it as closer.

Linear perspective

When parallel lines appear to meet in the distance, helping us perceive depth.