AP Psychology Sensation and Perception

What does the eye detect?

Wavelengths of light

Where does light enter?

Cornea

Wavelength

The distance from one wave peak to another

How do we see light?

Electromagnetic energy that travels in waves

Cornea

Clear membrane covering the visible part of the eye that helps gather and direct incoming light

Pupil

The opening in the middle of the iris that changes size to let in different amounts of light

Iris

Colored part of the eye which is the muscle that controls the size of the pupil

Lens

 A transparent structure located behind the pupil that actively focuses or bends light so that the light falls on the retina

Accommodation

The pupil actively bending light

Retina

A thin light sensitive membrane located at the back of the eye that contains the sensory receptors for vision

Fovea

Small area in the center of the retina composed entirely of cones, where visual information is most sharply focused.

Rods

The long thin blunt sensory receptors of the eye that are highly sensitive to light (but not color) and are primarily responsible for peripheral vision and night vision.

Cones

The short, thick, pointed sensory receptors of the eye that detect color and are responsible for color vision and visual acuity

Blind Spot

The point at which the optic nerve leaves the eye, producing a small gap in the field of vision

Optic Nerve

Made up of the fibers of the ganglion cells that carry neural impulses from the retina to the brain

Pinna

Skin and cartilage on the side of the head that catches sound waves and funnels them into the auditory and ear canal

Eardrum

Tightly stretched membrane at the end of the ear canal that vibrates when hit by sound waves

Middle Ear

Amplifies sound waves and consists of 3 tiny bones called the hammer, anvil, and stirrup

Oval Window

Membrane that separates the middle ear from the inner ear

Inner Ear

The part of the ear where sound is transduced into neural impulses, consists of the cochlea and the Basilar membrane

Cochlea

Coiled fluid filled ear structure that contains the sensory receptors for sound

Basilar Membrane

Membrane in the cochlea that contains the hair cells

Hair Cells

Hair like sensory receptors for sound found in the basilar membrane of the cochlea

Auditory Nerve

A bundle of fibers that carries nerve impulses from the inner ear to the brain

Hammer, Anvil, Stirrup

The three small bones of the middle ear that concentrates the eardrums vibrations on the cochlea

Ear Canal

The sound waves pass through this area and are brought to a point of focus on the eardrum

Difference Threshold

The smallest possible difference between 2 stimuli that can be detected half the time, also called the just noticeable difference (JND)

Weber’s Law

The principle of sensation that holds the size of the just noticeable difference will vary depending on its relation to the strength of the original stimulus

Sensory Adaptation

The decline in sensitivity to a constant stimulus

Subliminal Perception

Perception of stimuli that are below the threshold of conscious awareness

Ganglion Cells

In the retina the specialized neurons that connect to the bipolar cells and the bundles axons of the ganglion cells form the optic nerve

Bipolar Cells

In the retina and are specialized neurons that connect the rods and cones with the ganglion cells

Optic Chiasm

The point in the brain where optic nerve fibers from each eye meet and partly cross over to the opposite side of the brain

Hubel and Wiesel

Identified feature detectors and feature detectors are nerve cells in the brain that respond to specific features of a stimulus such as shape, angle, or movement and then the brain perceives the portrayed image

Parallel Processing

The processing of several aspects of a problem simultaneously, the brain divides a visual scene into subdimensions such as color, depth, movement, and form and works on each aspect simultaneously

Color

The perceptual experience of different wavelengths of light involving Hue saturation and brightness

Sensation

The process of detecting a physical stimulus such as light, heat, sound, or pressure

Perception

The process of integrating, organizing, and interpreting sensations

Sensory Receptors

Specialized cells unique to each sense organ that respond to a particular form of sensory stimulation

Transduction

The process by which a form of physical energy is converted into a code, neural signal that can be processed by the nervous system

Absolute Threshold

The smallest possible strength of a stimulus that can be detected half of the time

Signal Detection Theory

• How and when we detect the presence of a faint stimulus (signal) it assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and level of fatigue

Hue

The property of wavelengths of light known as color, different wavelengths respond to different colors

Saturation

The property of color that corresponds to the purity of the light wave

Brightness

The perceived intensity of a color which corresponds to the amplitude of the light wave

Trichromatic Theory of Color Vision

Sensitive to either red light (Long wavelengths), green light (Medium wavelengths), or blue light (Short wavelengths)

Color Blindness

One of several inherited color deficiency or weakness in which an individual can’t distinguish certain colors

Opponent Process Theory of Color Vision

Color vision is the product of opposing pairs of color receptors, red-green, blue-yellow, black-white

After Image

A visual experience that occurs after the original source of stimulation is no longer present 

Signal Detection Theory

• How and when we detect the presence of a faint stimulus (signal) it assumes there is no single absolute threshold and that detection depends partly on a person's experience, expectations, motivation, and level of fatigue