3.4 Visual Anatomy & 3.5 Auditory Sensation and Perception

the transparent, dome-like structure on the front part of the eye that gives the eye focusing or refracting power

the adjustable opening in the center of the eye through which light enters

• controls the amount of light that enters into the eye

a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening

• colored part of the eye

the transparent structure behind the pupil that changes shape to help focus images on the retina

• focus due on near or far objects

light-sensitive layer that lines the back of the eye

• contains photoreceptors that absorb light and then transmit those signals through the optic nerve to the brain

rods and cones

light-detecting cells that are concentrated near the retina and that function in daylight or in well-lit conditions

• directly involved in our ability to perceive color

Specialized photoreceptors that work well in low light conditions

• involved in our vision in dimly lit environments as well as in our perception of movement on the periphery of our visual field

Rods and cones> Bipolar cells> Ganglion cells

a type of nerve cells that combine the impulses from many of the visual receptor cells in the retina and then transmits those impulses to the ganglion cells.

neurons that relay information from the retina to the brain via the optic nerve.

the nerve that carries neural impulses from the eye to the brain (cross sectioning) and then sends information into a number of structures in the occipital lobe at the back of the brain for processing

The point at which the optic nerve leaves the eye, creating a blind spot because no receptor cells are located there

• saccade eye have rapid eye movement from side to side to help fill in missing info. created by blind spot

There are three receptors in the retina responsible for the perception of color (green, blue, red)

• Colors red, blue, and green can be combined to create all colors of light

They simply lack functioning red-or-green sensitive cones or sometimes both, missing cones that respond to a specific color

• comonchromatic (one color) or dichromatic (2 colors) instead of trichromatic

• Make it impossible to distinguish red and green

Retinal processes only occur in 3 sets of opponents

• Red-Green Complex

• Blue-yellow complex

• Black-white complex

  • Cells can only detect the pretense of one color at a time because the two colors oppose one another

Describes the continuation of a visual sensation after removal of the stimulus

In the visual cortex, specialized neurons that react to the strength of visual stimuli responding to snapes, angles, edges, lines, and movement in field of vision

the ability of the brain to do many thins at onces

• For visual processing, color, motion, shape, and depth are processes simultaneously

The biological process by which our ears process sound waves

• in order for something to be sound it must be perceived

• helps survival

• evolutionary psych

Vibrations of molecules that travel through the air

• sound haves result from the mechanical vibration of molecules

• vibrations move in mediums, such as air outward from the source, first compressing molecules then letting them move apart

Height of sound waves, the psychological quality of loudness

• intensity measured in decibles

• Higher amplitude= louder volume

Number of wavelength cycles measured in hertz

• shorter wavelength= higher pitch

The highness/lowness of a wavelength’s sound

the outer ear

• directs sound waves into the ear canal

The eardrum

• sound waves make the eardrum vibrate (conduct)

Sound waves travel to vibrate bones (auditory ossicles) of the ear

• Unbreakable bones: Mallues, incus, stapes

coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses

• on the top of this membrane is the organ of the corti which contains hair cells that convert vibrations into nerve impulses and send to auditory nerves)

• inner most part of the ear

in hearing, explaining how we distinguish high-pitch sounds that possess a frequency that exceeds 5,000 hertz

• we hear pitch based on where on the basilar membrane the hair vibrates

new neural signals travel throughout the medulla, pons, and thalamus (sensory relay station) to temporal lobe

• auditory cortex is where your brain perceives and makes sense of what you just heard

We hear pitch based on HOW FAST the hair cells vibrate

• sond eaves cause the entire basilar membrane to vibrate at different rates which, in return, cause the neural impulses to be transmitted at different rates

sound waves strike one ear sooner and more intensely than the other

• from this info our brain (nimble) computes the sound localization

• using parallel processing, your brain processes both intensity differences and timing differences to determine where the sound is

caused by structural damage (eardrum rupture) to the mechanical system that conducts sound waves to the cochlea

• age, genes, environment, exposure contribute

• common as ppl get older

Occurs when the inner ear cochlea or auditory nerve itself is not functioning properly

• hearing aids are ineffective since no auditory message can reach the brain

• Hair cells can be abnormal at birth, infection or trauma can damage them, once damaged they are deaf and can no longer function

a device for converting sounds into electrical signals and stimulating the auditory nerve through electrodes threaded into the cochlea

interactions w/ vision on hearing an illusion that when visual component of another sound leading to a third sound

our tendency to organize our sensations into wholes of what they call gestalts

we naturally organize what we see into objects

Straight or curvy lines that are seen as connected lines and not separated lines

when you’re presented with a set of ambiguous or complex objects, your brain will make them appear as simple as possible

states that similar things tend to appear as grouped together (both visually and auditory)

our brain fills in groups of info +ignores contradictory information in order to recognize + complete images

things that are closer together seem more related than things spaced further apart

objects that are higher are perceived to be farther away from us

objects that are closer to us are previewed to be larger than the same size object that is further from the lens

create the illusion that when we perceive movement in slightly varying images shown in rapid succession

this is created when adjacent lights blink on and off in a quick succession

another example of how our brain plays tricks on us as we interpret the objects in our visual field