Even though the illumination varies, we think of an object as having a constant brightness.
The black paper reflects less light than the white paper.
The black paper will still look black even if it reflects 100 times more light than the white paper.
If you view black paper through a narrow tube, it will look gray because it reflects a fair amount of light.
It is black because it reflects less light than the objects around it.
Square A is thought to be lighter than Square B because of its surroundings.
Cut out the squares and compare them, if you believe your eyes are lying.
This principle is important to artists, interior designers, and clothing designers.
Our perception of the color and brightness of a wall or a streak of paint on a canvas is determined by the surrounding colors, not just by the paint in the can.
Our brain is able to do this because of the rapid learning of different views of an object.
As the door opens, it casts a picture on our eyes.
We still think it is rectangular.
When we see a tiny image of a car two blocks away, we assume it's large enough to carry people.
We can see the object's size by looking at its distance.
Knowing that the object is a car gives us a clue to its distance.
We consider an object's context even in size-distance judgments.
For at least 22 centuries, scholars have wondered.
Monocular cues to an object's distance make the horizon Moon seem farther away.
Our brain assumes that it must be larger than the Moon in the night sky if it's farther away.
The horizon Moon will appear smaller if you use a paper tube to take away the distance cue.
Perceptual illusions reinforce a fundamental lesson, that perception is not just a projection of the world onto our brain.
Our brain reassembles itself into its own functional model of the external world when our sensations are disassembled.
Our assumptions can lead us astray during this reassembly process.
Form perception, depth perception, motion perception, and perceptual constancies show how we organize our visual experiences.
We can't hear where one word stops and the next begins in an unfamiliar language.
We hear different words when we listen to our own language.
This also shows perceptual organization.
"The dog ate meat" is more likely to be "The do gate me at" than "The do gate me at" (McBurney & Collings, 1984).
discerning meaning in what we perceive is part of the process.
Philosophers have debated if our perceptual abilities should be credited to our nature or nurture.
We are able to process sensory information.
We link an object's distance with its size.
Molyneux's hypothetical case was put to the test with a few dozen adults who were blind from birth.
The clouded lens that allowed them to see only diffuse light, rather than a foggy image, is what most were born with.
The patients were able to distinguish figure from ground and differentiate colors after the surgery.
Locke said they were unable to visually recognize objects that were familiar by touch.
Researchers have restricted the vision of infant kittens in order to gain more control.
The kittens behaved like humans after their vision was restored.
They were able to distinguish color and brightness, but not the form of a circle from a square.
Without early stimulation, their brain's cortical cells had not developed normal connections.
The animals were blind to shape.
Mike May lost his vision when he was 3 years old.
He got to see his wife and children for the first time after he had a new eye.
Although signals were reaching his visual cortex, it lacked experience to interpret them.
May could not distinguish between faces and expressions.
He can see an object in motion and has learned to navigate his world.
Children who are blind from birth can benefit from the removal of cataracts if they are younger.
Their visual acuity may never be normal.
Exposure to certain stimuli is an optimal period.
Sensory restrictions later in life do not harm.
After the eye patch is removed, an adult animal's vision will not be affected.
The return to normal vision is what most people are excited about when surgeons remove cataracts.
A new pair of glasses may make us feel confused.
We adjust within a day or two.
The world seems normal again because of our changed visual input.
Imagine a new pair of glasses that shift the location of objects 40 degrees to the left.
When you toss a ball to a friend, it sails to the left.
You go to the left to shake hands.
Not if you were a baby chicken.
Humans are able to adapt quickly.
Within a few minutes your throws would be on target.
You could still adapt, even if you have a pair of glasses that turn the world upside down.
George Stratton was a psychologist.
The ground was up and the sky was down.
As he attempted a handshake while looking at the world through goggles, researcher Hubert Dolezal thought, "oops, missed."
Humans, cats, and monkeys can adapt to an inverted world.
It was nearly impossible to eat.
He was able to reach for an object and walk without bumping into things after he persisted.
When the headgear was removed, he adapted quickly.
Research participants who wore such gear while riding a motorcycle, skiing the Alps, or flying an airplane did the same.
They were able to adapt to their new world by coordinating their movements.
We constantly adjust to changed sensory input.
Early nurture sculpts what nature has provided, according to research on critical periods.
Throughout our lives, nurture continues to do so.
The brain pathways that enable our perception are maintained by experience.
You can check your answer by clicking on the e-book and Appendix C of the printed text.
According to research, trying to answer these questions on your own will improve retention.
The characteristic of light that determines the color is _____.
Our perception of brightness is determined by the light wave's amplitude.
There are no cones in the blind spot.
Cones are the eye's cells that are sensitive to light and are responsible for our vision.
There are two theories for color vision.
The Young-Helmholtz trichromatic theory shows that the eye has something in it, and Hering's theory shows that the nervous system has something in it.
The cells in the visual cortex respond to certain lines.
The brain can process many aspects of a problem at the same time.
Our tendencies to fill in the gaps and to perceive a pattern as continuous are two different examples of the principle of interposition.
When listening to a concert, you look at the orchestra as an accompaniment.
This shows the principle of figure-ground.
Babies have not yet developed depth perception, according to the visual cliff experiments.
Our ability to group similar items is dependent on depth perception.
Interposition and linear perspective are two examples of depth cues.
A tomato that is consistently red is an example of a constancy shape.
Adults who had been blind from birth had difficulty recognizing objects.
People wear glasses that turn their visual fields upside down.
They learned to function well after a period of adjustment.
This ability is called a ability.
You can find answers in the e-book and at the back of the printed text.
Our hearing helps us adapt and survive.
Hearing gives information and allows relationships.
When we hear people, they are more thoughtful, competent, and likable than when we read their words.
Hearing is amazing.
It allows us to communicate without being seen, shooting unseen air waves across space and receiving the same from others.
Hearing loss is an invisible disability.
To not catch someone's name, to not grasp what someone is asking, and to miss a funny joke can be isolating.
I can understand why adults with significant hearing loss experience a doubled risk of depression, because I am a person with hearing loss.
Most of us can hear a wide range of sounds, but the ones we hear best are those in the range of the human voice.
We are sensitive to faint sounds, such as a child's cry.
When hunting or being hunted, our distant ancestors depended on this keen hearing.
A violin's short waves create a high pitch.
A lower pitch is created by the waves of a cello or bass.
Different degrees of loudness can be created by differences in the waves' height.
We are very familiar with sound variations.
We can easily recognize an unseen friend's voice among thousands of possible voices.
Hearing is fast.
It might take you a full second to notice something out of the corner of your eye, turn your head toward it, and respond to it.
A fraction of a second after such events, millions of neurons coordinate in order to get the essential features.
The sound waves will be unleashed if you draw a bow across the violin.
Waves of compressed and expanded air are created by air molecule bumping into each other.
As we swim in the ocean, our ears detect air pressure changes.
Sound waves vary in shape.
The high or low tone we experience is determined by their length.
Long waves have low frequencies and low pitches.
Short waves have high frequencies.
The sound waves produced by a Soprano are shorter and faster than those produced by a Baritone.
Normal conversation is 10,000 times more intense than a whisper.
The subway train is 10 billion times more intense than the faintest sound.
Hearing loss can be caused by exposure to sounds above 85 decibels.
The Kansas City Chiefs broke the Guinness World Record for the Loudest Stadium in the National Football League.
The bones of the middle ear amplify the sound of the eardrum and send it into the cochlea.
Hair cell movements cause impulses at the base of the nerve cells.
The hair cells allow us to hear thanks to their "extreme sensitivity and extreme speed" (Goldberg, 2007).
A cochlea has 16,000 of them, but we compare that to an eye's 130 million or so photoreceptors.
Consider a hair cell's responsiveness.
Sensorineural hearing loss can be caused by damage to the cochlea's hair cell receptors.
People can hear sound but have trouble distinguishing what is being said.
Hair cell receptors can be damaged by disease, but more often the culprits are biological changes linked with aging and ear-splitting noise.
Damage to the mechanical system that conducts sound waves to the cochlea can cause sensorineural hearing loss.
The hair cells of the cochlea are similar to carpets.
They may never recover if a heavy piece of furniture is left on them.
Loud machinery, fans screaming at a sports event, music blasting at maximum volume are all noise that can be harmful.
We have been bad to our hair cells if our ears ring after such experiences.
Hearing damage can be detected by ringing of the ears.
It's like hearing is bleeding.
A study of 3 million Germans found that professional musicians had almost four times the normal rate of noise-related hearing loss.
The need to blast music at dangerous volumes is reduced by modern headphones.
1.23 billion people are challenged by hearing loss.
1 in 5 teens are affected by teen hearing loss, which has risen by a third since the early 1990s.
Exposure to loud music, both live and through headphones, is a culprit: After three hours of a rock concert average 99 decibels, 54 percent of teens reported not hearing as well, and 1 in 4 had ringing in their ears.
Teens blast themselves with loud volumes more than adults.
Men's hearing tends to be less acute than women's.
Men and women who spend a lot of time in loud nightclubs, behind a power mower, or above a jackhammer should wear ear plugs.
Sex educators say condoms or Abstinence is safer.
Earplugs or walking away is what hearing educators say.
Nerve deafness can't be reversed.
There is only one way to restore hearing.
50,000 people, including 30,000 children, receive these electronic devices each year.
The implants translate sounds into electrical signals that are sent to the brain.
Cochlear implants seem to awaken the brain area when given to deafness kittens and human infants.
The devices can help children become proficient in oral communication, especially if they receive them as preschoolers or ideally before age 1.
Cochlear implants can help restore hearing for most adults, but only if the brain learns to process sound as a child.
The risk of depression can be reduced by the restored hearing.
Our perception of loudness and pitch is determined by the sound wave's amplitude.
The longer the sound waves are, the more frequencies and pitches they have.
Cochlear implants translate sounds into electrical signals that are sent to the cochlea and relayed to the brain.
It's not related to the intensity of the hair cell's response.
Only the few hair cells that are sensitive to its frequencies are activated by a soft, pure tone.
Hair cells respond to louder sounds.
The hair cell may still respond to loud sounds if it loses its sensitivity to soft sounds.
It helps explain that loud sounds can be loud to people with or without normal hearing.
I used to wonder what loud music would sound like to people with normal hearing.
It sounds the same, but we differ in our perception of soft sounds.
There are two theories on how we discriminate pitch.
Place theory presumes that we hear different pitches because different sound waves cause activity at different places.
The brain can determine a sound's pitch by recognizing the specific place that is generating the neural signal.
When von Bekesy cut holes in the cochleas of guinea pigs and human corpses, he discovered that the cochlea vibrated in response to sound.
Near the beginning of the cochlea's membrane, high frequencies produced large vibrations.
The low frequencies vibrated more than the high frequencies.
Place theory explains how we hear high-pitched sounds.
The brain uses neural impulses to read pitch.
Neural impulses are sent to the brain at the same rate as the sound wave, because the basilar membrane vibrates with the incoming sound wave.
If the sound wave has a Frequency of 100 waves per second, then 100 waves per second travel up the auditory nerve.
An individual neuron can't fire faster than 1000 times per second.
Neural cells can alternate firing like soldiers do.
Our perception of pitch can be aided by place theory and frequency theory.
The wolf said to Little Red Riding Hood, "All the better to hear you with."
The placement of our ears gives us stereophonic hearing.
For at least two reasons, two ears are better than one.
Sound waves hit one ear faster than the other.
Our brain can figure out the sound's location from this information.
People who lose all hearing in one ear have difficulty locating sounds.
The time lag and intensity difference are small because sound travels 761 miles per hour and human ears are 6 inches apart.
Our supersensitive auditory system can detect minute differences.
Dogs and sharks have large smell-related brain areas.
The human brain allocates more space to see and hear.
Our other senses also see extraordinary things.
Without our senses of touch, taste, smell, and body position and movement, we humans would be seriously handicapped, and our capacities for enjoying the world would be greatly diminished.
Touch is important.
Rats without their mother's grooming produce less growth hormone and have a lower metabolism, which is a good way to live until the mother returns.
The monkeys were allowed to see, hear, and smell, but not touch.
Premature human babies gain weight faster and go home sooner if they are stimulated by hand massage.