We will look at the systems that receive sensory information about vision, hearing, taste, smell, body position, and movement.
We look at how we process information to bring meaning to it.
The meaning varies according to experience and culture.
People see a woman trying to escape from her husband.
The problem is related to how we experience and understand our world.
Information can be transmitted to the brain when the receptors are stimulated.
Neural impulses to the brain aren't enough to give us an understanding of our surroundings.
Without stimulation from the environment or being unable to process the information they receive, no information is transmitted to the brain and perception does not occur.
It sounds simple--activate the receptors and then send the information to the brain to make sense of it.
Write the words of light and sound waves and those of smell and taste on one side and the definitions on the other must be changed.
This is the process of converting something to something else.
Sound waves can cause hairs in your inner ear to bend.
These hairs are used for hearing.
Hearing information can be sent to your brain.
When a sewer is blocked, adaptation is highly desirable.
When preparing dinner for friends, adaptation may be disadvantageous.
Think back to the beginning of the chapter.
Your repeated tastings have caused your receptors to adapt, so more spices are required to make them work.
Adding spices may cause a bigger problem than you think.
A group of German psychophysicists was studying the relation between stimuli and the participant's experience at the same time that Wilhelm could be used by the nervous system.
The individual was asked to Loss of sensitivity to a stimuli when only one was presented or if the other one was different from the other one.
They looked at the relation between the mind and the body.
Weber wanted to determine the smallest difference between two stimuli.
The constant is the same for all tests of the same sense, but it varies from one sense to another.
The constant for seeing changes in vision is 8% while the constant for hearing changes is 5%.
You wouldn't be able to differentiate 95 watt and 100 watt, or 100 watt and 105 watt, but you could differentiate 95 watt and 105 watt.
Weber showed that the amount of stimulation needed to notice a change, divided by the original stimulation, was a constant.
Researchers have treated psychophysical laws as if they applied to both stimuli.
Gustav Fechner refined and expanded Weber's work through his study of sensory thresh olds.
Historians of psychology believe Fech ner is the originator of modern psychology because of his extensive research on psychophysics.
The absolute threshold and differential threshold were studied by Fechner.
The absolute threshold for each of our senses is very low.
A psychophysicist studying the differential threshold might observe how much the intensity of a light or tone must be increased for a participant to notice the change.
When you were trying to decide how much spice should be added, you were dealing with a differential threshold problem.
The research on the absolute and differential thresholds failed to take into account two factors: the condition under which the stimuli were perceived and the nature of the perceiver.
Thresholds are determined by both factors.
The task of determining the absolute threshold for a light is more difficult in a brightly lit room than it is in a dark room.
There are many signal detection problems in everyday life.
The detection of the signal is influenced by the importance of detecting it.
Hearing the phone ring is very important if you are waiting for a call telling you that your car is ready.
As long as you answer the phone when the repair shop calls, you can make a few mistakes.
A radar operator who is monitoring incoming enemy aircraft cannot afford to make any false-positive mis takes; such errors would result in a full-scale alert and the deployment of many personnel.
The radar operator can't afford to miss any enemy air craft.
Loss of life and property can be caused by such errors.
The study raises an interesting question.
If a persuasive message could arouse our unconscious motives, it might stand a better chance of succeeding, because we wouldn't try to resist it.
The use of subliminal perception in advertising is based on this premise.
Some researchers believe that the nature of the stimuli may affect our behavior.
The interval is too short for conscious Stimuli that are below the threshold awareness, so people wouldn't have seen the ads.
The sales of popcorn and soft drink were said to have risen dramatically.
Data was never presented despite the claim of success for subliminal perception.
The studies that were adequately controlled failed to reproduce the results.
In the pop corn and soft drink example, there is some evidence that repeated subliminal presentations may change our attitudes and opinions.
Researchers reported that participants who had 25 repeated subliminal exposures to novel and ambiguous visual stimuli rated their mood more positively than participants who only had one sub liminal exposure.
In an intriguing experiment, psychology graduate students were asked to come up with ideas for research projects.
Some students were exposed to very brief flashes of either the smiling face of a familiar colleague or the scowling face of their faculty supervisor.
Students who were exposed to the scowling faces of their supervisors gave lower ratings to their own research ideas than students who were not.
It appears that subliminal stimuli can have an effect on our reactions.
We can now see how our sensory systems work with this general information about sensation, perception, and the methods of psychophysics in mind.
If you watch other people a lot, you will see that they blink frequently.
The blink rate goes up when the air is dry.
Vision is the most valued sense according to many people.
Ask several people which sense they would least be willing to lose, and almost all of them will say vision.
We fear being blind because we are mostly visual creatures.
Our brain is more focused on vision than it is on hearing, taste, or smell.
If you lost your sense of smell, you would have to make some adjustments.
It is not surprising that vision has been studied the most thoroughly, given the importance of vision and the ease with which the eyes can be stud ied.
The vIsual stImulus is what we see.
Vision involves the recep tion of waves by visual cells.
Waves that vary greatly in length are where this kind of energy travels.
Some of the waves involved in broadcasting are miles long.
The red light wavelength is associated with different colors.
We can see a wavelength of violet and a wavelength of red.
Light waves can be different in two ways: amplitude and saturation.
The more saturated a color is, the more likely you are to see only one wavelength.
To understand the concept of saturation, we need to distinguish between the two light sources.
The sun, light bulbs, and other hot, energy-releasing objects are the only sources of radiant energy.
You can see in the picture that it's bright for visual stimuli.
You will see white if you add a blue light to the green mixture.
You see the colors of grass, a rose, and your energy reflected by objects sweater as a direct result of the light reflected from those objects.
Adding all wavelength of mixing.
There are red and green lights.
Black yellow and blue paint combine to form a dark or black color.
Think about how the reflection of different wavelength can be made possible.
Before you read further, write down your suggestions.
Knowing that objects absorb light waves in addition to reflecting them should help you avoid the reflection of different colors.
The object or surface appears black if all of the light waves are absorbed, and white if all of the light waves are reflected.
When certain wavelengths are reflected, we can see colors.
The color you see is pure if the surface reflects only one wavelength.
A complex chain of events is involved in vision.
Light waves travel through the eye and we trace how light waves travel through the muscles.
The light waves are focused by the cornea.
The fluid that is recycled supplies sustenance to the eye.
The light waves travel through a small opening in the middle of the iris.
The iris has two muscles, one that makes it close and the other that makes it dilate or open.
The amount of light that enters the eye is regulated by the iris.
The vitreous humor gives shape to the eye.
The three major layers are the ganglion cell layer, the bipolar cell layer and the photoreceptor layer.
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The cells transmit information to each other.
The eye is seen as sight.
Light waves cause the nerve endings to change.
The axons of the cells come together to form the nerve, which carries visual information to higher brain centers.
The only way the receptors can be positioned close to the blood supply that lies behind the retina is through the arrangement.
At the point where the axons of the cells come together, there is no way to detect them.
We suggested at the beginning of this section that blinking may have more to do with sensation than just keeping the eyes moist.
Light doesn't enter your visual system when you blink.
Each minute, you should experience 15 or more brief visual black outs because no light is being processed during a blink.
Before reading further, write down some possible reasons.
The book is in front of you.
Gradual moved the book towards you.
When the brain signals the eyelids to close in a blink, it also stops activity in the visual system.
The visual system works normally when the blink is complete.
Information about visual blackouts is not transmitted or processed.
We remember the object and don't notice the blinks.
The pathway taken by the brain is shown in Figure 3-6.
The fibers from the side of the eye closest to the nose cross to the other side.
In color processing, the LGN is very important.
Higher-level visual processing begins in the occipital lobes of the cortex, where the visual information is received.
The rods and cones are so important to what we see that they deserve special attention.
They do not detect color and have a lower threshold than cones.
Light strikes the rods and cones and causes a different brain chemical reaction.
The visual cells send a message to the brain.
If you're not sure, consider this analogy: Suppose you're having a one-on-one discussion with a friend about the next psychology test, and you're not having a rod discussion.
Each of you knows what the other is talking about.
It is clear and direct, like the information sent by the able to detect color cones to the bipolar cells.
Because of the size of the class, you can't tell who is talking at a given moment.
A path is taken from the eye to the brain.
If you want to see the difference in acuity between the rods and cones, hold the book close to your face and look at it.
The letters to the left and right are hard to read.
Give the situation some thought, and then write down your thoughts in a notebook.
The letters are not focused on the same areas of the eye.
The cone-rich fovea is the focus of the target letter, whereas the letters to the left and right are focused on areas of the retina.
Rods are the most popular in these areas.
The image becomes blurry due to the lowered acuity of the rods.
To focus the print on the cones in the fovea is why you hold the apartment lease in front of your eyes.
Rods have a lower threshold than cones, so less light is required to awaken them, and cones are used for color vision.
The threshold for activation 2 should be lower.
A higher threshold is needed for activation 3.
Do not process color 4 if you have higher acuity.
You can only see black, white, and gray on the rose levels.
You should be able to watch objects lose their color as we gradually use our high levels of illumination.
Figure 3-7 can be used to see color.
Researchers have known for a long time that the sensation of to rod vision and cannot see color is transmitted to the brain by the cones in the retina.
Our progress toward understanding this process has been guided by two theories that were originally proposed in a room in the 1800s.
Young and Helmholtz believed that there are three types of turn the intensity of the lights cones, each maximally responding to one of three wavelength: short, medium, and down.
The to rod can be seen according to the trichromatic vision.
There is support for this theory.
Three types of cones in the retina are sensitive to one of the primary colors.
There are three types of cones that are maximally sensitive to certain wavelengths.
Researchers didn't think about the existence of three types of cones for several years after they were verified.
Support for another theory of color vision has been provided by continued research.
The operation of one member of a pair directly affects the operation of the other member.
The opponent-process theory was abandoned when the trichromatic theory was verified.
These cells are not cones, but they are located outside of the retina.
The opponent-process theory states that constant viewing of red weakens the ability to inhibit green.
Context plays an important role in the colors we see.
Monochromats have only one type of cone, so the brain ignores all received light waves as the same, and only shades of gray are seen.
It's possible to experience what it's like to be a monochromat.
The rods only process shades of gray.
If you can't see color in dim light, you will know how monochromats see the world.
A monochromat can be described as color-blind.
People with a deficiency in color are called dichromats.
A person who only sees shades has trouble with the opponent-process function because they lack one type of cone.
The person sees shades of gray and blues and yellows if the deficiency involves a red or green cone.
Special tests have been developed to evaluate color de Person who has trouble seeing one ficiencies; the most common test is called the Ishihara Test, in which you try to detect the primary colors (red, blue, or a hidden pattern of different-colored circles).
Difficulty distinguishing reds and greens is the most common type of color deficiency, followed by difficulty distinguishing blues and yellows.
Color deficien cies probably have a genetic or hereditary basis because there are more males than females.
Women are most likely carriers of the color deficient gene.
Although most cases of color deficiency are inherited, it is possible to get color deficiency due to injury to the eye.
Diabetes, Alzheimer's disease, Parkinson's disease, and multiplesclerosis are some of the diseases that may cause color deficiency.
Drugs for treating heart problems, high blood pressure, infections, and psychological problems can affect color vision.
A change in the lens of the eye can lead to an acquired color deficiency.
The lens becomes yellow as we grow older and loses some of it's ability to filter short wavelength light.
This change can cause confusion between greens and blues.
Color confusion can be life threatening for elderly people who have to deal with colored medicine pills.
Psychophysicists such as ernst Weber and Gustav Fech studied the relationship between the mind and the body.
The waves are light.
Information related to cal is received by which sensory receptors.
He only sees bright colors.
He can't differentiate colors.
He likes one color over the others.
He can only pay attention to one thing at a time.
Sound waves are the same as light waves.
The section explores what we hear and how we hear it.
The audItory stimulus is what we hear.
We need to answer that question.
The movements of air molecule make up sound waves when objects vibrate.
Shorter wavelength occur more frequently than longer wavelength.
Sense of hearing.
The inten Unit of measure is affected by the sound wave's height in cycles per sity.
A sound CD player's volume control adjusts the intensity of the sound you hear.
The Decibel level is the amount of measure of the amount of energy producing the pressure of the vibrations we perceive as sound.
We don't hear one pure tone at a time, just as we don't see pure colors.
Consider the variety of sounds you hear on the radio.
A limited range of sound waves are sensitive to the auditory receptors.
We hear sounds between 20 and 20,000 Hz.
We don't hear all sounds the same.
If we want to hear tones at lower and higher frequencies, we need greater inten sity.
The range of sound we can make from the outer ability suggests an intricate system.
When the nerve impulses reach the temporal cortex, they are interpreted as sounds.
The brain has the auditory nerve.
The 3 is caused by the vibrating eardrum.
The bones of the middle ear are set by the moving fluid and they have to strike each other.
The hammer, anvil, and stirrup in the middle ear are activated by sound waves.
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The fluid in the cochlea is set in motion when the window vibrates.
The hair cells are part of the ear.
Contact with the inner ear's bicyle causes it to bend, when it does, they depolarize.
The neurons that syn apse with them to fire are caused by sufficient depolarization of the auditory receptors.
The auditory nerve travels from the cochlea to the medulla.
The fibers don't cross.
The cor theory states that the basilar tex is used for processing.
There are two theories about how we hear different pitches.
The basilar the organ of Corti transmit information about different pitches according to the theory stated by Hermann von Helmholtz in 1863.
The perception of different cies is created by the perception of higher frequen, whereas the perception of lower pitches is created by the perception of lower frequencies.
The basilar is supposed to vibrate in an un even manner for this theory to be correct.
The basilar membrane is thin near the window, but becomes thicker as time goes on (von Bekesy, 1956).
According to Rutherford, we can perceive pitch by how quickly the basilar vibrates.
The theory works well with frequencies up to 100 hertz, but not with more than 100 times per second.
According to this view, at frequencies above 100 hertz, the brain does not all fire at the same time.
For a 300-Hz tone, one group would fire at 100 Hz, followed by a second group that also fired at the next interval, and then a third group that fired at the next interval.
The three groups of neurons that were activated would tell the nervous system what you had heard.
An important attribute is the ability to discriminate.
Our ability to locate sound in space is equally important.
If we couldn't tell where sounds were coming from, driving would be a nightmare, we couldn't tell which people were talking to us, and it would be hard to find a lost child.
The source of a sound can be found through two mechanisms.
Certain sounds are blocked by the head.
The sound waves coming from the opposite side of the body are a bit weaker because the head partially blocks them.
If someone on your right side is talking to you, the sounds of their speech enter your right ear.
The sounds enter your left ear before your head blocks them.
Time delay in neural processing is a second mechanism.
The difference in time between when a sound enters one ear and when it enters the other is related to the brain processes associated with transmission.
It is enough time for your brain to process and help you locate to the inner ear, even if it is deafness caused by damage only a few milliseconds.
You can review facts about deafness caused by light and sound waves.
Loud noises from rock concerts, jet planes, sirens, and air hammers can cause hearing damage, according to reports in the media.
Most people want to know if these claims are true.
There are damage-risk comparisons in Table 3-4.
Hearing loss can be caused by exposure to sounds with intensities greater than 70 decibels.
Exposure time needed to produce damage decreases as decibel level increases.
The shorter the exposure time before your hearing is damaged, the louder the sound.
The loud noise from a car stereo that has an added bass box to increase the power, or standing near the speakers in a club or at a concert, can cause other problems of a medical nature.
The extent of exposure to potentially dangerous sounds is within your control.
Approximately 1% of people suffer total deafness, and 250 million people suffer from some form of disabling hearing impairment.
Exposure to loud noises may cause the first two.
Damage to the hammer, anvil, or stirrup can be caused by excessive earwax or exposure to loud noises that can cause the eardrum to burst.
This type of deafness can be caused by noise that is loud enough to cause hair cells to break.
Hearing aids can be used to offset hearing loss caused by damage to the bones of the middle ear.
There is no way to restore hearing when there is sensorineural or central deafness.
The smell and taste of a liquid and air are related.