Most people experience red as a visual phenomenon.
This color may be associated with stoplights or stop signs.
You enjoy eating chocolate.
You can associate this taste with pleasure.
Every moment of your life, you are processing information from your senses.
Some people have strange descriptions for their experiences.
William doesn't like driving because the sight of road signs tastes like pista chio ice cream and earwax.
In synesthesia, sensory input in one form leads to an experience in another.
In synesthesia, each number printed in black ink is seen as a particular color.
synesthesia is almost impossible to imagine if you have never experienced it.
synesthesia is a very personal and consistent experience for each person who has it.
A number printed in black ink may appear to be one color.
Estimates of the percentage of the population that reports cross- sensory experiences range from 1 in 2,000 to 1 in 200.
Your brain is making millions of calculations to create a unified experience of your environment.
Your brain processes allow you to see, hear, taste, smell, and touch.
Imagine taking half a grapefruit out of the fridge and using a spoon to dig into it.
There is juice hitting your nose and mouth.
You smell a strong scent.
You feel a chill on your skin.
You like something on your tongue.
Your experience so far is raw.
Features of the juice have been detected by your sensory systems.
When people experience the same sensory input, they experience it differently.
This splash might be pleasant if you like grapefruit.
Maybe you have been told by your father to eat grapefruit.
You might experience the splash as unpleasant.
Every second of your life, you are bombarded with feedback from the world around you.
You can experience sights, sounds, smells, tastes, and touches of this information in your own way.
The sensation is the detection of physical stimuli from the world around you and the sending of that information to your brain.
Light waves, sound waves, food molecule, odor molecule, temperature changes, or pressure changes on the skin are examples of physical stimuli.
When you detect a splash of grapefruit juice, you can smell food, smell odors, and feel pressure on your skin.
The brain's further processing of sensory information is called perception.
Interpretation of sensation is the essence of perception.
Perceptual systems translate sensation into information that is useful.
perception is your interpretation of the sensations of cold droplets, a strong smell, and a sharp taste as qualities of grapefruit Try it yourself to understand the differences between sensation and perception.
The traffic signal changes from red to green when you drive.
There is no red or green color in the signal or light you see.
Your eyes and brain work together to see the redness or greenness of the light.
The physical world doesn't have color.
Light waves are reflected by each object.
The waves are seen as different colors by our visual systems.
Ask other people to do the things in Step 1.
Some people may have labeled the car the same way you did.
Some people have different labels.
The label a person chooses doesn't tell us what they think.
If you chose a different color sample from the one you chose, even people who labeled the car the same way could have chosen a different one.
Each person has a different perception of that input.
Neural signals travel along nerve green.
Light waves are sensory signals.
Then the physical stimulation.
The process of changing sensory input into a personal experience is summarized here.
Your brain most likely processes information about a green traffic light through the thalamus.
Imagine driving up to a traffic signal and seeing it turn green.
The green light is a form of light waves.
Sensory receptors are specialized cells that detect stimuli.
The firing of action potentials is reviewed by sensory organs.
For vision, more process stimulation from the outside world is needed before the information iscoded as action potentials.
When stimulation into the information brain does process the action potentials, you will see them as green light.
The brain can process that.
This example shows how sensation and perception work.
The details are different for each sense.
The taste and smell are in the primary auditory cortex.
Each major sensory system has four steps of sensation and perception.
In each case, the physical stimuli are detected, the sensory information is transduced, and the neurons fire action potentials.
The action potentials are the sensory information that is sent through the thalamus to different parts of the brain for interpretation.
Your huge range of percep tions is the sum of this activity.
Your perception adds up to your experience of the world.
If you see the color of a traffic light or get splashed with grapefruit juice, your sensations and perception allow you to respond appropriately.
You can decide if the juice is good or bad.
Don't read for a while and listen carefully.
Imagine looking out the smallest window you can find.
You can see people talking, but you can't hear them.
Half of the time a sensory input is present, lation is required to detect it.
Before you can experience a sensation, you have to go beyond some of the stimulation and a person's level.
The minimum ability to detect the input is the absolute threshold.
The absolute threshold is the smallest amount of a stimuli correctly detect half the time.
Table 5.1 shows the minimum amount of physical stimuli that are required for each sense.
Your friend is watching tv.
You are not paying attention to what is on the screen.
If a commercial is louder than the show, you might notice that something has changed.
The minimum change in volume required to detect a difference is the difference threshold.
As theStimulus becomes more intense, the difference threshold increases.
Pick up a jar of spice and a jar of spice.
The difference of 1 ounce is easy to detect.
Pick up a package that weighs 5 pounds and 1 ounce.
It will be difficult to detect the same difference of 1 ounce between these two.
The law is based on the work of a psychologist.
You may have turned it into a container.
A specific change in input can be detected but not heard by a person.
Assume that the original stimulation is more intense.
You put it in a 5-pound package.
The same change in input is harder to change.
Our sensory systems notice changes because the music is already there.
It's important for us to be able to hear the changes.
They might require responses later on.
It's not important to keep responding to the car under quieter conditions.
You were probably surprised at how loud the music was.
You are studying at a construction site.
The sounds of loud equipment might startle you.
It makes sense for your sensory systems to process these noises.
The noises fade into the background after a few minutes.
It makes sense that your sensory system responses will diminish over time if stimuli are presented continuously.
When the stimuli continue for a long time, they don't indicate danger that you need to respond to.
Answers to the red Q questions can be found in appendix B.
Vision is an important source of knowledge because we acquire information through our senses.
Half of your brain springs into action when you open your eyes.
Your brain is racing to make sense of the light waves in your eyes.
Your brain can only do this if it gets signals from your eyes.
You need intricate processes in your eyes to see an image of a friend.
Light bounces off that object.
Light waves enter your eyes.
The small opening looks like a dark circle at the center of the eye.
The light that is sent to the brain is focused on by the action potentials.
The sensations and perception of visual information are shown here.
The iris allows the opening of the eye to be larger in dim lighting.
When you like a painting or a baby, the iris increases the size of the pupils.
The shape of the lens is changed by the muscles behind the iris.
The structure behind the eye will flatten if you look far.
You can focus on something in the light on the retina with this flattening.
If you look at something close to you, your eyes will swell up.
Your eyes will feel uncomfortable if you look at something too close to you.
The muscles can't make the lens any bigger.
You have to back away from the back of the point to see the object.
Light is used for sensory processing.
The glasses and contact lens help the eye detect light waves and help it see by bending the light.
As we get older, the muscles of the lens lose their ability to change the shape of the lens.
It becomes hard to focus on the vision of the brain.
Most of us have to hold our menus far away from us low levels of illumination, and therefore to be able to read them, or we need to get reading glasses to bend the light more than they do not support color vision or see fine detail.
Light waves can be felt by the rods and cones in the retina.
Each type of visual sensory cell has a name.
The signals from each field are sent to the other side of the eye.
They travel along the thalamus and are processed in the primary visual cortex, which is opposite the visual field.
The retina holds 120 million rods and 6 million cones.
Cones are spread throughout the rest of the eye, except in the blind spot.
Near the outside edge, they become more scarce.
Cones are responsible for seeing under bright conditions.
The small features of each face and the colors of the clothes are being processed by your cones.
The rods are concentrated at the edges of the eye.
There are no ones in the fovea.
Rods respond well to extremely low levels of light.
Rods are used for night vision.
They don't support color vision and they don't give information about fine details.
On a moonless night, objects appear in shades of gray.
The star will appear to disappear if you look directly at it on a moonless night.
The star will be visible if you look at it from the side, because the light will fall on the rods in the fovea.
Our ability to perceive objects means that we have to process this visual stimulation in our brains.
Rods and cones are the visual sensory cells that detect light waves and send them to other support cells in the retina.
Ganglion cells are the first true neurons in the visual system.
Each cell has its axons gathered into a bundle.
If you can't see the red dot, move the book away from your face.
The brain fills in the missing information with what you would most likely see based on the context.
There are blind spots in your left and right visual fields.
Your brain fills in the gap.
You are not aware that there are blind spots in your field of vision because you don't seem to be missing visual information.
Try it yourself to find these blind spots.
Half of the axons cross to the other side of the brain.
The axons are on the same side of the brain.
You are looking at something far away.
The left side of the visual field is sent to the right side of the brain by the arrangement of the axons.
Everything is sent to the left side of the brain from the right side.
Basic information about what is seen is provided by this region of the brain.
The orientation, size, and movement of objects are included in basic information.
More complex information is processed in other brain regions.
The wavelength of light that the object reflects and how the eye processes the light are some of the factors that affect an object's color.
Millions of different shades of color can be identified because of these two factors.
The spectrum of color that is spectrum of colors can be seen when white light shines through a visible light.
The colors violet and red are visible from the 400 to 700 wavelength range.
The peak is the height of the light wave.
The lower the amplitude, the darker the color, and the higher the amplitude, the brighter the color.
The difference between a bright blue and a dark blue is called brightness.
Your perception of hue is affected by this distance.
The height between baseline and peak is low, so you can't see the color of your skin.
You perceive blue because of the distance between short.
The tor cells in the retina mix to create colors.
A green hue can look more blue or green.
Depending on the light's dominant wavelength, each type responds in different ways.
Most of us would say that a flower is yellow rather than blue.