Chapter 3, psychology

What psychological factors influence pain?

Psychological factors that can intensify the experience of pain include anxiety, fear, sense of helplessness, feelings of depression, and sadness. On the other hand, positive mood and a sense of control can reduce the perception of pain. Women tend to have a lower threshold for pain than men. African Americans, Hispanic Americans, and Asians tend to have a lower pain threshold and white Americans. Native Americans have a much higher pain threshold than white Americans. Cultural beliefs influence this.

Steve Novella, neuroscientist

"What we perceive is a constructed illusion, based on algorithms that make reasonable assumptions about distance, shading, size, movement, and color, but they are assumptions nonetheless, and sometimes they can be wrong or misleading."

Weber's law states that:

A principle of sensation that holds that the size of the just noticeable difference will vary depending on its relation to the strength of the original stimulus. Example: hold a pebble in your hand and add a second pebble, and you will notice the added weight of the second pebble. Next hold a rock in your hand, and then add a pebble, and most likely you won't notice the weight difference due to the size of the rock. It underscores that our psychological experience of sensation is relative.

Fovea

A small area in the center of the retina, composed entirely of cones, where visual information is most sharply focused. Most of the cones are located here. Images that do not fall on the fovea tend to be perceived as blurry or indistinct.

Retina

A thin, light-sensitive membrane, located at the back of the eye, which contains the sensory receptors for vision. There are over 130 million receptor cells in each retina. And only about 1 million ganglion cells.

eardrum

A tightly stretched membrane at the end of the ear canal that vibrates when hit by sound waves funneled by the pinna. When the sound wave hits the eardrum, the eardrum vibrates, matching the vibrations of the sound wave in intensity and frequency. It also separates the outer ear from the inner ear.

lens

A transparent structure, located behind the pupil, that actively focuses, or bends, light as it enters the eye

monocular cues

Distance or depth cues that can be processed by either eye alone. Also called pictorial cues. Artist use these to create perception of distance or depth in paintings.

binocular cues

Distance or depth cues that require the use of both eyes.

Presbyopia

During middle age, another form of farsightedness often occurs. It is caused when the lens becomes brittle and inflexible.

What affects perceptual interpretations?

Educational, cultural, and life experiences shape what we perceive, From person to person and also from culture to culture. Additionally, perception can be influenced by an individual's expectations, motives and interests.

Basic steps of sensation and perception

Energy from an environmental stimulus activates specialized receptor cells in the sense organ. Coded neural messages are sent along a specific sensory pathway to the brain. These neural messages are decoded and interpreted in the brain as a meaningful perception.

Hyperopia

Farsightedness, where objects near the eyes appear blurry because light reflected off the objects is focused behind the retina

Mike and illusory contours

Fine presented Mike with perceptual illusions containing illusory contours, like the picture. Mike could not identify the hidden picture, but when the red lines were drawn in, Mike perceived the square.

Processing the signals from rods and cones in the retina

For the most part, a single ganglion cell receives information from only one or two cones but might receive information from 100 or more rods. The messages from the different rods are combined in the retina before they are sent to the brain. Thus the brain receives less specific visual information from the rods and messages of much greater visual detail from the cones. From rods, like listening to 100 people at once vs 1 person.

How do both frequency theory and place theory explain our discrimination of pitch?

Frequency theory helps explain our discrimination of low frequencies. Place theory helps explain our discrimination of higher pitched sounds. For intermediate frequencies or midrange pitches, both place and frequency are involved. The senses of smell and taste are closely linked. P. 94/95.

five basic tastes

From an evolutionary view, taste supplies the information we need to seek out nutrient-rich foods and avoid potentially hazardous substances. Sweet taste attracts us to energy-rich foods, umami to protein-rich nutrients. Bitter and sour taste warns us to avoid many toxic or poisonous substances. Sensitivities to salty tasting substances helps us to regulate the balance of electrolytes in our diets.

figure-ground relationship

Gestalt principal stating that a perception is automatically separated into the figure, which clearly stands out, from its less distinct background, the ground. Gestalt psychologists noted that figure and ground have vastly different perceptual qualities. The ground has no shape. We notice the shape of the figure but not the shape of the background, even when the ground is used as a well defined frame (see picture). Brain neurons respond differently to a stimulus that is perceived as a figure versus the ground.

What is the relation between olfactory function and age?

Half of those between 65 and 80 have a significant loss of olfactory function, a number that increases to 2/3 for those aged over 80. At any age, air pollution, smoking, and exposure to industrial chemicals can decrease the ability to smell.

Cultural comfort zones and brain functioning

Hedden And assoc. compared brain functioning in E Asian and US participants while they made perceptual judgments comparing the images of a square with an embedded line (see picture). The relative task involved determining whether the lines in the two images were in the same proportion to the surrounding squares. The absolute task - are the two lines were the same absolute length, regardless of the size of the squares? Each participant made his judgments while brain activity was tracked by an FMRI scanner. Both groups were equally proficient and used the same brain regions in making the simple perceptual judgments. But the pattern of brain activity differed. The individualistic US participants showed greater brain activity, meaning they had to exert more mental effort, while making relative judgments. Opposite for the collectivistic E Asians, who devoted greater brain effort in making absolute judgments that required them to ignore the context. People from different cultures notice different things and think differently about what they do see.

human chemosignals

Human pheromones; the most likely candidates are chemicals found in steroid compounds that are naturally produced by the human body, and found in sweat, armpit hair, blood, and semen. Example, exposure to a chemical compound in the perspiration of breast-feeding mothers significantly increased sexual motivation in other, non-breast-feeding women. It acts as a social signal. Also evidence that they are involved in communicating emotional states, including stress, anxiety and fear. After exposure to either neutral sweat or fear sweat, women watched either a frightening video or neutral video. Regardless of which video they watched, women who were exposed to the fear sweat were more likely to react with fearful expressions than the women who were exposed to the neutral sweat. They seem to play an important role in communicating and synchronizing emotional states among people in groups.

Visual disorder

If the eyeball is abnormally shaped, the lens may not properly focus the incoming light on the retina, resulting in a visual disorder

winetasting

In an experiment comparing a $90 bottle of wine with a $10 bottle of wine, people overwhelmingly selected the taste of the $90 bottle; however both bottles were exactly the same, suggesting expectations matter.

Parts of the eye

Includes iris, pupil, cornea, lens, retina, fovea, optic disk and optic nerve

Problems with the long-term use of opioid painkillers?

Increasing evidence shows that these painkillers can actually increase the pain and pain sensitivity in chronic pain sufferers. Also, a new study found that it can increase the duration of chronic pain as well. Rats with chronic nerve pain who were treated with morphine for five days and experience pain sensitivity for 2 to 3 months, while rats in the control group experienced pain sensitivity for just six weeks. Even after healing, the morphine treated rats experienced heightened pain sensitivity.

Visual processing in the retina

Information from the sensory receptors, the rods and cones, is first collected by specialized neurons called bipolar cells. These cells then funnel the collection of raw data to the ganglion cells. Each ganglion cell receives information from the photoreceptors that are located in its receptive field in a particular area of the retina. Each ganglion cell combines, analyzes, and codes the information from the photoreceptors in its receptive field before transmitting the information to the brain.

top-down processing

Information processing that emphasizes the importance of the observer's knowledge, expectations, and other cognitive processes in arriving at meaningful perceptions; analysis that moves from the whole to the parts. Cultural influences affect these perceptual processes

bottom-up processing

Information processing that emphasizes the importance of the sensory receptors in detecting the basic features of a stimulus in the process of recognizing a whole pattern; analysis that moves from the parts to the whole. This process is often at work when we're confronted with ambiguous stimulus. We aren't immediately sure what it is as a whole, so we assemble individual features.

flavor

Involves several sensations, including the aroma, temperature, texture, and appearance of food.

How is loudness determined?

It is determined by the intensity, or amplitude, of a sound wave and is measured in units called decibels. Zero dB represent the loudness of the softest sound that humans can hear, or the absolute threshold for hearing. As dB increase, perceived loudness increases.

Opioids to treat pain?

Morphine, OxyContin, and other opioid prescription painkillers mimic the brains natural pain killers, the endorphins. They have no effect on the fast pain system but very effectively block painful sensations in the slow pain system, at least in the short term. Unfortunately there is a high potential for misuse of these drugs, including addiction.

Shepherd tables

Named after psychologist Roger Shepard, this perceptual illusion creates the perception that one table is longer than the other, when both are the same. Mike was not susceptible to the perceptual illusion as most are.. This is because he does not automatically use many depth perception cues that most people use.

Myopia

Nearsightedness, where distant objects appear blurry because the light reflecting off the objects focuses in front of the retina

Can behavior be profoundly influenced by subliminal messages?

No, Subliminal messages do not influence behavior or consumer decisions

Subliminal emotion experiment

Participants were subliminally exposed to faces expressing fear and disgust, or to a neutral emotion, before being asked to rate the pleasantness of other faces presented afterwards. Faces that were presented to participants with subliminal fear stimuli were rated as more unpleasant than the control group. Same with odors.

Culture and the Müller-Lyer illusion - the carpentered-world hypothesis

People in industrialized cultures are more susceptible to the illusion than non-industrialized societies. They have more experience judging lines, corners, edges. And so they are more susceptible because the illusion involves arrows mimicking a corner that is jutting toward or away from the receiver, than in non-industrialized societies.

Extrasensory perception

Perception of information by some means other than through the normal process of sensation. 50% in the US believe.

Perception

Perception refers to the process of integrating, organizing and interpreting sensory information into meaningful representations. A diverse range of stimuli from the environment is transmitted to the brain, And to make sense of this raw sensory data, we must organize, interpret, and relate the data to existing knowledge. Three basic and important questions: What is it? How far away is it? And where is it going?

illusory contours

imagined "boundaries" between one object and another; often created by the perception of "lines" that divide areas of color or texture.

perception of motion

The brain perceives motion by comparing visual frames. A rapid series of slightly varying images creates perception of motion. As we follow a moving object with our gaze, the image of the object moves across the retina. Our eye muscles make microfine movements to keep the object in focus. We also compare the moving object to the background, which is usually stationary. When the retinal image enlarges, we perceive the object is moving towards us. Our perception of the speed of the object's approach is based on our estimate of the object's rate of enlargement.

cochlea

The coiled, fluid-filled inner ear structure that contains the basilar membrane and hair cells. Greek word for snail, size of a pea.

Iris

The colored structure that we refer to when we say that someone has brown eyes. It is actually a ring of muscular tissue that contracts or expands to precisely control the size of the pupil and thus the amount of light entering the eye. In dim light, the iris widens the pupil to let light in, and in bright light the iris narrows the pupil.

Timbre

The complexity of a sound wave, or its unique combination of frequencies, produces this distinctive quality of a sound, which enables us to distinguish easily between the same note played on a saxophone and on a piano. Each human voice has its own distinctive timbre.

sensory adaptation

The decline in sensitivity to a constant stimulus. Smell onions and garlic cooking when enter kitchen and then the smell diminishes. This experience of sensation is relative to the duration of exposure. Because of this, it allows us to quickly notice new or changing stimuli.

Binocular cue - convergence

The degree to which muscles rotate your eyes to focus on an object. The more the eyes converge, or rotate inward, to focus on an object, the greater the strength of the muscle signals and the closer the object is perceived to be. More convergence is required to look at a dime 6 inches away then at arm's length away.

subliminal perception

The detection of stimuli that are below the threshold of conscious awareness; non-conscious perception. Example, rapidly flashed visual images, sounds or odors. It can evoke a brain response.

Wavelength

The distance from one wave peak to another

Path of sound, simple

The ear is made up of the outer ear, the middle ear, and the inner ear. Sound waves are collected in the outer ear, amplified in the middle ear, and transduced, or transformed into neural messages, in the inner ear.

olfactory bulb

The enlarged ending of the olfactory cortex at the front of the brain where the sensation of smell is registered.

Meer Exposure Effect

The finding that repeated exposure to a stimulus increases a persons preference for that stimulus, an example of how subliminal stimuli can affect us. Subliminal shapes, flashed to people, resulted in the same people selecting and preferring the flashed shapes over other shapes.

hair cells

The hair-like sensory receptors for sound, which are embedded in the basilar membrane of the cochlea. Tiny, projecting fibers. They bend as the basilar membrane ripples. It is here that the transduction finally takes place. The physical vibration of the sound waves is converted into neural impulses. They stimulate the cells of the auditory nerve, which carries the neural information to the thalamus and the auditory cortex in the brain.

induced motion

The illusory movement of one object that is caused by the movement of another object that is nearby. This occurs when we look at a stationary object against a moving background, and we perceive that the object is moving.

Characteristics of sound waves

The length of a wave, its height, and its complexity determine the loudness, pitch, and timbre that we hear. The sound produced by A would-be high-pitched and loud. The sound produced by B would be soft and low. The sound in C is complex, like the sound we usually experience in the natural world.

Rods

The long, thin, blunt sensory receptors of the eye that are highly sensitive to light, but not to color, and that are primarily responsible for peripheral vision and night vision. Many rods surround the cones - see picture

basilar membrane

The membrane within the cochlea of the ear that contains the hair cells. As fluid in the cochlea ripples, the vibration in turn is transmitted to this membrane, which runs the length of the coiled cochlea. Embedded in it are the sensory receptors for sound, called hair cells.

perceptual illusion

The misperception of the true characteristics of an object or an image. They underscore the idea that we actively construct our perceptual representations of the world according to psychological principles.

Why don't we notice the hole in our vision, the blindspot?

The most compelling explanation is that the brain actually fills in the missing background information. In effect, signals from neighboring neurons fill in the blind spot with the color and texture of the surrounding visual information.

Pain as actively constructed?

The notion that pain is determined by expectations and personal experience.

Assumptions about perceiving movement

The object, or figure, moves while the background, or frame, remain stationary. So you see the bowling ball moving down the alley and not the alley, which serves as the background.

Pinna

The oddly shaped flap of skin and cartilage that is attached to each side of the head. It helps pinpoint the location of sound. It's primary role is to catch sound waves and funnel them into the ear canal.

pupil

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

middle ear

The part of the ear that amplifies sound waves; consist of three small bones: the hammer, the anvil, and the stirrup. Each bone sets the next bone in motion, and the joint action of these three bones almost doubles the amplification of the sound. The innermost bone, the stirrup, transmits the amplified vibration to the oval window.

outer ear

The part of the ear that collects sound waves; consists of the pinna, the ear canal, and the eardrum.

inner ear

The part of the ear where sound is transduced into neural impulses; consists of the cochlea and the semicircular canals.

perceptual set

The tendency to perceive objects or situations from a particular frame of reference. These usually lead us to reasonably accurate conclusions, but they can sometimes lead us astray. For example, people are prone to see faces in ambiguous stimuli, see picture. One reason is that the brain is wired to be uniquely responsive to faces or face like stimuli.. Our extraordinary neural sensitivity to facial identification makes us more liable to false positives, to see faces that aren't there.

perceptual constancy

The tendency to perceive objects, especially familiar objects, as constant and unchanging , despite changes in sensory input. Example, a car passes you on the highway, and as it speeds further and further ahead, the car appears smaller and smaller, but we know it is still the same size. Color, size, and shape constancy promote a stable view of the world.

How do snakes hear?

With their jaws, which pick up vibrations in the sand

Do the trichromatic theory and opponent-process theory of color vision co-exist?

Yes

Does a pit viper see a bird at night?

Yes, they see infrared light, which we sense only as warmth

anosmia

absence of the sense of smell

What forms the olfactory tract?

axons of mitral cells, forming neural pathways projecting to different brain areas including the temporal lobe and structures in the limbic system. The projections to the temporal lobe are thought to be part of the neural pathway involved in our conscious recognition of smells. The projections to the limbic system are thought to regulate our emotional response to odors.

Artist's monocular cues

1. Relative size. If two or more objects are assumed to be similar in size, the object that appears larger is perceived as being closer. 2. Overlap. When one object partially blocks or obstructs the view of another object, the partially blocked object is perceived as being further away. 3. Aerial perspective. Faraway objects appear hazy or blurred by the atmosphere. 4. Texture gradient. As a surface with a distinct texture extends into the distance, the details of the surface texture gradually become less clearly defined. 5. Linear perspective. Parallel lines seem to meet in the distance. The closer together the lines appear to be, the greater the perception of distance. 6. Motion parallax. When you move, you use the speed of passing objects to estimate the distance of the objects. Nearby objects seem to zip by faster than do distant objects. When on a train, houses and parked cars zip by while mountains go by more slowly.

Gestalt laws/principles that we tend to follow in grouping elements together to arrive at the perception of forms, shapes, and figures.

1. Similarity, 2. closure, 3. good continuation, and 4. proximity. These help us more efficiently remember groups of objects and perceive the relationships among them. See picture

Olfactory receptor cells - dogs vs people

200 million receptors vs 12 million; humans can sniff chocolate line in ground, 1-2 inches per second

slow pain system

A burning, dull throbbing sensation, caused by the activation of the unmyelinated fibers of this system. Less intense but longer lasting than the fast pain system. They travel first to the hypothalamus and thalamus and then to limbic system structures such as the amygdala. This suggests more involvement in the emotional aspects of pain.

Cornea

A clear membrane that covers the front of the eye and helps gather and direct incoming light.

conduction deafness

A condition that happens in old age, the tiny 3 bones of the middle ear become damaged or brittle, resulting in this. Hearing aids help, which amplify sound.

Müller-Lyer illusion

A famous visual illusion involving the misperception of the identical length of two lines, one with arrows pointing inward, one with arrows pointed outward. Size constancy plays a role. Because they are the same length, the two center lines produce retinal images that are the same size. However, the center lines are embedded in visual depth cues that make you perceive them as farther away.

oval window

A membrane many times smaller than the eardrum, that separates the middle ear from the inner ear. As it vibrates, the vibration is next relayed to an inner structure called the cochlea, a fluid-filled tube that's coiled in a spiral.

acupuncture

A pain-relieving technique that has been used in traditional Chinese medicine for thousands of years. It involves inserting tiny, sterile needles at specific points in the body. They are then twirled, heated, or stimulated with mild electrical current. Meta-analysis of dozens of studies found that this was significantly more effective than a sham form or usual care treatment in relieving pain associated with chronic headaches, arthritis, and chronic back, neck and shoulder pain.

moon illusion

A visual illusion involving the misperception that a full moon is larger when it is on the horizon then when it is directly overhead. The retinal size of the moon is the same in all positions, so why the illusion? 1. People perceive objects on the horizon as farther away than those directly overhead in the sky. 2. The horizon contains distance cues (buildings, trees) as it fades into the distance, and so the moon is perceived as being behind these depth cues, so the depth perception cue overlap adds to the perception that the moon on the horizon is farther away. 3. It also involves the misapplication of size constancy, so the moon looks larger when the perception of its distance increases. If you look at the full moon on the horizon through a cardboard tube, you'll remove the distance cues and it looks the same size as it does when overhead.

The path of sound through the human ear

After being caught by the outer ear, sound waves are funneled down the ear canal to the eardrum, which transfers the vibrations to the structures of the middle ear. In the middle ear, the vibrations are amplified and transferred in turn to the oval window and on to the fluid-filled cochlea in the inner ear. As the fluid in the cochlea vibrates, the basilar membrane ripples, bending the hair cells, which appear as rows of yellow tips in picture. The bending of the hair cells stimulates the auditory nerve, which ultimately transmits the neural messages to the auditory cortex in the brain.

The perception of shape, what is it?

Although, to some degree, we rely on size, color, and texture to determine what an object might be, we rely primarily on the object's shape to identify it.

Astigmatism

An abnormally curved eyeball results in blurry vision for lines in a particular direction

Optic disk

An area of the retina that lacks rods and cones (photoreceptors) all together. It is the point at which the fibers that make up the optic nerve leaves the back of the eye and project to the brain. Because there are no photoreceptors in the optic disc, we have a tiny hole or blind spot, in our field of vision.

phantom limb pain

An example of a type of pain that can continue even after an injury has healed is the removal of a limb. Sensitization occurs, it happens when pain pathways in the brain become increasingly more responsive over time. As the pain circuits undergo sensitization, pain begins to occur in the absence of any sensory input. The result can be the development of persistent, chronic pain that continues even after the injury has healed. In the case of phantom limb pain, sensitization has occurred in the pain transmission pathways from the site of the amputation. These pathways produce painful sensations that feel as though they are coming from a limb that is no longer there.

Pacinian corpuscles

And important receptor located beneath the skin. When stimulated by pressure, it converts the stimulation into a neural message that is relayed to the brain. If a pressure is constant, sensory adaptation takes place.

Saturation

Corresponds to the purity of the wavelength; a color produced by a single wavelength will appear vivid while a color produced by a mix of wavelengths will appear faded

Hearing

Auditory sensation, or hearing, results when sound waves are collected in the outer ear, amplified in the middle ear, and converted to neural messages in the inner ear.

Why is it difficult to distinguish colors in very dim light?

Because only the cones are sensitive to the different wavelengths that produce the sensation of color and cones require much more light than rods do to function effectively.

Binocular disparity (stereopsis)

Because our eyes are set a couple of inches apart, a slightly different image of an object is cast on the retina of each eye. When the two retinal images are very different, we interpret the object as being close by. When the two retinal images are more nearly identical, the object is perceived to be further away. Hold a pencil close to nose and look at with one eye and then the other. They look very different.

Pheromones

Chemical signals released by an animal that communicates information and affects the behavior of other animals of the same species. They may mark territories, advertise sexual status, or serve as warning signals. From insect to mammals. Used to communicate aggression, alarm, and fearful states. Used to regulate sexual attraction, meeting, and reproductive behavior. A lusty male cabbage moth can detect a lusty female several miles away.

The chemical and body senses: smell, taste, touch and position

Chemical stimuli produce the sensations of smell and taste, while pressure and other stimuli are involved in touch, pain, position, and balance sensations.

Culture and top-down processes

Chia and colleagues - eye movement difference between Chinese students and US students, see picture. The Chinese students tended to see and remember object and background as a single perceptual image. This reflects the collectivistic cultural background. US students look at the vocal object in the foreground, reflecting their individualistic cultural backgrounds. Culture may operate as a top-down mechanism that guides and interacts with basic neuro-perceptual processes.

Exposure to light

Contained in the retina are sensory receptor cells that respond to light, called rods and cones, and are often called photoreceptors. When exposed to light the rods and cones undergo a chemical reaction that results in a neural signal.

cochlear implants

Convert sound into electrical impulses that directly stimulate the auditory nerve via electrodes implanted in the cochlea. They do not restore normal hearing. But they can allow hearing-impaired individuals to perceive speech and other every day sounds.

Can magnets relieve pain?

Magnets fall under the category of complementary and alternative medicines (CAMs). These are a diverse group of healthcare systems, practices, or products that are not currently considered to be part of conventional medicine. Scientific evidence exists for some CAM therapies such as massage. Therapies that are scientifically proven to be safe and effective usually become adapted by the main stream healthcare system. There is no evidence supporting the claim that magnets relieve pain.

vestibular system

Maintains your sense of balance, posture, and position in space. Changes in gravity, motion, and body position are detected by hair-like receptor cells embedded in fluid in the semicircular canals and vestibular sacs in the inner ear. When visual information conflicts with the vestibular information, dizziness and disorientation may result. One strategy to combat motion sickness is to minimize sensory conflicts by focusing on a fixed point in the distance.

ESP experiments

Many initially convincing demonstrations of ESP later shown to be the result of research design problems with the researchers and intentional cueing of the participant. Another problem involves replication.

Mike may, prologue chapter 3

Mike had an accident as a child resulting in one eye being destroyed and the right eye being severely damaged. He was completely blind for approximately 40 years but was able to play soccer, wrestling and go skiing at speeds of 65 mph, with his wife in front of him giving directions. He create a company that produced GPS systems for the blind. And in '99 he had surgery to restore his site. Anatomically he is normal in his right eye but only has 20/1000 vision, resulting in blurry faces he finds distracting. He sees but his brain does not know how to interpret the signals it receives. After surgery he had the correct sensations but his brain was not making sense of the information, perception. In brain fMRI scans, Mike's occipital lobe does not respond to faces as normal peoples do. Mike's accident happened before these perceptual skills had been developed.

What are the two chemical senses?

Olfaction and gustation

color blindness

One of several inherited forms of color deficiency or weakness in which an individual cannot distinguish between certain colors. This supports the trichromatic theory. In most cases, people have normal blue-sensitive cones but their other cones are sensitive to either red OR green. More common in men than women. 8% of males. And 25% of those experiencing only the colors coded by the blue -yellow cones.

Light

One of the many different kinds of electromagnetic energy the travel in the form of waves. Others kinds include x-rays, microwaves, infrared signals or radio waves transmitted by your TV's remote control. These various types of electromagnetic energy differ in wavelength.

Parts of the retina

Optic nerve nerve, optic nerve fibers, ganglion cells, bipolar cells, sensory receptor cells, rod, cone

nerve cell deafness

Or hair cell damage. The damage is cumulative, and noise exposure, not age is the leading cause of hearing loss. 12 to 15% of school age children have some hearing deficits due to noise exposure.

Law of Pragnanz

Or the law of simplicity. Gestalt general principle that states when several perceptual organizations of an assortment of visual elements are possible, that perceptual interpretation that occurs will be the one that produces the best, simplest and most stable shape. The implication is that our perceptual system works in an economical way to promote the interpretation of stable and consistent forms. In effect, we actively and automatically construct a perception that reveals "the essence of something" which is roughly what the German word pragnantz means.

Types of ESP (paranormal phenomena)?

Outside the range of normal experience. Telepathy, the direct communication between the minds of two individuals; clairvoyance, the perception of a remote object or event such as a "sensing" that a friend has been injured in a car accident; psychokinesis, the ability to influence a physical object without touching it; and precognition, the ability to predict future events.

Gestalt Psychology, founded by German psychologist Max Wertheimer

School of psychology that maintained sensations are actively processed according to consistent perceptual rules, producing meaningful whole perceptions, or gestalt.

Figures have shape, ground doesn't

See picture

The different perceptual qualities that figure and ground have

See picture

Using distraction for pain

Self-administered strategies for pain #1, When focusing your attention on some non-painful task, you can often reduce it. For example, you can mentally count backwards by 7s from 901, draw different geometric figures in your mind, or focus on the details of a picture or other object. Listen to a podcast or to calming music also.

Imagery for pain

Self-administered strategies for pain, #2, Creating a vivid mental image can help control it. Creating a pleasant and progressive scenario such as walking along the beach or hiking in the mountains. Imagine all the sensations.

Relaxation and meditation for pain

Self-administered strategies for pain, #3, deep relaxation can be very effective and one method is deep breathing. Another form is practicing meditation, which may reduce the subjective experience of pain through multiple pathways, including relaxation, distraction, and inducing a sense of detachment from the painful experience.

Positive self-talk and reappraisal for pain

Self-administered strategies for pain, #4, This strategy involves making positive coping statements, either silently or out loud, during a painful episode or procedure. These include statements like "It hurts but I'm OK, I'm in control" and "I'm uncomfortable but I can handle it." Reappraising or redefining the pain helps too.

Processing visual information

Signals from the rods and cones undergo preliminary processing in the retina before they are transmitted to the brain. It undergoes preliminary processing in the retina by specialized neurons called ganglion cells.

taste buds

The specialized sensory receptors for taste that are located on the tongue and inside the mouth and throat. Taste buds are located on the tongue, inside the cheeks, on the roof of the mouth, and in the throat. No tongue map. Each taste bud shows maximum sensitivity to one particular taste and lesser sensitivity the others.

sensory receptors

Specialized cells unique to each sense organ that respond to a particular form of sensory stimulation. They convert physical energy to electrical impulses that go to the brain. Ex. Cotton candy - smell, taste, sound, touch, sight.

Proprioceptors

Specialized neurons in the muscles and joints that continually communicate changes and body position and muscle tension to the brain.

Nociceptors

Specialized sensory receptors for pain that are found in the skin, muscles, and internal organs. These are small sensory fibers, called free nerve endings. Millions in the body but mostly in the skin. Fingers have 1200 per square inch. Muscles and joints have fewer, and internal organs have the fewest.

Fast pain system (sharp pain)

Stubbing your toe activates the myelinated fibers of this system. It Transmits the sharp, intense, but short-lived pain of the immediate injury. The pain signals travel up the spinal cord to the brain to the thalamus, then to the somatosensory cortex, where the sensory aspects of the pain message are interpreted such as the location and intensity of the pain.

Subliminal perception in the elderly

Subjects (elderly) saw flashing visual images or words at a rate too fast to be consciously perceived, including the words spry and wise, reflecting a positive view of aging. Others actually saw words and images reflecting positive aging. The subliminal group showed improved physical function for up to three weeks after the study, compared to the control group. Possibly the participants adopted healthier behaviors because they internalized the more positive views of aging, but not replicated yet.

Olfaction

Technical name for the sense of smell.

Gustation

Technical name for the sense of taste - It results from the stimulation of special taste receptors by chemical substances in food and drink. When dissolved by saliva, these chemicals activate the 50-odd taste receptor cells found in the taste buds. Note: these receptors are also found in the gut and upper airways, triggering immune responses.

From the eye to the brain

The 1 million axons of the ganglion cells are bundled together to form the optic nerve which extends to the brain. The optic nerve exits the retina at the optic disk. The optic nerves from the left and right eyes meet at the optic chiasm, then split apart. One set of nerve fibers crosses over and projects to the opposite side of the brain and another set of nerve fibers continues along the same side of the brain. Most of the nerve fibers travel to the thalamus and then on to the visual cortex of the occipital lobe, where the signals are decoded and interpreted. Specialized neurons, sometimes called feature detectors, because they detect particular features or aspects of more complex visual stimuli, get to work when signals are received.

audition

The technical term for the sense of hearing. The ability to sense and perceive very subtle differences in sound is important to physical survival, social interactions, and language development.

size constancy

The perception of an object is maintaining the same size despite changing images on the retina. If the retinal image of an object does not change but the perception of its distance increases, the object is perceived as larger. To illustrate, stare at a 75 W lightbulb for 10 seconds. Then focus on a bright, distant well, and you should see an afterimage of the lightbulb on the wall. The lightbulb looks several times larger than the original lightbulb. Why? Because when you looked at the wall, the lingering afterimage of the lightbulb on your retina remains constant but your perception of distance increased. So the perception of the lightbulb size increased.

shape constancy

The perception of familiar objects as maintaining the same shape regardless of the image produced on the retina.

stroboscopic motion

The perception of smooth motion in a film. Photographs are projected onto a screen at a rate of 24 frames per second. Each image is slightly different from the one before. When presented in rapid sequence we fill in the movement between them, creating the perception of continuous motion.

Color

The perceptual experience of different wavelengths of light, involving hue, saturation (purity), and brightness (intensity)

Blind spot

The point at which the optic nerve leaves the eye, producing a small gap in the field of vision. There are no photoreceptors in the optic disk.

Optic chiasm

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

Transduction

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

accommodation

The process by which the lens changes shape to focus incoming light so that it falls on the retina.

Sensation

The process of detecting a physical stimulus, such as light, sound, heat, or pressure. All forms of sensation involve the stimulation of specialized cells called sensory receptors.

Perception

The process of integrating, organizing, and interpreting sensations.

Frequency

The rate of vibration, or the number of sound waves per second, measured in hertz, the number of wave peaks per second. The faster the vibration, the higher the frequency, the closer together the waves are, and the higher the tone produced. If you pluck the high E and the low E strings on the guitar, you'll notice that the low E vibrates far fewer times per second then does the high E.

Vision - rods and cones

The receptor cells for vision respond to the physical energy of light waves and are located in the retina of the eye.

pitch

The relative highness or lowness of a sound, determined by the frequency of a sound wave.

parapsychology

The scientific investigation of claims of paranormal phenomena and abilities. To evaluate, must consider the likelihood of coincidence and the fallacy of positive instances. Coincidence describes an event that occurs simply by chance. The fallacy of positive instances is the tendency to remember coincidental events that seem to confirm our belief about unusual phenomenon and to forget all the instances that do not. Example, the number of dreams that do come true versus the number that do not.

Proprioception

The sense of body movement and position. (Touch your right ear in the dark)

How do we smell?

The sensory stimuli that produce our sensation of an odor are molecules in the air. They are emitted by the substance we are smelling. We inhale them through the nose and the opening in the palate. The molecules encounter millions of olfactory receptor cells located high in the nasal cavity. The receptor cells last only 30 to 60 days. The stimulation of the receptor cells is converted into neural messages to pass along their axons, bundles of which make up the olfactory nerve. We have 350 olfactory receptors, like an alphabet- combine to identify smell.

Cones

The short, thick, pointed sensory receptors of the eye that detect color and are responsible for color vision and are especially important in visual acuity. Cones are specialized for seeing fine details and for vision in bright light. See picture

difference threshold

The smallest possible difference between two stimuli that can be detected half the time; also called just noticeable difference, or jnd

absolute threshold

The smallest possible strength of a stimulus that can be detected half the time. Arbitrarily defined due to person to person and trial to trial variations. Examples by Eugene Galanter: Vision, a candle flame seen from 30 miles away on a clear, dark night; hearing, the tick of a watch at 20 feet; taste, one teaspoon of sugar in 2 gallons of water; smell, one drop of perfume throughout a three-room apartment; touch, A bee's wing falling on your cheek from a height of about half an inch

perceptual grouping

The tendency to organize patterns of stimuli into larger units according to proximity, similarity, and continuation. The urge to organize.

Opponent-process theory of color vision

The theory that color vision is the product of opposing pairs of color receptors, red-green, blue-yellow, and black-white; when one member of a color pair is stimulated, the other member is inhibited. This theory does explain afterimage. Flag afterimage. Since white light is made up of the wave links for all colors, the receptors for the original color have adapted to the constant stimulation by staring at the flag and are temporarily turned off. Therefore they do not respond to that color when looking at the white piece of paper and the opposite colors show up, resulting in a red, white and blue flag.

Gate-control theory of pain

The theory that pain is a product of both psychological and physiological factors that cause spinal gates to open and relay patterns of intense stimulation to the brain, which perceives them as pain. If, because of psychological, social, or situational factors, the brain signals the gates to open, pain is experienced or intensified. If the brain signals the gates to close, pain is reduced. This helps explain the variation in pain that people experience.

Trichromatic theory of color vision

The theory that the sensation of color results because cones in the retina are especially sensitive to red light (long wavelengths), green light (medium wavelengths) or blue light (short wavelengths). Hermann von Helmholtz, mid-1800s. Substantiated in 1964 when George Wald showed the different cones were activated by red, blue and green light.

Optic nerve

The thick nerve that exits from the back of the eye and carries visual information to the visual cortex in the brain.

pain

The unpleasant sensory and emotional experience associated with actual or potential tissue damage. Necessary to our survival, as a warning.

depth perception

The use of visual cues to perceive the distance or three dimensional characteristics of objects. Perception of distance in motion helps us gauge the position of stationary objects and predict the path of moving objects. This has survival value regarding potential threats like snarling dogs or an oncoming train.

place theory

The view that different frequencies cause larger vibrations at different locations along the basilar membrane, different pitches excite different hairstyles along the basilar membrane. Higher pitched sounds are interpreted according to the place where the hair cells are most active.

place theory

The view that different frequencies cause larger vibrations at different locations along the basilar membrane. Example, high frequency at the stirrup end of the basilar membrane.

frequency theory

The view that the basilar membrane vibrates at the same frequency as the sound wave. Used to explain how we distinguish pitch. For example, a sound wave of 100 Hz would excite each hair cell along the basilar membrane to vibrate 100 times per second and neural impulses would be sent to the brain at the same rate. However there is a limit to how fast neurons can fire. They cannot go faster than 1000× per second, but sound frequency can be much higher than 1000 Hz. Volley principle to hear this - neurons firing in rapid succession.

Afterimage

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

How many rods and cones are there in an eye? How do they differ?

There are 7 million cones and 125 million rods in each eye. Rods are long and thin, with blunt ends. Cones are shorter and fatter, with one end that tapers to a point. Rods are much more sensitive to light than cones. Once rods are fully adapted to the dark they are about 1000 X better than cones at detecting weak visual stimuli. We rely primarily on rods for our vision in dim light and at night. Rods adapt relatively slowly, reaching maximum sensitivity to light in about 30 minutes. Cones adapt quickly to bright light, reaching maximum sensitivity in about 5 minutes. That's why it takes several minutes for your eyes to adapt to the dim light of a darkened room but only a few moments to adjust to the brightness when you switch on the lights.

Bern's eight precognition experiments

There were small but statistically significant effects in favor of precognition, which are hard to explain. Much criticism, primarily focused on the statistical methods used to analyze the data. So far replication attempts have been unsuccessful. Bern published a meta-analysis of 90 replication attempts, concluding that the results showed solid support for the existence of prerecognition.

skin senses

These provide essential information about your physical status and your physical interaction with objects in your environment. Skin is the largest and heaviest organ. It covers about 20 ft.² of surface area and weighs about 6 pounds on the average adult. There are many kinds of sensory receptors in the skin. Some respond to just one kind of stimulus such as pressure, warmth or cold and others respond to more than 1 stimulus. Sensory receptors are distributed unevenly among different areas of the body, which is why sensitivity to touch and temperature varies from one area of the body to another. Your hands, face and lips, for example, are much more sensitive to touch than your back, arms and legs.

How are the olfactory neurons unique?

They are the only neurons that directly link the brain in the outside world.

hue

Varies with the wavelength of light, different wavelengths are perceived as different colors

Electromagnetic spectrum

We are only able to see less than 1% of the entire spectrum of electromagnetic energy. Some electronic instruments, like radio and television, are specialized receivers that detect a specific wavelength range. The human eye is sensitive to a specific and very narrow range of wavelengths. See picture

In focus, the dress that broke the Internet

What color is the dress? See picture. 28 million views within 48 hours on Facebook. White and gold, or blue and black? The most likely explanation involves color constancy. In determining the color of an object your brain takes additional factors into account, such as the amount and brightness of background illumination. The brain accommodates for shadows and other changing light conditions to perceive the color of familiar objects as unchanging. In the photo, the light conditions are ambiguous. Is the dress in shadow or bright light? If the unconscious assumption is shadow, the dress looks white and gold, because white tends to look blue in dim light. But those who assumed that the dress was in bright light saw it as blue and black, the actual colors.