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Courtesy Dr. Julie Gralow

LO 1 Define sensation and perception and explain how they are different.

LO 2 Define transduction and explain how it relates to sensation.

LO 3 Describe and differentiate between absolute thresholds and difference thresholds.

LO 4 Explain how electromagnetic energy is transduced into a sensation of vision.

LO 5 Describe the function of rods and cones.

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LO 6 Compare and contrast the theories of color vision.

LO 7 Summarize how sound waves are transduced into the sensation of hearing.

LO 8 Illustrate how we sense different pitches of sound.

LO 9 Describe the process of olfaction.

LO 10 Discuss the structures involved in taste and describe how they work.

LO 11 Describe how the biopsychosocial perspective is used to understand pain.

Courtesy Dr. Julie Gralow

LO 12 Illustrate how we sense the position and movement of our bodies.

LO 13 Identify the principles of perceptual organization.

LO 14 Identify concepts involved in depth perception.

LO 15 Define extrasensory perception and explain why psychologists dismiss its legitimacy.

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To help us understand sensation and perception, meet the Dunn sisters.

Sophie (left), Zoe, and Emma (front), are the world’s only deaf and blind triplets. Emma and Zoe can see nothing, while Sophie has very limited vision even when wearing corrective lenses. All three girls wear devices known as cochlear implants, which simulate the sensation of hearing.

Worldwide Features / Barcroft Media/Landov

Courtesy Dr. Julie Gralow

Sensation and Perception 101

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ABSORBING AND DECIPHERING INFORMATION FROM THE ENVIRNOMENT

Sensation

Process by which receptors in our sensory organs (such as in the eyes, ears, nose, mouth, skin and other tissues) and the nervous system receive and detect stimuli

Perception

Process through which information about these stimuli is organized, interpreted, and transformed into something meaningful

Are you a synesthete?

Painter David Hockney stands before his massive Bigger Trees Near Water at an exhibition in London. Hockney reportedly has synesthesia, a rare condition whereby a person experiences a combination of perceptions in response to a “single sensory modality” (Rich & Mattingley, 2002).

AP Photo/Sang Tan

Courtesy Dr. Julie Gralow

A synesthete may, for instance, describe the color green as having a scent, or the word “Tuesday” as being maroon with black stripes. Hockney created he stage sets for various operas by painting what he saw in the music (Ward, 2006, June 10).

Sensation and Perception 101

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Sensory input from environment

Translates in electrical a nd chemical signals of neurons

Through TRANSDUCTION

Neural signals processed by CNS

Resulting in SENSATION

Sensations assigned meaning

Through PERCEPTION

Sensation and Perception 101

DATA-BASED AND KNOWLEDGE-BASED PROCESSING

Data-based processing

Describes how the brain takes basic sensory information and processes the incoming stimuli

Knowledge-based processing

Generally involves the next step, utilizing past experiences and knowledge to understand sensory information

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Sensation and Perception 101

STUDYING SENSATION

Human sensation

Great variability in stimulus detection in human

Sensory systems prone to interference making study difficult

Absolute thresholds

Weakest stimuli detected 50 percent of the time

Not necessarily for particular person over time

THE TRIPLETS

Zoe became increasingly frustrated with a musical toy. Her mother noticed this behavioral change and consulted a specialist.

A problem with Zoe’s sensory receptors in her ears was found.

Courtesy Dr. Julie Gralow

Absolute Thresholds

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Sensation and Perception 101

STUDYING SENSATION

Sensory adaptation

Difference thresholds

Or just noticeable difference, is the between two stimuli noticed 50 percent of the time

Most people are painfully aware of their new braces, but after a while they begin to notice them less. If a stimulus is ongoing and steady, we tend to become less aware of it. This process of sensory adaptation helps keep us on alert for changes in the environment.

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Sensation and Perception 101

STUDYING SENSATION

Weber’s Law

Thresholds are determined by ratios, not absolute numbers

The five senses each have their own Weber ratios

Subliminal influences

Neuroimaging studies suggest neural activity is evident with subliminal presentation of stimuli.

Do you believe people can be manipulated by these influences? Why? Why not?

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Sensation and Perception 101

STUDYING SENSATION

Signal detection theory

Explains how various factors influence ability to detect weak environmental signals

Suggests the ability to detect a stimulus depends on sensory factors (such as the intensity of the stimulus or the presence of interfering stimuli) and psychological state (such as how alert one is)

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1. ________ makes the information received by the sensory receptors more meaningful by drawing from experience to organize and interpret sensory data.

a. Perception

b. Transduction

c. Sensation

d. Signal detection

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2. Imagine you have been asked to watch a neighbor’s property while she is away. According to signal detection theory, what factors may influence your ability to detect an intruder’s flashlight in the middle of the night?

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3. At the supermarket, a woman next to you in line has some very strong-smelling cheese in her basket. You notice the odor immediately, but within a matter of minutes you can barely detect it. This reduced sensitivity to a constant smell results from the process of:

a. sensation.

b. transduction.

c. perception.

d. sensory adaptation.

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Vision

LIGHT IS SIGHT

Eyes do not sense faces, objects, or scenery—they detect light!

Visible light is the only part of the spectrum detectable by human eyes.

Electromagnetic (EM) waves in everyday life

Gamma waves

X-rays

Ultraviolet

Infrared

Microwaves

Radio waves

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Light visible to humans fall along a spectrum or range of electromagnetic energy.

Visible Light and the Electromagnetic Spectrum

Radioactive symbol, Thinkstock; X-Ray hand, AJ Photo/ Science Source; Marines, Lance Cpl. Tucker S. Wolf. U.S. Marine Corps; Hand holding phone, ˝ Rob Bartee/Alamy; Radio tower, TERADAT SANTIVIVUT/Getty Images

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The various types of electromagnetic energy can be distinguished by their wavelengths, which is the distance from one wave hump to the next.

Gamma waves have short wavelengths and are located on the far left of the spectrum. At the opposite extreme (far right of the spectrum) are the long radio waves. The light humans can see falls in the middle of the spectrum, measuring between 400 to 700 nanometers (nm) or billionths of a meter.

Wavelength also plays an important role in determining the colors humans and animals can detect.

Vision

THE COLORS WE SEE

Features of light: Color factors

Hue

Brightness

Saturation

Perception of color

Perceptions of color are product of what is in the environment and brain’s interpretation.

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The colors you see result from light reflecting off of objects and reaching your eyes.

Hue: Refers to color; determined by wavelength reflecting off object.

Brightness: Represents continuum from bright to dime; depends on wave length (amplitude).

Saturation determined by uniformity of wavelength.

Average person sees some 2.3 million colors.

Try This

Go find the brightest, most saturated object you possess that has a yellow hue, and grab a strong flashlight while you are at it.

Wait until it is dark outside.

Now put the object on a table right in front of you and look at it with a dim light shining overhead.

Next, shine the flashlight directly onto the yellow object and notice how your perception of the color changes.

Finally, turn off all the lights in the room and notice again how your perception of the color changes.

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Vision

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Cornea

Includes clear outer layer over colored portion of eye

Shields eye from damage by dust, bacteria, and pokes

Focuses incoming light wavers

Iris

Includes muscle responsible for changing size of pupil

Pupil

Controls amount of light entering eye

Lens

Include tough, transparent structure that focuses incoming light and changes shape to adjust images to near and far through accommodation.

Vision

THE RETINA

Retina

Contains photoreceptor cells and site for transduction

Photoreceptors

Absorb light energy and convert it into neural activity

Rods

Cones

Rods and Cones

STEVE GSCHMEISSNER/SCIENCE PHOTO LIBRARY

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You can see why the light-sensing neurons in the back of the eye are called rods (tan) and cones (green).

Rods outnumber cones by a factor of 20 and are found everywhere in the retina except the centrally located fovea. The color-sensing cones are mostly in the fovea.

Cones provide color vision and aid fine detail.

Steve Gschmeissner/Science PhotoLibrary

Vision

The retina

Bipolar cells

Optic nerve

Blind spot

Fovea

Optic chiasm

Interneurons

Feature detector

Can you describe each of these terms?

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Bipolar cells

Are in close proximity to rods and cones

Convey signals to ganglion cell whose axons bundle together to form optic nerve

Optic nerve

Contain bundled axons of ganglion cell which hook the retina to the brain

Blind spot

Found where bundle of ganglion cells in optic nerve which exit the retina at the optic disc

Fovea

Includes central part in retina that contains no rods; cones excel at sensing detail

Optic chiasm

Involves place in brain where optic nerves from each eye intersect

Interneurons

Shuttle data from optic chiasm to visual cortex

Feature detectors

Detects specific features of visual experience, such as lines, angles, and movements

Interneurons

Shuttle data from optic chiasm to visual cortex

Vision

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THE RETINA

Dark adaptation

Ability of eyes to adjust to light after being in dark

Ability of eyes to adjust to dark after exposure to brightness

Light adaptation

SEEING…After all these definitions, let’s put it all together!

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Light waves bounce off an object and enter eye through the cornea, pupil, and lens.

Iris dilates and contracts pupil to control amount of light entering eye.

Cornea and lens focus light waves toward the retina, bending the light and projecting an inverted image.

Light strikes the retina, exciting photoreceptors.

Rods and cones fire, activating bipolar cells found in retina.

This excites ganglion cells, which form the optic nerve carrying messages to the brain.

Vision

Theories of color vision

The trichromatic theory

Three types of cones: red, green, and blue

Brain identifies precise hue by calculating patterns of excitement among three cones

Relative activity of three types of cones that brain uses to make its color calculations

Courtesy Dr. Julie Gralow

Light Mixing

The color of a light is the result of a mixture of wavelengths from the visible spectrum.

When red, blue, and green light wavelengths are combined in equal proportions, they produce white light.

This may seem counterintuitive, because most of us have learned that mixing different-colored paints yields brown (not white).

The rules of light mixing differ rom those of paints and other pigmented substances.

2009 Richard Megna – Fundamental Photographs

Vision

Theories of color vision

Code deficiency and color blindness

Color deficiency occurs with loss or damage to cone(s)

Deficiencies may stem from problems with cones

Red-green color defects

8 percent male and >1 percent female with European ancestry

See It?

SSPL/Getty Images)

Courtesy Dr. Julie Gralow

If you cannot make out the number 45 in this Ishihara color plate, then you might have a red–green color deficiency, the most common variation of “color blindness.”

Red–green deficiency results from a problem with the red or green cones.

SSPL/Getty Images

Vision

Theories of color vision

Opponent-process theory

Herring proposed theory to explain afterimage effect and suggested a special group of neurons responds to opponent colors (in addition to color-sensitive cones)

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Across the World

China: Red is lucky color

Nigeria: Red is bad fortune

U.S.: White represents virginity and cleanliness

East Asia: White associated with dying and bereavement

Blue: Most popular favorite color in world

COLORS AND CULTURE

Perception of color may vary significantly across cultures, and even between individuals, but the early stages of sensation are virtually the same for everyone with normal vision.

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1. The hue of a color is determined by the ______ of the light reflecting off an object.

2. Cells contained in the retina that absorb light energy and turn it into chemical and electrical signals are called .

a. opponent-processing

b. photoreceptors

c. fovea

d. feature detectors

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3. Explain the two theories of color vision presented in the chapter and how they differ.

4. It’s dark in your house, and you are struggling to see what time it is without turning on the light. You notice that if you turn your gaze slightly to the side of your watch, you can make out the large numbers. The ability to see these large details in the dark is due to your:

a. presbyopia.

b. optic disc.

c. cones.

d. rods.

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Hearing

Audition: Sense of hearing

Sound waves: Alternating zones of high and low pressure moving through the environment

Qualities of sound

Loudness

Pitch

Timbre

During toddlerhood, the triplets were diagnosed with deafness and vertigo. Both conditions arose from deterioration of inner ear and dated back to antibiotics given during the first weeks of their premature lives.

Worldwide Features / Barcroft Media/Landov

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DECIBELS AND DAMAGE

Loudness is measured in decibels (dB). The absolute threshold for human hearing—the softest sound a human can hear—is described as 0 dB.

Loud noises, such as the 140 dB produced by a jet engine, cause immediate nerve damage leading to hearing loss.

Chronic exposure to moderately loud noise, such as traffic or an MP3 player near maximum volume, can also cause damage.

Airplane, istockphoto/Thinkstock; Motorcycle: Vasiliy Vishnevskiy/Alamy; Whispering women, Photosindia/ Getty Images

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(Keith, Michaud, & Chiu, 2008). Airplane, istockphoto/Thinkstock; Motorcycle: Vasiliy Vishnevskiy/Alamy; Whispering women, Photosindia/Getty Images

Qualities of Sound

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Pitch

Timbre

Degree to which a sound is high or low determined by frequency of its sound wave

Number of sound waves passing a given point per second; higher frequency is perceived as higher pitch, and lower frequency is perceived as lower pitch

POOR MUSCLE CONTROL, NOT AURAL PERCEPTION, UNDERLIES MOST CASES OF BAD SINGING

Recent research suggests that nonmusicians could adjust an instrument to match a specific note, but had trouble imitating the same note with their voice.

It was suspected that poor vocal muscle motor control was partly to blame. Almost anyone can learn to sing!

Physically Out of Tune

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Hearing

Coming to terms with terms

Eardrum: Membrane which separates outer from inner ear

Hammer, anvil, stirrup: Bones in middle ear

Oval window: Membrane leading to inner ear

Cochlea: Primary component of inner ear; contains auditory recptors

Basilar membrane: Hair receptor cells for sound waves

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TRANSFORMING SOUND WAVES INTO THE LANGUAGE OF THE BRAIN

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COCHLEAR IMPLANTS

Hearing is enabled by circumventing damaged parts of the inner ear. An external microphone gathers sound, which is organized by a speech processor. Internally, an implanted receiver converts this signal into electrical impulses that directly stimulate the auditory nerve.

This x-ray shows the cochlear implant’s electrode array coiling into the cochlea, directly reaching nerve fibers leading to the auditory nerve.

Debbie Noda/ Modesto Bee/ ZUMA Press/Newscom

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Credits: Close-up of the external portion of the cochlear implant, May 7, 2010, on

16-month-old Brinley Reiswig, Debbie Noda/Modesto Bee/ZUMA Press/Newscom;

Controversies

CONFLICTED FEELINGS ABOUT COCHLEAR IMPLANTS

The deaf community is divided about cochlear implants.

Not everyone thinks this device is a miracle.

Some view deafness as a gift and would not change.

Would you seek a cochlear implant for your own young child? Why? Why not?

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All Ears

DISTINGUISHING BETWEEN SOUND WAVES OF HIGH AND LOW FREQUENCIES

Place theory

Pitch corresponds to the location of the vibrating hair cells along the cochlea

Frequency theory

Pitch is determined by the vibrating frequency of the sound wave, basilar membrane, and associated neural impulses

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All Ears

PITCH AND THE COCHLEA

Volley principle

Perception of pitches between 400 and 4,000 Hz is made possible by neurons working together to fire in volleys

Sum of all the groups firing, one after another, allows for frequency of their firing to result in perception of the pitch of the sound

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I CAN’T HEAR YOU

Hearing loss is common.

Damage to hair cells or auditory nerve lead to sensorineural deafness.

Damage to eardrum or middle-ear bones cause conduction hearing impairment.

Sound does not need to be earsplitting to do damage.

Next time you use your earbuds, remember long-term exposure to loud music can cause hearing damage!

Granger Wootz/Blend Images

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1. The pitch of a sound is based on the of its waves.

a. frequency

b. timbre

c. amplitude

d. purity

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2. When a sound wave hits the eardrum, it causes vibrations in the bones of the middle ear, making the fluid in the cochlea vibrate.

Hair cells on the basilar membrane bend in response to the motion, causing nerve cells to fire. This process is known as:

a. the volley principle.

b. transduction.

c. the frequency theory.

d. audition.

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3. A researcher studying the location of neural activity in the cochlea finds that hair cells nearest the oval window vibrate more to high-frequency sounds. This supports the ________ theory of pitch perception.

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4. The mechanisms underlying how we sense the pitch of a sound are complicated. We have included two theories and one principle to explain pitch sensation. Try to solidify your understanding of how we hear pitch by creating a sketch of the process.

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Smell, Taste, Touch: The Chemical and Skin Senses

SMELL: NOSING AROUND

Olfaction

Sense of smell

Chemical sense

Involve sensing odor molecules in currents of air

Olfactory epithelium

Site of receptor neurons for odor molecules

Even without sight, Zoe is able to recognize her mother’s scent from 15 feet in an outdoor setting.

How does she do this?

Worldwide Features / Barcroft Media/Landov

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Olfaction

When enough odor molecules attach to an olfactory receptor neuron, it fires, sending a message to the olfactory bulb in the brain.

Glomeruli then communicate the signal to the higher brain centers.

Collage Photography/Veer

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OLFACTION AND THE BRAIN

Olfactory receptor neurons stimulate the olfactory bulb and converge with similar neurons in clusters called glomeruli.

Higher brain centered are signaled on a fast track to the limbic system.

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Didn’t See That Coming

Some research suggests that ambient odors can sway customer perceptions of stores and products.

Upscale hotels: Lavender, white tea, citrus

Clothing stores: Gender congruent scents

Dentist office: Orange essence

Does this make scents to you?

THE SCENT OF MONEY

Liudmila Sundikova / ALAMY

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Smell, Taste, Touch: The Chemical and Skin Senses

TASTE: JUST EAT IT

Gustation refers to the ability to detect five basic tastes: Sweet, salty, sour, bitter, and umami

Tasting

Taste buds located in the papillae are made up of receptor cells that communicate signals to the brain when stimulated by chemicals from food and other substances.

Let’s take a closer look.

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TASTING

Omikron/Science Source

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Some 5000 to 10000 taste budds are embedded in the papillae.

Each taste bud contains 50 to100 taste receptor cells.

Taste receptors are constantly being replenished; but the life span is only about 10 days.

By age 20, you have already lost half of the taste receptors you had at birth.

With age, turnover rate gets slower, making it more difficult to appreciate the basic taste sensations.

Alcohol and smoking impair the ability of receptors to receive taste modecules.

Smell, Taste, Touch: The Chemical and Skin Senses

Evolution and taste

Evolutionary advantages

Individual preferences

Touch and skin

Epidermis

Data collection mechanisms

Thermoreceptors

Pacinian corpuscles

Meissner’s corpuscles

Zoe approaches eating in a very tactile way, digging in and feeling the food on her skin. her senses of smell, taste, and touch are extremely fine-tuned.

Worldwide Features / Barcroft Media/Landov

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Evolutionary advantages

Taste is essential to species survival.

Gravitating toward sweet, calorie-rich foods for life-sustaining energy was an adaptive trait during primitive times.

Salty foods provides valuable minerals.

Umami signals the presence of protein

Bitter and sour warn about foods to avoid.

Individual preferences

May begin development before birth when early exposure shapes taste preferences for later life.

The sensation of touch begins with our skin, which houses a variety of receptors including those shown above.

TOUCH

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COLD DRINKS CAUSE A MAJOR ARTERY IN THE SKULL TO DILATE.

Researchers at Harvard Medical School found that the brain’s major artery widens to infuse blood and protect the brain from extreme cold. At the same time, increased pressure inside the skull may cause the pain known as “brain freeze”.

Anybody for a snow cone?

Brain Freeze Explained

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Pain

Pain pathways

Fast pain pathways

Pain location

Slow pain pathways

Pain information-often with emotion

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Smell, Taste, Touch: The Chemical and Skin Senses

Pain: Biopsychosocial perspective

Biological factors

Psychological factors

Social factors

Gate control theory

Perception of pain is increased or decreased by how brain interprets pain through interaction of biopsychosocial factors

Courtesy Dr. Julie Gralow

Complex interaction between neurological pathways and psychological and social factors, and a gate involved in the shuttling of information back and forth between the brain and the rest of the body.

Depending on the situation, psychological factors, and social influences, the gates will open, to increase the experience of pain, or close, to decrease the experience of pain.

Smell, Taste, Touch: The Chemical and Skin Senses

PAIN

Psychology of pain

Negative feelings can amplify pain; laugher and distractions can soften it.

Phantom limb pain

Intense pain in amputated limb

Causes: Theories

Changes in structure of neurons

Reorganization of brain in relation to sensations felt in different parts of body

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Smell, Taste, Touch: The Chemical and Skin Senses

KINESTHESIA

Kinesthesia enabled this stuntman to cross Niagara Falls.

What roles did his proprioception and vestibular sense play?

AP Photo/The Canadian Press, Frank Gunn

Courtesy Dr. Julie Gralow

Kinesthesia endows us with the coordination we need to walk without stumbling, dance the salsa, and put on our clothes without looking in the mirror.

Proprioceptors monitor changes in the position of body parts and the tension in muscles. When proprioception is impaired, the ability to do things ike hold a book, walk without falling over, or drive is impacted.

Vestibular sense helps the body deal with the effects of gravity, movement, and position and this gives us the information to balance and be balanced.

1. The chemical sense called ________ provides the sensation of smell.

2. Chemicals from food that is being eaten are released in saliva, where they dissolve and bathe the taste buds in your mouth. The chemicals find matching receptors and latch on, sparking action potentials. This is an example of:

a. olfaction.

b. transduction.

c. sensory adaptation.

d. thermoreceptors.

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3. Describe the common features and characteristics of smell, taste, and touch.

4. Maya consulted her physician about severe back pain. In order to help her understand pain perception, her doctor recommended she consider ________ , which suggests that the interpretation of pain can either increase or decrease the perception of pain through an interaction of biopsychosocial factors.

a. the theory of evolution

b. an absolute threshold

c. the gate-control theory

d. gustation

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Perception

A QUICK REVIEW

Sensation

Data-based processing

Perception

Knowledge-based processing

When your friend texts you a smiley face, your brain sees two dots, a hyphen, and a parenthesis. But how does it know what these symbols mean collectively? Through knowledge-based processing, you draw on past experience to make sense of the new information you encounter.

LOL :-)

Mathias Wilson/Getty Images

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Perception:

THE MÜLLER-LYER ILLUSION

Which line looks longer? They are actually the same length. Visual depth cues cause you to perceive that (b) and (d) are longer because it appears farther away.

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Illusions

Perception incongruent with real sensory data

Strobocopic motion

Perception

PERCEPTUAL ORGANIZATION

Gestalt psychology

Initially interested in perception as result of noticing motion illusions

Suggested that whole is greater than sum of parts: brain naturally organizes stimuli in their entirety ather than perceiving the parts and pieces

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Perception

PERCEPTUAL ORGANIZATION

Gestalt organizational principles

Figure-ground

Proximity

Similarity

Connectedness

Closure

Continuity

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Gestalt organizational principles

Perception

DEPTH PERCEPTION

Visual cliff

A baby appears distressed when he encounters the visual cliff, a supportive glass surface positioned over a drop-off, or “cliff.” Most babies will a trusted caregiver.

This finding suggests that depth perception is already in place by the time a child is crawling

So what do you think?

Is depth perception innate or learned?

(Gibson & Walk, 1960). Mark Richards/Photo Edit

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Perception

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Binocular cues

Information gathered from both eyes to help judge depth and distance.

Convergence

A binocular cue used to judge distance and depth based on the tension of the muscles that direct where the eyes are focusing.

Retinal disparity

A binocular cue that uses difference between the images the two eyes see to determine the distance of objects

Monocular cues

Depth and distance cues that require the use of only one eye.

Relative size

Linear perspective

Interposition

Texture gradient

DEPTH PERCEPTION

Binocular cues

Information gathered from both eyes to help judge depth and distance.

Convergence

A binocular cue used to judge distance and depth based on the tension of the muscles that direct where the eyes are focusing.

Retinal disparity

A binocular cue that uses difference between the images the two eyes see to determine the distance of objects

Monocular cues

Depth and distance cues that require the use of only one eye.

Perception

What is perceptual constancy?

Even when angle, lighting, and distance change, we know through experience that objects do not change in shape, size, or color although the sensory data might tell us otherwise.

Why is this important?

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SHAPE CONSTANCY

How do you know that all these doors are the same size and shape? The images projected onto your retina suggest that the closing doors are narrower, nonrectangular shapes. Your brain, however, knows from experience that all the doors are identical rectangles. This phenomenon is known as shape constancy.

Getty Images/Image Source

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Some studies suggest that children learn to perceive size constancy and this skill may not develop properly when children are deprived of certain types of stimuli.

Color constancy

Allows us to see the world in stable colors, even when the sensory data arriving at our photoreceptors change.

Perception

PERCEPTUAL SET

Tendency to perceive stimuli in a specific manner based on past experiences and expectations

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Letters or Numbers?

Look in the green square. What do you see? That depends on whether you viewed the symbol as belonging to a row of letters (A B C) or a column of numbers (12 13 14).

Perceptions are shaped by the context in which a stimulus occurs, and our expectations about that stimulus.

Think Again

EXTRASENSORY PERCEPTION

There is not scientific evidence to support the existence of ESP.

Bem published research that demonstrated human ability to predict the future. His statistical analysis was questioned and his work could not be replicated.

Psychologist might call reports of ESP an illusory correlation.

Do you know why? What do you think about the validity of ESP?

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Mother and Daughters

Liz and her eldest daughter Sarah (back left) relax with the triplets: Zoe (front left), Emma (front right), and Sophie (back right).

Zoe and Emma currently attend the Texas School for the Blind and Visually Impaired, while Sophie goes to middle school in the local district.

Worldwide Features/Barcroft Media/Landov

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1.________ occur when perceptions are incongruent with real sensory data.

2. One binocular cue called is based on the brain’s interpretation of the tension in muscles of the eyes.

a. convergence

b. retinal disparity

c. interposition

d. relative size

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3. Using what you have learned so far in the textbook, how would you try to convince a friend that extrasensory perception does not exist?

4. Have you ever noticed how the shape of a door seems to change as it opens and closes, yet you know its shape remains the same? This refers to the fact that even though stimuli may change, we know that objects do not change in shape, size, or color.

a. perceptual set

b. perceptual constancy

c. convergence

d. texture-gradien

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