SENSATION AND PERCEPTION

http://www.youtube.com/watch?v=Ahg6qcgoay4

THE DIFFERENCE

Sensation: stimulation of sense organs

Perception: selection, organization, and interpretation of sensory input

Psychophysics =(FECHNER) the study of how physical stimuli are translated into psychological experience

Stimuli: an energy source that causes a receptor to become alert to information (light, sound, gaseous molecules, etc)

Receptor: the organ that takes in sensory information

WHAT DO YOU PERCEIVE

HERE?

BASICS OF PSYCHOPHYSICS—THRESHOLDSWHAT IS THE MINIMAL AMOUNT OF A STIMULUS NEEDED TO

ACTIVATE A SENSATION?

Sensation begins with a detectable stimulus

Fechner: the concept of the threshold

Absolute threshold: detected 50% of the time

Just noticeable difference (JND): smallest difference detectable

Weber’s law: size of JND proportional to size of initial stimulus

BASICS OF PSYCHOPHYSICS—

CONCEPTS AND ISSUES

Signal-Detection Theory: Sensory processes + Decision Processes

Detectability with HUMAN ERROR

Subliminal Perception: registering sensory inputs without conscious awareness ---Subliminal Advertising

Sensory Adaption: Decline in Sensitivity

SUBLIMINAL ADVERTISEMENTS

THE SENSES

Five Basic Senses:

Vision

Hearing

Taste

Smell

Touch

The Other Senses: Pain, balance, acceleration, temperature, kinesthetic, vestibular

VISION

Light = electromagnetic radiation

The eye: housing and channeling

Components:

Cornea: where light enters the eye

Iris: colored ring of muscle, constricts or dilates via amount of light

Pupil: regulates amount of light

Lens: focuses the light rays on the retina

VISION

Retina: absorbs light, processes images

Optic disk: optic nerve connection/blind spot

Receptor cells:

Rods: black and white/low light vision

Cones: color and daylight vision

RODS V CONES

RODS

Elongated Shape

125 million in the retina

Night vision and peripheral vision

Strong sensitivity to dim light

CONES

Stubby Shape

6.4 million in the retina

Daylight and color vision

Rapid speed of adaption to dark

HOW VISION WORKS

1. Light enters through the PUPIL

2. The IRIS helps the PUPIL make adjustments to alter the amount of light reaching the RETINA

3. It then hits the LENS…Which focuses light on the RETINA.

4. The RETINA contains receptors called RODS and CONES.

5. Information then travels over the OPTIC NERVE to the brain. (Visual Cortex in the Occipital Lobe)

EAR

External Ear: collects sound

PINNA

AUDITORY CANAL

EARDRUM

Middle ear:

the ossicles (hammer, anvil, stirrup)

Inner ear: the cochlea

a fluid-filled, coiled tunnel

contains the hair cells, the auditory receptors

lined up on the basilar membrane

Stimulus = sound waves (vibrations of molecules traveling in air)

HOW DOES IT WORK?

1. The PINNA collects sound waves, funnels them down along the AUDITORY CANNAL to the EARDRUM

2. The EARDRUM Sound waves vibrate bones of the middle ear – HAMMERANVIL STIRRUP

3. STIRRUP hits against the oval window of COCHLEA (Sets the fluid inside in motion)

4. HAIR CELLS are stimulated with the movement of the BASILER MEMBRANE

5. Sent through the thalamus to the auditory cortex (temporal lobes)

THE “OTHER SENSES”

Our brain gives priority to Hearing and Seeing, but the other 4 senses

touch, body position and movement, taste, and smell

we would be seriously handicapped

HOW DO WE EXPERIENCE

TASTE?

TASTEGUSTATORY

Energy Source: soluble chemical substances (Chemicals mixed into saliva)

Receptor cells found in taste buds

4 primary tastes: sweet, sour, bitter, and salty

5th Taste: UMAMI

Temporal Lobe The MYTH of the Tongue Map

HOW DO WE EXPERIENCE

TASTE?

TASTE and ADAPTION:

Our basic tastes are the product of survival adaptation!

SWEET Indicates an energy source that gives protein

SALTY Indicates sodium which is essential for physiological process

SOUR Indicates a potential toxic acid

BITTER Indicates a potential poison

Umami indicates proteins need to grow and repair tissue

HOW DO WE EXPERIENCE

SMELL?

Smell Olfactory

Energy Source: substances carried in the air

Olfactory receptors = olfactory cilia in the olfactory channel

There are nearly 10, 000 odors we can detect

Because smell is such a primitive sense, it bypasses the Thalamus

Smell and Memory

HOW DO WE SENSE TOUCH?

TOUCHTACTILE SENSE

“Touch is both the alpha and omega of affection”

-William James 1890

Energy Source: Pressure, warmth, cold, and pain

Our sense of touch is actually a mix of distinct senses with specialized nerve endings in the skin

HOW DO WE SENSE OUR

BODIES POSITION AND

MOVEMENT?KINESTHESIS

Kinesthesis -knowing the position and movement of the various parts of the body

Receptors in joints, tendons, bones, and ears

VESTIBULAR

Vestibular -equilibrium/balance [monitors your head and body’s position and movement

Receptors: The Semicircular canalsof the ear

PARAPSYCHOLOGY

PHENOMENON

Is there EXTRASENSORY Perception (ESP)?

Paranormal Phenomena (PSI)

ESP:

Telepathy: mind-to-mind communication

Clairvoyance: perceiving remote events

Precognition: perceiving future events

Psychokinesis:

Telekinesis: moving objects w/ the mind

HOW DO WE PERCEIVE

FORMS, PATTERNS, AND

OBJECTS?

What do you

PerceiveWhat do

you “SEE”?

BASICS OF PERCEPTIONTHE SAME VISUAL INPUT CAN RESULT IN

RADICALLY DIFFERENT PERCEPTIONS!!!

Reversible figures has two interpretations that can shift back and forth

Perceptual sets what you want to perceive

Inattentional blindness the failure to see fully visible objects or events in a visual display

Gestalt psychologists: the whole is more than the sum of its parts

CONTINUITY: viewers tend to see elements in ways that produce smooth continuation

FIGURE-GROUND PERCEPTION: figure—the object being looked at; ground—the background against which the image stands [HIGHER-ORDER FIGURES]

PHI PHENOMENON: THE ILLUSION OF

MOVEMENT IS CREATED BY PRESENTING

VISUAL STIMULI IN RAPID SUCCESSION

CLOSURE: SUPPLYING MISSING ELEMENTS TO

CLOSE OR COMPLETE A FAMILIAR FIGURE

FIGURE AND GROUND

AMES ROOM

Opponent Process Theory: cells within the thalamus respond to opponent pairs of receptors: black/white; red/green; blue/yellow– if one color is activated the other is turned off

http://www.youtube.com/watch?v=U9PZizBDBZw&feature=list_related&playnext=1&list=SPD277B91443934192

http://www.youtube.com/watch?v=xQp_oCgAH-E

http://www.youtube.com/watch?v=vmkaVoLoFEU&NR=1&feature=endscreen

SENSATION AND PERCEPTION

ACTIVATES

ACTIVITIES

Find 2 toothpicks and hold them together so that the points can both touch your skin at the same time. Separate the toothpicks by about 1 cm. Touch your cheeks with the toothpicks and describe the sensation. Now touch your calf with the toothpicks and notice whether the sensations are different. Move the toothpicks closer together and touch your cheek again. How close together can the toothpicks be before you perceive a single touch? Now move the toothpicks farther apart and touch your calf again. Continue to move the toothpicks apart until you can feel two distinct touches on your calf. How far apart can they be moved until you feel the two distinct touches?

Place a square piece of paper the size of a pea on the hairy-skin side of your hand and notice how long it takes until you can no longer feel the paper. Repeat this exercise with the glabrous-skin side of your hand. Continue these comparisons in touch adaptation by trying stimuli of different sizes and weights and on different regions of both sides of your hand. Compare touch adaptation in both locations and notice the general phenomenon of touch adaptation.

KINESTHETICS

This one may be a little weird. You’ll need a good friend and two chairs. First, set up the two chairs, one behind the other. Now, sit in the first chair, and have your friend sit in the chair right in front of you. Close your eyes and have your friend take your dominant hand and place it on their nose. Here comes the weird part. Put your other hand on your own nose. Start tapping and stroking your friend’s nose at random intervals, the more random your movements, the better this works. Imitate these movements on your own nose. Try to make the movements synchronize as best as possible. Continue this for thirty seconds to a minute. If you are susceptible, you may start to feel as if your nose is three feet long! Not everyone will feel it, so don’t worry if you try it a few times and you don’t feel anything different.

KINESTHETICS

Close your eyes and extend your arms out at your

sides. Point your index fingers. Now bring your index

fingers quickly towards each other in front of your

body. See whether you can make them touch

without looking. Try this several times and assess

your success. Then close your eyes and use an index finger

to touch each of your toes. Repeat this exercise several

times to assess your success. You might also be interested

in seeing whether you are equally successful touching your

index fingers together behind your back; most people are

somewhat less accurate

VESTIBULAR SENSE

Stand up and lift one leg. Notice how your body automatically adjusts to retain your balance in this somewhat precarious position. Now repeat this exercise with your eyes closed. You should find the task to be much more difficult. Vision clearly aids the vestibular sense in maintaining body balance. As one final illustration, first spin around rapidly and then try to stand on one leg. The unusual stimulation of your vestibular sense caused by spinning around will make the task very difficult—even with your eyes open. Thus, the vestibular sense must be very important for maintaining our balance.