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
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
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
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
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
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
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.