SENSATION AND PERCEPTION

Transcription

1 SENSATION AND PERCEPTION

2 THE DIFFERENCE 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 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

3 WHAT DO YOU PERCEIVE HERE?

4 BASICS OF PSYCHOPHYSICS THRESHOLDS WHAT 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

5 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

6 SUBLIMINAL ADVERTISEMENTS

7 THE SENSES Five Basic Senses: Vision Hearing Taste Smell Touch The Other Senses: Pain, balance, acceleration, temperature, kinesthetic, vestibular

8 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

9 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

10 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

11 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)

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

13 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 HAMMER ANVIL 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)

14 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

15 HOW DO WE EXPERIENCE TASTE? TASTE GUSTATORY Energy Source: soluble chemical substances (Chemicals mixed into saliva) Receptor cells found in taste buds 4 primary tastes: sweet, sour, bitter, and salty 5 th Taste: UMAMI Temporal Lobe The MYTH of the Tongue Map

16 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

17 HOW DO WE EXPERIENCE Smell Olfactory SMELL? 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

18 HOW DO WE SENSE TOUCH? TOUCH TACTILE 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

19 HOW DO WE SENSE OUR BODIES POSITION AND MOVEMENT? KINESTHESIS VESTIBULAR Kinesthesis - knowing the position and movement of the various parts of the body Receptors in joints, tendons, bones, and ears Vestibular - equilibrium/balance [monitors your head and body s position and movement Receptors: The Semicircular canals of the ear

20 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

21 HOW DO WE PERCEIVE FORMS, PATTERNS, AND OBJECTS? What do you Perceive What do you SEE?

22 BASICS OF PERCEPTION THE 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

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

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

25 PHI PHENOMENON: THE ILLUSION OF MOVEMENT IS CREATED BY PRESENTING VISUAL STIMULI IN RAPID SUCCESSION

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28 CLOSURE: SUPPLYING MISSING ELEMENTS TO CLOSE OR COMPLETE A FAMILIAR FIGURE

29 FIGURE AND GROUND

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46 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

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48 SENSATION AND PERCEPTION ACTIVATES

49 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?

50 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.

51 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.

52 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

53 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.