Sensation & Perception

1. Sensation & Perception Andy Filipowicz AP Psychology – Chapter 6 (Myers, 9thed) Ocean Lakes High School Virginia Beach, VA Tons of Illusions! Flash-Lag Effect

2. Thinking Question • If you had to give up 1 sense, which would you least be willing to give up and why? Most willing? • Places to find: • 1) Locker • 2) Favorite upstairs classroom • 3) Library • 4) Baseball Outfield fence • 5) Mr. Wheeler’s classroom • Be back in 10 minutes total…so back at…

3. Thinking Question What’s your favorite color? Why? If you could only perceive 3 people’s faces, whose would they be and why? If you could only hear 1 song (or someone’s voice if you don’t like music), what would it be and why? If you could perceive only 1 type of taste, what would it be and why?

4. Thinking Question • Optic Nerve • Lens • Cornea • Ganglion Cells • Fovea • Rods / Cones • Iris • Pupil • Retina • Blindspot • Occipital lobe • Basilar membrane • Ear canal • Hair cells • Eardrum • Cochlea • Oval window • Auditory nerve • Temporal lobe • Hammer, anvil, stirrup Without looking in your notes / book, attempt to trace the path of transduction of a sound wave or light wave all the way through to the brain Create a Diagram – parts & basic function Use as many parts/names as possible!

5. How many SENSES do we have? BARNEY IS WRONG! • Energy Senses • Vision = light • Hearing = sound waves • Touch = pressure • Chemical Senses • Taste • Smell • Body Position & Balance • Kinesthetic • Vestibular

6. Absolute Threshold • Detected @ rate of 50%

7. What Can You Hear?

8. Subliminal • Demonic messages in songs? • Backwards Songs • Movies with it? • The Manchurian Candidate • The Mind: #9: Subliminal Messages • Greater liking for geometric shapes flashed subliminally (Kunst-Wilson & Zajonc, 1980) • “Brainwashing” not possible…

9. Researchers can study blindsight in the lab by using electromagnetic stimulation on normally sighted people to reproduce temporary blindness. They can then measure the subjects' ability to sense objects that they cannot see. Blindsight Moving Images #11 Damage to Primary Visual Cortex Experience it How about just being blind? Blind ppl process Braille in the visual cortex, too!

10. Change Blindness • Lots of Short Video Examples! • Original Door Study • Basketball • Fruit • http://www2.psych.ubc.ca/~rensink/flicker/download/

11. JNDs & Weber’s Law • Weber’s Law = Detect diffs @ rate of 50% • EXAMPLES of JNDs: • Light = 8% Pitch = 1/3 of 1% • Weight = 2 % Loudness = 10 % • Taste = 20% • 100th Birthday! 100db…how much more until you noticed? • 3 Quarters, 2 Envelopes and a Pair of Shoes • Applied Psych: Salesman…Suit ($300) or Sweater ($75)…if you want the customer to buy both, which do you show first and why?

12. Signal Detection Theory How is it a Top Down Idea?

13. Top Down vs. Bottom Up • Toe Touching Demonstration • Interlocked Arms Demonstration • Nervous system does not come with automatic prewired sensory relationships

14. Sensory Adaptation Switch watch hands Friends’ houses smell funny? Cross-Adaptation  OJ & Toothpaste Demonstration: Salt water becomes less salty, then drink regular water Eyes are always moving…if you mechanically keep them still, you will notice that things seem to disappear

15. Cite Movement Aftereffects (MAEs) Cause: adaptation of motion-specific detectors that are tuned to the direction of the movement of the stimuli being viewed TRIPPY!

16. Electromagnetic Spectrum Like any sensory process, vision converts some energy to neural messages = ?term?

17. Color • NOTHING has color!! …rather color is our interpretation of reflected wavelengths of light • So, trees are “green” because they reflect the “green” wavelength of light; they keep in everything else • Amplitude = how much energy(or photons) the light contains = Brightness (rods) • Wavelength = determines hue(cones) • Shorter than “visible light” = UV-rays, X-rays • Longer than “visible light” = infrared, microwaves, radio waves • Colors short to long = violet (400nm), indigo, blue, green, yellow, orange, and red (700nm) NM = billionths of a meter

18. Fun • Breathing Square • And a related one (Motion Binding) • Hollow Faces • Hermann Grid AND Hermann Grid • But, curiously, not as often (1:3 vs. 9:10) in schizophrenics

19. The Retina • 2 Photoreceptors: • Rods for night, brightness • Cones for day, color creation • Photons activates rods cones • RODS/CONESBIPOLAR cells  GANGLION cells • Axons of ganglion cells converge like strands of rope to form the optic nerve to the brain

20. Distribution of Rods & Cones • Demonstration—Guess the Marker • What are the function of cones? Rods? • Where are the cones distributed? Rods? • What does “fovea” mean? • BLIND SPOT demonstration: • 1) card • 2) Blindspot – next slide • 3) Not the Blind Spot...but still pretty darn sweet • Magic Eye (not at all related)

22. You can eliminate the blind spot But only if you are an octopus…!

23. Eye-ness Which eye is your dominant eye… 1) Select an object that is a few feet away from you 2) Stare at the object and then point to the object using your index finger. 3) When your eyes are focused on the object and not on your finger, you will see two blurry fingers in your line of sight. 4) Now, close one eye and then close the other eye. Expected results: with 1 of your eyes close, your index finger will point exactly at the object, however, when the other eye is closed, your finger will point at an area slightly shifted to the side of the object…

25. Another problem: Prosopagnosia Complete sensation but incomplete perception Best example is the inability to recognize faces Moving Images 10: Sensation w/out Perception: Visual Prosopagnosia

26. Color Vision • Trichromat: 3 color combos (RGB) • Dichromat: See things in 2 colors combos • Red-green (most common) • Yellow-blue (dogs) • Monochromat – sees only light & dark (gray, black, white, etc.) (rats)

27. Young-Helmholtz Trichromatic Theory • What does this theory do well? • RGB • What doesn’t it explain? • Afterimage

28. Interesting Stuff • Why eat carrots? • Contains carotene which produces rhodopsin, the photochemical in rods (helps night vision) • Rods don’t respond to red light, so night watchmen (sailors) often wear “red” goggles to allow time (45 minutes) for rhodopsin to replenish to allow for “night vision”

29. DOGS Color Vision CATS Color Vision Animal Stuff Nocturnal animals can’t see red. Turn white light on at night (makes them sleep) Turn red light on during day (when they are awake, so we can see them!)

30. Opponent Process Theory • After leaving the cones • Some Ganglion cells—excited by input from red cones, inhibited by input from green cones (red-green opponent process) • Blue-Yellow • Black-White • What does it explain? • Afterimages • What DOESN’T explain? • Colorblindness – we now know this is VERY complicated…let’s take a look at how complicated it is and be glad you don’t have to memorize this stuff 

31. Stare at this

33. Figure 4-4Test for Color Blindness

34. HEARING: some basic definitions • Amplitude = strength of a sound (Loudness) • Decibel = 1/10 of a bel, a unit of measurement named after the inventor Bell • 0 = absolute threshold level • 20dB = soft whisper • 60dB = regular conversation • Frequency = number of cycles in a sound wave (Pitch) • Hertz = cycles of sounds waves per second • Pitch = high or low (longer wave is lower, shorter is higher)

35. Helmholtz’s Place Theory • Different frequencies make different parts of the basilar membrane vibrate • High frequencies, @start of cochlea • Low frequencies spread out across cochlea, peaking @end of it • Larger the cochlea, the better the ability to hear low freq sound • Cats & Dogs have smaller cochleas (hear hitch pitch stuff) • The vacuum cleaner freaks out the cat b/c it produces very high pitch

36. Frequency theory • Frequency of vibrations? • If freq = 100 waves/s, then 100 impulses/s to the brain • Problem: Neurons cannot fire over 1000times/s, so how do we hear over 1000 Hz? (speech = 4000Hz) • Volley Principle: Neurons alternate firing like soldiers, so that their combined their frequency = something above 1000/s • In the end, it is probably both theories

37. Sound Localization • DEMONSTRATION • Car honking? Emergency Sirens? WHY? • Parallel processing: • Timing difference in one neural pathway • Intensity differences in another • Info merged in temporal lobe

38. Tinnitus • Defined = persistent sound in one or both ears…sound does not come from external source • High pitched hiss, ring, buzz, or roar • Continuous or pulsating (often coinciding with the heartbeat) • Sound originates in the inner ear and is triggered by the auditory nerve • Causes: side effect of taking aspirin!, wax in outer ear, ear infection, impacted teeth, infected sinuses or tonsils, nerve disorders, arteriosclerosis, hypertension, loud noise, head injury, antibiotic drugs, Meniere’s disease (eventually causes hearing loss), otitis (inflammation of the ear) • Explanation: Science News

39. Touch • 5 million receptors overall • 5 general types (though all are different structurally) • Pain • Heat • Cold • Touch • Pressure • Abundance varies

40. Touch Thresholds • 2 Point Thresholds (Guide  16) • 2 toothpicks, 1 cm apart • Touch cheek, then calf • Touch fingertips, then forearm • 2 toothpicks (or same pencils), 1 inch apart on crease of elbow • Keep distance between toothpicks equal, “draw” them to the middle and index fingers

41. The Aristotle Illusion Cross index, middle finger Touch small spherical object between them (end of a ballpoint pen)

42. More Top Down Concepts Toe Touching Demonstration Purpose: Nervous system does not come with prewired sensory relationships Interlock hands

43. Pain…In the beginning: • Descartes: Pain is a physical phenomenon of injured nerves sending impulses to the brain • He was right…kinda! • Nociceptors – sensory receptors for “hurtful” stimuli including temperatures, pressures, and chemicals • Usually respond either to chemical, thermal, or mechanical environments upon reaching a particular “pain” threshold • Noxious heat or cold • Excess pressure / breaks in the skin • Capsaicin • Sleeping nociceptors – like the others, but can’t be activated unless tissue inflammation surrounds it (meaning the tissue is damaged)

44. Wall’s Gate Control Theory • Axons of nociceptors transmit to spinal cord (glutamate), then the thalamus (general perception of pain happens here) then sensory cortex in parietal lobe (locate pain) • Axons are either: • A-Delta Fibers (sharp, acute, pricking pain 6-30M/second) • Mechanical, Thermal • C-Fibers (longer acting pain, 0.5-2M/sec, Aching, Throbbing, Burning Pain) • Chemical Pain

45. Briefly on Headaches Brain does not actually have any nocioceptive tissue = cannot perceive pain So headaches CANNOT = stimulation of pain fibers in the brain itself The membrane surrounding CNS, dura matter, has pain receptors Evolutionary, probably any injury that was severe enough to be able to cause pain in the brain would probably kill you first anyway

46. Diagram…Then, Aspirin • How does aspirin work? • Actually doesn’t work in the brain • Blocks the production of prostaglandins throughout the body • Prostaglandins (named by a Sweed who thought they were produced in the prostate) are in virtually every cell of the body…they produce inflammation, pain, and fever when triggered by appropriate stimuli • Aspirin blocks them from doing this

47. Can plants feel pain? Since pain is defined as a signal of present or impending tissue damage affected by a harmful stimulus, the ability to experience pain or irritation is observable in most multicellular organisms. Even some plants have the ability to retract from a noxious stimulus. Whether this sensation of pain is equivalent to the human experience is debatable.

48. Taste (Gustation) Types of sensations: Sweet, Sour, Salty, Bitter, & Umami

49. Smell (Olfaction) • Anosmia – no sense of smell (2 million Americans) • Most common cause = head trauma • 10 million olfactory neurons, each having 1000 different possible types of receptors • 4 other ways to detect chemicals in the air (kinda like smell, but not what we think of when we say “smell”) • Vomeronasal organ – snakes forked tongues collect scent molecules and deposit them here on the roof of their mouths; in mammals its in the nasal cavity • Septal organ of Masera – ? • Nervusterminalils – ? • Tigeminal nerve – irritating odors