Sensation

1. Sensation Module 9

5. What is Sensation? • The awareness that world around you. • The Process by which our sensory systems and nervous system receive stimuli from the environment.

6. Examples of Sensation • What do you see? • What are you listening to? • What can you feel? • What do you taste? • What do you smell? • Remember your five senses

7. Bottom-UpProcessing • Information Processing that focuses on the raw material entering through the eyes, ears, and other organs of sensation.

8. What is Perception? • It is the process of organizing and interpreting sensory information.

9. Top-Down Processing • Information Processing that focuses on expectations and experiences in interpreting incoming sensory information.

10. Take a look at this Picture kiddos! • Do you notice any of the marks that look the same as some of the others, but are meant to be interpreted differently?

11. What are absolute Thresholds and difference thresholds? How are they different? Thresholds

12. Absolute & Difference Thresholds • Absolute Threshold is the minimum amount of stimuli needed to detect a particular stimulus. • Example-The dimmest star in the sky. • -Spaghetti Sauce. The least amount of Basil you can taste in it would be at the absolute threshold. • Difference Threshold: Just the noticeable difference. The minimum difference that a person can detect between two stimuli. • -When a sound suddenly becomes too loud? When does a piece of clothing become too tight?

13. Signal Detection Theory • X-Ray: Is it scar tissue or a tumor? • 1950’s: S.D.T. came out of the Cold War. • Created to improve our ability to detect incoming nuclear warheads. • Our national security depends on accurate Signal Detection Theory! • What exactly is the Signal Detection Theory? • Set of formulas and principles that predict when we will detect the presence of a faint stimulus (signal) amid background stimulation (noise).

14. S.D.T. (continued) • 3 Kinds of Variables: • 1. Stimulus -How bright is the blip on the radar screen? • 2. Environmental -How much distracting noise is there in the room with the radar equipment? • 3. Organismic -Is the operator properly trained and motivated? • Used in Air Traffic control and other non military ways today.

15. Sensory Adaption • Diminished sensitivity as a result of constant stimulation. • When we filter out the non-changing aspects of our environment • If something is unchanging, we may fail to respond to it. • Ever smelled a trash can and then got used to it? Did you stop responding to it. • Think of the way your car smells? Do other people ever say it stinks, but you just don’t notice it anymore? • Swimming pool that is a little chilly? • You are cold at first? Then what happens?

16. Selective Attention • Focusing conscious awareness on a particular stimulus to the exclusion of others. • We can’t pay attention to everything at once! • Allows us to function in a world filled with many stimuli. • We have the ability to focus on one thing at a time… • Ever blocked something out so you could focus on studying for your Psychology test? Sounds? • Ever blocked something out so you could sleep? Light? Sound?

17. Look at this Picture • Do you guys see an old woman or a young lady? • You cannot see both images at the same time, you can however switch back and forth…. • Let’s look at some more….

18. What is light? The Visual System: The nature of Light

19. Electromagnetic Energy • An energy spectrum that includes X-Rays, radar and radio waves. • A small portion of this spectrum includes visible light energy which can be detected b the human eye. • Light enters the eye as waves of electromagnetic energy.

20. Electromagnetic Spectrum • The energy in this spectrum ranges from short gamma rays to long radio waves. Our eyes can only pick up a small amount of these waves which is the visible light (spectrum).

21. Hue • 1st characteristic of waves • The color of light. It’s determined by the wavelength of the light energy. • What color is this power point slide? • ROYGBIV-includes them all ya’ll! • Did you know we could detect over 7 million separate hues?! OMG!

22. Wavelength

23. Amplitude • 2nd characteristic of waves • Brightness of light is determined by the height of the wave! • The taller the wave the brighter the color. • Greater amplitude=stronger hue!

24. Wave Height

25. What are the major parts of the visual system? What roles do these parts play in our ability to see? The structure of the visual system

26. Cornea • The clear bulge on the front of the eyeball! • Protects the eye • Light first strikes the cornea. • Begins to focus the light by bending it toward the central focal point.

27. Iris • Colored part of your eye • What color are your eyes? • A ring of muscle tissue that forms the colored portion of the eye and creates a hole in the center (pupil). • Regulates the size of the pupil by changing it’s size– allowing more or less light to enter the eye.

28. Pupil • The adjustable opening in the center of the eye that controls the amount of light entering the eye. • In bright conditions the iris expands, making your pupil smaller. • In dark conditions the iris shrinks, making the pupil bigger.

29. Issues with your sight! Nearsightedness Farsightedness If Emilia is farsighted that means her lens causes light rays from close objects to converge behind the retina. • If LIAM is nearsighted his lens causes light rays from distant objects to converge in front of the retina, which blurs the retina.

30. Nearsighted and Farsighted

31. Normal Vision vs. Corrective Lenses • With normal vision, the lens changes in thickness to cause the light rays from a viewed object to converge AT the retina. • You get a clear image ; and it’s focused. • Corrective Lenses: These help the eye’s own lenses focus the image correctly. • Glasses and Contact Lenses (such a great invention!)

32. Retina • All other structures in the eye lead straight to the retina (think of it like a bunch of roads leading to one place). • Important processing information center in the back of the eyeball. • Made up of three layers of cells • Receptor Cells • Bipolar Cells • Ganglion Cells

33. Receptor Cells • Deepest layer • Can change light energy into nerve impulses. • The brain can interpret it! • Without this do you think that the brain would be isolated from information in the outside world? • As Ducky from Land Before Time would say “Yep yepyep..yep yep!” Two different kinds: Rods and Cones Visual receptor cells located in the retina. These two are different in appearance and function.

34. Rods vs. Cones Rods Cones Sharp images and color Less of them Needs more light. Many of your cones are clustered in the fovea where your vision is best! • Black and White • Lower Absolute threshold • Respond to less light than cones do. • You see the world in shades of gray when in dim light, because only the rods respond.

35. Rods vs. Cones Comparison….Again?

36. Fovea • Central focal point of the retina. • Vision is best here!

37. BiPolar and Ganglion Cells • Bipolar cells: • Middle Layer • Gathers information from Rods and Cones • Sends it to the Ganglion Cells • Ganglion Cells: • Top Layer • Receives info from the bipolar cells. • Transmits the info through the axons. • These two together form the OPTIC NERVE!

39. Optic Nerve • Nerve that carries visual information from the eye to the occipital lobe of the brain.

40. Blind Spot • Point at which the optic nerve travels through the retina to exit the eye. • Blind spot is because of the lack of receptor rods and cones.

41. What are the two theories of color vision? Which one offers the best explanation of how we see colors? Color vision

42. #1: Trichromatic Theory (three color) • Cones are “tuned” to be sensitive to Red, Green, and blue light. • Every color that we see is just a combination of these three. • The work of Helmholtz and Young. • T.V. color

43. Subtractive Color Mixing: • Each NEW color subtracts or soaks up another wavelength. • Red, Blue and Yellow combine to make black paint. • Addictive Color Mixing: • Each NEW color ADDS another wavelength. • Red, Green, and Blue combine to make WHITE light.

44. Color Deficient Vision • People who lack one of the three types of cones. • Usually red or green receptors are missing • Color blindness • My friend Josh: Can’t see blue…. I always forget  • Inherited and found more in males. • Sometimes a person does not know that the problem exists

45. #2 Opponent- Process Theory of Color • EwaldHering • Color is processed by two opponent pair of colors. • Red and Green • Yellow and Blue • Black and white • Light that stimulates one of the colors inhibits the other. • Explains the after image effect

46. The Situation Says… check this out

47. Stare at the white dot without blinking…..

49. A little weird huh?!?

50. What is sound? Hearing: The nature of Sound