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  1. Agenda • Concept Map Return/Discussion • Bingo • Quiz after lunch • Go over Unit 4

  2. Sensation and Perception • Sensation: the detection of physical stimulus in the environment. • light- vision • Sound- hearing • Chemicals- smell and taste • Pressure, temperature, pain- sense of touch • Orientation, balance- kinesthetic senses • Perception: the interpretation of a sensation.

  3. Process of Sensation • 1) an accessory structure (lens of the eye, outer ear)will collect and modify information from the environment • 2) sensory receptors- when a stimuli exceeds the threshold an action potential is fired • 3) When sensory receptors detect energy transduction begins • 4) Transduction occurs when physical energy is converted to neural code, making it possible for the brain to interpret the energy. • 5) Transmitted to the CNS via sensory nerves • 6) Sent to the Thalamus (except smell) and is analyzed and relayed to the appropriate area of the cerebral cortex • 7) Sensory cortex processes the information

  4. Taste Transduction Demo • Unwrap Hershey kiss • Dry your tongue (awkward I know) • Place the kiss on the back of your tongue (look up) • What do you notice? How is this effecting your senses? • Why did this occur?

  5. Perceptual Organization • Bottom-up processing • Organization of information without prior knowledge • Driven by senses not our expectations • Top-down processing • We construct perceptions based on sensations and experience/expectations • You know more about the information given because of previous experiences, not simply what you sense

  6. Top Down Processing • For example, understanding difficult handwriting is easier when reading complete sentences than when reading single and isolated words. This is because the meaning of the surrounding words provide a context to aid understanding.

  7. Example of Top-Down Processing • Aoccdrnig to rscheearch at Cmabrigde Uinervtisy, it deosn't mttaer in waht oredr the ltteers in a wrod are, the olny iprmoetnt tihng is taht the frist and lsat ltteer be at the rghit pclae. The rset can be a total mses and you can sitll raed it wouthit a porbelm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe.

  8. Absolute threshold • The smallest amount of stimulus energy necessary for sensation to take place 50% of the time. • Subliminal stimuli: not strong enough to exceed the absolute threshold and thus are not perceived • Used by marketers!

  9. Absolute Thresholds • Taste: 1 gram (.0356 ounce) of table salt in 500 liters (529 quarts) of water • Smell: 1 drop of perfume diffused throughout a three-room apartment • Touch: the wing of a bee falling on your cheek from a height of 1cm (.39 inch) • Hearing: the tick of a watch from 6 meters (20 feet) in very quiet conditions • Vision: a candle flame seen from 50km (30 miles) on a clear, dark night

  10. Signal Detection Theory • Mathematical formula that determines when people will report detection of a stimulus that is right around the threshold level. • Whether a person detects the stimuli depends on the individuals sensitivity and response criterion. • There is no absolute threshold because each individuals level of motivation, attentiveness, fatigue, experience/expectations, differs.

  11. Difference Threshold • Just noticeable difference (jnd) is the smallest detectable difference between two stimuli • Difference between two musical notes • If you can’t tell the difference, there isn’t enough variation

  12. Weber’s Law • Suggests that a difference threshold depends on the strength of the new stimulus in relation to the original stimulus. • Example: if a person who weighs 200 pounds and a person who weighs 400 pounds each lose 20 pounds, you will notice the change in the person who weighed 200 pounds more.

  13. Weber’s Law Two stimuli must differ by a constant minimum percentage (rather than a constant amount), to be perceived as different. Weber fraction: k = dI/I.

  14. Psych Immersions? (Connections to something else in psychology, another text, or your world.) • Critical questions from the reading?

  15. Agenda • Psych Immersions • Review Bio test • Term warm-up • Marker demo • Eye and Ear Diagram

  16. Term Review • Sensory Adaption: Decreased responsiveness to stimuli due to constant stimulation. • Do you feel your watch all day? Clothing? • Transduction: the process by which we encode stimulus energy into neural messages. • Weber’s Law: Suggests that a difference threshold depends on the strength of the new stimulus in relation to the original stimulus. • Example: if a person who weighs 200 pounds and a person who weighs 400 pounds each lose 20 pounds, you will notice the change in the person who weighed 200 pounds more. • Processed in the Thalamus: except smell, processed in the olfactory bulb to the temporal lobe and limbic where recognition of the smell and emotional significance is associated with smell.

  17. Vision Demo • 1 volunteer • Explain the demonstration and what it teaches us about vision.

  18. Parts of the Eye •`am/index.asp • Fill in the diagram and function of each part

  19. Vision: Parts of the Eye • Cornea: transparent covering on the front of the eye • Pupil:adjustable opening in the center of the eye • Iris: a ring of muscle the forms the colored portion of the eye around the pupil and controls the size of the pupil opening • Lens:transparent structure behind pupil that changes shape to focus images on the retina Accommodation: change in shape of lens focus near objects • Retina • Layers of neurons on inner surface of eye • light sensitive • contains rods and cones • beginning of visual information processing • Fovea: central point of focus on the back of the eye

  20. Receptors in the Human Eye Cones Rods Number 6 million 120 million Periphery Location in retina Center Low High Sensitivity in dim light Color sensitive? Yes No Retina’s Reaction to Light Receptors • Rods • Located in periphery of retina • detect black, white and gray • twilight or low light Cones • near center of retina (fovea) • fine detail and color vision • daylight or well-lit conditions

  21. Pathways from the Eyes to the Visual Cortex

  22. Vision Continued • Bi-polar cells: neurons that transmits information from rods and cones to ganglion cells • Ganglion cells: specialized cells that process information before it is sent to the brain • Optic Nerve: made up of axon’s of ganglion cells, carries visual information to the brain • Contains a blind spot where the optic nerve leaves the retina • Accounted for by other eye • Blind spot demos: • Optic Chiasm: point where the nerves from each eye meet in the brain and then cross to the opposite side of the brain • Thalamus: sends information to the primary visual cortex. • Feature receptors: neurons in the visual cortex that respond to different aspects of an image (size, shape, angle)

  23. How Can I Possibly Remember All of That in Order? Cool = Cornea People = Pupil Like = Lens Frosties = Fovea (Rods & Cones) Because = Bipolar Cells Gangsters = Ganglion Cells Never = Optic Nerve Cheat = Optic Chiasm The = Thalamus Officers = Occipital Lobe Don’t like this one? Create Your Own!!!

  24. Blue Man Group • •

  25. Color Vision • How we perceive color depends on three characteristics of light waves: hue, saturation and purity.

  26. Hue • Hue is the color of light as determined by the wavelength of the light energy • Includes: red, orange, yellow, green, blue, indigo and violet (ROY G. BIV) • The eye can detect 7 million separate hues

  27. Amplitude/Brightness • The brightness of light as determined by height of the wave • The taller the wave, the brighter the color

  28. Theories of Color Vision • Trichromatic theory (Young-helmoltz): there are three types of cones each sensitive to a specific wavelength • Red: long wavelengths • Green: medium wavelengths • Blue: short wavelengths • Explains color blindness

  29. Color Deficient Vision • People who lack one of the three types of cones • Usually the red or green receptors are missing • Usually referred to as color blindness • 1 in 50 people are color blind. Inherited and found more in males (sex-linked trait). • Trichromats – people with normal color vision • Monochromats – no color vision • Dichromats – blind to red/green or yellow/blue

  30. Normal Vision

  31. Red/Green Colorblindness

  32. Theories of Color Vision • Opponent Process Theory: color sensitive components of the eye are grouped into three pairs: red-green, blue-yellow, black-white • On-off switch • Light that stimulated one half of the pair inhibits/hinders the other half • EwaldHering developed this

  33. Afterimages

  34. Look at the White Dot-without blinking

  35. Put the bird in the cage! Stare at the bird, then look at the cage!

  36. After Images • In addition to demonstrating opponent-process theory, what else does this show? • Sensory Adaption

  37. Which is right? • Trichromatic or opponent process? • Our current view of color vision is that it is based on both the trichromatic and opponent process theories • Color Vision is a two stage process • The Retina’s red, green, & blue cones respond in varying degrees to different colors (trichromatic theory) • Their signals are then processed by ganglion cells that encode color in terms of opposing pairs while they are sending the info to the thalamus and visual cortex which also encode the info by opponent pairs (opponent-process theory)

  38. Audition • Ear Diagram/vocab • Pitch: highness or lowness of a sound, determined by frequency • Frequency: the number of complete waves that pass through a medium every second • Waves that are close together have high frequency and thus high pitch • Hertz: measurement of frequency • Timbre: purity of a sound wave

  39. Sound Illusions •

  40. Brain Games Video • Hearing Section Episode 2 (26 minutes on)

  41. Psych Immersions? (Connections to something else in psychology, another text, or your world.) • Critical questions from the reading?

  42. Agenda • Warm-up Questions • Taste • Smell • Touch • Synesthesia • Selective Attention

  43. Theories of Audtion • Frequency matching theory • “volley principle” • The vibrations of the basilar membrane are determined by the frequency of the vibrations • Only accounts for low frequencies • Place theory • Pitch depends on where the vibrations stimulate the basilar membrane • Explains high frequencies