PSYC 1101 Introduction to Psychology

1. PSYC 1101Introduction to Psychology L Clack

2. Chapter 4 Sensation and Perception

3. Sensation The stimulation of sense organs

4. Perception The selection, organization, and interpretation of sensory input

5. Psychophysics The study of how physical stimuli are translated into psychological experience Contributor: Gustav Fechner

6. Stimulus Any detectable input from the environment What is the limit?

7. Absolute Threshold For a specific type of sensory input, the minimum stimulus intensity that an organism can detect

8. A Just Noticeable Difference The smallest difference in stimulus intensity that a specific sense can detect

9. Weber�s Law Ernst Weber States that the size of a just noticeable difference is a constant proportion of the size of the initial stimulus

10. Signal-Detection Theory Proposes that the detection of stimuli involves decision processes as well as sensory processes, which are both influenced by a variety of factors besides stimulus intensity

11. Detecting Signals Hits Misses False alarms Correct rejections

12. Subliminal Perception The registration of sensory input without conscious awareness

13. Sensory Adaptation A gradual decline in sensitivity to prolonged stimulation

14. Sense of Sight: The Visual System Light: a form of electromagnetic radiation that travels as a wave, moving at the speed of light

15. Variation of Light Waves Amplitude Wavelength Purity Saturation

16. The Eye 2 Purposes: 1) Channel light to the retina 2) Houses the retina Retina: the neural tissue lining inside back surface of the eye that absorbs light, processes images, sends visual info to the brain

17. Structures of the Eye Cornea: transparent window at the front of the eye where light enters Lens: the transparent structure that focuses the light rays falling on the retina Accommodation: when curvature of the lens adjusts to alter visual focus

18. Visual Deficiencies Nearsightedness: close objects are seen clearly but distant objects appear blurry Farsightedness: distant objects are seen clearly but close objects appear blurry

19. Structures of the Eye Iris: colored ring of muscle that regulates the amount of light entering the eye by controlling the size of the pupil Pupil: the opening in the center of the iris that permits light to pass into the rear chamber of the eye

20. The Brain�s Messenger in the Eye Retina Optic Disk: a hole in the retina where the optic nerve fibers exit the eye

21. Visual Receptors Cones: specialized receptors that play a key role in daylight vision and color vision Rods: specialized visual receptors that play a key role in night vision and peripheral vision

22. Visual Acuity The sharpness, precise detail of vision Fovea: tiny spot in the center of the retina that contains only cones

23. Adapting to Light Dark Adaptation: the process in which the eyes become more sensitive to light in low illumination Light Adaptation: the process whereby the eyes become less sensitive to light in high illumination

24. Information Processing in the Retina Optic Nerve: collection of axons from ganglion cells that connect the eye with the brain Receptive Field: the retinal area that, when stimulated, affects the firing of that cell

25. Interactive Effects of the Receptive Field Lateral Antagonism: occurs when neural activity in a cell opposes activity in surrounding cells

26. Visual Pathways to the Brain Optic Chiasm: point at which the optic nerves from the inside half of each eye cross over and then project to the opposite half of the brain Diverges into 2 pathways

27. 2 Pathways 1) Most axons from the retinas synapse in the lateral geniculate nucleus (LGN) then signals are distributed to the occipital lobe 2) The others leave the optic chiasm and branch off in the midbrain at the superior colliculus and then travel through the thalamus to the occipital lobe

28. The Main Visual Pathway Subdivided into 2 specialized pathways: 1) Magnocellular Channels- info on brightness 2) Parvocellular Channels- perception of color Both engage in Parallel Processing: involves simultaneously extracting different kinds of information from the same input

29. The Second Pathway Principal Function is the perception of motion and the coordination of visual input with other sensory input

30. Specialized Cells in the Primary Visual Cortex Simple cells: respond best to a line of the correct width, oriented at the correct angle, and located in the correct position in its receptive field Complex Cells: respond to any position in their receptive fields

31. Feature Detectors Neurons that respond selectively to very specific features of more complex stimuli

32. 2 Streams of Visual Input Ventral Stream: processes details of what objects are out there Dorsal Stream: processes where the objects are

33. The Stimulus for Color Color- is a psychological interpretation, not a physical property

34. Perception of Color 3 Dimensions of Color: Wavelength: hue Amplitude: brightness Purity: Saturation

35. 2 Kinds of Color Mixture Subtractive Color Mixing: works by removing some wavelengths of light, leaving less light than was originally there Additive Color Mixing: works by superimposing lights, putting more light in the mixture than exists by itself

36. Trichromatic Theory of Color Vision Helmholtz Holds that the human eye has three types of receptors with differing sensitivities to different light wavelengths

37. Color Blindness Encompasses a variety of deficiencies in the ability to distinguish among colors Most are Dichromats: only have two types of color receptors

38. Opponent Process Theory of Color Vision Says that color perception depends on receptors that make antagonistic responses to three pairs of colors

39. Complementary Colors Pairs of colors that produce gray tones when mixed together

40. Afterimage A visual image that persists after a stimulus is removed Color of the afterimage is the complement of the color of the original image

41. Theories of Color Vision Which is right? Trichromatic Theory vs. Opponent Process Theory

42. Perceiving Forms, Patterns, and Objects Reversible Figure: drawing compatible with 2 interpretations that shift back and forth Perceptual Set: readiness to perceive a stimulus in a particular way Inattentional Blindness: the failure to see visible objects b/c of shift in focus of attention

43. Assembling Forms Feature Analysis: the process of detecting specific elements in visual input and assembling them into a more complex form

44. Processing in Feature Analysis Bottom-up Processing: progression from individual elements to the whole Top-Down Processing: progression from the whole to the elements Subjective Contours: perception of contours where none exist

45. Looking at the Whole Picture Gestalt Psychology: says the whole can be greater than the sum of its parts Phi Phenomenon: illusion of movement created by presenting visual stimuli in rapid succession

46. Principles of Gestalt Psychology Figure and Ground Proximity Closure Similarity Simplicity Continuity

47. Formulating Perceptual Hypotheses Perceptual Hypothesis: an inference about which distal stimuli is responsible for the proximal stimulus Distal Stimuli: lie in the distance Proximal Stimuli: impinge directly on sensory receptors

48. Perceiving Depth or Distance Depth Perception: interpretation of visual cues that indicate how near or far away objects are

49. 2 Types of Cues for Distance Binocular Cues: clues about distance based on differing views of the 2 eyes Monocular Cues: clues about distance based on the image in either eye alone

50. Binocular Cues Retinal Disparity: the fact that objects within 25 feet project images to slightly different locations on the right and left retinas, so each eye sees a slightly different view of the object

51. Binocular Cues Convergence: involves sensing the eyes converging toward each other as they focus on closer objects

52. Monocular Cues Motion Parallax: involves images of objects at different distances moving across the retina at different rates Pictorial Depth Cues: clues about distance that can be given in a flat picture

53. 6 Pictorial Depth Cues 1) Linear Perspective 2) Texture Gradients 3) Interposition 4) Relative Size 5) Height in Plane 6) Light and Shadow

54. Perceptual Constancies in Vision Perceptual Constancy: a tendency to experience a stable perception in the face of continually changing sensory input

55. Misleading Cues Visual Illusion: an apparently inexplicable discrepancy between the appearance of a visual stimulus and its physical reality Impossible Figures: objects that can be represented in 2-Dimensional Pictures but cannot exist in 3-Dimensional space

56. Sense of Hearing Sound Waves: Vibrations of Molecules Characteristics: Amplitude: loudness Wavelength: pitch Purity: timbre

57. Hearing Capabilities Frequency: wavelengths of sound Measured in Hertz (Hz) Amplitude: measured in decibels (dB)

58. Sensory Processing in the Ear 3 Sections of the Ear: External Ear- vibration of air molecules Middle Ear- vibration of moveable bones Inner Ear- waves in a fluid

59. External Ear Consists of the pinna: sound-collecting cone Sound waves are collected by the pinna and funneled to the eardrum which vibrates in response

60. Middle Ear Consist of 3 bones (ossicles): Hammer Anvil Stirrup The ossicles amplify tiny changes in air pressure

61. Inner Ear Consists of: Cochlea: fluid-filled, coiled tunnel that contains the receptors for hearing Sound enters the cochlea through the oval window, which is vibrated by the ossicles

62. Inner Ear Contains the ear�s neural tissue which sits on the basilar membrane Basilar membrane: runs the length of the spiraled cochlea, holds the auditory receptors (hair cells), and divides the cochlea into upper and lower chambers

63. Theories of Hearing Place Theory: holds that perception of pitch corresponds to the vibration of different portions, or places, along the basilar membrane

64. Theories of Hearing Frequency Theory: holds that perception of pitch corresponds to the rate, or frequency, at which the entire basilar membrane vibrates

65. Theories of Hearing Which is right? Volley Principle: holds that groups of auditory nerve fibers fire neural impulses in rapid succession, creating volleys of impulses

66. Perception of Sound Auditory Localization: Locating the source of a sound in space 2 cues that contribute: Intensity: loudness Timing of sounds arriving at each ear

67. Chemical Senses: Taste and Smell Gustatory System: sensory system for taste Olfactory System: sensory system for smell

68. Gustatory Receptors Taste Buds Primary Tastes: Sweet Sour Bitter Salty

69. Sensitivity to Tastes: Perception of Flavor Nontasters Medium Tasters Supertasters

70. Smell: The Olfactory System Receptors: Olfactory cilia: hair-like structures in the upper portion of the nasal passages Perception of odors

71. Sense of Touch Tactile Pathway- responds to specific patches of skin Projects through the thalamus to the somatosensory cortex

72. Pain Perception 2 Pathways: Fast Pathway: registers localized pain and relays it to the cortex in a fraction of a second Slow Pathway: lags a second or two behind the fast system, conveys less localized,longer-lasting, aching or burning pain that comes after initial injury

73. Gate Control Theory of Pain Says that incoming pain sensations must pass through a �gate� in the spinal cord that can be closed, thus blocking ascending pain signals

74. Our Other Senses Kinesthetic System: monitors the positions of the various parts of the body Vestibular System: responds to gravity and keeps you informed of your body�s location in space