05-感觉

Myers’’PSYCHOLOGY MyersChapter 5SensationSensation§Sensation§a process by which our sensoryreceptors and nervous system receiveand represent stimulus energy§Perception§a process of organizing and interpreting sensory information, enabling us torecognize meaningful objects andeventsSensation§Oursensoryandperceptualprocessesworktogether tohelp ussort outcomplextprocessesSensation§Bottom-Up Processing§analysis that begins with the sense receptorsand works up to the brain’s integration ofsensory information§Top-Down Processing§information processing guided by higher-levelmental processes§as when we construct perceptions drawing onour experience and expectationsSensation- BasicPrinciples§Psychophysics§study of the relationship betweenphysical characteristics of stimuli andour psychological experience of them §Light- brightness§Sound- volume§Pressure- weight§Taste- sweetnessSensation- Thresholds§Absolute Threshold§minimum stimulation needed to detect aparticular stimulus 50% of the time§Difference Threshold§minimum difference between two stimulirequired for detection 50% of the time§just noticeable difference (JND)Sensation- Thresholds§Signal Detection Theory§predicts how and when we detect the presence of a faint stimulus (signal) amid backgroundstimulation (noise)§assumes that there is no single absolutethreshold§detection depends partly on person’s§experience§expectations§motivation§level of fatigueSensation- ThresholdsSensation- Thresholds§Weber’s Law- to perceive as different, two stimuli must differ by a constant minimum percentage§light intensity- 8%§weight- 2%§tone frequency- 0.3%§Sensory adaptation- diminished sensitivity as a consequence of constant stimulationVision- StabilizedImages on the RetinaVision§Transduction§conversion of one form of energy toanother§in sensation, transforming of stimulusenergies into neural impulses§Wavelength§the distance from the peak of onewave to the peak of the nextVision§Hue§dimension of color determined bywavelength of light§Intensity§amount of energy in a wavedetermined by amplitude§brightness§loudnessThe spectrum of electromagnetic energyVision- Physical Properties of Waves Short wavelength=high frequency(bluish colors, high-pitched sounds)Long wavelength=low frequency(reddish colors, low-pitched sounds)Great amplitude (bright colors, loud sounds)Small amplitude (dull colors, soft sounds)Vision§Pupil- adjustable opening in thecenter of the eye§Iris- a ring of muscle that forms thecolored portion of the eye around the pupil and controls the size of thepupil opening§Lens- transparent structure behindpupil that changes shape to focusimages on the retinaVisionVision§Accommodation- the process by whichthe eye’s lens changes shape to helpfocus near or far objects on the retina§Retina- the light-sensitive inner serface of the eye, containing receptor rods andcones plus layers of neurons that beginthe processing of visual informationVision§Acuity- the sharpness of vision§Nearsightedness- condition in which nearby objects are seen more clearly than distant objects because distant objects in front of retina§Farsightedness- condition in which faraway objects are seen more clearly than near objects because the image of near objects is focused behind retinaVision§Normal Nearsighted Farsighted Vision Vision VisionRetina’s Reaction to Light- Receptors§Rods§peripheral retina§detect black, white and gray§twilight or low light§Cones§near center of retina§fine detail and color vision§daylight or well-lit conditionsRetina’s Reactionto Light§Optic nerve- nerve that carries neural impulses from the eye to the brain§Blind Spot- point at which the optic nerve leaves the eye, creating a “blind spot” because there are no receptor cells located there§Fovea- central point in the retina, around which the eye’s cones clusterVision- ReceptorsPathways from the Eyes to the Visual CortexProcessingHow the BrainPerceivesIllusory ContoursVisual InformationProcessing§Parallel Processing§simultaneous processing of severalaspects of a problem simultaneouslyVisual InformationProcessing§Trichromatic (three color) Theory §Young and Helmholtz§three different retinal color receptors §red§green§blueColor-Deficient Vision§People who sufferred-greenblindness havetrouble perceivingthe number withinthe designVisual InformationProcessingOpponent-Process Theory- opposing retinal processes enable color vision“ON”“OFF”red greengreen redblue yellowyellow blueblack whitewhite blackOpponent Process- Afterimage EffectVisual InformationProcessing§Color Constancy§Perceiving familiar objects as havingconsistent color, even if changingillumination alters the wavelengthsreflected by the objectAudition§Audition§the sense of hearing§Frequency§the number of complete wavelengthsthat pass a point in a given time §Pitch§a tone’s highness or lowness§depends on frequencyThe Intensity of SomeCommon SoundsAudition- The Ear§Middle Ear§chamber between eardrum and cochleacontaining three tiny bones (hammer, anvil,stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window§Inner Ear§innermost part of the ear, contining thecochlea, semicurcular canals, and vestibularsacs§Cochlea§coiled, bony, fluid-filled tube in the inner earthrough whichAudition§Place Theory§the theory that links the pitch we hear withthe place where the cochlea’s membrane isstimulated§Frequency Theory§the theory that the rate of nerve impulsestraveling up the auditory nerve matches thefrequency of a tone, thus enabling us tosense its pitchHow We LocateSoundsAudition§Conduction Hearing Loss§hearing loss caused by damage to themechanical system that conducts soundwaves to the cochlea§Nerve Hearing Loss§hearing loss caused by damage to thecochlea’s receptor cells or to the auditorynerveAudition§Older people tend to hear lowTouch§Skin Sensations§pressure§only skinsensation withidentifiablereceptors§warmth§cold§painPain§Gate-Control Theory§theory that the spinal cord contains aneurological “gate” that blocks painsignals or allows them to pass on to the brain§“gate” opened by the activity of painsignals traveling up small nerve fibers§“gate” closed by activity in larger fibersor by information coming from the brainTaste§Taste Sensations§sweet§sour§salty§bitter§Sensory Interaction§the principle that one sense may influenceanother§as when the smell of food influences its tasteSmellReceptor cells in olfactory membraneNasal passageOlfactory bulbOlfactory nerveof SmellBody Position andMovement§Kinesthesis§the system for sensing the position and movement of individual body parts§Vestibular Sense§the sense of body movement andposition§including the sense of balance。