Sensation and perceptionSensationPerceptionKeep in mind!Absolute threshold (fig 4.2)Just Noticeable DifferenceSignal Detection TheorySubliminal perceptionSensory adaptationLightsaturationThe light spectrumEYE spyNearsightedFarsightedretinaPerceiving forms, patterns, and objectsGestalt PrinciplesDepth perceptionDepth Perception cont.Visual illusionsAuditory System: hearingEarTasteSmelltouchSensation and perceptionLecture 9/24/12, 9/26/12SensationThe stimulation of the sense organsPerceptionThe selection, organization, and interpretation of sensory inputKeep in mind!We experience sensory and perception at the same time, however they are two separate processesAbsolute threshold (fig 4.2)Minimum amount of stimulus that we need in order to detect that stimulusSignal detection theory: in an effort to detect the signal, we take into account other factors like motivation and perceiving other stimuliJust Noticeable DifferenceCheck definitionSignal Detection TheoryFig 4.3Subliminal perceptionThe registration of sensory input without conscious awarenessSensory adaptationGradual decline in sensitivity to prolonged stimulationBody adapts to a pool of cold waterLightForm of electromagnetic radiation that travels as a wave moving at the speed of light…Amplitude and Wavelength distinguish the wave perception and colorAmplitude: height, brightnessWavelength: the distant between peaks, colorHumans usually see a mixture of wavelengthssaturationThe relative amount of whiteness in a colorAs whiteness declines, saturation increasesThe light spectrumWhen light passes through a prism, the wavelengths are separated (component wavelength) into visible light spectrum from purple to redRanges from 400 to 1000 nanometersHumans can see a small fraction of the entire light spectrumUV and infrared light are seen by animalsEYE spyProvides a house for and channels light towards the retinaRetina: neural tissue that absorbs, processes, receives light and sends to brainChannels light towards the retinaCornea: transparent window where the light enters the eyeLens: behind the cornea; focuses the light rays on the retinaIris: colored ring on muscle around the pupil which constricts or dilates according to situation or amount of lightNearsighted You can see close objects clearlyWhy?Focus of light from the distant objects fall short of the retina (in front)Cornea or lens can bend the light too muchEyeball is egg-shaped and too longFarsightedYou can see distant objectsWhy?Close objects fall behind the retinaOr eyeball is too shortretinaAbsorbs lightProcesses imagesSends visual information to the brainBlindspot is where there is a hole in the occipital nerve crossing (aka optic disk)Contains receptors rods-night vision, sensitive to dim light cones- day light vision, color vision)Perceiving forms, patterns, and objectsReversable figure- same visual input can result in radically different perceptionsTop-down processing- progress from the whole picture to the elements, MOSTLY AT WORKBottom-up processing theory- progression from specific elements to the whole pictureFeature analysis- synonym of bottom up theory, very rarely backed up in realityGestalt PrinciplesProximity: things that are near one another seem to belong togetherClosure: viewer supplies missing elements of an imageSimilarity: group stimuli of similar likeness togetherSimplicity: Continuity: image creates a directional stimulusDepth perceptionInvolves interpretation of visual cues that indicate how near or far something isMonocular cues: utilize one eye at a time to detect: depth linear perspective (parallel lines closer to each other are farther away) texture gradient (texture becomes less distinct on further objects) interposition (shapes of near objects overlap and mask more distant objects)relative size (larger objects seem closer to viewer) height in plane (idea that near objects are lower in the visual field than are distant ones)light and shadow (patterns of light and dark suggest 3-D impressions of shape).Depth Perception cont.Binocular cues:Visual illusionsMuller-lyer <---------> versus >---------<Auditory System: hearingSound waves, vibrations that travel into the earSoundwaves: air pressure, sound quality (timbre)Wavelengths: pitchAmplitude: loudness (decibels)EarHuman ear is divided into three sections: external ear, middle ear, and inner earExternal ear collects the soundMiddle ear has hammer, anvil, and stirrup, make up ossicles-- a mechanical chain that stimulates the transition of soundCochlea (fluid filled, has hair cells) has auditory receptors used to HEAR various frequenciesTastegustatory systemReceptors in the taste buds absorb chemicals and trigger neural impulses, which are then sent through the thalamus into the cortexThere is no “bitter/sweet/savory/salty” area of the tongue. Taste buds can pick up a taste in any part of the mouthSmell Olfactory cilia are the receptor cells located in the upper portion of the nasal passageHumans can distinguish between 10,000 different odors because there are 350 different types of olfactory receptorsOlfactory cells pick up stimuli and route it directly to olfactory cortex in temporal lobeOnly sensory system where the stimuli DOES NOT travel through thalamustouchSix different types of sensory receptors in the skinFree nerve endings- one of the six specific for detecting cold and warmthPain has become a popular phenotype to study because it is very subjectiveChronic pain effects psychological perspective and life