Sensation and Perception Part. 1Bottom-up ProcessingA  /-  ATop-Down ProcessingInformation processing guided by higher-level mental processes as we construct perceptions, drawing on our experience and expectationsSensationDetect physical energy (stimulus) from the environmentThe type of physical energy depends on the type of senses we use to detect itConvert into neural signalsEx: vision – light waves are the stimulusStimulus of receptor sites  neural representation of the stimulusEx: light waves  visual representation of a flowerPerceptionTypically follows sensationSelect, organize and interpret sensationsTransductionProcess, whereby, physical energy is converted into neural impulse form*** Stimulus  sense organ  nerve impulses cortex for processingSensationJust noticeable difference:Smallest difference detectable 50% of the timeAbsolute threshold:Just how much of a stimulus does there have to be for a human to detect that it is thereLeast amount of energy for correct stimulus detection 50% of the timeDifferent threshold for different types of stimulusSubliminal PerceptionSubliminal stimuliStimuli just below the level of conscious awarenessHabituation and Sensory AdaptationHabituationBrain stops attending to constant, unchanging stimuli (cognitive)Sensory adaptationSensory receptors lessen response to constant stimuli over time (biological)Ex: pain after piercing, discomfort wearing new watch constantlyVisionThe stimulus input is light energyBrightnessThe amplitude of a waveGreat amplitude = bright colors, louder soundsSmall amplitude = duller colors, quieter soundsHue (color)Determined by the wavelength of the lightShort wavelength = high frequencyBluish colors, high-pitched soundsLong wavelength = low frequencyReddish colors, low-pitched soundsDifferent wavelengths of light result in different colorsThe EyeCorneaWhere light enters the eyeIrisBehind the corneaA muscle that expands or contracts to change the size of the pupilPupilIn the center of the irisChanges size in regard to the amount of light coming into the eyeLensBehind iris and pupilFocuses light waves on the retinaResponsible for changing ability to see things from afar or nearRetinaIn the back of the eyeContains the sensory receptorsWhere transduction occurs in the visual systemSends information to the back of the eye (to the optic nerve)Optic nerveAt the very back of the eyeWhere information is sentFoveaIn the back of the eyeThe central point of focus in the retinaContains particular structuresContains rods (black, white and gray) and cones (color vision)AccommodationEx: LensChanges shape to focus near or far objects on retinaVisual ProcessingOptic nerves connect to thalamusThalamus connects to visual cortex (occipital lobe)Trichromatic TheoryHelmholtzRetina has 3 types of color receptors (cones in the fovea), each sensitive to red, green and blueExperienced perceptions of different colorsColor BlindnessGenetic disorder“blindness” to red and greendefect to cones in the foveasupports the trichromatic theoryOpponent Process TheoryThere are 4 primary colors that we process and we combine them in pairsBlue-yellow, red-green, black-whitePerceptionSelect, organize and interpret sensationsShape ConsistencyPerceiving objects as unchanging even as illumination and retinal images changeIt is an assumption that even though the visual image is different when an object is moved, our perception is that the shape remains constant even though it looks different as it movedSize ConsistencyStable size perception amid changing size of the stimuliThe size of the object stays the same even though it may be closer or father away by perceptionColor ConstancyPerceiving familiar objects as having consistent color even when changing illumination filters the light reflected by the objectEven when lighting or surrounding color changes, we assume objects maintain a constant colorGestalt“the whole is greater than the sum of its parts”Reversible figure:EX: 3D drawn squareDepth PerceptionEnables judgment of distancePSY 0010 1st Edition Lecture 6 Exam 1I. Intro to PsychologySensation and Perception Part. 1II. SensationIII. PerceptionCurrent Lecture Sensation and Perception Part. 1 Bottom-up Processing- A  /-\  A Top-Down Processing- Information processing guided by higher-level mental processes as we construct perceptions, drawing on our experience and expectations Sensation- Detect physical energy (stimulus) from the environmento The type of physical energy depends on the type of senses we use to detect it- Convert into neural signalso Ex: vision – light waves are the stimulus- Stimulus of receptor sites  neural representation of the stimuluso Ex: light waves  visual representation of a flower Perception- Typically follows sensation- Select, organize and interpret sensations  TransductionThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Process, whereby, physical energy is converted into neural impulse form *** Stimulus  sense organ  nerve impulses cortex for processing Sensation- Just noticeable difference:o Smallest difference detectable 50% of the time- Absolute threshold:o Just how much of a stimulus does there have to be for a human to detect thatit is thereo Least amount of energy for correct stimulus detection 50% of the timeo Different threshold for different types of stimulus- Subliminal Perceptiono Subliminal stimuli Stimuli just below the level of conscious awareness  Habituation and Sensory Adaptation- Habituationo Brain stops attending to constant, unchanging stimuli (cognitive)- Sensory adaptationo Sensory receptors lessen response to constant stimuli over time (biological) Ex: pain after piercing, discomfort wearing new watch constantly Vision- The stimulus input is light energy - Brightnesso The amplitude of a wave Great amplitude = bright colors, louder sounds Small amplitude = duller colors, quieter sounds- Hue (color)o Determined by the wavelength of the light Short wavelength = high frequency Bluish colors, high-pitched sounds Long wavelength = low frequency Reddish colors, low-pitched sounds Different wavelengths of light result in different colors The Eye- Corneao Where light enters the eye- Iriso Behind the corneao A muscle that expands or contracts to change