Sensation and Perception Essay Example for Free

Sensation and Perception EssayMemory knowing the pastThinking knowing the futureCognition = the influence of perception, memory, and thinking Aug 29th, 2012Basic principles of perception1.Stimulation-Many kinds of energy implode on the bodyElectromagnetic energy ( sparkling)Mechanical energy-Pressure waves in airPressure on skinBody workThermal energy (heat)Chemical energy (molecules in air, food)-Energy miscellanys detected by receptors2.Informationa.Our sensory systems evolved to pick up information (not just stimulation)b.In general, information is provided by changec.Change can occur over time, or over space3.Transduction-The process of converting stimulus energy into nerve impulses -Generally, stimulus energy causes a change in a receptor cells electrical potential (voltage) -If change is enough, it will trigger nerve impulses4.Transmission-For perception to occur, sensory organs (containing receptors) must enthral nerve impulses to the originator -Perception occurs in t he brain, not in the sensory organs5.Mediation-Our perception of the world is mediated by various processes between transduction and our conscious sentience -These processes alter the neural information-What we consciously grasp may not be an accurate reflection of the original stimulation6.Interpretation-Sensory information is equivocal (there argon ALWAYS multiple possible interpretations)7.Construction-Sensory information is sketchy the brain fills in missing information8.Modularity-Your brain consists of independent modules. These modules may construct different, possibly conflicting, interpretations of the world. -You externalise one interpretation of an ambiguous**Missed Classlocked bulge of room** kinsperson 5th, 2012Signal detection Theory(Slides and appendix in book)Sept 7th, 2012The marrowLight-Light is electromagnetic radiation varying inWavelengthIntensityRadiance intensity of light as it leaves the light source Illuminance intensity of light as it is absorbed by object (white objects higher in light than black objects) Luminance amount of light that is reflected by object100 illuminance omits 40 luminants albedo = 40/100= .4Retinal Illuminance light that reaches your eyeBrightness perception of radiance, illuminance, or luminance Lightness perception of the reflectance (albedo)Brightness is a perception of the light lightness is a perception of the object surface Myopia = nearsighted = focal length is shorter than distanceto retina pre romance = farsighted = focal length is longer than distance to retina Presbyopia = aged vision, lens cant adjust because of age (reading glasses for old people)Sept 10th, 2012The RetinaFovea is the part of eye where visual acuity is highestVision involves rods and cones in the back of the retinaPhotopic = conesScotopic = rodsPurkinje Shift as illumination decreases, red objects lose brightness more(prenominal) quickly than green, blue red goes to black whereas green and blue pass through shades of g ray **2 Missed Classes Canada**Sept 19th, 2012Gestalt Psychology-Brief biography of behaviorism, psychoanalysis-The laws of perceptual groupingOctober 1st, 2012Distance PerceptionWhy is depth perception important?-Effective action (e.g. grasping) requires correct perception of distance -Correct perception of size and shape requires correct perception of distance Size and shape consistencyJust as an infinite number of object sizes and shapes can cast the train same image on the retina, a single object can cast an infinite number of sizes and shapes of retinene imageSize Consistency = we (usually) perceive the size of an object as constant, despite changes in the size of the retinal imageShape Consistency = we (usually) perceiveThe farther away something is from your eye, the less the retinal disparity will beStereopsis-Retinal Disparity = the mismatch between the left and right eyes retinalimages -Stereopsis = the ability to use retinal disparity as a depth cue Motion parallaxIn terposition = idea that an object in front of another object will block that object out Aerial Perspective-Refers to effects of the air on distance perceptionClarity = as light passes through more air, light is scattered and so the image gets blurrier oBlueness = as light passes through more air, long wavelengths argon filtered out and so the image gets bluerChapter 2Transduction and receptive fieldsSignal Detection Theory-Always noise (random activity)Eye MovementsEXAM 2 MATERIAL OCT 12TH 2012Perceptual Ambiguity (Lecture 9)States of form perception1.Feature extraction2.Perceptual grouping3.Figure-ground differentiation4.Figural resolving power5.Pattern recognitionAmbiguity multiple possible interpretations can occur at any level (2-5) Figure-ground differentiation-Some perceptual groups ar treated as prefigure, other groups are treated as ground Yates Thesis-Yates. J (1985). The content of awareness is a model of the world. Psychological Review, 92, 249-284 -Visual images are inherently ambiguous (allow multiple interpretations) -Coherent action requires selection of one interpretation-We tend to represent in awareness the simplest interpretation of the most sensory data Figural firmness of purpose-After figure has been differentiated from ground, it may still benecessary to resolve the organise of the figure -Figural resolution influenced byBottom up vs. top-downOctober 15th, 2012Lecture 10 Pattern sciencePattern Recognition knowing what figures in the visual field ARE. Requires interaction of sensation/perception with memory (pre-existing knowledge) pathfinder Matching-Match of only pattern to a stored pattern-Problemsonfinite variation of problemsNo access to feature differencesCant recognizeFeature Analysis-Patterns are recognized by detection of particular critical features -Accounts for recognition of partially obscured patterns-Predicts that objects with more features in common are more confusableProblemnot ALWAYS trueSome confusions are pred icted better by the whole shapeNew configural properties (or emergent features) arise from the combination of features Impossible to define difficult objects entirely by simple featuresTemplate Matching vs. Feature Analysis-Template matching emphasizes the whole, fails to account for importance of parts -Feature analysis emphasizes the parts, fails to account for importance of the whole-Possible solutionsMaybe more than one brain mechanism for pattern recognition oA hybrid approach that encompasses both the whole AND the partsStructural Theories of Pattern RecognitionObjects are recognized by their structural description, how their parts are organized into the whole DO NOT CONFUSE WITH STRUCTURALISM (Structuralism assumed that the structure can be decomposed into elemental partsYates Thesis-We tend to represent in awareness the simplest explanation for the most sensory data Oct 17th, 2012Three kinds of brain damage1.Agnosia = loss of knowledgea.Prosopagnosia loss of ability to rec ognize facesb.Object agnosia loss of ability to recognize objectsc.Word agnosia (alexia) loss of ability to recognize written words2.Object agnosia neer occurs without either word agnosia or prosopagnosia Oct 24th, 2012LightLight is electromagnetic radiation varying inWavelengthIntensityAmplitude, if considered as a waveNumber of photons, if considered as particulateColor is all in your headHue does not exist in the physical world wavelength is a simple quantitative continuum, worry intensity, or frequency of sound, or length, or weight You brain CONSTRUCTS categories of perception, resulting in qualitative differences in the perceptionDimensions of Color-HUE the perception of wavelength, or (in a mixture) governing wavelength-SATURATION the perception of purity (proportion of the dominant wavelength in a mixture)-BRIGHTNESS perceived intensitySubtractive Color Mixture-A paint pigment absorbs certain wavelengths, reflects others-When two pigments are mixed, each subtracts o ut certain wavelengths-You see whats left overExam 2Perceptual ambiguityPattern recognitionColor visionSound MusicThe EarEar to BrainVisual IllusionsInner ear- cochlea, organ of corti,Moon Illusion moon looks larger when at horizon than when it is over-head perceive size = retinal image size x perceived distanceEXAM 3 MATERIAL(FINAL EXAM)NOV 9TH, 2012Final Exam Friday Dec 14th, 330-53066 questions, appx. 2/3 material last 3rd of classStudy 1st 2 exams for remaining 1/3Dont adopt to know every single experiment, just the general results Medial and lateral superior olives-Loudness in 2 ears and time of arrival in 2 ears