PSYC 1020H Exam Review - PDF

lOMoARcPSD|32080969 PSYC 1020H —Exam review Introduction to Psychology Part 1: Experimental and Biological Bases of (Trent University) Sensation and Perception - Lecture 6, Chapter 4 Key Concepts and Terms Sensation...

lOMoARcPSD|32080969 PSYC 1020H —Exam review Introduction to Psychology Part 1: Experimental and Biological Bases of (Trent University) Sensation and Perception - Lecture 6, Chapter 4 Key Concepts and Terms Sensation Vision for perception and action (brain areas involved Perception in both) Absolute Threshold Additive and subtractive colour mixing Just noticeable Trichromatic vs. opponent process theories of difference colour vision Signal-detection theory Reversible figure and perceptual set Subliminal perception Bottom-up vs. top-down perception Sensory adaption Gestalt principles (phi phenomenon, proximity, Variations in light closure) Perceptual hypothesis (amplitude, Monocular vs. binocular cues wavelength, purity) Parts of the human ear (cochlea, basilar Parts of the human eye membrane) Place vs. frequency theories of (lens, pupil, retina, rods, hearing cones, etc.) Light and dark Review Overview of Five Major Senses adaption Receptive field Sensation = detecting, bottom-up process, is the stimulation of sense organs (absorption of energy - light or sound waves by sensory organs such as the ears and eyes) Perception = translating, top-down processing - is the selection, organization and interpretation of sensory input (organizing and translating sensory input into something meaningful ex. Best friends face) Absolute Threshold = smallest amount of stimulation needed to detect a stimulus half of the time, determines the limit (boundaries) of sensory abilities - for a specific type of sensory input is the minimum amount of stimulation that an organism can detect (as stimulus intensity increases, subjects’ gradually increases) - an absolute threshold is simply the JND from nothing/no stimulus ex: how much sugar before coffee tastes sweet? How much movement before lights turn on? Just noticeable difference = (difference threshold) smallest difference between 2 stimuli needed to detect a change at least half of the time the smallest difference in the amount of stimulation that a specific sense can detect —> Weber’s Law = size of a JND is a constant proportion - Weber fraction of the size of the initial stimulus (applies to all senses, different fractions apply to different types sensory input) - percentage not amount of change (proportionate to the size of the initial stimulus) - ex: 50 cent off coupon - worth using it for small purchase [bananas] but not for expensive car, 50 lOMoARcPSD|32080969 marshmallows + 1 = imperceptible +10 = noticed! —> JND 10 or 20% Signal-detection theory = proposes that the detection of stimuli involves decision processes as well as sensory processes (no 100% detection accuracy, accurate detection is influenced by both external and psychological factors) Influence detectability - responses will depend part on criterion set before you react) —> hits (detecting signals when they are present) misses (failing to detect signals when they are present) false alarms (detecting signals when they are not present) correct rejections (not detecting signals when they are absent) Subliminal perception = the registration of sensory input without conscious awareness (below the threshold) ex. Sexual urges be manipulated by messages hidden under music - effects of subliminal perception are relatively weak, little or no practical concern Sensory adaption = the gradual decline in sensitivity due to prolonged stimulation (another factor influences registration of sensory input) ex. Putting on clothes - initially fell them but the sensation starts to fades, standing near garbage - after continued expos are sensitivity decreases Variations in light = the stimulus (light), is a form of electromagnetic radiation that travels as a wave moving at the speed of light amplitude —> lights waves vary in amplitude (height, affects perception of brightness) wavelength —> distance between peaks, affects perception of colour - Most objects reflect light, light seen by humans is normally a mixture of several wavelengths purity —> how varied the mix is, influences perception of saturation/richness of colours Parts of the human eye = the eyes - channel light to the neural tissues that receives it lens —> transparent eye structure that focuses the light rays falling on the retina (capable of adjustments that facilitate a process called accommodation = occurs when the curvature of the lens adjusts to alter visual focus (close - eye gets fatter, distant - flattens out) - Iris = coloured ring of muscle surrounding the pupil pupil —> the opening in the centre of the iris that helps regulate the amount of light passing into the rear chamber of the eye (black centre) - when the pupil constricts it lets less light into the eye but it sharpens the image (bright light) - when the pupil dilates (opens) it lets more light in but the image is less sharp (dim light) Saccades —> eye movements (essential to good vision, small reduction = our vision degrades) - cornea = the cornea and the crystallized lens located behind it form an upside-down image of objects on the retina retina —> the neural tissues lining the inside back surface of the eye with millions of light receptors (absorbs light), light enters the eye through a transparent “window” at the front - processes images and sends visual information to the brain (part of central nervous system) - axons that run from the retina to the brain converge at the optic disk = a hole in the retina where the optic nerve fibres exit the eye (blind spot, cannot see the part of an image there) 2 types of receptor cells: 1) rods —> specialized visual receptors that play a key role in night vision and peripheral vision - concentrated on periphery (100-125 million) greatest density outside the fovea 2) cones —> are specialized visual receptors that play a key role in daylight vision and colour vision (5-6.4 million cones, cone shaped) concentrated in the fovea - centre - don’t respond well to dim light - sharper than rods, cones are concentrated most heavily in the centre fall off in density toward periphery Fovea = tiny spot in the centre of the retina that contains only cones, visual acuity is greatest at this spot (to see something sharply, move your eyes to centre the object in the fovea) Light and dark adaption = dark adaption —> process of eyes becoming more sensitive to light in low illumination (cones adapt more rapidly than rods) Entering a dark theatre on a bright day light adaption —> process where the eyes become less sensitive to light to high illumination ex. Emerge from dark theatre on a sunny day (squinting) Receptive field = of a visual cell is the retinal area that, when stimulated affects the firing of the cell (100 million rods and cones converges to travel along 1 million axons in optic nerve) Vision for perception and action (brain areas involved in both) = Goodale and Humphrey — > Two functions that vision serves Vision for perception = to create an internal representation or model of the external world Vision for action = the related process of controlling your actions that are directed at those objects (both obstacles/correcting for changes in location in the target you are reaching for ex. #1 - creating an internal representation of your best friend #2 - guiding your actions (patting them on the back for congratulation) —> perception in the brain… millions of bits of data come in via thalamus to the primary visual cortex (occipital lobe) these activate feature detectors = specialized neurons, respond selectively to specific aspects of stimuli —> shape, angle, movement, colour, face Feature detectors = neurons respond selectively to very specific features more complex stimuli 1. ventral stream = processes details of what objects are out there (perception of form/colour) associated w our perception of the world 2. Dorsal stream = processes where the objects are (perception of motion/depth) visuomotor modules emerged related to vision for action/control of goal directed movements Additive and subtractive colour mixing = 1. Subtractive = colour mixing works by removing some wavelengths of light, leaving less light than was originally there (ex. Mixing paints yellow + blue = green) paints yield this mixing because pigments absorb most wavelengths 2. Additive = colour mixing works by superimposing lights, putting more light in the mixture that exists in any one light by itself (ex. shine red, green, blue spotlights on a white surface) human colour perception depends on processes that resembles additive colour mixing 9 Trichromatic vs. opponent process theories of colour vision = Trichromatic theory of colour vision = holds that the human eye has 3 types of receptors with differing sensitivities to different light wavelengths (Young —> Helmholtz) - Eye contains specialized receptors sensitive to the specific wavelengths associated w red, green and blue (people can see all the colours of the rainbow) —> Colour blindness = encompasses a variety of deficiencies in the ability to distinguish among colours (more frequent in males) Dichromats = make do with 2 colour channels —> 3 types and each one is insensitive to one of the primary colours (red, green, blue) Opponent process theories of colour vision = holds that colour perception depends on receptors - make antagonistic responses to 3 colour pairs (red vs green, yellow vs blue, black vs white) —> Complementary colours = are pairs of colours that produce grey tones when mixed together —> Afterimage = a visual image that persists after a stimulus is removed (colour will be the complement of the colour you originally stared at) Reversible figure and perceptual set = Reversible figure = a drawing that is compatible with two interpretations that can shift back and forth (see a old woman’s face, or a young woman’s face) - the same visual input can result in radically different perceptions —> no one to one correspondence exists between sensory input and what you perceive, people’s experiences in the world are subjective Perceptual set = a readiness to perceive a stimulus in a particular way (creates a certain slant in how someone interprets sensory input) —> various psychological factors that determine when and how external stimuli will be perceived - same stimulus can be perceived as something different, perception is subjective Bottom-up vs. top-down perception = Bottom-up perception = progression from individual elements to the whole, sensory systems receive raw stimuli from the world “out there”, convert them into neural impulses and relay them to the brain —> sensation Top-down perception = a progression from the whole to the elements, the brain organizes and interprets the incoming sensory info to give it meaning, brain (re)constructs the world “out there” —> perception Recognize stimulus Top-down processing Combine specific features into Formulate perceptual hypothesis about the nature of more complex forms ^ the stimulus as a whole >  Detect specific features of stimulus ^ Select and examine features to check hypothesis > Bottom-up processing Recognize Gestalt principles = Gestalt psychology = emerged in Germany (form or shape) whole can be greater than the sum of its parts (features) Form perception —> the whole is other than the sum of its parts, the brain’s rules for organizing data bits together and making coherent extrapolations (Top down processing) 1. Phi phenomenon = Max Wertheimer - is the illusion of movement created by presenting visual stimuli in rapid succession (ex. movies, tv = consists of separate still pictures projected rapidly one after the other (property - motion, any of its pats - individual frames) 2. Proximity = objects close to each other are perceived as belonging together, things that are closer to one another seem to belong together (similarity) 3. Closure = people often group elements to create a sense of closure or completeness - may have gaps in them, completing a familiar form when it appears to have gaps 5. Continuity = tendency to follow in whatever direction they’ve been led Perceptual hypothesis = inference about which distal stimuli could be responsible for the proximal stimuli sensed (make educated guesses - what form responsible for a pattern of sensory stimulation) about: colour, form, depth - brain makes quick and automatic extrapolations, brain actively constructs reality Monocular vs. binocular cues = Monocular cues = either eye alone (helps determine scale and distance) ex. Cover one eye shake head - closer objects appear to move more than distant objects 2 types —> #1 motion parallax = involves images of objects at different distances moving across the retina at different rates (based on motion) #2 pictorial depth = clues about distance that can be given in a flat picture 1. Liner perspective - parallel lines appear to converge in the distance (details are too small to see when they are far away) 2. Texture gradients - provide information about depth (close objects are more detailed than far objects) 3. Interposition - object comes between you and another object it must be closer to you (overlap cue) the object that blocks another object from view, perceived as being closer 4. Relative size - closer objects appear larger, similar objects will appear larger when closer and smaller when further away 5. Height in plane - distant objects appear higher in a picture 6. Light and shadow - useful in judging distance (see desirable objects closer) binocular cues = two eyes, each eye receives slightly different retinal images, brain compares the two images to judge distance and depth (closer objects = greater disparity) retinal disparity —> refers to the face that objects project images to slightly different locations on the right and left retinas, right and left eyes slightly different views of the subject increases as objects come closer (convergence - sensing the eyes converging toward each other as they focus on closer objects Parts of the human ear —> —> External ear = depends on vibration of air molecules, consists mainly of the pinna - sound collecting cone (cupping hand behind ear to hear better, augmenting the cone) sound waves Downloaded by Emma Mingie ([email protected]) lOMoARcPSD|32080969 collected by the pinna are funnelled along the auditory canal toward the eardrum - a taut membrane that vibrates in response —> Middle ear = depends on vibration of movable bones, the vibrations of the eardrum are transmitted inward by a mechanical chain made up of the 3 tiniest bones in your body —> the hammer, anvil and stirrup - ossicles - serve to amplify tiny changes in air pressure —> Inner ear = depends on waves in a fluid (finally converted into stream of neural signals sent to the brain) consists largely of the cochlea = a fluid filled coiled tunnel that contains the receptors for hearing, sound enters the cochlea through the oval window (vibrated by the ossicles) basilar membrane = which runs the length of the spiralled cochlea, holds the auditory receptors (auditory receptors = hair cells because of the tiny bundles of hairs that protrude from them) - waves in the fluid of the inner ear stimulate the hair cells which convert this physical stimulation into neural impulses that are sent to the brain —> signals are routed through the thalamus to the auditory cortex (temporal lobes of the brain) Place vs. frequency theories of hearing = Place theory = holds that perception of pitch corresponds to the vibration of different proportions, or places, along the basilar membrane (assumes hair cells at various locations respond independently, different sets of hairs cells are vibrated by different sound frequencies) - brain detects frequency of a tone according to which area in basilar membrane is most active Frequency theory = holds that perception of pitch corresponds to the rate or frequency at which the entire basilar membrane vibrates (the whole membrane vibrates in unison in response to sounds) brain detects the frequency of a tone by the rate at which the auditory nerve fibres fire Review Overview of Five Major Senses Downloaded by Emma Mingie ([email protected]) lOMoARcPSD|32080969