Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download sensation and perception
Transcript
SENSATION AND PERCEPTION Sensation Perception Absolute threshold Signal Detection Theory Difference threshold Weber’s law Receptor cells Sensory coding Visual sensation process Feature detectors Young-Helmholtz Theory Opponent Process Theory Color blindness Auditory sensation process Frequency Theory Place Theory Deafness SENSATION AND PERCEPTION Olfaction (smell) Gustation (taste) Cutaneous & tactile receptors (touch) Vestibular sense Sensory adaptation Selective attention Perceptual processes Bottom-up processing Top-down processing Visual perception Visual cliff Monocular depth cues Relative size Texture gradient Interposition Linear perspective Binocular depth cues SENSATION AND PERCEPTION Binocular convergence Binocular disparity Gestalt approach Proximity Similarity Symmetry Continuity Closure Constancy Motion detection Apparent motion Phi phenomenon Stroboscopic effect SENSATION AND PERCEPTION SENSATION AND PERCEPTION Sensation -- physical stimulation Perception – how we recognize, interpret and organize our sensation Absolute threshold – minimum level of stimulus that can be detected ½ of the time Signal Detection Theory – investigates the effects of the distractions and interference we experience while perceiving the world – tries to predict what we will perceive among competing stimuli ● takes into account moods, bias, feelings and decision making Difference threshold – JND – minimum difference necessary to detect a change Weber’s law – the greater the magnitude (mass) of the stimulus, the larger the difference must be to be noticed Receptor cells – sensory organ’s specialized cells that detect stimuli Sensory coding – process by which receptors convey range of information to the brain Visual sensation process – cornea pupil (iris) lens retina…rods/cones bipolar cells ganglion cells (optic nerve brain (occipital lobe) Feature detectors – neurons in brain that “see” different parts of the pattern being viewed…like lines, angles, forms, etc. & these parts are assembled then into actual pictures Young-Helmholtz Theory – Trichromatic – 3 color receptors – red, blue & green – see all colors by mixing them Opponent Process Theory – color is in 3 pairs – blue/yellow, red/green, black/white – if one color active, another is not…AFTERIMAGES produced when stare at one color for too long and receptors become fatigued Color blindness – color deficiency – receptor missing or not working…usually red/green or yellow/blue…genetic…mostly males Auditory sensation process – auditory canal eardrum (tympanic membrane) ossicles (bones of middle ear) oval window cochlea basilar membrane (inner cochlea w/sound receptors) auditory nerve Frequency Theory – sound heard based on how stimulated the hair cells are high pitch/frequency = more stimulation (accounts for high pitches) Place Theory – (volley principle) different places or parts of the hair cells are stimulated…accounts for low sounds Deafness – conduction = injury to outer ear or middle ear Nerve (sensorineural) = damage to cochlea, basilar membrane (hair cell), nerve Olfaction (smell) – chemical sense…scent molecules contact receptor cells deep in nasal cavity…axons carry info. directly to olfactory bulbs in brain…info then goes to olfactory cortex and limbic system (showing relationship with memory) Gustation (taste) – taste buds…4 main tastes = sweet, salty, sour, bitter…5th = umami Cutaneous & tactile receptors (touch) – pain, pressure, temperature – receptor cells pressure/movement are myelinated neurons to spinal cord to medulla, thalamus & sensory SENSATION AND PERCEPTION cortex – pain/temperature NOT myelinated to spinal cord to limbic system to sensory cortex Vestibular sense – sense of balance/orientation in space…in inner ear (3 semicircular canals) * Kinesthetic sense – feedback about the position and orientation of specific body parts Sensory adaptation – unconscious, temporary change in response to environmental stimuli – get used to the stimuli (pool or smelly room) Selective attention – attend to one item, while ignoring another (others) – cocktail party effect: carry on a conversation with one person in a noisy room….can identify out of noise our name being called Perceptual processes – how our mind interprets stimuli Bottom-up processing – recognizing an object by breaking it down into its component parts…relies heavily on senses Top-down processing – relies on previous experiences…compare object with items already in brain (memory)…faster, yet not as accurate Visual perception – depth, size, shape and motion Visual cliff – child won’t go out on glass-topped table that creates illusion of a cliff…showing infants at crawling age have depth perception Monocular depth cues -- only need one eye to see Relative size – images farther away project a smaller image on the retina than those closer Texture gradient – patterns grown more dense as distance increases (lose texture as get farther away) Interposition – near object partially blocks view of object behind it Linear perspective – parallel lines appear to converge in distance Binocular depth cues – need both eyes to see Binocular convergence – eyes turn inward to look at items near…closer object is, more eyes turn in Binocular disparity – closer item is, the less similar info with be that hits the retina…farther away items appear more similar in each eye Gestalt approach – the sum(whole) is greater than its parts…top-down processing Proximity – tendency to see objects near each other as forming groups Similarity – tendency to prefer to group like objects together Symmetry – tendency to perceive preferentially forms that make up mirror images Continuity – tendency to perceive fluid, continuous forms, rather than jagged/irregular Closure – tendency to prefer to “close up” objects that are not complete Constancy – means that we know that stimulus remains the same size, shape, brightness, weight and/or volume even though it does not appear to Motion detection – perceived in two ways…1) records changing position of an object as moves across retina 2) tracks how we move our head to follow the stimuli Apparent motion – non-movement, but perceived movement Phi phenomenon – blinking lights appear to move (signs with arrows) Stroboscopic effect – still pictures move fast enough to imply movement (motion pictures/flip books)
