Introductory Psychology Lectures 16 PDF

Introductory Psychology Lectures 16 Harinder Aujla 1 / 36 Sensation and Perception 2 / 36 Sensation & Perception Terms Sensation Stimulation of our sense organs by features of the outer world The process by which stim...

Introductory Psychology Lectures 16 Harinder Aujla 1 / 36 Sensation and Perception 2 / 36 Sensation & Perception Terms Sensation Stimulation of our sense organs by features of the outer world The process by which stimulation of sensory receptors produces electrical impulses that travel to the brain and represent our internal or external experiences Physical process Perception Act of attending to, organizing, and interpreting sensory experience Psychological process 3 / 36 Bottom-up and top-down processing Yourhome the spaceturn Light Spielman, Rose M.; Jenkins, William; and Lovett, Marilyn, “Psychology 2e” (2020). Open Access Textbooks. 1. https://commons.erau.edu/oer-textbook/1 4 / 36 Basic Sensory Processes Transduction e-x light hitting neurons in your eyer Conversion of one form of energy to another (i.e., physical → neural impulses) Sensory adaptation Reduction of activity in sensory receptors with repeated exposure to a you than exhaust the habituation stimulus More basic n outside ex you seeing things as dim from brightness when into room you walk Doctrine of Speci c Nerve Energies Different senses are separated in the brain 5 / 36 Transduction Systems most straightforward 6 / 36 Sensory Knowledge of the World art of larged brain It is essential to be able to obtain reliable information about the world (sensory organs) The Psychophysics The study of the correspondence between physical stimulation and psychological experience Fechner devised methods to study the intensity of sensory experiences & relating that to the magnitude of experience 7 / 36 Basic Principles Thresholds Amount of stimulus or amount of change need to be detected Absolute Threshold Minimum stimulation needed to detect the presence of a particular do stimulus 50% of the time stimulation much South -how ; detect bot need 8 / 36 Di erence Thresholds Minimum difference between two stimuli that a subject can detect 50% of the time Just Noticeable Difference (JND) Increases with magnitude of stimulus (Weber’s Law) Weber’s Law To perceive a difference between two stimuli, they must differ by constant proportion Light Intensity - 8% to proportion of relative Weight - 2% chang Tone Frequency - 0.3% 9 / 36 Basic Principles Weber’s Law for weight Difference of 2% needed for detection Initial Weight 2% Detectable Difference 100g 2g 102g 1000g 20g 1020g 2000g 40g 2040g 10000g 200g 10200g 10 / 36 Stages of Perception Perceptual Organization The process where an internal representation of an object is formed in the brain and a percept of the external stimulus is developed Involves the synthesis of sensory features Identi cation and recognition The process of assigning meaning to perceptions Involves higher level cognitive processes to determine what an object is, what it is called, and how we respond to it Outcome of this process is a percept These processes are often completed quite automatically and seemingly without effort 11 / 36 Stages of Perception Jigger loser 12 / 36 Proximal and Distal Stimuli I There are two different stimuli involved in perception: brap closest one to your cor Proximal stimulus - The optical image on the retina Distal stimulus - reality The physical object in the world Goal to perceive the distal stimulus (real object) based on the information derived from the proximal stimulus (retinal image) 13 / 36 Ambiguity Sometimes single images are ambiguous and open to multiple interpretations during perceptual and identi cation processes Nicholls, M.E.R., Churches, O. & Loetscher, T. Perception of an ambiguous gure is affected by own-age social biases. Sci Rep 8, 12661 (2018). https://doi.org/10.1038/s41598-018-31129-7 14 / 36 Ambiguity cont’d ABC Seeing b por compared to , 13 12 , 4. Nicholls, M.E.R., Churches, O. & Loetscher, T. Perception of an ambiguous gure is affected by own-age social biases. Sci Rep 8, 12661 (2018). https://doi.org/10.1038/s41598-018-31129-7 15 / 36 Ambiguity cont’d woman Younger or woman Older Nicholls, M.E.R., Churches, O. & Loetscher, T. Perception of an ambiguous gure is affected by own-age social biases. Sci Rep 8, 12661 (2018). https://doi.org/10.1038/s41598-018-31129-7 16 / 36 Illusions Illusions occur when you're definitely wrong Perceptual systems deceive you into experiencing a stimulus pattern in a manner that is demonstrably incorrect Linked to ambiguity in interpretation Shared experiences because of physiological properties of sensory systems Illusions exist in our everyday experience 17 / 36 Ebbinghaus Illusion Nicholls, M.E.R., Churches, O. & Loetscher, T. Perception of an ambiguous gure is affected by own-age social biases. Sci Rep 8, 12661 (2018). https://doi.org/10.1038/s41598-018-31129-7 18 / 36 Cureved Lines Nicholls, M.E.R., Churches, O. & Loetscher, T. Perception of an ambiguous gure is affected by own-age social biases. Sci Rep 8, 12661 (2018). https://doi.org/10.1038/s41598-018-31129-7 19 / 36 Tilted Checkerboard Nicholls, M.E.R., Churches, O. & Loetscher, T. Perception of an ambiguous gure is affected by own-age social biases. Sci Rep 8, 12661 (2018). https://doi.org/10.1038/s41598-018-31129-7 20 / 36 Müller-Lyer illusion Spielman, Rose M.; Jenkins, William; and Lovett, Marilyn, “Psychology 2e” (2020). Open Access Textbooks. 1. https://commons.erau.edu/oer-textbook/1 21 / 36 Perceptual Grouping How do we determine what parts of a scene go together? Gestalt Psychology Perspective that psychological phenomena could be understood only when viewed as organized, structured wholes and not when broken down into primitive perceptual elements - Similarity ~ Proximity - Good continuation 22 / 36 Perceptual Grouping: Similarity Nicholls, M.E.R., Churches, O. & Loetscher, T. Perception of an ambiguous gure is affected by own-age social biases. Sci Rep 8, 12661 (2018). https://doi.org/10.1038/s41598-018-31129-7 23 / 36 Perceptual Grouping: Proximity group part of theyreclose - cuz together similarity-rows proximity-columns Nicholls, M.E.R., Churches, O. & Loetscher, T. Perception of an ambiguous gure is affected by own-age social biases. Sci Rep 8, 12661 (2018). https://doi.org/10.1038/s41598-018-31129-7 24 / 36 Perceptual Grouping: Good Continuation assume direction in the smth stays same Nicholls, M.E.R., Churches, O. & Loetscher, T. Perception of an ambiguous gure is affected by own-age social biases. Sci Rep 8, 12661 (2018). https://doi.org/10.1038/s41598-018-31129-7 what's "under" the 3rd image of expect /Ist rather that square. 25 / 36 Attention and Perception Divided Attention Paying attention to more than one stimulus at the same time Selective Attention Focusing on one particular event or task to the exclusion of others Inattentional Blindness A failure to notice clearly visible events or objects because attention is directed elsewhere 26 / 36 Inattentional Blindness demo https://www.youtube.com/watch?v=IGQmdoK_ZfY 27 / 36 Vision 28 / 36 Vision - Light Energy Wavelength Distance from peak of one wave to peak of next Amplitude Vertical distance from peak to trough 29 / 36 Vision - Psychological experience Hue Dimension of color determined by wavelength of light Intensity Amount of energy in wave determined by amplitude Brightness Saturation Variety of wavelengths from the same point Colorfulness or “purity” 30 / 36 Vision - Light Energy 31 / 36 Vision - Spectrum of Electromagnetic Energy 32 / 36 Eye The NOBA Project 33 / 36 Vision: Eye Lens: Transparent structure behind pupil Changes shape to focus images on retina Accommodation Change in shape of lens to focus near objects 34 / 36 Vision - Eye Acuity Sharpness of vision Nearsighted Nearby objects seen more clearly Lens focuses distant objects in front of retina Farsighted Faraway objects seen more clearly Lens focuses near objects behind retina 35 / 36 Vision - Eye Farsighted Vision Nearsighted Vision Normal Vision 36 / 36 Introductory Psychology Lecture 17 Harinder Aujla 1 / 51 Perceptual Constancies ISS Size constancy Ability to perceive the true size of an object despite variations in the size of its retinal images Shape constancy Ability to perceive an object’s shape correctly even when the object is slanted away from you changing the shape of the retinal image Lightness constancy Tendency to perceive whiteness, greyness, and blackness as constant across changing levels of illumination 2 / 51 Perceptual Constancies 3 / 51  Depth Perception BmCI Binocular cues notrly helpful at medium distance Require use of two eyes Retinal Disparity Images from the two eyes differ Closer object, larger themoves finger disparity (right) -your you close eithe When object to compared eye that barely away Convergence far moves. Neuromuscular cue Two eyes move inward for near objects Part eye called phobia : of 4 / 51 Depth Perception eye for Monocular Cues need one - only Relative size: Smaller image more distant Interposition: Closer object blocks distant object Relative clarity: Hazy object seen as more distant Texture: Coarse → close, Fine → distant smaller 5 / 51 Depth Perception: Relative Size 6 / 51 Depth Perception: Interposition 7 / 51 Depth Perception: Clarity 8 / 51 Depth Perception: Texture Stimuli that are nearer have coarser texture. 9 / 51 The Ames Room 10 / 51 Ames Room: Size-Distance Relation 11 / 51 Monocular Cues: Shading Major light sources tend to come from above, so shading is another source of depth information. Objects shaded lighter on top seen as “sticking out towards us”. Here, crater (top) becomes mound (bottom) when picture turned upside down. crater See us eter upside down 12 / 51 Monocular Cues: Depth of Focus the small brains cut percreuses something its very close up. as 13 / 51 Attention and Perception Lactuali driving & texting listening to music & studying) Divided Attention or e x - Paying attention to more than one stimulus at the same time Selective Attention Focusing on one particular event or task to the exclusion of others Inattentional Blindness A failure to notice clearly visible events or objects because attention is directed elsewhere ball video Ex Gorilla & players passing 14 / 51 Inattentional Blindness demo https://www.youtube.com/watch?v=IGQmdoK_ZfY 15 / 51 Vision 16 / 51 Vision - Light Energy Wavelength Distance from peak of one wave to peak of next Amplitude Vertical distance from peak to trough 17 / 51 Vision - Psychological experience Hue Dimension of color determined by wavelength of light Intensity Amount of energy in wave determined by amplitude Brightness Saturation Variety of wavelengths from the same point Colorfulness or “purity” 18 / 51 Vision - Light Energy 19 / 51 Vision - Spectrum of Electromagnetic Energy weaves of -now ligh me get. losing saturation 20 / 51 Eye Brain is filling blindspot constantly in so · we don't really havea spot - The NOBA Project 21 / 51 Vision: Eye Pupil: Adjustable opening in center of eye Iris : Ring of muscle that controls size of opening Lens: Transparent structure behind pupil Changes shape to focus images on retina Accommodation Change in shape of lens to focus near objects 22 / 51 Vision: Eye Acuity Sharpness of vision Nearsighted Nearby objects seen more clearly Lens focuses distant objects in front of retina Farsighted Faraway objects seen more clearly Lens focuses near objects behind retina 23 / 51 Vision - Eye ↑ rigue clear rigig Hurry Farsighted Vision Nearsighted Vision Normal Vision 24 / 51 Vision: Retina Inner surface of eye from Layers of neurons retinal diff ganglie photorea ~ Light-sensitive rods and cones Beginning of visual information processing Image inverted on retina 25 / 51 Retina: Reaction to Light Fovea Central point in retina, around which cones cluster Optic nerve - when blindspot leaves a Nerve that carries neural impulses from eye to brain Blind Spot Point at which optic nerve leaves eye, creating “blind spot” because no receptor cells there 26 / 51 Retina: Receptors React to Light light sensitive 27 / 51 Retina: Receptors React to Light More yellow 28 / 51 Vision: Contrast The ability to discern different objects in the environment is critical for survival Our visual system enhances our survival by enhancing contrast through a process known as lateral inhibition whereby neurons decrease the activity of their neighbours (i.e. inhibit) in a manner proportional to their own activation. The stronger the activation (i.e. the brighter the light) the more the neighbouring neurons are inhibited (i.e. surround is perceived as darker). Conversely, the weaker the activation (i.e. dimmer the light), the less the neighbouring neurons are inhibited (i.e. surround is perceived as lighter) 29 / 51 Vision: Lateral Inhibition a darkermeans or & []))) The NOBA project 30 / 51 Lateral Inhibition: Receptive Fields - antidor : cur circle lightingea Shine 31 / 51 Hering Grid 32 / 51 Hering Grid Explanation 33 / 51 Mach Bands 34 / 51 Mach Bands Explanation 35 / 51 Sensory Adaptation Our sensory systems are more sensitive to changes in the environment Sensory adaptation: Involves the diminishing responsiveness of sensory systems to prolonged stimulus input Dark adaptation refers to recovered sensitivity of our rods in dim lighting Contrast gain refers to the visual system’s ability to adjust for relative contrast by processing the average lighting conditions. Adaptive value Occurs for colour information as well. Colour constancy refers to the perception of the same colour when lighting conditions, and consequently the wavelength of light re ected from an object, change. 36 / 51 How many colours? 37 / 51 Theories of Colour Vision 38 / 51 Theories of Colour Vision Trichromatic Theory Young & Helmholtz Suggests there are three types of colour receptors: red, green, blue All other colours are additive or subtractive combinations of the three taking away ~ I adding pigments 39 / 51 Tri-Colour 40 / 51 Opponent-Process Theory A competing theory of colour vision assumes that the visual system treats pairs of colours as opposing or antagonistic This view is consistent with patterns of ganglion cell ring. Ganglion cells collect information over a range of photoreceptors 41 / 51 42 / 51 The Visual Pathway Neural impulses leave the retina through the optic nerve (axons of ganglion cells) Spot where the optic nerve exits the retina has no receptors and is associated with a blind spot Optic nerve divided into 2 bundles at optic chiasm (creates pathways of visual system) 43 / 51 Visual Information Processing Further processing of visual information occurs in the visual cortex which receives information from the retina via that thalamus The lateral geniculate nucleus is the thalamic nucleus that relays visual information to the cortex Information rst arrives in the cortex at V1 and then diverges into streams that process different kinds of visual information The dorsal pathway process information for location (i.e. where and how?) the ventral stream process information for object identi cation (i.e. what?) More specialized areas also exist, like the fusiform gyrus which process ne details involved in face recognition. 44 / 51 Visual Information Processing 45 / 51 Visual Information Processing Receptive Fields Region of eye to which neuron responds (either increase or decrease in activity) Stimuli of different shapes placed at different locations and moved in different directions Measure reaction of single cell in visual cortex (or other visual regions) to identify what features cell responds to Feature Detectors Neurons in visual cortex respond to speci c features Shape Angle/orientation Movement 46 / 51 Receptive Fields 47 / 51 Dorsal and Ventral Streams The NOBA Project 48 / 51 Where and What Pathways 49 / 51 Where or How/Action? Goodale and Milner (1992) presented a patient, D.F., whose de cits re ned the function of the dorsal stream Severe anomia (object-naming de cit) Could not orient her hand to match the slot However, she could “post” 50 / 51 Ventral Stream: Visual Agnosias Dif culty recognizing objects using vision Various forms which depend on the location of the damage Can be very selective – affecting only the recognition of a particular type of object Prosopagnosia A de cit in face perception Results from damage to the fusiform face area (FFA) 51 / 51 Introductory Psychology Lecture 18 Harinder Aujla 1 / 59  i eute o X - or Let 2 / 59 The Visual Pathway Neural impulses leave the retina through the optic nerve (axons of ganglion cells) Spot where the optic nerve exits the retina has no receptors and is associated with a blind spot Optic nerve divided into 2 bundles at optic chiasm (creates pathways of visual system) 3 / 59 Visual Information Processing Further processing of visual information occurs in the visual cortex which receives information from the retina via that thalamus The lateral geniculate nucleus is the thalamic nucleus that relays visual information to the cortex privat , Information rst arrives in the cortex at V1 and then diverges into streams that process different kinds of visual information The dorsal pathway process information for location (i.e. where and - how?) - the ventral stream process information for object identi cation (i.e. what?) More specialized areas also exist, like the fusiform gyrus which process ne details involved in face recognition. 4 / 59 Visual Information Processing Talarms O 5 / 59 Visual Information Processing Receptive Fields Region of eye to which neuron responds (either increase or decrease in activity) Stimuli of different shapes placed at different locations and moved in different directions Measure reaction of single cell in visual cortex (or other visual regions) to identify what features cell responds to Feature Detectors Neurons in visual cortex respond to speci c features Shape Angle/orientation Movement 6 / 59 Receptive Fields 7 / 59 Dorsal and Ventral Streams agination spatatrecto * F6 The NOBA Project 8 / 59 Where and What Pathways toersua sportion 9 / 59 Where or How/Action? Goodale and Milner (1992) presented a patient, D.F., whose de cits re ned the function of the dorsal stream ↳ how to do to recognize Severe anomia (object-naming de cit) how Could not orient her hand to match the slot However, she could “post” 10 / 59 Ventral Stream: Visual Agnosias Dif culty recognizing objects using vision Various forms which depend on the location of the damage Can be very selective – affecting only the recognition of a particular type other exorgating fitfu of object Prosopagnosia it ↓ not A de cit in face perception Results from damage to the fusiform face area (FFA) 11 / 59 Audition 12 / 59 Hearing The physics of sound involves vibrational energy that is transmitted through the air producing waves Two physical properties: Xprequency Frequency = the number of = Mwavelenghts cycles the wave completes in a given time (hertz) Amplitude = the physical property of the strength of the sound wave (decibels) 13 / 59 Hearing The psychological dimensions of sound involve three components: Pitch = highness or lowness of sound (Hz) Loudness = amplitude of the sound wave (dB) Timbre = complexity of a sound wave Most of the “noise” we hear contains a combination of frequencies & amplitudes to create complex waves 14 / 59 Intensity of Some Common Sounds Decibel scale is a logarithmic scale 10 10x 101 20 100x 102 30 1,000x 103 40 10,000x 104 50 100,000x 105 Normal conversation is 60 – 20 = 40 = 104 = 10,000 times as loud as a whisper 15 / 59  Hearing: The Ear The Auditory System Pinna – external ear Tympanic membrane – eardrum Middle ear – contains the hammer, anvil, & stirrup wea -resesin areCochlea – A uid lled, contains basilar membrane & tiny hair cell receptors · Thalamus Auditory nerve – impulses leaving the cochlea Auditory cortex – in the temporal lobe 16 / 59 Hearing: The Ear comp steer e & Cocklea allows just - 17 / 59  The Basilar Membrane sta s banaro 8... , therate 18 / 59 Hearing Transformed Four basic energy transformations take place in hearing Airborne sound waves must get translated into uid waves within the cochlea of the ear The uid waves must stimulate mechanical vibrations of the basilar membrane Vibrations must then be converted into electrical impulses Impulses then travel to the auditory cortex 19 / 59 Theories of Pitch Perception #voi ↓ Low Place Theory high get's out more high worn side Pitch determined by place (location) where basilar membrane in cochlea stimulated Problem explaining medium to low frequencies (two many frequencies to be represented by a limited number of hair cells) more Ligh frequences = high outch Frequency Theory bass causes frequencies Rate of nerve impulses traveling up auditory nerve matches frequency of tone Problem explaining high frequencies: nerves cannot re that rapidly (refractory period) Volley principle may help alleviate this problem - staggered ring may effectively code higher frequencies. Combination may be required 20 / 59 Hearing: Localizing Sound Having two ears is important for sound localization Front/back and above/below more dif cult to localize due to how are ears are placed on our heads 21 / 59 Hearing: Localizing Sound Interaural time difference (ITD) - one ear hears the sound sooner and more intensely (unless it is along our mid-line) 1-2 degree discrimination in front (13 microsecond difference) particularly useful at low frequencies and more useful with everyday sounds with broad frequency spectrums. Interaural level difference (ILD) - the head casts an acoustic “shadow” which causes the sounds to be louder at one ear vs. the other. useful at high frequencies sensitivity as small as 1 dB 22 / 59 Hearing Loss Hearing loss Conduction hearing loss Caused by damage to mechanical system that conducts sound waves to cochlea Nerve hearing loss Caused by damage to cochlea’s receptor cells or auditory nerve 23 / 59 Hearing Loss Older people tend to hear low frequencies well but suffer hearing loss for high frequencies Affects speech perception 24 / 59 Hearing and the Brain Similar to visual system with processing at thalamic and cortical areas of the brain. Inferior colliculus → medial geniculate nucleus (thalamus) → auditory cortex (temporal lobe) Hemispheric difference recall that language was largely localized to the left hemisphere the right hemisphere processes non-verbal auditory information - such as music 25 / 59 Hearing and the Brain Difference frequencies are processed in different parts of the brain The “map” is ordered by frequency range (i.e. moves from low to high) 26 / 59 Taste 27 / 59 Taste Receptors are located in fungiform papillae. density of fungiform papillae indicates how sensitive an individual is to a particular type of avour 28 / 59 Taste Four standard tastes are well- known Sweet, Sour, Salty, Bitter Umami: after Japanese word for Tasty (Xianwei in Chinese) Savory in English: monosodium glutamate, ketchup, aspartame, etc 29 / 59 Structures Involved in Taste Tongue is covered with papillae; some contain clusters of receptor cells called taste buds Once thought taste receptors concentrated in different regions of tongue Less certainty about this now More accurate description is that different regions of tongue have slight differences in sensitivity to different avours Information from the tongue travels through chorda tympani and the glossopharangyeal nerves → VPM nucleus of the thalamus → gustatory cortex. 30 / 59 Smell 31 / 59 Smell 32 / 59 Smell and Taste Interaction Sensory Interaction Principle that one sense may in uence another, as when smell of food in uences taste Retronasal olfaction is when odorants enter from “the back” (i.e. when you eat food) projection is sent to a different area of the brain that combines this information with taste 33 / 59 Skin Sensations Cutaneuous senses Skin sensation with identi able receptors Merkel disks – steady pressure Meissner corpuscles – rubbing Pacinian corpuscle – ne texture, vibration (e.g. tickling) Ruf ni corpuscles - stretching Sensitivity varies across body 34 / 59 Mechanoreceptors 35 / 59 Mechanoreceptors 36 / 59 Somatosensory Representation of the Body Surface 37 / 59 38 / 59 Thermoreception Temperature Warmth Cold Hot = ??? Specialized receptor? (capsaicin) Warm + Cold activation? 39 / 59 Pain Pain is the body’s response to stimulation from harmful stimuli Temperature, chemical, mechanical receptors Interoceptive - originating from tendons, joints, internal organs Referred pain involves damage to an external organ that is perceived as originated in a different part of the body. Exteroceptive - originating from the surface (i.e. skin) Fast and slow pathways for sharp and dull pain, respectively. Both top-down and bottom-up modulation of pain perception. 40 / 59 Pain Gate control theory Suggests that cells in the spinal cord act as neurological gates, interrupting and blocking some pain signals and allowing others to get through to the brain “Gate” closed by activity in larger A- bre mechanoreceptors (also known as Aα or Aβ bres) or by information coming from brain “Gate” opened by activity of pain signals traveling up small C-pain nerve bre (or Aδ bres) nociceptors. C-tactile bres, associated with gentle stroking, are also able to mediate the pain response. This mitigation of pain through gentle cutaneous sensation is the basis for the social touch hypothesis. 41 / 59 Gate Control Theory By default the inhibitory system prevents transmission throw the projection (P) neurons. 42 / 59 Gate Control Theory Activation of C-pain bres inhibits the inhibitory system (double negative) which opens the gate, transmitting pain signals 43 / 59 Gate Control Theory Activation of large A- bres (A-alph or A-beta) activates the inhibitory system which closes the gate, preventing or diminishing pain signals. 44 / 59 Pain Pathways 45 / 59 Chronic Pain Unlike many of the other sensory systems that we’ve covered, pain often does not show tolerance or habituation. Instead, we experience sensitization which is the opposite - i.e. increased pain with repeated exposure. Allodynia - where neuronal disease or injury makes touch that is normally pleasant feel unpleasantly painful. Caused by altered role of Aα and Aβ bres in pain. Individuals with chronic pain also experience increased sensitivity to exteroreceptive sources of pain. 46 / 59 “Painful” Emotions Empathy and Pain What does it mean to feel someone’s pain? Is this just metaphor or is there some other basis for describing emotional discomfort in this way? 47 / 59 Brain Activation During Observation of Another’s Pain Panels A and B depict activation during pain caused by accident. Panel C depicts pain caused intentionally. 48 / 59 Emotional Pain There is some (but not complete) overlap in brain activation between physical and observed pain. In the case of intentional pain, areas associated with moral reasoning are also recruited. Notably, under similar conditions, activation of some of these areas are absent in individuals diagnosed with anti-social personality disorder (i.e. psychopathy) 49 / 59 Cortical Sensation Processing 50 / 59 Multi-Modal Perception So far, the previous sections in perception have mostly considered sensation/perception processes as separate processes Unimodal stimuli - those are independent to one sense (i.e. feature a common transduction/processing mechanism) Do we really experience the world as separate sensory/perceptual “streams”? Multi-modal perception - experience that integrates information from different sensory modalities. 51 / 59 Multi-modal Perception 52 / 59 How do we integrate information across senses? Recall the McGurk effect Perception of “sound” is not limited to our auditory system! What about other senses? Do we have cross-modal information that in uences other perceptual experiences? 53 / 59 The Rubber Hand illusion http://www.youtube.com/watch?v=sxwn1w7MJvk 54 / 59 Features of multisensory integration Superadditive effect of multisensory integration (aka multisensory enhancement) - responses to multimodal stimuli are typically greater than the combined response to either modality independently Follows the Gestalt idea of “the whole is greater than the sum of its parts” We can describe the unimodal components of such a phenomena (i.e. reduce an experience to individual sensation components and compare against the aggregate effect) Principle of Inverse Effectiveness - the degree of enhancement is increased when any individual unimodal input is weak (i.e. doesn’t dominate). We will see a related phenomena later in the learning chapter 55 / 59 How does the brain produce multi-modal integration? At some point during processing, unimodal systems need to “talk” to each other Areas in the brain that respond to more than one sensory modality are known as multisensory convergence zones. In the case of orienting and basic motor responses - this may occur very early in a processing. Connections between fear-related areas, and the supperior and inferior colliculi (discussed previously in the context of visual and auditory processing, respectively), regulate defensive and appetitive behaviours at a basic level. 56 / 59 How does the brain produce multi-modal integration? Cross-modal receptive elds - multisensory neurons that receive input from two unimodal neurons in different sensory modalities will refer to the same area in space. This facilitates a uni ed experience where external stimuli are perceived as generating multimodal information. The overlap also produces the multisensory enhancement. Spatial principle of multisensory integration: Multisensory enhancement is observed when the sources of stimulation are spatially related to one another. At the level of individual neurons, experience has been shown to enhance the response to multisensory information in multimodal neurons. 57 / 59 How does the brain produce multi-modal integration? Integration also happens in cortical areas This may occur with direct contact between sensory cortices OR This may result from feedback to earlier levels of processing (e.g. auditory cortex → superior colliculus) Large number of multisensory cortical have been identi ed which challenges the traditional unimodal view of sensory/perceptual processing. 58 / 59 Behavioural e ects of multi-modal perception Multimodal phenomena - concerns the binding of inputs from multiple sensory modalities and the effects of this binding on perception Audiovisual speech Tactile/visual integration Cross-modal phenomena - concerns the in uence of one sensory modality on the perception of another Ventriloquism Cross-modal speech 59 / 59 Introductory Psychology Lecture 19 Harinder Aujla 1 / 40 Hearing: Localizing Sound Having two ears is important for sound localization Front/back and above/below more dif cult to localize due to how are ears are placed on our heads 2 / 40 Hearing: Localizing Sound Interaural time difference (ITD) - one ear hears the sound sooner and more intensely (unless it is along our mid-line) 1-2 degree discrimination in front (13 microsecond difference) particularly useful at low frequencies and more useful with everyday sounds with broad frequency spectrums. Interaural level difference (ILD) - the head casts an acoustic “shadow” which causes the sounds to be louder at one ear vs. the other. up & down - can't get from useful at high frequencies sensitivity as small as 1 dB 3 / 40 Hearing Loss Hearing loss Conduction hearing loss Caused by damage to mechanical system that conducts sound waves to cochlea Nerve hearing loss - involves near Caused by damage to cochlea’s receptor cells or auditory nerve 4 / 40 Hearing Loss Older people tend to hear low frequencies well but suffer hearing loss for high frequencies Affects speech perception 5 / 40 Hearing and the Brain Similar to visual system with processing at thalamic and cortical areas of the brain. belug - Inferior colliculus → medial geniculate nucleus (thalamus) → auditory f cortex (temporal lobe) Hemispheric difference recall that language was largely localized to the left hemisphere the right hemisphere processes non-verbal auditory information - such as music 6 / 40 Hearing and the Brain Difference frequencies are processed in different parts of the brain The “map” is ordered by frequency range (i.e. moves from low to high) 7 / 40 Taste 8 / 40 Taste Receptors are located in fungiform papillae. density of fungiform papillae indicates how sensitive an individual is to a particular type of avour 9 / 40 Taste Four standard tastes are well- known Sweet, Sour, Salty, Bitter Umami: after Japanese word for Tasty (Xianwei in Chinese) Savory in English: monosodium glutamate, ketchup, aspartame, etc 10 / 40 Structures Involved in Taste Tongue is covered with papillae; some contain clusters of receptor cells called taste buds Once thought taste receptors concentrated in different regions of tongue Less certainty about this now More accurate description is that different regions of tongue have slight differences in sensitivity to different avours Information from the tongue travels through chorda tympani and the glossopharangyeal nerves → VPM nucleus of the thalamus → gustatory cortex. 11 / 40 Smell 12 / 40 Smell 13 / 40 Smell and Taste Interaction Sensory Interaction Principle that one sense may in uence another, as when smell of food in uences taste Retronasal olfaction is when odorants enter from “the back” (i.e. when you eat food) projection is sent to a different area of the brain that combines this information with taste 14 / 40 Skin Sensations Cutaneuous senses Skin sensation with identi able receptors Merkel disks – steady pressure Meissner corpuscles – rubbing Pacinian corpuscle – ne texture, vibration (e.g. tickling) Ruf ni corpuscles - stretching Sensitivity varies across body 15 / 40 Mechanoreceptors no ano 16 / 40 Mechanoreceptors 17 / 40 Somatosensory Representation of the Body Surface 18 / 40 19 / 40 Thermoreception Temperature Warmth Cold Hot = ??? Specialized receptor? (capsaicin) Warm + Cold activation? 20 / 40  carrapes belong year Pain Cut of attention Pain is the body’s response to stimulation from harmful stimuli Temperature, chemical, mechanical receptors Interoceptive - originating from tendons, joints, internal organs Referred pain involves damage to an external organ that is perceived as originated in a different part of the body. Exteroceptive - originating from the surface (i.e. skin) Fast and slow pathways for sharp and dull pain, respectively. Both top-down and bottom-up modulation of pain perception. 21 / 40  dry perspective Pain Gate control theory Suggests that cells in the spinal cord act as neurological gates, interrupting and blocking some pain signals and allowing others to get through to the brain “Gate” closed by activity in larger A- bre mechanoreceptors (also known as Aα or Aβ bres) or by information coming from brain “Gate” opened by activity of pain signals traveling up small C-pain nerve bre (or Aδ bres) nociceptors. C-tactile bres, associated with gentle stroking, are also able to mediate the pain response. This mitigation of pain through gentle cutaneous sensation is the ↑ basis for the social touch hypothesis. 22 / 40 Gate Control Theory By default the inhibitory system prevents transmission throw the projection (P) neurons. 23 / 40 Gate Control Theory Activation of C-pain bres inhibits the inhibitory system (double negative) which opens the gate, transmitting pain signals 24 / 40 Gate Control Theory Activation of large A- bres (A-alph or A-beta) activates the inhibitory system which closes the gate, preventing or diminishing pain signals. 25 / 40 Pain Pathways 26 / 40 Chronic Pain Unlike many of the other sensory systems that we’ve covered, pain often does not show tolerance or habituation. Instead, we experience sensitization which is the opposite - i.e. increased pain with repeated exposure. Allodynia - where neuronal disease or injury makes touch that is normally pleasant feel unpleasantly painful. Caused by altered role of Aα and Aβ bres in pain. Individuals with chronic pain also experience increased sensitivity to exteroreceptive sources of pain. 27 / 40 “Painful” Emotions Empathy and Pain What does it mean to feel someone’s pain? Is this just metaphor or is there some other basis for describing emotional discomfort in this way? 28 / 40 Brain Activation During Observation of Another’s Pain Panels A and B depict activation during pain caused by accident. Panel C depicts pain caused intentionally. 29 / 40 Emotional Pain There is some (but not complete) overlap in brain activation between physical and observed pain. In the case of intentional pain, areas associated with moral reasoning are also recruited. Notably, under similar conditions, activation of some of these areas are absent in individuals diagnosed with anti-social personality disorder (i.e. psychopathy) - 30 / 40 Cortical Sensation Processing 31 / 40 Multi-Modal Perception So far, the previous sections in perception have mostly considered sensation/perception processes as separate processes Unimodal stimuli - those are independent to one sense (i.e. feature a common transduction/processing mechanism) Do we really experience the world as separate sensory/perceptual “streams”? Multi-modal perception - experience that integrates information from different sensory modalities. 32 / 40 Multi-modal Perception 33 / 40 How do we integrate information across senses? Recall the McGurk effect Perception of “sound” is not limited to our auditory system! What about other senses? Do we have cross-modal information that in uences other perceptual experiences? 34 / 40 The Rubber Hand illusion http://www.youtube.com/watch?v=sxwn1w7MJvk 35 / 40  a ealie correspondent Features of multisensory integration a realised a there's with Superadditive effect of multisensory integration (aka multisensory enhancement) - responses to multimodal stimuli are typically greater than the combined response to either modality independently Follows the Gestalt idea of “the whole is greater than the sum of its parts” We can describe the unimodal components of such a phenomena (i.e. reduce an experience to individual sensation components and compare against the aggregate effect) Principle of Inverse Effectiveness - the degree of enhancement is increased when any individual unimodal input is weak (i.e. doesn’t dominate). 36 / 40 How does the brain produce multi-modal Field receptive integration? 6 At some point during processing, unimodal systems need to “talk” to each other ? Areas in the brain that respond to more than one sensory modality are known as multisensory convergence zones. In the case of orienting and basic motor responses - this may occur very early in a processing. Connections between fear-related areas, and the supperior and inferior colliculi (discussed previously in the context of visual and auditory processing, respectively), regulate defensive and appetitive behaviours at a basic level. 37 / 40 How does the brain produce multi-modal integration? Cross-modal receptive elds - multisensory neurons that receive input from two unimodal neurons in different sensory modalities will refer to the same area in space. This facilitates a uni ed experience where external stimuli are perceived as generating multimodal information. - The overlap also produces the multisensory enhancement. egt Vision strongly influences Spatial principle of multisensory integration: Multisensory Ventricque bias in any situation , your enhancement is observed when the sources of stimulation are are when the other senses disrupted - spatially related to one another. At the level of individual neurons, experience has been shown to enhance the response to multisensory information in multimodal neurons. 38 / 40 How does the brain produce multi-modal integration? Integration also happens in cortical areas This may occur with direct contact between sensory cortices OR This may result from feedback to earlier levels of processing - (e.g. auditory cortex → superior colliculus) - & Large number of multisensory cortical have been identi ed which challenges the traditional unimodal view of sensory/perceptual processing. 39 / 40 Behavioural e ects of multi-modal perception Multimodal phenomena - concerns the binding of inputs from multiple sensory modalities and the effects of this binding on perception Audiovisual speech Tactile/visual integration Cross-modal phenomena - concerns the in uence of one sensory modality on the perception of another McGurk Ejject Ventriloquism Cross-modal speech 40 / 40 Introductory Psychology Lecture 20 Harinder Aujla 1 / 29 “Painful” Emotions Empathy and Pain What does it mean to feel someone’s pain? Is this just metaphor or is there some other basis for describing emotional discomfort in this way? 2 / 29 Brain Activation During Observation of Another’s Pain Panels A and B depict activation during pain caused by accident. Panel C depicts pain caused intentionally. 3 / 29 Emotional Pain There is some (but not complete) overlap in brain activation between physical and observed pain. In the case of intentional pain, areas associated with moral reasoning are also recruited. Notably, under similar conditions, activation of some of these areas are absent in individuals diagnosed with anti-social personality disorder (i.e. psychopathy) 4 / 29 Memory 15 / 29 Memory Persistence of learning over time some on es Involves storage, encoding retention, and retrieval of information ex remembera long ago Fundamental to many human (and non-human animal) activities Learning to speak, read, walk, ride bike, etc. School and other explicit learning Not always conscious 16 / 29 Multiple Types of Memories Implicit versus explicit memory Implicit = availability of information through memory without ninzerti Explicit = conscious effort to recover information conscious effort ex walking Procedural versus declarative memory implicit Procedural = memory for how to do things name Declarative = recollection of facts and events usually explicit your ex Declarative memory can be broken down further into episodic and semantic memory name Semantic - facts not associated with a speci c time O your. X - Episodic - tied to time and space (i.e. autobiographical - from an event dinner in your life) ·What you for had 17 / 29 Memory as Information Processing Encoding Processing of information into memory system Storage Retention of encoded information over time Engram - a memory trace represented somewhere in the brain Retrieval Process of getting information out of memory 18 / 29 Basic Memory Model Multi Store model of Atkinson and Shiffrin (1968) shortest Sensory memory Immediate, initial recording of sensory information Plays role in perception Working memory / short term memory (STM) and do most impt-cur you moment in the stuff Activated memory that holds a few items brie y J with it e.g., look up phone number, then quickly dial before information is forgotten Focus is on processing of brie y stored information Long term memory (LTM) Relatively permanent and limitless storehouse e.g., study chapter in text and remember information for later use 19 / 29  maintenance (not - efficient that - = else replacin https://commons.wikimedia.org/wiki/File:Information_Processing_Model_-_Atkinson_%26_Shiffrin.jpg 20 / 29 Sensory Memory Complete image of stimulus Visual sensory memory & Also called iconic memory - 1/2 second or less Auditory sensory memory - Also called echoic memory 1-2 seconds - Connects new to old info so it's to be in memory easier Primarily allows for perceptual processing of information Do not “remember” information in usual sense of term Iconic memory studied by Sperling 21 / 29 Sensory Memory: Sperling Task Display set of letters (up to 16 or more) VERY brie y (15/1000 sec or 15 ms) Clearly seen by viewer Partial Report: AFTER display off, cue one of rows e.g., low tone -> report Two kinds of recall bottom row Full Report: try to recall all People able to report ALL letters letters in cued row Recall about 5-6 letters Suggests very temporary but Rest fade before recalled complete image for all information shown 22 / 29 Visual Sensory Memory 23 / 29 Auditory Sensory Memory 24 / 29 Sensory Memory Encoding Automatic No time for complex processing Limited encoding; basic sensory information Storage Very brief: 0.5 sec for visual, about 2 sec for auditory Interference by later input from same sensory channel (called Masking) Show 9 letters brie y, followed by 9 x’s in same locations Now no retention and even no awareness of original letters Retrieval Automatic and not organized. 25 / 29 Working and Short Term Memory Attended information from sensory or long-term Memory exexam questions are friends as Look up phone number in phone book -using name # que to get info from que for , Lim to codsim Think of phone number in LTM → Stored in LTM but transferred to STM when we think of it (consciousness?) Properties of STM Limited in duration but longer than sensory memory → only 15-30 sec, or somewhat longer at most, unless continuous rehearsal is allowed Limited capacity: 7 +/- 2 chunks Miller's magic # 26 / 29 STM Strategies Rehearsal Maintenance rehearsal involves repeating information repetitively Lack of rehearsal and interference related to decreased memory ability Chunking The process of recon guring items by grouping them on the basis of similarity or some other organizing principle (or patterns based on LTM) things Chunk = meaningful unit of information a already know based existing knowledge. on Expertise can increase chunking ability 27 / 29 Working Memory Resource involved in tasks such as reasoning and language comprehension Foundation for moment-by-moment uidity of thought and action & integration of information Four components (Baddeley - next slide): · jo eagins maintany i7 Phonological loop ~ by audit except Visuospatial sketchpad top G - same freori Episodic buffer ce - info flow Central executive - directs 28 / 29 Working Memory: Model W 29 / 29 Introductory Psychology Lectures 21 and 22 Harinder Aujla 1 / 36 4 / 36 Long-Term Memory (LTM) Most sophisticated of memory systems Extremely large capacity (limitless??) Some information retained for very long periods of time (perhaps permanently?) Much school learning involves LTM Different kinds/components of LTM Our primary focus will be on explicit or declaritive LTM 5 / 36 LTM - Encoding Encoding unique Distinctiveness - Emotional signi cance memory expiso combo ofbothepisodic Flashbulb memory - remember Effortful Processing - when studying Requires attention and conscious effort Many Kinds of Effortful Processing Repetition or Rehearsal episode new inje Processing for Meaning - connecting to know e- sou make a connection Elaboration by Imagery, Chunking, etc. Organization by Relating pieces of information to one another 6 / 36 LTM - Encoding Rehearsal Conscious repetition of information Maintain information in consciousness (STM) Encodes information for storage in LTM Can bene t, but not most effective strategy 7 / 36 Retrieval Cues Ex : Exam questions are retrival cues > Retrieval cues The stimuli available as you search for a particular memory (can be seeexternally or internally generated) Two tests of memory: Recall = reproduction of information to which you were previously exposed Recognition = realization that a certain stimulus is one you have seen has more or heard before cues retrieval Recognition cues often stronger & more straightforward - feelings of knowing 8 / 36 Context & Encoding - Learning&Conditionina Encoding speci city Memories emerge most ef ciently when the context of retrieval matches the context of encoding Similar to the concept of state-dependent learning from classical and operant conditioning Cue overload principle - if one cue is associated with too many memories, retrieval will suffer. group in a ex Identifying a mugger mea of Context-dependent memory improves recall Retrieval can be altered by the context and distinctiveness of the experience being recalled (contextual distinctiveness) 9 / 36  can't get priming Long-Term Memory - youwithout encoding Implicit memory searche - a Procedural memory Priming Explicit memory Semantic Episodic 10 / 36 LTM - Storage Rehearsal and the serial position effect Primacy effect: Good memory for early words (LTM) Early words rehearsed more (right) Recency effect : · 11 / 36 Encoding & Retrieval Processes Levels of processing theory (Craik & Lockhart, 1972) Information processed at a deeper level is more likely to be retained Structural encoding = paying attention to the structural properties of words & how it looks (shallow) Phonological (phonemic) encoding = paying attention to the sound qualities of words (intermediary) Semantic encoding = paying attention to the meaning of the words (deepest processing) 12 / 36 LTM - Encoding Depth or Levels of Processing Participants perform different amounts or kinds of processing on to- be-remembered material e.g., study word “DOG” or “dog” Visual Processing of word: Is word printed in upper or lower case letters? Acoustic processing: Does word rhyme with “log”? Semantic processing: Is it a kind of animal? Deeper processing produces better memory i.e., Semantic better than Acoustic better than Visual 13 / 36 LTM - Encoding Kinds of “deep” or “semantic” processing Imagery (mental pictures) Powerful form of semantic encoding Mnemonics (memory aids) Keyword mnemonic: CARTA – LETTER (image to right) Especially those techniques that use vivid imagery and organizational devices Organizational Hierarchies e.g. outlines 14 / 36 Organized Presentation 15 / 36 LTM - Encoding: Levels of Processing 16 / 36 Forgetting “Facts crammed at examination time soon vanish, if they were not grounded by other study and later subjected to a suf cient review.” Ebbinghaus (1885) 17 / 36 Forgetting Ebbinghaus designed the rst methods used in systematic study of forgetting: Use of nonsense syllables & rote learning Recall decreases most in short period after learning, but levels off over time due to savings - 18 / 36 Memory Biases TABMCS Transience Information is temporary and fades with time a Absent-mindedness ~ greeres Disruption of encoding due to insuf cient resources (e.g. attention) applied to the task Blocking its there - Retrieval failure – memory is encoded but hard to get out. Feelings of knowing 19 / 36 Memory Biases memory event Misattribution - connections wrong to Event is related to the wrong source Conger the Consistency bias mood Similar to state-dependent effects We current state is consistent with older state Suggestibility Consistent with the idea of memory as reconstruction False memory event differently) change (interprete an can · Memory in long term memory 20 / 36 Forgetting Interference is when retrieval cues do not point effectively to one speci c memory Proactive interference Information you have acquired in the past makes it more dif cult to acquire new information Retroactive interference Acquisition of new information makes it dif cult to remember old information 21 / 36 Memory as Reconstructive Memory is not an accurate permanent record of experiences Two types of Gestalt reconstructions: Levelling – simplifying the story Common when new information can be functionally replaced with existing schema 2 X all Nigerian - are evil men Sharpening – highlighting & overemphasizing certain details Due to attentional focus and emotional value of stimuli 22 / 36 Memory Construction Memory Construction Aspect of both retrieval and forgetting/retention During retention or retrieval, information ltered and missing pieces lled in suggests that retrieved memories are not integrated units, but rather reconstructions with some of the pieces being incorrect 23 / 36 Memory Construction Misinformation effect Misleading information incorporated into memory of event Elizabeth Loftus: research on memory for accidents View lm of accident in which two cars hit each other Later asked how fast car was going Some people asked “how fast?” Others asked “how fast when they SMASHED into each other?” 24 / 36 LTM: Memory Construction Eyewitnesses reconstruct memories when questioned Depiction of actual accident (top) Leading question “About how fast were the cars going when they smashed into each other?” Memory construction (bottom) 25 / 36 Results for Loftus Experiment 26 / 36 Results for Loftus Experiment 27 / 36 LTM - Storage Karl Lashley (1950) Where is the engram? brain representation of memory Rats learn maze → lesion (destroy) cortex → test memory Often little effect of quite large lesions Memory distributed across brain, not localized in speci c area Hormones such as corticotropin releasing factor boost encoding e.g., strong emotions can make for stronger memories Exholograms Role of hippocampus Neural centre in limbic system that helps process explicit memories for storage Accidental or surgical destruction of this area can result in poor LTM (e.g., Korsakoff’s disease) 28 / 36 29 / 36 Amnesia Amnesia patients provide researchers with information about where certain types of memories are processed or stored Findings suggest different brain regions for different types of encoding & retrieval h Anterograde amnesia: inability to form memories for events that occur after brain damage Retrograde amnesia = inability to remember events that occurred prior to brain damage 30 / 36 The Biological Basis of Memory Vision → Occipital lobes Hearing → Temporal lobes Touch → Parietal lobes 31 / 36 Long-Term Memory Storage in the Cortex Different types of long-term memory are stored in different places in the brain Procedural memories in “older” brain regions like the striatum Parkinson’s disease 32 / 36 Emotion, Memory, and the Brain Emotional memories are easier to recall One of the functions of emotions is to help encode and retrieve memories that are particularly important in an organism’s survival. 33 / 36 Hebb’s Law Long-term Potentiation (LTP) Strengthening of a synaptic connection that results when the synapse of one neuron repeatedly res in a short period of time (i.e. massed action potentials) and excites another neuron LTP involves persistent modi cation of the synapse (next slide). 34 / 36 How Practice Makes Perfect Enter Conversion from short-term to & long-term memory storage requires spaced repetition CREB Recall that mechanism for reward- related learning, from the drugs section, also involved persistent modi cation of synapses. 35 / 36 T Long Term Potentiation (LTP) Mechanism There are many changes induced by LTP – some earlier than others. NMDA and AMPA glutamate receptors play a critical role 36 / 36