Cognition Human Mind and Behavior PDF

Cognition Human Mind and Behavior Interim Summary I Intro ~ Object Recognition Instructor: Sang Wook Hong 1 Introduction What is ‘Cognition’? The mental processes such as Perception, Attention, Memory, Deci...

Cognition Human Mind and Behavior Interim Summary I Intro ~ Object Recognition Instructor: Sang Wook Hong 1 Introduction What is ‘Cognition’? The mental processes such as Perception, Attention, Memory, Decision-Making … What ‘Mind’ does! Cognition = Mind 2 1  Introduction So, what ‘Mind’ does? Mental processes to find out the keys Perception Attention: Searching Memory Thinking & Reasoning Emotion Decision Making Language 3 Introduction What is Cognitive Psychology? The scientific study of the human mind. The study of the structures and processes of the mind and brain that take in, transform, and use information 4 2  Timeline of Psychology Psychophysics Weber’s law, Fechner’s law, Donders’ Experiment, Ebbinghaus’s Experiment Introspection, Structuralism and “Birth of Psychology” – Wundt, Titchener Functionalism – William James Gestalt Psychology Behaviorism Cognitive Psychology 5 Psychophysics Detection Absolute Threshold Differential Threshold Magnitude Estimation Recognition Reaction (Response) Time 6 3  Psychophysics (Detection) Absolute Threshold Smallest amount of stimulus energy (e.g. light, pressure etc.) required to be detected How to measure Absolute Threshold? Method of Limit Method of Adjustment Method of Constant Stimuli 7 Psychophysics (Detection) Method of Limit Present stimulus’ intensity in ascending or descending order Advantage: Fast Disadvantage: Hysterisis 8 4  Psychophysics (Detection) Method of Limit (Hysterisis) 9 Psychophysics (Detection) Method of Adjustment Observers control the intensity until they detect the stimulus Advantage: Fast Disadvantage: Hysterisis 10 5  Psychophysics (Detection) Method of Constant Stimuli Present stimulus’ intensity in random order 100 Percentage Stimuli Detected 50 0 Light Intensity Advantage: Reliable, Free from Hysterisis Disadvantage: Slow 11 Psychophysics (Detection) Differential Threshold Smallest difference between two stimuli that a person can detect How to measure Differential Threshold? The same methods for Absolute Threshold can be used for Differential Threshold Standard and Comparison Weber’s Law 12 6  Psychophysics (Detection) Ernst Weber discovers “Weber’s Law” (1840s) Which is heavier? 20 lbs 16 lbs 10 lbs 8 lbs 5 lbs 4 lbs J.N.D. = 4 lbs J.N.D. = 2 lbs J.N.D. = 1 lb Weber’s Law: “In observing the disparity between things that are compared, we perceive not the differences between the things but the ratio of this difference to the magnitude of the things compared.” 13 Psychophysics (Magnitude Est.) Magnitude Estimation Measure the relationship between perceived magnitude and stimulus intensity Method Present observers with different strength of stimuli (generally random) Ask observers to estimate the strength of perception (generally give a number compared to the number of the standard) Fechner’s Law 14 7  Psychophysics (Magnitude Est.) Fechner’s Law (1850) Perceived Intensity S= k log(I) Physical Intensity A lawful relationship between psychological experience and physical world Foundation of “Psychophysics” 15 Psychophysics (Magnitude Est.) Response Compression and Expansion Response Expansion Response Compression 16 8  Psychophysics Donders’ Pioneering Experiment (1868) The experiment measured “Reaction Time” to infer how long it took to make a decision 17 Psychophysics Ebbinghaus’s Experiment The Forgetting Curve Percent Saving (%) Retention Period 18 9  Psychophysics The importance of Psychophysics All experiments described earlier slides show that how measurements of behavior can be used to investigate an aspect of the mind All of them can be called Cognitive Psychology because they are studying “Mind” 19 Structuralism and Introspection Structuralism Our overall experience is determined by combining basic elements of experience Method: Introspection The study of conscious mental events by “introspecting” or “looking within” Introspection involve the observation and recording of one’s own thoughts and experience 20 10  Structuralism and Introspection Wilhelm Wundt (1832 – 1920) “First” psychology lab, Leipzig, Germany, 1879 Separate from philosophy and physiology Psychology’s Goal: to study consciousness and the elementary units of thought Method: Introspection Careful, systematic observation and report of one’s thoughts or perceptions Requirements: extensive training, repeated observations Each sensation can be described by its: quality, intensity, duration, clearness, and extent 21 Gestalt Psychology (1910 – 1940) Gestalt: “Configuration” or “Pattern” Gestaltists studied: Perceptual organization, problem solving, insight learning, social psychology Argued against structuralism Complex perceptions cannot be reduced to their most basic elements because the whole is greater than the sum of the parts 22 11  Behaviorism Behaviorists wanted to restrict psychology to truly objective, observable data Stimulus Response The mind, they argued, is like a “black box”. The contents cannot be observed scientifically. Thus, we should concentrate our efforts on understanding the relationships between stimulus and response. 23 Behaviorism Psychology is the “science of behavior” Emphasis on what can be directly observed Stimuli Responses Reinforcements / Rewards Ignore the mind (unobservable). Goal: predict behavior 24 12  Behaviorism Ivan Pavlov (1849 – 1936) Classical Conditioning Unconditional Stimulus (Food) Unconditional Response (Salivation) Conditional Stimulus (Bell Sound) Unconditional Stimulus (Food) Conditional Response (Salivation) 25 Behaviorism Skinner (1950’s) Operant Conditioning Effects of rewards and punishments on animal behavior If an action is followed by a reinforcer (e.g., food), likelihood of performing that action will increase Behavior is determined by “Environment” Free will is an illusion 26 13  Behaviorism Problems with Behaviorism Cannot account for creativity and diversity of human behavior example of language Limiting science to observable things is a bad idea Who’s ever seen an electron? 27 Cognitive Revolution (1950 – 1960) Inspired by Inadequacy of behaviorism Information theory and computers New evidence of “hidden” cognitive processes: Maze learning by rats using “cognitive maps” (Tolman) Linguistic rules (Chomsky) Attentional bottlenecks in air traffic controllers (Broadbent) Limited short-term memory (Miller) 28 14  Cognitive Revolution (1950 – 1960) Information theory and computers Information Processing Approach Understand mental operations as information processing e.g., Sensory Information Processing Computational View of the Mind The mind operates like a computer Input Filter Detector Output Flow diagram for Broadbent’s filter model of attention 29 Neuron Structure and Function of each part of the Neuron 30 15  Neuron: Electric Signal Electric Signals in Neuron Resting Potential Hyper-Polarization Hypo-Polarization Action Potential Propagation of Action Potential 31 Neuron: Electric Signal Electric Signals in Neuron: Resting Potential -70mV At rest, inside of neuron is more negatively charged than outside (-70mV difference) 32 16  Neuron: Electric Signal Electric Signals in Neuron Hyper-Polarization Inside cell is charged negatively more than resting potential Hypo-Polarization (Depolarization) Inside cell is charged positively more than resting potential 33 Neuron: Electric Signal Electric Signals in Neuron: Action Potential Action Potentials are “All or None” If membrane potential exceeds threshold, neuron fires with same amplitude 34 17  Neuron: Electric Signal Electric Signals in Neuron: Action Potential Not the Size, “Firing Rate” 35 Neuron: Synapse Chemical Communication at the Synapse Presynaptic Membrane Synaptic Gap Postsynaptic Membrane 36 18  Neuron: Synapse Chemical Communication at the Synapse Neurotransmitter binds to the receptor at the postsynaptic membrane NT binding cause opening of ion channels in postsynaptic membrane (neurotransmitter-dependent ion channel) Membrane potential at the dendrite changes due to ion fluctuation Type of NT determines Excitatory (depolarizing) or Inhibitory (hyperpolarizing) synapse 37 Neuron: Synapse Neurons “Compute” information through synapse Integration of all signals from all dendrites determines the electric signal of the cell 38 19  Cognitive Neuroscience A Variety of Methods Neuro-anatomy Stimulation Imaging (structure and blood flow) Electrophysiology Disorders/Lesions (neuropsychology) 39 Cognitive Neuroscience Neuro-anatomy: The Limitation It allows you to examine the structure of the brain but not how it functions 40 20  Cognitive Neuroscience Brain Stimulation Advantages Can test if stimulating a region has a causal effect on cognitive function High Spatial Resolution Clinical Application Disadvantages Extremely Invasive, and hard to test patients in detail Stimulation effect might not be happening locally, but spreading elsewhere A significant number of brain regions appear to play a role in more than one cognitive function 41 Cognitive Neuroscience Disorder and Lesion Studies: The Limitation Extremely invasive Can’t select your participants or brain damage Deficits may not be specific Temporal resolution very poor 42 21  Cognitive Neuroscience Neuroimaging: The Limitation Relies on subtraction of baseline activity from when the brain is ‘really working’ Temporal resolution poor (tied to slow vascular responses) Expensive Shows correlation, not causation 43 Cognitive Neuroscience Electrophysiology: Single-Cell Recording Advantage High Spatial and Temporal Resolution Only way to measure response properties of individual neurons in vivo Disadvantage Limited Coverage: Measures only one neuron at a time, therefore, don’t know what is going on elsewhere Sampling Bias: Measure neurons with bigger response Input Specificity vs. Output Specificity 44 22  Cognitive Neuroscience Electrophysiology: EEG and ERPs Advantage High Temporal Resolution Whole-brain coverage Non-Invasive Disadvantage Poor Spatial Resolution Data can be hard to interpret Artifacts (e.g., blinks), noisy 45 Cognitive Neuroscience: Summary 46 23  Central Themes Nature of Perception? Self-Referenced Object Oriented Selective Invariant and Variant Relative Sensitive to Changes 47 The Perceptual Process Perception Knowledge Recognition Processing Action Transduction Environmental Stimulus Stimulus on Attended the Receptors Stimulus 48 24  Central Themes Bottom-Up and Top-Down Processing Computational Approach Center-Surround Receptive Field Elongated Receptive Field in Primary Visual Cortex Prior Knowledge Unconscious Inference Physical Regularity Semantic Regularity 49 The Perceptual Process Bottom-Up Processing: Computational Approach Physiological Supports Center-Surround Receptive Field - Excitatory-Center + Inhibitory-Surround RF + Inhibitory-Center - Excitatory-Surround RF 50 25  The Perceptual Process Bottom-Up Processing: Computational Approach Physiological Supports Center-Surround Receptive Field and Edge Detection +- +- +- +- +- +- +- 51 The Perceptual Process Bottom-Up Processing: Computational Approach Physiological Supports Elongated Receptive Field in Early Visual Cortex - + - + - + - - + - - + - + + - - 52 26  The Perceptual Process Bottom-Up Processing: Computational Approach Physiological Supports Elongated Receptive Field in Early Visual Cortex - - - - - ++ - ++ - ++ - ++ - + - - + - - + - - + - - + - - + - - ++ - - ++ - - ++ - - ++ - - + - - + - - + -- + -- + -- + -- - ++ - + - - ++ - - + - - - - - + + -- - ++ - ++ - ++ - + - + - - + - - + - - + - - ++ - - + - - + - - + - - + - - ++ - - ++ - - ++ - + -- + -- + -- + -- 53 The Perceptual Process Principles of Perceptual Organization Gestalt Approach The Whole differs from the sum of its parts Perception is not just created by combining elements Perceptual organization creates a ‘whole’ from small parts 54 27  The Perceptual Process Principles of Perceptual Organization How do we combine components to perceived the whole? Is there any basic rules that we use? Law of Pragnanz (Law of Simplicity) Law of Similarity Law of Good Continuation Law of Proximity Law of Common Fate Law of Familiarity 55 The Perceptual Process Principles of Perceptual Organization Gestalt Laws are Heuristics Heuristics: rules of thumb that provide a best-guess solution to a problem Algorithm: a procedure that is guaranteed to solve a problem 56 28  Perception and Action Neural Basis of Perception and Action Visual Processing Stream for What and Where Object Discrimination Problem Object recognition Landmark Discrimination Problem Relative Location 57 Perception and Action Neural Basis of Perception and Action Visual Processing Stream for What and How Dorsal stream involves in HOW TO direct actions for interacting with objects in environment Interacting with an object involves knowing the location of the object (where) 58 29  Perception and Action Neural Basis of Perception and Action Visual Processing Stream for What and How Neuropsychological Study Showing How-Pathway Behavior of Patient D.F. (with temporal lobe damage) Cannot make an orientation match, but can put a card into an oriented slit (single dissociation) Rod-and-Frame task Matching Task Grasping Task 59 Perception and Action Neural Basis of Perception and Action Visual Processing Stream for What and How Neuropsychological Study Showing How-Pathway Behavior of Patient D.F. Cannot make an orientation match, but can put a card into an oriented slit (single dissociation) Are these two (orientation judgment and interaction with orientation) functions independent? A patient whose symptoms are exactly the opposite to D.F. can be found (double dissociation) 60 30  Perception and Recognition Why is visual recognition hard? Different Sizes Different 2D Orientations Different 3D Views Different Exemplars Subordinate-level Recognition Occlusion Inverse Projection Problem 61 Perception and Recognition Why is visual recognition hard? Inverse Projection Problem 62 31