Chapter 2 - How To Study Cognition PDF

CHAPTER 2: HOW TO STUDY COGNITION STUDYING COGNITION How does one study cognition? Measure the physical brain? Study behavior produced by the brain? Reflect on subjective experiences? Create simulations? FOOD FOR THOUGHT Nature vs. nurture We’re born with it We le...

CHAPTER 2: HOW TO STUDY COGNITION STUDYING COGNITION How does one study cognition? Measure the physical brain? Study behavior produced by the brain? Reflect on subjective experiences? Create simulations? FOOD FOR THOUGHT Nature vs. nurture We’re born with it We learn it NATURE NURTURE NATURE NURTURE MIND AND BRAIN Mind-Body Problem What is the relationship between the mind and the body? How do physical mechanisms taking place in the body give rise to the mental events of the mind? Are these the same thing? Are all the things of mental life (remembering, thinking, reasoning, etc.) produced by the same physical stuff that allows us to move and breathe? MIND AND BRAIN: DUALISM VS. MONISM Dualism The mind and body are fundamentally different, but work together The physical body affects the mind and vice versa Monism There is only one substance in the world Physicalism/materialism Neutral monism MIND AND BRAIN: THE CURRENT VIEW Products of the mind may ultimately be understood in terms of the workings of the physical brain A form of materialism? Neutral monism? Believes a full understanding of how the brain works is possible We’re not there yet… Observable behaviors may be explained by physical mechanisms Subjective experience may not be THE BRAIN AND BEHAVIOR The physical brain is the ‘cause’ of cognition…so why not just study the brain? The brain is complex and our understanding is poor Human and chimpanzee brains are very similar Brains of different people are very similar but we are different Limitations of our current understanding: Why do different brains produce different behaviors? Solution? Observe the behavior to know what the brain does THE BRAIN AND BEHAVIOR HISTORICAL APPROACHES TO COGNITIVE PSYCHOLOGY Structuralism Behaviorism The Cognitive Approach THIS IS YOUR BRAIN… STRUCTURALISM Founded by Wilhelm Wundt in 1876 Study the workings of the mind directly Introspection Carefully consider and describe your own internal experiences Hope to discover basic principles of how the basic elements of consciousness combined to form the working mind THIS IS YOUR BRAIN ON STRUCTURALISM… LIMITATIONS OF STRUCTURALISM Data can only be seen by one individual Not objectively verifiable by others No ability for replication Different researchers performing the same experiment using the same method should get the same, verifiable results LIMITATIONS OF STRUCTURALISM Brain activity takes place outside of our awareness Language Knowledge of grammar is implicit The small red house  La pequeña roja casa Three beautiful small rectangular old Spanish mahogany study desks Cortical blindness Damage to part of the brain that processes incoming visual stimuli Blindsight Responding to visual stimuli without consciously perceiving them INDUCING BLINDSIGHT BEHAVIORISM Founded by John Watson in 1913 Objectively observable data Stimulus  Response Stimulus Conditions to which an experimental subject is being subjected Response The behavior a subject engages in THIS IS YOUR BRAIN ON BEHAVIORISM… THE FACTORY METAPHOR BEHAVIORISM: CLASSICAL CONDITIONING Ivan Pavlov Classical conditioning An involuntary behavior can be induced by a stimulus that wouldn’t normally cause such a reaction, based on the fact that the stimulus was previously paired with a different stimulus that naturally causes that reaction BEHAVIORISM: CLASSICAL CONDITIONING TERMS Unconditioned Stimulus (UCS) Conditioned Stimulus (CS) Neutral Stimulus (NS) Unconditioned Response (UCR) Conditioned Response (CR) BEHAVIORISM: PAVLOV’S DOG…RING A BELL? BEHAVIORISM: LITTLE ALBERT Step 1 BEHAVIORISM: LITTLE ALBERT Step 2 BEHAVIORISM: LITTLE ALBERT Step 3 LITTLE ALBERT: STIMULUS GENERALIZATION BEHAVIORISM: OPERANT CONDITIONING B.F. Skinner Operant Conditioning Change voluntary behavior based on stimulus-response feedback Response feedback Reward & punishment Reinforcement learning Learning which behaviors are rewarded and punished and choosing actions accordingly RECAP Historical Perspectives Structuralism Introspection (study the mind directly) Behaviorism Stimulus  response (observable behavior) Classical conditioning (training involuntary responses) Operant conditioning (reward & punishment) BEHAVIORISM: OPERANT CONDITIONING Reward Positive Reward (candy for correct answers) Negative Reward (turning off alarm) Punishment Positive Punishment (getting extra homework) Negative Punishment (getting grounded) BEHAVIORISM: OPERANT CONDITIONING BEHAVIORISM: SKINNER BOXES Operant Conditioning Chambers REINFORCEMENT SCHEDULES Continuous Reinforcement Receiving a reward or punishment every time Intermittent Reinforcement Fixed Interval: Reinforcement after a fixed amount of time Fixed Ratio: Reinforcement after a fixed number of responses Variable Interval: Reinforcement after a random amount of time Variable Ratio: Reinforcement after a random number of responses LIMITATIONS OF BEHAVIORISM People engage in novel behaviors Generating novel, meaningful sentences Latent learning Learning in the absence of conditioning LIMITATIONS OF BEHAVIORISM: TOLMAN’S MAZE THE RISE OF COMPUTERS Computers are machines that can compute functions A mapping between one set of objects and another Functions take an input and produce an output Algorithm A method for producing the correct output from an input THE RISE OF COMPUTERS: ALAN TURING Universal Turing Machine Takes any input Takes a set of instructions for what function to compute Produces an output A programmable computer! Its function can be changed by different sets of instructions THE RISE OF COMPUTERS: BINARY Binary The encoding of information based on whether some device is on or off The brain as a computer? Neurons can fire (ON) or not (OFF) Cognitive Revolution THE COGNITIVIST PERSPECTIVE Cognition can be viewed as a type of function Input = sensory input Information processing = what happens in the middle Output = behavior The Goal: What underlying algorithm does the brain use to compute its functions? THE COGNITIVE APPROACH Based on the idea that we can measure objective behavior in order to test theories of the underlying mental processes What’s in here??? THE COGNITIVE APPROACH: DONDERS (1868) How do individual responses consist of component processes? THE COGNITIVE APPROACH: MENTAL IMAGERY Mental Imagery The experience of seeing something in your mind in the absence of real stimulation Cognition as a form of information processing The way the mind represents and manipulates information might lead to observable behaviors THE COGNITIVE APPROACH: MENTAL ROTATION Does the mind actually perform an operation like rotation to do the task? Yes, it does! COGNITIVE PSYCHOLOGY AS A DISCIPLINE An indirect science Cognitive psychologists are typically concerned with testing the properties of proposed underlying mechanisms Not concerned with the task itself Some areas are concerned with task performance Human factors: how people interact with physical systems EXPERIMENTAL MEASURES Behavioral experiments The point of an experiment is to test the effect of different stimuli or levels of a stimulus on one or more outcome measures EXPERIMENTAL MEASURES Subjects/participants Independent variables Dependent variables Outcome measures Accounting for variability INDEPENDENT AND DEPENDENT VARIABLES Independent Variable The properties of a stimulus that are manipulated by the experimenter Dependent Variable The behavioral response of interest Must be measurable OUTCOME MEASURES Correctness Was the response accurate? Thresholds When can you tell the stimulus changed? Reaction time How long did it take to produce a response? Subjective measures THRESHOLD EXAMPLE THRESHOLD EXAMPLE VARIABILITY PROBLEMS Confounding variables An extraneous variable that unintentionally affects the results of a study Individual differences There may be significant differences in the way two people perform a task ACCOUNTING FOR VARIABILITY Numerous trials Multiple repetitions of each condition in a task Analyze the average of all trials Representative samples Include a large sample size characteristic of the population of interest COMPLEMENTARY APPROACHES TO COGNITIVE PSYCHOLOGY Cognitive neuroscience Behavioral neuroscience Computational neuroscience COGNITIVE NEUROSCIENCE Hybrid field Combines behavioral experiments with methods for measuring brain activity Provides empirical triangulation for a theory Mental rotation example BEHAVIORAL NEUROSCIENCE Incorporates behavioral experiments and physiological measures of the brain Majority of research includes animal populations Lesioning Causing irreparable damage to parts of the brain Electrodes Implant electrodes to record activity of individual neurons Optogenetics Introducing a chemical agent that binds to specific neurons COMPUTATIONAL NEUROSCIENCE Building computer-based models designed to simulate some aspect of the brain or carry out a cognitive task Artificial neural networks Help understand the brain as a computer Deep neural networks consist of many layers of simulated neurons