PSY 3360 / CGS 3325 Historical Perspectives on Psychology Minds and Machines since Psychopathic criminals have empathy switch

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1 PSY 3360 / CGS 3325 Historical Perspectives on Psychology Minds and Machines since 1600 Chimpanzee Intelligence Is Heritable Dr. Peter Assmann Summer The Mixed-Up Brothers of Bogotá Psychopathic criminals have empathy switch Vienna Circle (1920s) Logical positivism All knowledge is derived from experience. Science applies strict criteria of verifiability by empirical means to test the meaningfulness of any statement. All theoretical terms must be directly linked to empirical observations. Combined formal logic with radical empiricism. Percy Bridgman ( ) Bridgman (1927) every abstract concept in physics must be defined in terms of the procedures used to measure it. Operational definitions provide a basis for attaching every theoretical construct to observable empirical phenomena (or data). 1

2 Operationism Operationism: insistence that all abstract scientific terms must be operationally defined. Behaviorists attempted to provide operational definitions of concepts like drive, anxiety, and intelligence. Psychology in Russia: The Reflex School Emphasis on the physiological basis of behavior and learning External (physical) causes of behavior Psychology as the science of behavior: Origins of behaviorism Ivan Michailovich Sechenov ( ) Russian physiologist who trained with Müller and Helmholtz Viewed the mind as an epiphenomenon Concluded that introspection was often unreliable Major work: Reflexes of the Brain (1863) All external manifestations of brain activity can be attributed to muscular movement. All conscious voluntary movements are reflexes. Proposed that neural excitation and inhibition could serve as explanatory concepts in psychology. Ivan Michailovich Sechenov ( ) Excitation: an increase in neural activity following stimulation. Inhibition: a process by which neural activation is reduced following stimulation. Sechenov s approach was popularized by the Russian physiologist Vladimir Michaelovitch Bechterev ( ) who called it reflexology. Ivan Petrovich Pavlov ( ) Russian physiologist who developed the concept of the conditioned reflex. Won the Nobel Prize for Physiology and Medicine in Ivan Petrovich Pavlov ( ) Materialism mental processes are unnecessary concepts Atomism complex behaviors described as the product and accumulation of many simple elements Associationism Learned behaviors are the product of chains of associations or conditioned reflexes 2

3 Ivan Petrovich Pavlov ( ) Classical Conditioning Studied salivation in dogs; discovered that stimuli other than food can induce salivation. Developed methodology of classical conditioning (also called Pavlovian conditioning) a neutral stimulus leads to a response as a result of being paired with another stimulus that already produces the response. Pavlov called this a conditioned response. Unconditioned stimulus (US) Unconditioned response (UR) Conditioned stimulus (CS) Conditioned response (CR) Classical Conditioning Dogs have an innate tendency to salivate at the sight of food. Food is the US, and salivation is the UR. Next, the US (food) is presented with a CS that does not elicit the response, e.g. the sound of a metronome. After repeated pairing of the CS and US, the CS will begin to elicit the same response (UR), now called the conditioned response (CR). Generalization and Discrimination Generalization: Conditioned responses often occur to stimuli that are similar to (but not identical to) the original CS. Generalization and Discrimination Extinction Discrimination (or differentiation): At first animals respond indiscriminately to a range of stimuli (generalization). By selective reinforcement, Pavlov trained his animals to make a conditioned response to the reinforced stimulus, but not to other stimuli. Extinction: If the CS is paired repeatedly without the US, the CR will eventually disappear, or become extinguished. 3

4 Persistence of Conditioned Response Spontaneous recovery: after some time the response may reappear, and the CS will again elicit the CR. Presenting a sudden strong, irrelevant stimulus can also cause the CR to reappear. Pavlov interpreted this as evidence that extinction was the result of inhibition. Disinhibition resulting from the sudden strong stimulus displaces the inhibitory process and restores the CS. Experimental Neurosis Pavlov observed neurotic behavior (avoidance of the experiment room and unpredictable aggressive outbursts) when the dogs were required to make finer and finer discriminations between stimuli in a classical conditioning discrimination experiment. Pavlov attributed this behavior to unavoidable conflicts between two strong but incompatible conditioned responses. Language and Symbolic Behavior Problem for Pavlov: how to account for language? Symbolic activity that involves a link between an arbitrary symbol and its referent. Pavlov proposed a two-part theory of language: First signal system: association between a signal (CS) and biologically meaningful events. For example, the smell of smoke can serve as a warning signal. Second signal system: process by which we come to associate arbitrary symbols (words) with events and objects in the world ( signals of signals ). Eventually we respond to shouts of Fire! in the same way we respond to the smell of smoke. Edward Lee Thorndike ( ) Instrumental Learning Law of Effect: when several responses are made to the same situation, those which are accompanied with rewards are more likely to be repeated, while those accompanied by punishment are more likely to be avoided. Edward Lee Thorndike ( ) Law of Exercise: a response is more strongly linked to a situation the more often it has been linked with it in the past, and depending on how strong and long-lasting the link has been in the past. stimulus-response (S-R) learning theory John Broadus Watson ( ) Early life University of Chicago Jacques Loeb ( ) tropisms Henry Donaldson ( ) neurologist; CNS development in rats Robert Yerkes ( ) animal behavior Karl Lashley ( ) homing behavior in birds; localization of brain function; physiological basis of memory; the problem of serial order in behavior 4

5 John Broadus Watson ( ) Psychology as the behaviorist sees it Objective basis; no subjective data, introspection, or interpretation of conscious experience. Goal: predict & control overt behavior No accepted division between humans and other animals; focus on biological and psychological similarities among animal species John Broadus Watson ( ) The move to Johns Hopkins Instinct as a set of reflexes activated by heredity Conditioned responses Conditioned fear: Little Albert Scandal The move to advertising work Origins of the behaviorist movement Radical Environmentalism Give me a dozen healthy infants, wellformed, and my own specified world to bring them up in and I ll guarantee to take any one at random and train him to become any type of specialist I might select - doctor, lawyer, merchant-chief and yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors. B.F. Skinner ( ) Skinner did not see any need for abstract theoretical concepts in psychology; but insisted that all methodological terms be operationally defined. B.F. Skinner ( ) Burrhus Frederic Skinner Radical environmentalist Behaviorist Inventions: Air-crib, Skinner box Operant conditioning Reinforcement learning Principles of programmed learning B.F. Skinner ( ) Skinner described two main forms of learning: respondent (Pavlovian) conditioning operant (voluntary, learned) behavior 5

6 Experimental Analysis of Behavior Independent variables Dependent variables Locus of variables Descriptive behaviorism Respondent vs. operant behavior Contingencies of reinforcement Behavior is a product of reinforcement history B.F. Skinner ( ) The Behavior of Organisms (1938) Walden Two (1948) Science and Human Behavior (1953) Verbal Behavior (1957) The Analysis of Behavior (with J.G. Holland, 1961) Technology of Teaching (1968). Beyond Freedom and Dignity (1971) Particulars of My Life (1976) The Shaping of a Behaviorist (1979) A Matter of Consequences (1983) Recent Issues in the Analysis of Behavior (1989) Skinner Box B.F. Skinner Operant behavior: operant response (naturally occurring behavior) reinforcement (alters probability of response) setting (situation in which behavior is emitted) Experimental analysis of behavior: systematic description of contingencies of reinforcement Cumulative recorder Instrument used to record behavior Consists of a rotating drum of paper and a marking pen The marking pen starts at the bottom of the page and the drum turns the roll of paper horizontally. Each behavioral response moves the pen vertically along the paper by one unit. Operant Conditioning Cumulative record Total number of bar presses 50 reinforced responses 25 accidental responses Time in minutes 6

7 Operant Conditioning Extinction of an operant response Total number of bar presses response is extinguished Time in minutes Reinforcement Reinforcement strengthens responses Positive reinforcement Rewards participant while it is present Negative reinforcement Rewards participant when it is withdrawn Operant Conditioning Contingencies of reinforcement Reinforcement schedules Continual vs. intermittent reinforcement Interval vs. ratio schedules Fixed vs. variable schedules Operant Conditioning Fixed-interval reinforcement schedule Fixed-ratio reinforcement schedule Variable-interval reinforcement schedule Variable-ratio reinforcement schedule Operant behavior: B.F. Skinner operant response (naturally occurring behavior) reinforcement (alters probability of response) setting (situation in which behavior is emitted) Experimental analysis of behavior: systematic description of contingencies of reinforcement Project Pigeon (1944) WW II guided missiles Pigeons trained to peck at a target to hold guided missile on target 7

8 B.F. Skinner The innate behavior of animals is shaped and maintained by its contribution to the survival of the individual and species. Operant behavior is shaped and maintained by its consequences for the individual. Behavior Modification Change consequences of behavior Remove consequences that cause problems Arrange new consequences for desired behaviors that lack strength Skinner s teaching machine Speech and Language Verbal Behavior (1957) speech and language are forms of verbal behavior whose reinforcement is mediated by other people. Speech and Language Verbal Behavior (1957) Verbal operants vocal responses conditioned through operant learning operant responses contingencies of reinforcement tact: a verbal operant response under the stimulus control of the environment Theories of language behavior Pavlov language as conditioned responses first and second symbol systems Lashley complex planned behavior rejection of telephone switchboard metaphor central planning agency for mapping and controlling long sequences of behavior The problem of serial order in behavior 8

9 Operant behavior: B.F. Skinner operant response (naturally occurring behavior) reinforcement (alters probability of response) setting (situation in which behavior is emitted) Experimental analysis of behavior: systematic description of contingencies of reinforcement 9