II. Operant Conditioning A. Skinner’s Analysis B F Skinner expanded the Law of Operant Conditioning Effect in the 1940s and 1950s into (Lecture 6) a system called Operant Conditioning. Operant Conditioning is learning produced by the active behavior of an organism interacting with the environment. Skinner renamed some terms B (Behavior) C (Consequence) became R (Response) Sr (Stimulus reinforcer)
II. Operant Conditioning II. Operant Conditioning A. Skinner’s Analysis A. Skinner’s Analysis Skinner characterize two types of Sr(s) Increase probability Decrease probability of behavior of behavior Sr+ (pleasant or rewarding) Positive Extinction Sr- (aversive or noxious) Reinforcement (Negative Punishment ) He also characterized two types of effects that Sr+ R increases in frequency R decreases in frequency Sr can have on behavior: Pleasant because it introduces a because it no longer elicits Stimulus pleasant stimulus a pleasant stimulus increase the probability of the behavior occurring reinforcer. reinforcer (as it once did). again (Reinforcement). Negative Punishment decrease the probability of the behavior occurring Reinforcement (Positive Punishment) again (Punishment). Sr- R increases in frequency .R decreases in frequency because it introduces a Noxious because it removes noxious stimulus Thus we have four possible ways to change Stimulus (escapes) a noxious behavior. stimulus reinforcer reinforcer
1 II. Operant Conditioning II. Operant Conditioning B. Four ways to change behavior B. Four ways to change behavior 1. Positive Reinforcement 2. Negative reinforcement Increases the probability of behavior by the behavior Increasing the probability of avoidant or escape introducing a positive (pleasant) consequent (Sr+). behavior by removing a negative (noxious) An anorexic woman was treated by therapists consequent (SR-). making social visitation and other privileges (a A person with difficulty stuttering was given pleasant stimulus) contingent on her eating. negative reinforcement by wiring him up so that Thus the behavior of eating (R) was increased because it whenever he stuttered, he would get delayed had the consequent of a positive reinforcer (Sr+). auditory feedback (a noxious stimulus). Thus the behavior of normal speech (R) was increased because such behavior avoids the noxious stimuli (Sr-) that was made a contingency of stuttering.
II. Operant Conditioning II. Operant Conditioning B. Four ways to change behavior B. Four ways to change behavior 3. Punishment 4. Extinction Decreasing the probability of behavior by it being Decreasing the probability of behavior by having a followed by a negative (noxious) consequence (Sr-). positive (pleasant) reinforcer removed. Sometimes that is called Positive Punishment because Sr- Sometimes that is called Negative Punishment because is introduced or added to the situation Sr+ is taken away or removed from the situation. Autistic children have been shown to stop antisocial A child who throws temper tantrums when his behavior when a mild shock was made contingent. parent leave the child’s bedroom at night has his The probability of antisocial behavior was decreased by temper tantrums reduced by the parents merely introducing a contingent aversive reinforcer (Sr-). ignoring them. Problems with punishment The attention of the parent was supporting the tantrums, Mindless/enraged application, Fear in recipient, Effect is so to reduce their probability of occurring, the positive temporary, Not immediate enough, No shaping of reinforcer (Sr+) supporting the unwanted behavior was appropriate behavior. removed.
2 II. Operant Conditioning II. Operant Conditioning B. Four ways to change behavior C. Primary and Secondary Reinforcers Child who hits other children: Two types of Reinforcers: Decrease probability of hitting behavior. Primary: Sr which is inherently reinforcing or Increase probability of social behavior. punishing , typically by satisfying a biological need or being biologically aversive. Roommate who plays music too loud: Secondary: Sr which is not inherently reinforcing Decrease probability of loud music. or punishing but has acquired such properties Increase probability of softer music through association. Money, praise, demerits, Roommate who is does not leave messages: criticisms grades Increase leaving message behavior. Be careful not to evoke mental states such as Decrease not leaving message behavior. goals, wants, etc. when thinking about Srs
II. Operant Conditioning II. Operant Conditioning D. Shaping and successive approximations E. Sd Generalization and Discrimination Shaping: Procedure in which successive We have only considered behavior in light of approximations of a desired behavior are environmental contingencies that control it reinforced. after it has been performed: R Sr Successive approximations : Increasing There is another aspect of the control of behavior. closeness or similarity to the desired response. Think of a telephone call. Room Cleaning Your behavior of calling a sequence of numbers is a response (R) and you talking to a person is the positive 1. Reinforce child when he is in the room. reinforcement (Sr+). 2. Reinforce child for touch things on the floor. If you pick up a phone and don’t hear a dial tone, 3. Reinforce child for picking up things on the floor. you won’t dial. 4. Reinforce child for putting away things that are on If you pick up a phone and hear a dial tone, you floor. will dial
3 II. Operant Conditioning II. Operant Conditioning E. Sds, Generalization and Discrimination E. Sd Generalization and Discrimination The presence or absence of An animal trained to a tone (Sd) signaling that the dial tone serves as a Speaker Discriminative Stimulus a bar press (R) will be positively reinforced (Sd): (Sr+), will show two properties Sd: A stimulus that signals Generalization : Sds similar to target Sd will have that a response will (or will not) lead to a stimulus similar influences on behavior. reinforcer. Similar sounding tome will produce bar pressing Sd R Sr+ A hungry or thirsty rat in a Discrimination : Sds dissimilar to target Sd will dial tone dialing talking Skinner box quickly learns have dissimilar influences on behavior. Skinner studied the that pressing the bar (R) when Dissimilar sounding tone will produce less bar pressing environmental control the light or buzzer is on (Sd), behavior in Skinner Boxes a food pellet or drop of water designed for lab rats. is released (Sr+).
II. Operant Conditioning II. Operant Conditioning E. Sd Generalization and Discrimination F. Schedules of Reinforcement Pattern of generalization and discrimination Srs may be delivered after each behavior (R ) or on some schedule How might Continuous Schedule of Reinforcement: Every this apply R gets a Sr to the real Partial: Not every R gets Sr. It varies over time (interval) or by number (ratio) of Rs . Bar world? pressing Consider two women each going to a party and rate each meeting a new boy. Each boy says he will call her everyday at 6:00 o’clock. Boy A does so but boy B calls only every so often ay 6:00. Say each boy decides never to call again, which woman waits at 6:00 for a longer period of time? Low toneTrained tone High tone
4 II. Operant Conditioning F. Schedules of Reinforcement Rs under different Distribution schedules of Fixed Variable reinforcement FIXED VARIABLE INTERVAL INTERVAL Time Waiting for a letter and Studying frequently and regularly for unpredictable (Interval) checking more frequently as the time of mail delivery pop quizzes. Measure approaches Between Srs FIX VARIABLE RATIO RATIO . Number Piecework payment which Gambling (slot (Ratio) makes people work harder machine), which the next closer to completion of the payoff is unpredictably product than the beginning. related to the last one.
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