Empirical Background for Skinner s Basic Arguments Regarding Selection by Consequences Iver Iversen University of North Florida, Jacksonville Presentation at NAFO, April 2016 Gol, Norway
Skinner was Controvercial
1971
1948. A novel about a utopian society based on positive reinforcement. Fun to read!
Three Levels of Variation and Selection Evolution of life Conditioning, Pavlovian and Operant Evolution of Cultures
Second Level, Operant Conditioning Operant conditioning occurs at a speed at which it can be observed from moment to moment Operant conditioning is selection in progress. It resembles a hundred million years of natural selection or a thousand years of the evolution of a culture compressed into a very short period of time (p. 502)
Today s Purpose Try to show what Skinner had discovered in the laboratory that led him to these arguments about selection by consequences. What does he mean by moment to moment And by a very short time These expressions refer to concrete findings in his early research with rats (1930 s)
Ivan Pavlov First to seriously study intact animals one at a time in great detail under controlled conditions Pavlov was influenced by physiologists and received the Nobel Price in Physiology (1904) His later work is what he is famous for in Psychology 10
Example of Pavlov s Research, One Dog From Pavlov (1927) 11
Single Trial from One Dog Detailed Event Chart of Salivation Top: Salivation From Pavlov (1927) Bottom: Onset of Conditioned Stimulus (left) and Unconditioned stimulus (right) 12
Thorndike Thorndike at around the time he came to Harvard University From: Joncich (1968) The older Thorndike From:http://www.s9.com/Biography/Thorndike- Edward-Lee
Puzzle Box
From: Boakes (1984)
Examples of learning curves from Thorndike s book Animal Intelligence (1911). Each curve is from one animal in one box. Trials on the X-axis. Latency on the Y-axis (no scale).
Logical Diagram
Law of Effect : Trial and Error Unnecessary behavior was stamped out (the errors) Successful behavior was stamped in (occurred sooner) A Learning Curve represented the gradually shortening latencies as the undesirable responses dropped out Early work on Selection by Consequences The Effect mattered for behavior
Skinner 1904-1990 PhD from Harvard 1931 From: Skinner, 1979
Scientific Methods Skinner followed the mantra from Pavlov: Control your conditions and you will see order From Crozier (Skinner s mentor) and Pavlov, he learned to look for details in behavior and to set up experiments where each subject (rat) served as its own control 21
Initial Research Skinner first studied eating reflexes and had rats open a door to a food tray to make a pellet drop down and recorded door openings the eating reflex But this response was both learned and part of the food retrieval process To separate the two, he therefore made a lever that the rat had to press to deliver the food 22
First Lever Pressing Experiment Four food deprived rats Habituation to the box Magazine training (lever present but fixed so it couldn t move) Lever was released and each press produced a food pellet (no shaping) All 4 rats learned to press the lever 23
From: Skinner,. B. F. The behavior of Organisms, 1938.
Famous First Data, 1932 25
Skinner: Even one single reinforcer changes behavior
Time Scale These results are what led Skinner to later argue for moment to moment changes in behavior Plus even a single reinforcer can affect behavior These conditioning effects occur in very short time scales, even less than one minute Hence: Operant conditioning occurs at a speed at which it can be observed from moment to moment The effect was instantaneous, there was no behavior to stamp out, as for Thorndike, and there was no Learning curve
Acquisition Such data changed psychology Skinner said many times that one important aspect of reinforcement is that it may change behavior instantaneously But it is often forgotten that he also showed how a single reinforcer is sufficient for immediate change of behavior These findings are easy to observe and to replicate Video link
Extinction Skinner removed the reinforcer for already established behavior and saw dramatic extinction curves This was Pure Behavior resulting from previous conditioning history
Skinner (1979) in Iversen (1992)
Role of Extinction Extinction was the turning point for Skinner: Free operant without any kind of eliciting stimulus Extinction plays a role in Shaping creation of novel behavior Extinction plays a role in acquisition of complex, sequential behavior
Free Operant It meant behavior not prompted or elicited or goaded by a current stimulus In Thorndike s experiment the behavior was not free to occur at any time, animal had to get in and out of the box for each response In Skinner s box the rat could press any time In extinction, there is nothing happening before or after the response, yet it occurs Previous conditioning history is what controls the behavior
Skinner s Conclusions Acquisition can be very fast Can be seen in individual rats Extinction shows the influence of past history Voluntary behavior can be controlled Behavior is not goal directed The future does not affect behavior, only past consequences influence the behavior
Schedules of Reinforcement
Schedules Were discovered as combinations of extinction curves
Stimulus Control Later Skinner added a stimulus when a response could be reinforced and all other responses extinguished. The response would occur only when the stimulus was presented This was a method to control when (and where) a voluntary response will occur Skinner focused on the Function of a stimulus not on discrimination
Stimulus Control Development Skinner s methods were developed over many steps, too long and complicated to describe here Ending in a clear formulation: Three-Term Contingency Shows instantaneous selection of behavior, when the stimulus is presented. Voluntary behavior is controlled. Momentary stimulus control results of previous history
Summary Skinner revolutionized psychology by getting rid of the stimulus as a goad for behavior as in Reflexology The operant had no identifiable stimulus that made it occur, it was free of control at the moment it occurred, hence free operant = voluntary behavior Incredibly, the next revolution was to put the stimulus back again, but this time serving a discriminative function of voluntary behavior The Three-Term Contingency is a way for the environment to select behavior immediately: Stimulus On Behavior occurs This had a profound influence on Skinner s development of Verbal Behavior 38
Time Scales The time scale of behavior change was very short, minutes or even less This was a drastic change to Pavlov and Thorndike As Skinner said, conditioning can occur with one single reinforcement and nothing is faster than that Much modern research focuses on collecting data over large time scales
JEAB, 1976, 25, 218 These "molecular changes in probability of responding are most immediately relevant to our own daily lives.
Thank You 41
References Boakes, R. (1984). From Darwin to behaviorism: Psychology and the minds of animals. New York: Cambridge University Press. Iversen, I. H. (1992). Skinner s early research: From reflexology to operant conditioning. American Psychologist, 47, 1318-1328 Joncich, G. (1968). The sane positivist: A biography of Edward L. Thorndike. Middletown, CN: Wesleyan University Press. Pavlov, I. P. (1927). Conditioned reflexes. (G. V. Anrep, Trans). London: Oxford University Press. Skinner, B. F. (1938). The behavior of organisms: An experimental analysis of behavior. Appleton-Century-Crofts, New York. Skinner, B. F. (1948). Walden two. Macmillan, New York. Skinner, B. F. (1971). Beyond freedom and dignity. Knopf, New York. Skinner, B. F. (1976), Farewell my lovely! Journal of the Experimental Analysis of Behavior, 25, 218. Skinner, B. F. (1979). The shaping of a behaviorist. Knopf, New York. Skinner, B. F. (1981). Selection by consequences. Science, 213, 501-504 Thorndike, E. L. (1911). Animal intelligence. New York: Macmillan
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