B.F. Skinnner Radical and then Modern Behaviorism

Burris Fredric Skinner

Burris Frederic Skinner Born in Pennsylvania BA degree in English from Hamilton College Masters/PhD from Harvard in 1930, 1931 Taught at Univ of Minnesota – Behaviors of Organisms, to Indiana University 1948 to Harvard; there until his death in 1990 Several important “human rights” books – Beyond Freedom and Dignity – Walden Two – Enjoy Old Age 2 daughters: one is psychologist Julie Vargas (runs autism program at WVU) and a pianist

Why Behaviorism defines "behavior" as what the animal is (observed to be) doing. – avoid anthropomorphizing or implying conceptual schemes – Simply describe what the animal is doing avoids preconceived notions and concepts about the animal's behavior

Narration as a descriptor: defining what is behavior narrate what the animal is doing- running frame of reference stimulus refers to environment correlated behavior is the response reflex = observed relation between the stimulus and response – (implies lawfulness) – is a fact, not a theory not want to "botanize" - but come up with general laws of behavior

Several laws of classical conditioning uses to distinguish from operant behavior Static laws of the Reflex: Really discussing classical conditioning here – law of threshold: the intensity of the stimulus must reach or exceed a certain critical value in order to elicit a response – law of latency: an interval of time elapses between the beginning of the stimulus and the beginning of the response – law of magnitude of the response: the magnitude of the response is a function of the intensity of the stimulus – law of after discharge: the response may persist for some time after the cessation of the stimulus – law of temporal summation: prolongation of a stimulus or repetitive presentation within certain limiting rates has the same effect as increasing the intensity

several laws of classical conditioning Dynamic laws of reflex strength: – law of refractory phase: immediately after eliciation the strength of some reflexes exists at a low, perhaps zero, value. It returns to its former state during subsequent activity – law of reflex fatigue: the strength of a reflex declines during repeated elicitation and returns to its former value during subsequent inactivity – law of facilitation: the strength of a reflex may be increased through presentation of a second stimulus which does not itself elicit the response – law of inhibition: the strength of a reflex may be decreased through the presentation of a second stimulus which has no other relation to the effector involved also discusses law of conditioning of Type S and law of extinction of Type S

Distinguishes between PAVLOVIAN and OPERANT conditioning Operant behavior is EMITTED not elicited static laws DO NOT apply to operant behavior Remember: still in day when CC does NOT equal OC – Believed were different kinds of learning – CC: visceral muscles – OC: skeletal responses

Dynamic laws of Type R behavior: HIS version of the Law of Effect law of conditioning of Type R: if the occurrence of an operant is followed by a presentation of a reinforcing stimulus, the strength is increased -notice that conditioning = strength of the operant law of extinction of Type R behavior: if the occurrence of an operant already strengthened through conditioning is not followed by the reinforcing stimulus, the strength is decreased can get stimuli that are correlated with R-S connections: thus can set the occasion for the R-S contingency

The reflex reserve: reflex reserve = total available activity for an animal there is a relation between the number of responses appearing during the extinction of an operant and the number of preceding reinforcements changes in drive do not change the total number of available responses, although the rate of responding may vary greatly emotional, facilitative, and inhibitory changes are compensated for by later changes in strength

Interaction of reflexes: important in that responses not occur in isolation law of compatibility: two or more responses which do not overlap topographically may occur simultaneously without interference law of prepotency: with two reflexes overlap topographically, and the responses are incompatible, one response may occur to the exclusion of another law of algebraic summation: the simultaneous elicitation of two responses utilizing the same effectors but in opposite directions produces a response the extent of which is an algebraic resultant

Interaction of reflexes: law of blending: two responses showing some topographical overlap may be elicited together but in necessarily modified forms law of spatial summation: when two reflexes have the same form of response, the response to both stimuli in combination has a greater magnitude and a shorter latency law of chaining: the response of one reflex may constitute or produce the eliciting or discriminative stimulus of another law of induction: a dynamic change in strength of a reflex may be accompanied by a similar but not so extensive change in a related reflex, where the relation is due to the possession of some common properties of stimulus or response

Defines properties of a class of a reflex under what conditions does the R occur? – in operant conditioning: what are the defining characteristics for reinforcement – Under what stimulus conditions does a response occur? What are the results? – Really the ABCs of operant behavior! What does the animal DO to get reinforced – must show a correlation between R and S – We will argue later that this must be a contingency! – must show that dynamic laws apply

Defining Skinner's methodology: direction of inquiry: – inductive rather than deductive – hypotheses declared to direct the choice of facts – not necessary, but guide what is a useful vs useless fact The organism: – Skinner wants to limit to one single representative sample – the white rat and/or pigeon- many advantages in terms of control The operant: – use bar pressing – Skinner box – again- assume that is equivalent to any other response – easy to measure- reliable, controllable, etc.

Skinner box: Pigeon pecks or rat bar presses to receive reinforcers

System of notation S = stimulus R = response S.R = respondent S R = reinforcer properties of term indicated with lower letters: – R abc response with properties a b and c – superscripts comment upon term- place, formula, etc. e.g. S 1 or S D also composite stimuli: S 1 S D --> = is followed by Now can analyze a chain or sequence of behavior: and string together to make "behavior sentences"

Important to control Extraneous Factors use maximal isolation e.g. sound attenuating chamber control "hunger" with deprivation, etc. – Usually around 80% free feeding – This is higher today (85-90%) – Maintains a constant “hunger” standardize feeders and reinforcers control light/day cycles, etc. as much experimental control as possible to reduce variance in experiments

The Cumulative Recorder Measuring the Behavior: important characteristics of measurement: definition of behavior as that part of activity of the organism which affects the external world the practical isolation of the unit of behavior definition of a reponse as a class of events demonstration that the rate of responding is the principal measure of the strength of an operant cumulative record Responses accrue or are cumulative What happens if the line goes down?

Reinforcers vs. Punishers Positive vs. Negative Reinforcer = rate of response INCREASES Punisher = rate of response DECREASES Positive: something is ADDED to environment Negative: something is TAKEN AWAY from environment Can make a 4x4 contingency table

ReinforcementPunishment PositivePositive Reinforcement(Positive) Punishment Add make bed-->10centhit sister->spanked Stimulus NegativeNegative ReinforcementNegative Punishment Remove make bed-> Mom stopshit sister->lose TV Stimulusnagging

Parameters or Characteristics of Operant Behavior Strength of the response: – With each pairing of the R and Sr/P, the response- contingency is strengthened – The learning curve is Monotonically ascending Has an asymptote There is a maximum amount of responding the organism can make

Parameters or Characteristics of Operant Behavior Extinction of the response: – Remove the R  Sr or R  P contingency – Now the R  0 Different characteristics than with classical conditioning: – Animal increases behavior immediately after the extinction begins: TRANSIENT INCREASE – Animal shows extinction-induced aggression! – Why?

More parameters: Generalization can occur: – Operant response may occur in situations similar to the one in which originally trained – Can learn to behavior in many similar settings Discrimination can occur – Operant response can be trained to very specific stimuli – Only exhibit response under specific situations Can use a cue to teach animal: – S+ or S D : contingency in place – S- or S : contingency not in place – Thus: S D : R  Sr

Schedules of Reinforcement: Continuous reinforcement: – Reinforce every single time the animal performs the response – Use for teaching the animal the contingency – Problem: Satiation Solution: only reinforce occasionally – Partial reinforcement – Can reinforce occasionally based on time – Can reinforce occasionally based on amount – Can make it predictable or unpredictable

Partial Reinforcement Schedules Fixed Ratio: every nth response is reinforced Fixed interval: the first response after x amount of time is reinforced Variable ratio: on average of every nth response is reinforced Variable interval: the first response after an average of x amount of time is reinforced

More parameters Shaping – Final behavior must be within repertoire of organism – Break behaviors into smallest component – Chain up or down Secondary reinforcement – Stimuli can be paired with primary reinforcer – E.g. money Generalized reinforcers – Reinforcers reinforce many behaviors – E.g., money reinforcers many, many behaviors Chaining: – Make a chain of behaviors – E.g., 1 behavior leads to another to another to another……makes a chain of behavior.