Clark Leonard Hull

Hull Background Born 1884 in Akron NY Graduated U. of Michigan in 1913 Ph.D. U. of Wisconsin Professor of Psychology at Yale Died 1952 Developed Hypothetico- Deductive System

Clark Hull S E R = Reaction potential S H R = habit strength D = Drive I R = reactive inhibition S I R = conditioned inhibition S O R = oscillation effect S L R = Threshold S t R = reaction time p = response probability n = trials to extinction A = response amplitute

Clark Hull Postulate 1 & 2 Sensing the External Environment and the Stimulus Trace –Stimulus Trace S-s-R The Interaction of Sensory Impulses = 

Clark Hull S1S1 S2S2 S3S3 S4S4 S5S5 s1s1 s2s2 s3s3 s4s4 s5s5 srR

Clark Hull Postulate 3 Unlearned Behavior - an need arises an the individual has a hierarchy of responses patterns to take care of this need. These response patterns are innate and if the first response pattern doesn’t work then we go to the second.

Clark Hull Postulate 4 Contiguity and Drive Reduction as Necessary Conditions for Learning –If a stimulus leads to a response and its satisfies a biological need (drive reduction) the S-R bond is strengthened. –The more often leads to a need satisfaction the stronger the bond (Habit Strength S H R ) –Habit Strength or S H R = N

Clark Hull Postulate 5 Stimulus Generalization - a stimulus will elicit a conditioned response depending on how similar the stimulus is to the stimulus that was used during training (stimulus generalization) S H R = generalized habit strength - transfer of training

Clark Hull Postulate 6 Stimuli Associated with Drives - Primary motivation (D), at least that resulting from food deprivation, consists of multiplicative components: (1) the drive proper (D’) which is an increasing monotonic sigmoid function of h, the number of hours of food deprivation; and (2) a negative or inanition component (  ) which is positively

Clark Hull Postulate 6 accelerated montonic function of h decreasing from 1.0 to zero –D = D’ x  –where D’ = x *1/h  = h 2.486

Clark Hull Postulate 6

Clark Hull Postulate 7 Reaction Potential as a Function of Drive and Habit Strength - The likelihood of a learned response being made at any given moment is called reaction potential ( S E R ) S E R = S H R x D

Clark Hull Postulate 8 Responding Causes Fatigue, Which Operates Against the Elicitation of a Conditioned Response –Reactive inhibition (I R ) –reminiscence effect - stop studying prior to test –massed vs. distributed practice

Clark Hull Postulate 9 The Learned Response of Not Responding - fatigue is a negative drive state. –Conditioned Inhibition ( S I R ) Effective reaction potential = E R = S H R x D - (I R + S I R )

Clark Hull Postulate 10 Factors Tending to Inhibit a Learned Response Change from Moment to Moment - there is an “inhibitory potentiality” which varies from moment to moment and operates against the elicitation of a response –Oscillation effect ( S O R ) –This is a wild card in Hull’s theory

Clark Hull Postulate 10. Momentary Effective Reaction Formation = S E R –Momentary Effective Reaction Potential. S E R = S H R x D - (I R + S I R ) - S O R

Clark Hull Postulate 11 Momentary Effective Reaction Potential Must Exceed a Certain Value Before a Learned Response Can Occur. –The value of S E R must exceed the reaction threshold ( S L R )

Clark Hull Postulate 12 The Probability that a Learned Response Will Be Made Is a Combined Function of S E R, S O R, and S L R –In the beginning of training the momentary reaction potential will be close to the threshold therefore the oscillation effect will play a role. As training goes on the oscillation effect will play less of a role.

Clark Hull Postulate 13 & 14 The greater the Value of the Effective Momentary Reaction Potential the Shorter will be the Latency Between S and R –Latency = ( S t R ) The value of the Effective Momentary Reaction Potential will Determine Resistance to Extinction

Clark Hull Postulate 15 & 16 The Amplitude of a Conditioned Response Varies Directly with the Effective Momentary Reaction Potential When Two or More Incompatible Responses Tend to Be Elicited in the Same Situation, the One with the Greatest Effective Momentary Reaction Potential will Occur

Clark Hull Changes Performance is altered as a result of the size of the reinforcement, therefore Hull included incentive as a factor (K) –Crespi Effect - a rapid change in performance as a result of a change in the size of the reinforcement

Clark Hull stimulus-intensity Stimulus Intensity Dynamism –the greater the intensity of a sitmlus, the greater the probability that a learned response will be elicited. S E R = [ S H R x D x V x K- (I R + S I R )] - S O R Instead of drive reduction Hull decided that it should be drive stimulus reduction S D –Actual Drive does not leave for a while

Clark Hull r G Fractional Antedating Goal Response r G This is Hull’s “mental” component r G ) - this concept involves both operant and classical conditioning. A rat runs a T maze, no food is in the left wing and food is in the right wing. The rat will soon learn to go to the right

Clark Hull r G Turning the corner (since it always comes just prior to the reinforcement of food) becomes a secondary reinforcer. But, it also becomes a conditioned stimulus for salivation The corner therefore acts both as a conditioned stimulus and a secondary reinforcement.

Clark Hull r G Since the corner is a cs salivation follows, but the salivation becomes a secondary reinforcement as well since it is always followed by food. Likewise one could say that a variety of internal stimului (kinesthetic receptors) result in muscle twitches etc becoming secondary reinforcers, and keep the animal moving forward

Clark Hull r G SD1 SD2 SD3SD1 SD2 SD3 R1R2R3R4R1R2R3R4 r G -s G r G -s G r G -s G

Clark Hull Habit Family Hierarchy The habit family hierarchy simply refers to the fact that in any learning situation, any number of responses are possible and the one that is most likely is the one that brings about reinforcement most rapidly and with the least amount of effort. –If one way is blocked we try another

Clark Hull Habit Family Hierarchy SD1SD2SD3SD1SD2SD3 r G -s G r G -s G r G -s G R1R1 R2R2 R3R3 R1R1 R2R2 R3R3 R1R1 R2R2 R3R3

Mowrer Mowrer went through a series of transitions in his theory. –Two factor theory - worked with avoidance conditioning –Animal learns to avoid a shock because a bell sounds and warns the animal of the shock. The anima must perform a behavior to avoid the shock.

Mowrer –Sign learning - bell which tells animal to avoid the shock acts as a “sign” or warning. Thus Mowrer referred to it as “sign learning” –Once the animal is warned of the shock it must perform a behavior to avoid the shock thus this is operant conditioning that Mowrer called “solution learning”

Mowrer –Mowrer went on to note that many emotions can be explained with the two factor theory Decremental Learning is a stimulus that reduces a drive reduction like eating vs. Incremental Learning where a stimulus increases a drive like shock One can experience the emotion of hope if a bell sounds just prior to food or of disappointment if the bell sounds just prior to the removal of food

Mowrer Eventually Mowrer considered all learning “sign learning”. –Mowrer felt that even proprioceptive stimuli come to give a sign of what to expect and there was not the need for solution learning.

Kenneth Spence Spence believed in latent learning - no reinforcement is necessary in order to learn. –Supported Aristotles law of contiguity –Supported Aristotles law of frequency Incentive Motivation - Spence strongly believed in (K) Incentive Motivation –K was the energizer of learned behavior

Kenneth Spence –He believed that r G -s G –Spence therefore had the momentary effective reaction potential equal to: (D + K) x S H R - I N –Spence felt that an organism will make a response even if there is no reinforcement for doing so

Kenneth Spence Extinction - frustration competition theory of extinction –extinction does not occur because of fatigue as Hull suggests but rather because frustration of not receiving a reinforcer competes with the reinforcer. Spence felt that we have a primary frustration when we do not receive reinforcement and like a fractional antedating goal response we build a fractional antedating frustration response.

Abram Amsel Examined Spence’s idea that frustration causes extinction –Amsel and Roussel showed that animal increases responding before decreasing responding during extinction frustration effect –Bower showed that the larger the reinforcer the faster the extinction, assumably from frustration.

Abram Amsel Analyzed partial reinforcement effect - (extinction is slower when organism is being reinforced with a partial reinforcement) Developed fractional antedating frustration response

Neal Miller Visceral Conditioning and Biofeedback