1. Stimulus Control of Behavior Stimulus control of operant behavior Stimulus control of operant behavior Context drives appropriate behaviorContext drives appropriate behavior Depending on where you are, the situation you are in, etc., certain behaviors are acceptable; these same behaviors may be inappropriate in different contexts/situations Depending on where you are, the situation you are in, etc., certain behaviors are acceptable; these same behaviors may be inappropriate in different contexts/situations Behavior must adjust to the environmentBehavior must adjust to the environment

2. Stimulus Control of Behavior Stimulus discrimination and generalization Stimulus discrimination and generalization How organisms identify and distinguish different stimuli; considered one of the most important concepts in psychologyHow organisms identify and distinguish different stimuli; considered one of the most important concepts in psychology No situation repeats itself exactly, so a degree of generalization is necessary No situation repeats itself exactly, so a degree of generalization is necessary However, also critical to distinguish various stimuli However, also critical to distinguish various stimuli Stimulus discrimination Stimulus discrimination Differential responding to two or more stimuliDifferential responding to two or more stimuli Stimulus generalization Stimulus generalization Similar responding to two or more stimuliSimilar responding to two or more stimuli

3. Stimulus Control of Behavior How can we measure the degree of stimulus control in a given situation? How can we measure the degree of stimulus control in a given situation?

4. Basic Procedure Generalization test: A variety of stimuli from the same stimulus continuum are shown, one at a time, under extinction conditions. Generalization test: A variety of stimuli from the same stimulus continuum are shown, one at a time, under extinction conditions.

5. Basic Procedure Positive Stimulus Generalization Test

6. Basic Procedure Stimulus Color

7. Generalization Gradient A generalization gradient shows the relationship between the probability of response and stimulus value. A generalization gradient shows the relationship between the probability of response and stimulus value.

8. Gradients and Learning The accuracy of responding improves as the individual becomes more experienced with the stimulus dimension. The accuracy of responding improves as the individual becomes more experienced with the stimulus dimension.

9. Experience Changes the Gradient S+ NoviceExpert

10. Stimulus Control of Behavior How can we measure the degree of stimulus control in a given situation? How can we measure the degree of stimulus control in a given situation? Stimulus generalization gradientsStimulus generalization gradients Guttman & Kalish (1956) Guttman & Kalish (1956) Pigeon pecking reinforced to 580nm color (this is S+); no S- training conducted Pigeon pecking reinforced to 580nm color (this is S+); no S- training conducted Substantial responding to stimuli never associated with reinforcement Substantial responding to stimuli never associated with reinforcement Generalization to 570 & 590; evidence of greater discrimination (decreased responding) as wavelengths became increasingly different from original stimulus Generalization to 570 & 590; evidence of greater discrimination (decreased responding) as wavelengths became increasingly different from original stimulus

11. Gradient Shape Steep vs. flat gradients Steep vs. flat gradients Steepness of stimulus generalization gradient provides a measure of the degree of stimulus controlSteepness of stimulus generalization gradient provides a measure of the degree of stimulus control Steep gradient: differential responding (see FIGURE to right) Steep gradient: differential responding (see FIGURE to right) Evidence that the stimulus feature that is varied controls behaviorEvidence that the stimulus feature that is varied controls behavior Flat gradient: lack of differential responding Flat gradient: lack of differential responding Evidence that the stimulus feature that is varied does NOT control behaviorEvidence that the stimulus feature that is varied does NOT control behavior

12. Factors in Stimulus Control: Features What determines which features of stimuli gain control over behavior? What determines which features of stimuli gain control over behavior? Sensory capacitySensory capacity Ease of ‘conditionability’Ease of ‘conditionability’ Overshadowing Overshadowing Competition among stimuli simultaneously presented; stronger stimulus ‘wins out’Competition among stimuli simultaneously presented; stronger stimulus ‘wins out’ Type of reinforcementType of reinforcement Depending on conditioned stimulus sensory modality, kind of reinforcement may be a better natural fit Depending on conditioned stimulus sensory modality, kind of reinforcement may be a better natural fit ‘belongingness’ ‘belongingness’ Elemental vs. configural processingElemental vs. configural processing

13. Control by Specific Features Foree & LoLordo (1973) Foree & LoLordo (1973) Experiment Design: 2 groups of pigeonsExperiment Design: 2 groups of pigeons Reinforce pressing lever in presence of compound S+ (tone/light) Reinforce pressing lever in presence of compound S+ (tone/light) Group 1: food presented as S RGroup 1: food presented as S R Group 2: shock avoidance as S RGroup 2: shock avoidance as S R During testing, component stimuli presented individuallyDuring testing, component stimuli presented individually

14. Control by Features Foree & LoLordo (1973) Foree & LoLordo (1973) Results:Results: food reinforced birds – high responding to light; low responding to tone food reinforced birds – high responding to light; low responding to tone shock avoidance birds – high responding to tone; low responding to light shock avoidance birds – high responding to tone; low responding to light Conclusions: visual stimuli more likely to gain control in ‘appetitive’ situations, and auditory stimuli gain control in aversive situationsConclusions: visual stimuli more likely to gain control in ‘appetitive’ situations, and auditory stimuli gain control in aversive situations Adaptive advantage?Adaptive advantage?

15. Factors in Stimulus Control Elemental vs. configural learning Elemental vs. configural learning Elemental view: compound stimuli are seen as the addition of various features (AB = A + B)Elemental view: compound stimuli are seen as the addition of various features (AB = A + B) Configural view: compound stimuli seen as unique cue; ‘the whole does not equal the sum of its parts’ (AB NOT seen as A + B)Configural view: compound stimuli seen as unique cue; ‘the whole does not equal the sum of its parts’ (AB NOT seen as A + B) Organisms respond to compounds in terms of the elements and the unique configuration of cues Organisms respond to compounds in terms of the elements and the unique configuration of cues

16. Factors in Stimulus Control Stimulus discrimination training Stimulus discrimination training Beyond mere detection, whether stimuli control behavior ultimately depends on what is learned about the stimuliBeyond mere detection, whether stimuli control behavior ultimately depends on what is learned about the stimuli Pavlov: stimulus generalization as ‘transfer of learning’ Pavlov: stimulus generalization as ‘transfer of learning’ Lashley & Wade: stimulus generalization reflects absence of learning Lashley & Wade: stimulus generalization reflects absence of learning How to bring behavior under control of a stimulus?How to bring behavior under control of a stimulus? Stimulus discrimination procedure Stimulus discrimination procedure 2 distinct stimuli presented, 1 reinforced, other nonreinforced2 distinct stimuli presented, 1 reinforced, other nonreinforced

17. Factors in Stimulus Control Stimulus discrimination training Stimulus discrimination training S+, S-S+, S- With enough training,With enough training, respond to S+, withhold re- sponding to S- (differential responding) S+ & S- = discriminative stimuli Can be done with classical conditioning: CS1– US; CS2-NO US

18. Factors in Stimulus Control Precision of stimulus control Precision of stimulus control S+, S- not enoughS+, S- not enough Jenkins and Harrison (1960; 1962)Jenkins and Harrison (1960; 1962) Design: 3 groups of pigeons Design: 3 groups of pigeonsTraining: Group 1: S+ = 1,000 cps tone; S- = nothing (no tone)Group 1: S+ = 1,000 cps tone; S- = nothing (no tone) Group 2: S+ = 1,000 cps tone; S- = 950 cps toneGroup 2: S+ = 1,000 cps tone; S- = 950 cps tone Group 3: S+ = No discrimination (1,000 cps tone only)Group 3: S+ = No discrimination (1,000 cps tone only) Testing: pecking in presence of various tone frequencies Testing: pecking in presence of various tone frequencies Dependent measure: % responding to different tone frequencies Dependent measure: % responding to different tone frequencies

19. Factors in Stimulus Control Jenkins and Harrison (1960; 1962) Jenkins and Harrison (1960; 1962) Results :Results : Panel A: pitch of tones did not control behavior Panel A: pitch of tones did not control behavior Panel B: some stimulus control by pitch (intermediate) Panel B: some stimulus control by pitch (intermediate) Panel C: strongest stimulus control by pitch (steepest gradient) Panel C: strongest stimulus control by pitch (steepest gradient) Specific stimulus dimension more likely to gain control over behavior if S+ & S- differ along this dimension

20. Factors in Stimulus Control What is learned in discrimination training? What is learned in discrimination training? Multiple strategies could be adoptedMultiple strategies could be adopted Only learn about S+ (learn nothing of S-), or Only learn about S+ (learn nothing of S-), or Only learn to suppress responding to S-, or Only learn to suppress responding to S-, or Learn significance of both S+ & S- Learn significance of both S+ & S- Spence’s TheorySpence’s Theory “Differential responding to S+ and S- is assumed to reflect both the excitation of responding to S+ and the inhibition of responding to S-”. “Differential responding to S+ and S- is assumed to reflect both the excitation of responding to S+ and the inhibition of responding to S-”. How to determine experimentally?How to determine experimentally? Observe stimulus generalization gradients Observe stimulus generalization gradients

21. Factors in Stimulus Control Stimulus generalization gradients Stimulus generalization gradients Excitatory: greatest amount of responding to S+; increasingly different stimuli evoke less respondingExcitatory: greatest amount of responding to S+; increasingly different stimuli evoke less responding Inhibitory: stimuli increasingly different from S- should be less effective in inhibiting respondingInhibitory: stimuli increasingly different from S- should be less effective in inhibiting responding Honig et al. (1963)Honig et al. (1963) Tested Spence’s theory Tested Spence’s theory Design: 2 groups of pigeons Design: 2 groups of pigeons Group 1: pecking reinforced when key had white light w/ black vertical bar (S+); not reinforced when white light alone (S-)Group 1: pecking reinforced when key had white light w/ black vertical bar (S+); not reinforced when white light alone (S-) Group 2: contingency reversedGroup 2: contingency reversed Testing: degree of generalization tested by presenting black bar at different angles Testing: degree of generalization tested by presenting black bar at different angles

22. Factors in Stimulus Control Honig et al. (1963) Honig et al. (1963) ResultsResults Group 1: highest responding to same stimulus as training; progressively less as bar tilted more Group 1: highest responding to same stimulus as training; progressively less as bar tilted more Group 2: decreased pecking to vertical bar; pecking increased as bar tilted more Group 2: decreased pecking to vertical bar; pecking increased as bar tilted more Suggests discrimination training produces BOTH excitatory conditioning to S+ and inhibitory conditioning to S-Suggests discrimination training produces BOTH excitatory conditioning to S+ and inhibitory conditioning to S-

23. Peak Shift Learning to respond to S+ influences responding to S- (and vice versa) Learning to respond to S+ influences responding to S- (and vice versa) When S+ & S- differ along continuous values of one stimulus feature we call this intra-dimensional discriminationWhen S+ & S- differ along continuous values of one stimulus feature we call this intra-dimensional discrimination It is more difficult to discriminate stimuli differing along a dimension with no training (greater “expertise” needed) It is more difficult to discriminate stimuli differing along a dimension with no training (greater “expertise” needed) Interactions may occur between S+ & S-Interactions may occur between S+ & S- Hanson (1959) Hanson (1959) Design: ALL pigeons reinforced for pecking in presence of 550 nm light (had same S+ stimulus)Design: ALL pigeons reinforced for pecking in presence of 550 nm light (had same S+ stimulus) Group 1: S- = 590 nm light (color is “far” from S+) Group 1: S- = 590 nm light (color is “far” from S+) Group 2: S- = 555 nm light (color is “near” to S+) Group 2: S- = 555 nm light (color is “near” to S+) Group 3: No S- (no discrimination training) Group 3: No S- (no discrimination training) Testing: rate of pecking to various wavelengths (colors)Testing: rate of pecking to various wavelengths (colors)

24. Peak Shift Hanson (1959) Hanson (1959) ResultsResults Peak shifted to wavelengths never reinforced to (shifted for 590nm and 555 nm S- groups; no shift for control pigeons) Peak shifted to wavelengths never reinforced to (shifted for 590nm and 555 nm S- groups; no shift for control pigeons) Peak shift: Peak shift: Shift of generalization gradient peak away from original S+Shift of generalization gradient peak away from original S+ Occurs as function of similarity of S- to S+Occurs as function of similarity of S- to S+

25. Peak Shift How can peak shift phenomenon be accounted for? How can peak shift phenomenon be accounted for? Spence’s explanation :Spence’s explanation : Overlap of generalization gradients of S+ & S- Overlap of generalization gradients of S+ & S- More inhibition from S- to S+ if they are close together More inhibition from S- to S+ if they are close together

26. Intra-, Inter-, & Extra-Dimensional Discrimination All 3 are procedures that can sharpen generalization gradients (increase “tightness” of stimulus control) All 3 are procedures that can sharpen generalization gradients (increase “tightness” of stimulus control) INTRA-DIMENSIONAL – when the S+ and S- are values along the same stimulus dimension INTRA-DIMENSIONAL – when the S+ and S- are values along the same stimulus dimension Ex.) S+ = red light; S- = orange lightEx.) S+ = red light; S- = orange light Ex.) S+ = high tone; S- = middle toneEx.) S+ = high tone; S- = middle tone Usually produces the sharpest gradient around the S+ relative to no discrimination training at allUsually produces the sharpest gradient around the S+ relative to no discrimination training at all

27. Intra-, Inter-, & Extra-Dimensional Discrimination INTER-DIMENSIONAL – when the S+ and S- are values from 2 different stimulus dimensions (or contain 2 different features; or contain multiple different features [which is more “real-world”]) INTER-DIMENSIONAL – when the S+ and S- are values from 2 different stimulus dimensions (or contain 2 different features; or contain multiple different features [which is more “real-world”]) Ex.) S+ = red light; S- = toneEx.) S+ = red light; S- = tone Ex.) S+ = white key with line; S- = white key with no line at allEx.) S+ = white key with line; S- = white key with no line at all Usually produces a modestly sharp gradient around the S+ relative to no discrimination training at allUsually produces a modestly sharp gradient around the S+ relative to no discrimination training at all

28. Intra-, Inter-, & Extra-Dimensional Discrimination EXTRA-DIMENSIONAL – this is a 2-part procedure EXTRA-DIMENSIONAL – this is a 2-part procedure First, train a discrimination between 2 values along a dimension (intra) or 2 values from different dimensions (inter) First, train a discrimination between 2 values along a dimension (intra) or 2 values from different dimensions (inter) Then, train a NEW S+ from a totally different dimension (such as an angled line) Then, train a NEW S+ from a totally different dimension (such as an angled line) Finally, present different values along dimension from second part (e.g., angled lines) and measure resulting generalization gradient Finally, present different values along dimension from second part (e.g., angled lines) and measure resulting generalization gradient Usually produces a modestly sharp gradient around the S+ used in the second part relative to no discrimination training at allUsually produces a modestly sharp gradient around the S+ used in the second part relative to no discrimination training at all This is almost like “learning to discriminate”This is almost like “learning to discriminate”

29. Stimulus Disparity It is easier to discriminate between two stimuli the more physically disparate they are. Obviously! It is easier to discriminate between two stimuli the more physically disparate they are. Obviously! Animal studies have shown that if you begin with a wide disparity and teach a discrimination, you can then use stimuli that are closer and closer in terms of physical characteristics Animal studies have shown that if you begin with a wide disparity and teach a discrimination, you can then use stimuli that are closer and closer in terms of physical characteristics

30. Overshadowing vs. blocking Both of these issues are very important in understanding what stimulus (or feature of a compound stimulus) comes to control responding (see next slide) Both of these issues are very important in understanding what stimulus (or feature of a compound stimulus) comes to control responding (see next slide)

31. Overshadowing vs. blocking In overshadowing, a compound stimulus is used as the S+ In overshadowing, a compound stimulus is used as the S+ For example, a light and tone may be turned on at the same time For example, a light and tone may be turned on at the same time Then a response is taught and reinforced in the presence of the S+. Then a response is taught and reinforced in the presence of the S+. The big question is which PART of the compound will occasion responding? The big question is which PART of the compound will occasion responding? This usually a function of SALIENCE This usually a function of SALIENCE

32. Overshadowing vs. blocking In BLOCKING, the procedure (and effect) are a little different In BLOCKING, the procedure (and effect) are a little different Here, we begin with teaching a response to occur in the presence of an S+, such as verbally labeling a picture Here, we begin with teaching a response to occur in the presence of an S+, such as verbally labeling a picture

33. Child says “DOG” (I know, bad joke!)

34. Child says “DOG” (this is the real trial)

35. Overshadowing vs. blocking Then we add a new stimulus, essentially turning the original S+ into a compound stimulus Then we add a new stimulus, essentially turning the original S+ into a compound stimulus We continue to reinforce the correct response made in the presence of the new compound S+ We continue to reinforce the correct response made in the presence of the new compound S+

36. Child says “DOG”

37. Overshadowing vs. blocking We hope that the new added stimulus (written label DOG) will also occasion responding by itself We hope that the new added stimulus (written label DOG) will also occasion responding by itself We hope that there has been a “transfer of stimulus control” from the old stimulus (the picture) to the new stimulus (the written word) We hope that there has been a “transfer of stimulus control” from the old stimulus (the picture) to the new stimulus (the written word)

38. Will child say “DOG”

39. Blocking Probably NOT! Probably NOT! Let’s look at a study by Singh and Solman (1990) in JABA Let’s look at a study by Singh and Solman (1990) in JABA Participants were 8 grade school kids with moderate MR Participants were 8 grade school kids with moderate MR Words to be used were pre-tested for recognition and discarded if necessary Words to be used were pre-tested for recognition and discarded if necessary

40. Blocking - Singh & Solman (1990) They used an alternating treatments design with a baseline They used an alternating treatments design with a baseline During baseline, participants were shown 16 words on separate slides and asked what the word said During baseline, participants were shown 16 words on separate slides and asked what the word said Intervention had 4 alternating conditions Intervention had 4 alternating conditions 4 conditions: 4 conditions: A - A -

41. Blocking - Singh & Solman (1990) Condition A: pairs of slides presented with picture first and then a compound of picture plus word Condition A: pairs of slides presented with picture first and then a compound of picture plus word

44. Blocking - Singh & Solman (1990) Condition A: Condition A: Student asked “what is this word?” Student asked “what is this word?” If no response, given corrective feedback “this word is ____” If no response, given corrective feedback “this word is ____”

45. Blocking - Singh & Solman (1990) Condition B: single presented with a word only Condition B: single presented with a word only Student asked “what is this word?” Student asked “what is this word?” If no response, given corrective feedback “this word is ____” If no response, given corrective feedback “this word is ____”

46. Blocking - Singh & Solman (1990) Condition C: like condition A, pairs of slides presented with picture first and then a picture + word BUT word was much bigger Condition C: like condition A, pairs of slides presented with picture first and then a picture + word BUT word was much bigger Student asked “what is this word?” Student asked “what is this word?” If no response, given corrective feedback “this word is ____” If no response, given corrective feedback “this word is ____”

48. Blocking - Singh & Solman (1990) Condition D: like condition C, slides presented with words only but word was much bigger than in condition C Condition D: like condition C, slides presented with words only but word was much bigger than in condition C Student asked “what is this word?” Student asked “what is this word?” If no response, given corrective feedback “this word is ____” If no response, given corrective feedback “this word is ____”

50. Blocking - Singh & Solman (1990) RESULTS: kids took the longest to learn the words by sight for condition A RESULTS: kids took the longest to learn the words by sight for condition A When the word was made larger relative to the picture (as in condition C), they learned the words a bit quicker, probably b/c the size increase the word’s salience When the word was made larger relative to the picture (as in condition C), they learned the words a bit quicker, probably b/c the size increase the word’s salience