Chapter 8 – Stimulus Control of Behavior

1. Chapter 8 – Stimulus Control of Behavior • Outline 1 • Identification and Measurement of Stimulus Control • Differential Responding and Stimulus Control • Stimulus Generalization • Stimulus Generalization Gradients as Measures of Stimulus Control • Stimulus and Response Factors in Stimulus Control • Sensory Capacity and Orientation • Relative Ease of Conditioning Various Stimuli • Type of Reinforcement • Types of Instrumental Response

2. The concept of behavioral control • S (stimulus) • Can elicit responding (R) • Can create expectancies (O) • “Appropriate behavior” is often controlled by cues (stimuli) in our environment. • Get undressed for bed • Get undressed at school • Kiss girlfriend/boyfriend • Kiss random person walking on campus • This chapter considers how stimuli come to control our behavior.

3. Identification and Measurement of Stimulus Control • How do we know that a behavior is under stimulus control? • Consider Reynolds (1961) • Train pigeons to peck a white triangle on a red background. • VI schedule • Elicited steady pecking • Test with red key (no triangle) • Or white triangle (no red; background is black)

5. Stimulus Generalization • How specific is stimulus control? • Early researchers (like Pavlov) examined this question. • Guttman and Kalish (1956) • Train • VI schedule • S+ = 580nm light (yellowish orange). • Test • Different colors • 520 nm (green) • 540 nm • 550 nm • 570 nm (yellow) • 580 nm (yellowish orange) • 590 nm (orange) • 600 nm • 620 nm • 640 nm (red • Random order • In extinction

6. Generalization Gradient

8. The generalization gradient indicates stimulus control by color. • It is somewhat specific for the training stimulus. • But generalizes to similar colors. • There is no gradient for the hypothetically color blind pigeons • Color does not control responding.

9. What determines the degree of stimulus control obtained? • Stimulus and Response Factors • Sensory Capacity and orientation • Must be able to sense it • Rats don’t do well with color stimuli • They do very well with odor stimuli. • Horse study from book. • Trained to select color over gray. • Push lever with head. • 85% correct • All 4 picked blue and yellow over gray • 3 picked green over gray • Only 1 picked red over grey • Implies they may have poor red sensation

10. Relative ease of conditioning various stimuli. • Whether a stimulus exerts control depends on whether it stands out from other cues in the environment • Children’s book • Big pictures • Smaller words • Overshadowing (first noticed by Pavlov) • CS1 – loud sound • CS2 – dim light • More conditioning occurred to the stronger stimulus • Conditioning was better for CS2 if presented alone • Overshadowed by CS1if presented together

11. Type of Reinforcement • Aversive vs. Appetitive seems to matter • Foree and LoLordo (1973) • Two groups of pigeons • Both were trained to respond when presented with a compound discriminative stimulus • Red light and tone • Group 1 • Step on treadle to gain food • Group 2 • Step on treadle to avoid shock • Test both groups with • Red light alone • Tone alone

13. Visual stimuli tend to gain control over appetitive stimuli • Auditory stimuli tend to gain control over aversive stimuli. • Behavior systems? • Food RF activates feeding system? • Rats and pigeons are more likely to find food with vision rather than hearing. • Shock RF activates defensive system? • Auditory cues may be particularly adaptive for avoiding danger.

14. Outline 2 • Learning Factors in Stimulus Control • Stimulus Discrimination Training • Effects of Discrimination Training on Stimulus Control • What is Leaned in Discrimination Training? • Interactions Between S+ and S-: Peak Shift Effect • Range of Possible Discriminative Stimuli • Stimulus Equivalence Training • Contextual Cues and Conditional Relations • Conditioned Place Preference

15. Learning Factors in Stimulus Control • left to their own devices animals come under stimulus control based on the stimulus and response factors discussed above. • But can we train animals to make finer distinctions?

16. Stimulus Discrimination Training. • Let’s go back to the color generalization study • Train • VI schedule • S+ = 580nm light (yellowish orange). • Test • Different colors • 520 nm (green) • 540 nm • 550 nm • 570 nm (yellow) • 580 nm (yellowish orange) • 590 nm (orange) • 600 nm • 620 nm • 640 nm (red • Random order • In extinction

17. Generalization Gradient

18. Note that the pigeons treated the 590 nm stimulus nearly the same as the 580 nm • Can they tell the difference? • How could we find out?

19. Train with two stimuli. • In operant conditioning we call them S+ (Sd) and S- (S∆) • S+ responding will result in RF • S- responding will have no effect • Pavlovian • CS+ (CS-US) • CS- (CS- no US) • For our color discrimination • S+ = 580 nm • S- = 590 nm

20. Hypothetical Result

21. Effects of Discrimination on Stimulus control • Increased stimulus control • 1) Discrimination narrows the generalization curve • 2) Discrimination within a dimension narrows it even more • Makes the relevant dimension clear? • Tone vs. loudness • Example: Jenkins and Harrison (1962) • Trained with tones • 3 groups • 1) generalization • S+ 1000-cps tone • 2) discrimination • S+ 1000-cps tone • S- no tone • 2) within discrimination • S+ 1000-cps tone • S- 950 cps tone

23. What is learned in Discrimination Training? • Example • S+ (light) S- (tone) • 1) learn about S+ alone • Respond during light • Learn nothing about tone • 2) learn about S- alone • Suppress responding during tone • Learn nothing about light • 3) learn about both (Spence’s Theory) • Respond during light • Suppress responding during tone

24. Spence’s Theory of Discrimination Learning • The S+ becomes excitatory • Signals RF • The S- becomes inhibitory • Signals lack of RF • How do we test this? • Responding to S+ and not responding during S- is not enough • Any of the 3 theories predict this

25. The peak shift can be considered evidence for Spence’s view.

27. Range of Possible Discriminative Stimuli • Many kinds of stimuli have been examined • Simple • Color • Tone • Complex • Number • Time of day • Kind of music • Carp • Blues vs. Classical • John Lee Hooker vs. Bach

29. Types of Stimuli continued • Artists • Monet vs. Picasso • Internal • Hunger • Drugs

30. Drugs • Cocaine = left lever • Saline = right lever • Antagonist? • Other drugs? • Amphetamine? • Caffeine?

31. Stimulus Equivalence Training • We have seen that discrimination can sharpen stimulus control • Treat similar stimuli differently • Can we produce the opposite effect. • Train animals to treat very different stimuli similarly?

32. Honey and Hall (1989) Group 1Group 2 • Phase 1 Noise = Food Noise = nothing Clicker = Food Clicker = Food • Phase 2 Noise= foot shock Noise = Foot shock • Test Clicker Clicker • Which group is more afraid of the clicker? • Group 1 • Seems a common outcome causes the rats to treat the stimuli similarly.

33. Common Coding – a typical equivalence experiment • Based on Urcuioli, Zentall, Jackson-Smith, and Steirn (1989) • Phase 1 (Many-to-One Matching-to- Sample) • R  R+G- • V  R+G- • G  G+R- • H  G+R- • Phase 2 (new comparisons) • R  B+Y- • G Y+ B- • Test (does learning transfer)? • V  B Y? • H  Y B?

34. Does Equivalence training cause stimuli to become harder to discriminate? • Based on Kaiser, Sherburne, Steirn, and Zentall (1997) • Train • R  R+G- • V  R+G- • G  G+R- • H  G+R- Test (discrimination) • ConsistentInconsistent • R+ R+ • V+ V- • G- G- • H- H+ • Which Group learns faster? • pecks S+ 90% of the time

35. Sidman • True equivalence must demonstrate three concepts  • 1) Reflexivity (sameness) • If A = A, B = B, C = C, and so on. •  2) Symmetry (bidirectional equivalence) • If A = B then B = A • 3) Transitivity (transfer equivalence across stimuli) • If A = B and B = C then A = C

36. Spoken and written speech involves these three aspects of equivalence. • Reflexivity (sameness) • Apple = Apple • Orange = Orange   = =

37. Symmetry (bidirectional equivalence) • A(object) = B (word) • B (word) = A (object) • = Apple • Apple =

38. Transitivity. • If A (object) = B (spoken word) • And B (spoken word) = C (written word) • Then A (object) = C (written word) • If = • And = Apple • Then = Apple

39. Some have argued stimulus equivalence is a human trait • Requires language • People with good verbal skills can form equivalent relationships easily. • Those without have much more difficulty. • Animals?

40. Reflexivity (sameness) • Pick the thing that looks the same • Based on Zentall and Hogan (1978) • Train (Identity matching-to-sample) • R R+G- • G G+R- • Test (with “novel” stimuli) • B  B Y • Y  Y B

41. Symmetry (bidirectional equivalence) • Based on Zentall, Sherburne, and Steirn (1992) • If red = food, then food = red • If green = no food, then no food = green • Train (differential outcomes procedure) • R  R+G- (food) • G  G+R- (noFood) do over until correct to move on • Test • Food  R G? • No Food  G R?

42. Transitivity • Based on Steirn, Jackson-Smith and Zentall (1991) • Phase 1 (Differential Outcomes) • R  R+ G- (food) • G  G+ R- (no food) • Phase 2 • food  B+ W- • no food  W+ B- • Test • R  B W? • G  B W?

43. Train (Differential Outcomes) • Phase 1 • R R+ G- (food) • G  G+ R- (no food) • Phase 2 • food B+ W- • no food  W+ B- • Test • R B W? • G  B W?

44. Contextual Cues and Conditional Relations • Conditioned Place Preference

45. Inject Rat with drug and confine to one side of chamber • Test later (next day) • Drug free • Which side do they prefer?

46. Heroin – Good sick? • Two groups of Thirsty Rats • Morphine Group • Inject with morphine • Place in Side 1 with Sacch. • Control • Inject with Saline • Place in Side1 with Sacch.

47. Test • open access • two bottles in each side • Sacch vs. Water • Results • Morphine Group? • More time in Side 1 • avoid Sacch. • Control? • Equal time each side • prefer Sacch.