1. Stimulus Control

2. Stimulus Control of Behavior Having stimulus control means that the probability of the behavior varies depending upon the stimuli present. If a behavior is under stimulus control then –The behavior happens when the stimulus is present –The behavior doesn’t happen when the stimulus is absent Most of our behavior is under stimulus control –A person that contributes to charity generously while in church may watch every penny spent while at work

4. Discrimination and Stimulus Control Discrimination is demonstrated when the subject responds differently to different stimuli. Train Test Reynolds (1961)

5. Generalization Generalization is when responses to one stimulus occur to other, usually similar, stimuli Generally, as the training and test stimuli become more different responding will decline, producing what is called a generalization gradient

6. How to test generalization TrainGeneralizationTest T+ T = 1000hz tone No reinforcers Present tones of varying frequencies and examine lever pressing in response to each tone

7. Generalization Gradient Guttman & Kalish (1956) –pigeons reinforced for pecking a 580 nm lit key (orange-yellow) (S+) on a VI schedule –A test session was then given where many different colored key lights were presented in extinction S+

8. Interpreting Generalization Gradients Pigeons trained to peck a moderately bright light (S+) to get food. (S- = dim light) After asymptote is reached, present occasional non- reinforced probe trials at various wavelengths or levels of brightness.

9. Excitatory and inhibitory gradients Pigeons trained to peck at a 800 hz tone (S+), with a 500 nm light S-.

10. 1000 Hz Tone always on 1000 Hz Tone S+ / No Tone S- 1000 Hz Tone S+ / 950 Hz Tone S-

11. Peak Shift Effect – Hanson (1959)

12. Spence’s Theory to Account for Peak Shift S+ S-

13. Interdimensional discrimination Discrimination: S+ = 555nm Light; S- = Tone

14. How do we learn discriminations with complex stimuli?

15. Perceptual learning: Examples Pre-exposureDevalueTest --Saline-Lemon  LiCLSucrose-Lemon? LemonSaline-Lemon  LiCLSucrose-Lemon? Another example… Pre-exposureDevalueTest --Saline-Lemon  LiCLSucrose-Lemon? Sal-L/Suc-LSaline-Lemon  LiCLSucrose-Lemon?

16. How do we learn discriminations with complex stimuli? A B A+BA+B

17. Peceptual learning: Mechanism Trial 1Trial 2Trial 3Trial 4Trial 5Trial 6 Total # Presentations Sucrose 3 Saline 3 Lemon 6

18. Perceptual Learning: The Method of Pre- Exposure Matters Mondragon & Hall (2002) A = lemonB = saltC = sucroseX = quinine Pre-Exposure:AX  BX  AX  BX | CX  CX  CX  CX Devalue:AX  LiCL Test:BX?CX? Question:How much does aversion generalize to BX and CX?