1. Negative Reinforcement
Aversive Control
Punishment
Negative Reinforcement
Escape Learning
Avoidance

2. “Positive” PunishmentR
OAversive
Positive Relationship
p(O/R) > p(O/noR)

3. Skinner’s Experiment on Punishment
Stage 1:
Rats were reinforced with food on a VI schedule
Stage 2:
Extinction for two successive days
First 10 min of extinction:
One group of rats was punished
Another group was not punished

4. Skinner concluded that punishment was not an effective way to control behavior.

5. Increasing Effectiveness
intense/prolonged from start
response contingent rather than response independent
immediately after the response rather than delayed
continuous rather than partial reinforcement schedule

7. Increasing Effectiveness
punished response is not otherwise being reinforced
there is an alternative response to acquire reinforcer
the punished response is not a species-specific defence reaction
unsignaled

8. Problems
person associated with punishment becomes aversive (40 to 1 rule)
general suppression of responding
imitation of the aggressive behavior involved in punishment
escape/avoidance or aggressive responses in punishing situation (aka “vicious circle”)
identifying punishers is difficult (attention might be positive)

9. Escape/
Avoidance

10. Negative Reinforcement
Removes S R
OAversive
Negative Relationship
p(O/R) < p(O/noR)
Mum nags cries.
Note: if R removes OAversive = Escape
if R prevents OAversive = Avoidance

11. Signaled Escape And Avoidance
Light = CS
Gridshock= US
Rat Shuttle Box

12. Signaled Escape
Warning CS
Shock US
Shuttle
Time

13. Signaled Avoidance
Warning CS
Shock US
Shuttle
Time

14. Unsignaled (Sidman) Avoidance
S-S interval:
R-S interval:
20 s
40 s
60 s

15. Avoidance Puzzle
Question: How can the absence of an event act as a reinforcer?
Answer: Something tangible has happened. Fear is removed inside the organism.

16. The Two-Process Theory of Avoidance
1. (Pavlovian): Pairings of situational CSs with an aversive US cause a fear CR to develop
2. (Instrumental): Responding causes removal of the CS, which in turn removes the fear CR
Avoidance learning is escape learning; the organism learns to escape from the CS and the fear that it elicits.

17. Is Conditioned Fear Termination As a Reinforcer?
Stage Stage 2
CS-US Conditioning
ToneShock
Escape
Shuttle Tone Off

19. Challenges for the Two-Process Theory
1. “Unsignaled” avoidance
2. Avoidance does not readily extinguish
3. Level of fear is not always positively correlated with avoidance
Rats given avoidance training with 6, 9, or 24 trials when a tone was followed by shock unless the rat ran to the next chamber. The rats that had 24 trails were successfully avoiding all the shocks by the last trial. Then the extent to which the tone elicited fear was measured in a conditioned suppression paradigm. The tone suppressed responding more in the rats given 9 trials than in the those given 24.

20. Fear in Active Avoidance?
Fear declines with trials
Stage 1 Stage 2
Active avoidance training
Does warning CS suppress lever pressing?

21. Answers from the Two-Process Theory of Avoidance
1. Temporal conditioning and conservation of fear?
2. Response as a stimulus that inhibits fear (safety signal)?
3. Well learned response trigger by very small amounts of fear?
Rats given avoidance training with 6, 9, or 24 trials when a tone was followed by shock unless the rat ran to the next chamber. The rats that had 24 trails were successfully avoiding all the shocks by the last trial. Then the extent to which the tone elicited fear was measured in a conditioned suppression paradigm. The tone suppressed responding more in the rats given 9 trials than in the those given 24.
4. Response blocking will cause fear increase?

23. Alternative Theoretical Accounts of Avoidance Behavior
Species-Specific Defense Reactions (SSDRs)
more concerned with the actual response
aversive stimuli elicit strong innate responses
(e.g., freezing, flight to dark area, fighting)
species typical responses are readily learned as
avoidance responses (e.g., jump = two
trials versus lever-press = 1000s of trials)
punishment originally thought to be responsible for the selection of the avoidance response