Aversive Control

• Punishment

• Negative Reinforcement– Escape Learning– Avoidance

“Positive” Punishment

S R OAversive

Positive Relationship

p(O/R) > p(O/noR)

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

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

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

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

Problems

person associated with punishment becomes aversive (40 to 1 rule)

general suppression of responding

imitation of the aggressive behavior involved in punishment

identifying punishers is difficult (attention might be positive)

escape/avoidance or aggressive responses in punishing situation (aka “vicious circle”)

Escape/Avoidance

Negative Reinforcement

S RRemoves

OAversive

Note: if R removes OAversive = Escape

Negative Relationship

p(O/R) < p(O/noR)

if R prevents OAversive = Avoidance

Signaled Escape And Avoidance

Rat Shuttle Box

Light = CS

Gridshock= US

Signaled Escape

Shuttle

Warning CS

Shock US

Time

Signaled Avoidance

Shuttle

Warning CS

Shock US

Time

Unsignaled (Sidman) Avoidance

20 s 40 s 60 s

R-S interval:

S-S interval:

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.

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.

Is Conditioned Fear Termination As a Reinforcer?

CS-US Conditioning

ToneShock

Stage 1 Stage 2

Escape

Shuttle Tone Off

3. Level of fear is not always positively correlated with avoidance

2. Avoidance does not readily extinguish

1. “Unsignaled” avoidance

Challenges for the Two-Process Theory

Fear in Active Avoidance?

Stage 1 Stage 2

Active avoidance training

Does warning CS suppress lever pressing?

Fear declines with trials

2. Response as a stimulus that inhibits fear (safety signal)?

1. Temporal conditioning and conservation of fear?

Answers from the Two-Process Theory of Avoidance

3. Well learned response trigger by very small amounts of fear?

4. Response blocking will cause fear increase?

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