AversiveControl：令人厌恶的控制.pptVIP

Aversive Control Negative Reinforcement Avoidance Learning Escape Learning * Negative Reinforcement S: e.g. operant chamber R e.g. bar press Removes/Prevents SAversive e.g. shock Strengthens Note: if R removes SAversive = Escape Negative Contingency p(SAversive/R) p(SAversive/noR) if R prevents SAversive = Avoidance Discriminated or Signalled Avoidance A warning stimulus signals a forthcoming SAversive If the required response is made during the warning stimulus, before the SAversive occurs, the subject avoids the shock. If a response is not made during the warning stimulus, the SAversive occurs, and terminates when the required response is made e.g., one-way avoidance two-way avoidance The Two-Process Theory of Avoidance Explains avoidance learning in terms of two necessary processes: 1. The subject learns to associate the warning stimulus with the SAversive 2. The subject can then be negatively reinforced during the warning stimulus Thus the two-process theory reduces avoidance learning to escape learning; the organism learns to escape from the CS and the fear that it elicits. Acquired-drive experiments support the Two-Process Theory of Avoidance since animals do learn to escape from the CS The Two-Process Theory of Avoidance 1. Level of fear is not always positively correlated with avoidance 2. Avoidance behavior should cycle at asymptote, but it typically does not. 3. Avoidance behavior should not be learned if the response does not terminate the CS, but it is. Problems for the Two-Process Theory of Avoidance 4. Animals can learn Free-Operant (or Sidman) avoidance Alternative Theoretical Accounts of Avoidance Behavior Positive reinforcement through Conditioned Inhibition of fear Conditioned Safety Signals performance of the avoidance response results in distinctive feedback stimuli (i.e., spatial cues, tactile cues, etc…) the avoidance response produces a period of safety allowing the feedback cues to become signals for the absence of shock (