Reading focus
Syllabus: How Do Consequences Shape Action?
Reconstruct the response and nonresponse probabilities in the water-reinforcement experiments, especially the move to zero contingency.
Why you’re reading it. Complement outcome devaluation with a manipulation of action–outcome dependence, while distinguishing contingency from close temporal pairing.
A question to consider. Compare making an outcome less valuable with making it equally available without the action. What does each manipulation change, and why could the same decline in responding have different explanations?
Why this reading
An outcome may follow an action without depending on it. Hammond develops a way to vary outcome probabilities after responding and nonresponding, separating the action’s contingency from opportunities for close response–reward pairings.
Before you read
Free-operant responding is not divided into separate prompted trials. The apparatus divides time into one-second intervals and records whether at least one response occurs. Contingency here is the difference between reinforcement probabilities with and without responding. Contiguity concerns temporal closeness; the two are not interchangeable.
Read for
- Identify how the two programmed probabilities change across conditions, rather than classifying every delivery of water after a press as equally contingent.
- Follow the zero-contingency comparison in which reinforcement probability following a response is retained while reinforcement without responding increases.
- Compare the repeated condition changes with the between-group experiment, then inspect the limitations of the one-second definition of response and nonresponse.
Consider afterwards
- A machine sometimes gives a token after a button press. How could you weaken the press–token contingency while preserving the probability of a token in intervals containing a press? What would declining responding establish, and what would it leave open?
Editorial context
The paper reports two rat experiments, using 57 animals in total and water as reinforcement. It offers evidence of sensitivity to the arranged contingency, not a direct observation of an animal’s causal concept. The discussion stresses that only widely separated contingency values were compared and that the time-unit assumptions require scrutiny. Zero contingency here is also different from extinction: reinforcement remains available after responding.