EFFECTS OF EFFORT ON RESPONSE RATE 1

Pigeons were trained to peck for food reinforcement, and the minimum effective force for a peck was varied. In a single‐key situation, the response rate was unaffected up to a certain force value, beyond which increments caused a proportional decrement in response rate. Transient enhancement and suppression effects were observed following a change in the force requirement. A change from a high force requirement to a low force requirement resulted in a temporary enhancement of response rate above the stable performance level, whereas a change from a low to a high requirement produced a temporary suppression of the rate below the stable rate. In a two‐key situation, the response rate on a key with a given force remained unaffected by the force requirement on the other key. When the rate of response was plotted against the required force, the resultant function was remarkably similar to that obtained from the single‐key experiment. When the rates of reinforcement on the two keys differed, the decrement in response rate produced by an increase in the force requirement was proportionally greater on the key with the lower rate of reinforcement.