The effects of CS and cycle durations on stimulus-elicited keypecking in the pigeon

The relative duration of the CS to the inter-US interval has been found to determine the rate of acquisition and rate of maintained keypecking by pigeons in delay conditioning procedures. Also maintenance of keypecking, but not rate of acquisition, depends upon the absolute CS duration for a given CS/inter-US interval. However, in delay conditioning procedures, delay of US occurrence increases as CS duration increases. In the present study, the effects of CS/cycle ratio and CS duration were examined without the confounding effect of changes in delay of US occurrence by presenting the US at a constant rate during the CS. The CS was superimposed on a VI schedule of reinforcement so that both increases and decreases in the rate of keypecking could be measured