Effects of Contingent and Non-Contingent Signals During Delay Interval on Response Acquisition by Rats

Abstract

Research on delay of reinforcement effects under temporally defined schedules of reinforcement suggests delay effects are diluted under short cycle durations. This conclusion is tentative because attempts to replicate the seminal study conducted by Weil (1984) differed from the original study in a number of ways. The present study attempted a more direct replication of Weil`s study and also to extended the original manipulation to encompass two different signaled delay of reinforcement procedures. Thirty-six naive rats were exposed to a repetitive time cycle of 32-s. The cycle was divided into two portions, td  and t delta. A response during td produced food at the end of the cycle; responses emitted during t delta had no programmed consequences. For some experimental groups td was signaled by a response-produced signal; in other groups a non-contingent signal occurred during td ; in still other experimental groups td was unsignaled. The placement of td was varied to produce two different response reinforcer temporal relations; td duration was also varied to assess the generality of the results. Response rates were considerably lower when td was at the beginning of the cycle than when the opportunity to respond was at its end. Non-contingent signals produced low rates of responding; in contrast response produced signals were associated with high response rates. In general the results show that delay of reinforcement has detrimental effects on response acquisition even under short reinforcement cycles. Both non-contingent and contingent signals have facilitative effects on the response acquisition process, but the former favors low rates of responding and the later favors high response rates.