The effects of signaled reward on sign tracking and response rate

Abstract

If, while responding on a variable interval schedule, rats are given a brief cue prior to reward, their response rate is markedly lower than the rate for yoked partners who receive the cue randomly with respect to reward. This signaled-reward phenomenon has been explained in terms of sign tracking. Two experiments reported here replicated the phenomenon and examined sign tracking directly through visual inspection of the animals’ behavior. Although sign tracking did, indeed, occur more in the signaled reward condition, it did not fully account for the difference in response rates.