Can rats learn about brief significant cues?

Two experiments used the titration method to examine how rats learn about very brief significant visual cues. Experiment I demonstrated that hooded Lister rats were able to maintain a simple bright-dark simultaneous visual discrimination when the cue duration was gradually reduced to an average of 20 ms by the titration method. Experiment II looked at the effects of adding a fixed ratio (FR) requirement to the titration schedule and also found that response times to the S+ cue were significantly shorter than S- response times over the course of titration training; a result which agrees with the response time data for conventional visual discrimination tasks. The results of the experiments are examined in relation to the concepts of shaping and selective attention and the advantages of the titration method for comparative cognition are considered.