This piece of research concerns three experiments that have been conducted on rats. The aim was to find out what it is that can make a stimulus more or less salient. The hypothesis was to prove whether stimulus preexposure schedule and length are able to affect the salience of a stimuli. Two kinds of preexposures were involved; intermixed and blocked. What was concluded was that salience declined over recurrent preexposure, whereas length of the preexposure was not proven to have any effects on the salience. The authors assume that these experiments and their results are linked with perceptual learning, in the sense that the more salient a stimulus is in the learning process, the more effective it could eventually be in making the person acquire the new knowledge. Therefore, some more insight is provided into how the human cognitive system reacts to stimuli, and more importantly, to learning stimuli.