The one-trial object recognition task involves memory of a familiar object in parallel with the detection and encoding of a novel object. It provides the basis for the study of a wide range of cognitive and neuropsychological functions and processes in rats and mice. However, unlike in humans, primate and pigeon studies, object recognition in rats and mice has been mostly limited to memory while little is known about object perception, affordances and acquisition of a representation of an object. In the present paper, we addressed some of these issues. We also described novelty preference models and hypotheses that account for one-trial object recognition and question the validity of the novelty preference concept. In addition, we discussed whether one-trial object recognition involves working memory and how it involves memory of an episode.