Like many mammals, rats are attracted to novelty. In order to recognize something in the environment as novel, there needs to be memory for what has been encountered before. The relative attention the animal will devote to the novel compared to the familiar in the environment can therefore be used as a proxy for available memory.

The novel object recognition task makes use of this effect. The task typically consists of three phases – Habituation, Sampling, and Probe. During Habituation, animals are repeatedly exposed to the apparatus, usually a square open field. This serves to familiarize them to this environment. Then, during Sampling, animals return to the open field, that now contains objects. In the most simple form,

Typically, animals are exposed to objects in a familiar open field during the Sampling phase, and at a later point, they are re-exposed to the open field during the Probe phase, in which some objects from the Sampling phase have been replaced