The article looks at the psychologically privileged status of notions of a certain level of generalization (the basic level). It is believed that the effect of the basic level can be explained as a mechanism that temporarily facilitates access to data in the semantic memory. This mechanism can be interpreted as long-term activation of necessary information. This hypothesis is compared with the theory of prototypes and the basic level. The experiments carried out confirm that in certain conditions categories in which the basic level effect was not previously observed, may display it due to activation of appropriate notions (in tasks which require from the subjects thorough semantic processing of the material). The effect obtained was observable 24 hours later which testifies to its stability and long-term character.