The paper provides a detailed definition and basic facts about the phenomenon of synaesthesia of natural development (developmental synaesthesia). On the basis of modern discovery and historical data of the research indicating selective synesthetic reactions and their definite advantage in some types of cognitive activity, there are theoretical foundations to research synesthesia efficiently along with private methods of researching sensory mechanisms and more complex representations of individual dynamics of properties and mechanisms of individual cognitive sphere with features of synaesthetic perception.

As a hypothesis the paper uses functional genetic paradigm which includes the notion of age sensitivity (N.S. Leites), interpretation of synaesthesia in studying individual properties (B.G. Ananiev) and the idea of system genesis abilities (V. D. Shadrikov).

Empirical studies presented the thesis that it is more rational to consider synaesthesia as a system property on a par with cognitive, creative and personal values. Thus, synaesthesia is interpreted as an isomorphic mechanism, but with varied content (“cognitive strategy”), which develops out of a specific deposit and manifests itself in super-early ontogeny as rudimentary object, the special ability of the elemental type (property of perception). On the individual (phenomenological) level, this property is shaped as an additional response of a homogenous sensory quality, consistent and categorical in perceived involuntarily accompanying phenomena: symbolic systems (language, music, etc.), symbolically organized phenomena of reality (time-calculation, etc.), and partially perceived physical systems (odors, etc.).