This paper presents an analysis of existing approaches to understanding the psychological content of the “range of equivalence” cognitive style. The range of equivalence presents a bipolar dimension (wide vs. narrow) of individual-specific qualities of processing the information, which is diagnosed with the help of various modifications of the method “Free Sorting of Objects” (FSO) method. The author proposes a new interpretation of the construct, integrating a number of existing theories. New directions are suggested for the research of determinants and practical significance of the equivalence range phenomenon. An empirical study of equivalence range assessment is described. A hypothesis of association between the equivalence range phenomenon and conceptual generalization ability was proposed and confirmed. A new method of developed by V.A. Kolga was used in two modifications, ; the objects of one of which belong to the category of “stretches and moments of time”, and the other one – to categories of “capacities”, “vessels”, “watersheds”, and also the method of multiple classification was used. 29 subjects took part in the study, most of which whom were students and aspirants of psychological psychology departments of at various universities. The results showed that the number of groups in two methods (Kolga modification with Capacities and Free Sorting of Objects) correlate r = .39, p = .03. The cCorrelation with Time is not significant: r = 0.30, p = 0.12. The number of groups in FSO correlates with the number of groups in the Kolga modification with Capacities: r from .55 to .64, p< .05. The empirical study showed that the phenomenon of the equivalence range in the product of cognitive activity is connected to the ability of conceptual generalization. A new method for assessment of the equivalence range free of the influence of conceptual generalization ability, limited sorting of objects, was developed and validated.