Some new tendencies in application of the associative experiment (AE) to the study of structure and dynamics of cognitive activity are examined. The AE possibilities are discovered in the interrelation between an individual's active and passive knowledge (on the analogy with the active and passive lexicon). AE allows studying not only the content and volume of active knowledge about a given subject, but its dynamic interrelations with passive knowledge as well. The paper describes findings of a study in which the modified method of serial thematic association (STA) was used. For various themes and participants (schoolboys and students) some general attributes of associative dynamics were found: heterochrony, association rate, variance of category changes. A specific combination of these attributes along with the index of associative row volume and its semantic spectrum defines an individual style of handling personal knowledge.