A new approach to the research of dialogue's role in cognitive structure is presented. It is based on analysis of the dialogue components directed to interaction with another person. Three age stages (8-9, 12-13 and 15-16 years olds) in dialogue interaction were experimentally studied. It is shown that the development of dialogue thinking structure is characterised by qualitative changes having two general tendencies: ability to dialogue interaction with a partner and the development of inner dialogue.