Collaborative thinking activity integrates phenomenon when small group (2-5 persons) solves the problem or task and makes the decisions together. Collaborative thinking activity is described as generation of individual and common new formations: goals, senses and motives. Basing on the analyses of the experimental studies the specific patterns of the functioning and development of individual and common new formations are shown. Conceptions of the world image are discussed, the role of the world image in thinking activity is shown. The main criteria of incorporating the information into the world image are determinated. The influence of each participant during the processes of the incorporation, production and development of the individual and common new formations is ascertained. Psychological situation is represented as active part of the world image and it is considered to be the source of new formations generation. The common psychological situation includes two areas: value-semantic structure and potential active area. The model of collaborative thinking activity self-organization, which theoretically interprets the contributions of participants in new formations, is presented.