A growing conceptual and empirical literature is advancing the idea that language extends our cognitive skills. One of the most influential positions holds that language – qua material symbols – facilitates individual thought processes by virtue of its material properties. Extending upon this model, we argue that language enhances our cognitive capabilities in a much more radical way: the skilful engagement of public material symbols facilitates evolutionarily unprecedented modes of collective perception, action and reasoning (interpersonal synergies) creating dialogically extended minds. We relate our approach to other ideas about collective minds and review a number of empirical studies to identify the mechanisms enabling the constitution of interpersonal cognitive systems.
Acknowledging these intersubjective and cultural dimensions of the way language constitutes interpersonal cognitive systems, new lines of interdisciplinary research are opened in the field of extended and social cognition. In this paper we focused on language as a cognitive phenomenon that combines core aspects of intersubjectivity with the creation and maintenance of external vehicles of cognition. In this perspective, the extended mind hypothesis gets to be supported and further articulated by on-going research in social cognition investigating the constitution and dynamics of embodied intersubjective engagement. At the same time, research in social cognition is complemented by a focus on how dialogical engagement comes to constitute extended cognitive processes. Last but not least, our perspective fills a gap in the present debate by providing an initial account of the pervasive role of language in creating intersubjective coupling and thereby shared cognitive processes.