Preface: distributed cognition and educational practice.

Traditionally, cognition has been treated as residing in the head, as being a property of the individual mind. To a large extent, current psychological and educational practice is founded upon this conception of cognition. Nevertheless, in recent years and in cognitive traditions such as educational psychology and cognitive science it has been advocated that cognition does not reside only in the head. Rather, it is suggested that cognition extends beyond the skin, essentially being distributed along two main dimensions; material and social. Assuming that an individual is performing a certain task, the material dimension of the distribution refers to the incorporation of all kinds of mental and physical artifacts in which cognition is encapsulated. On the other hand, the social dimension of the distribution of cognition refers to the involvement of social others who provide assistance in many ways during task execution by functioning as cognitive resources.

The ideas that relate to the distributed cognition perspective have mainly surfaced over the last decade and have become so popular that the notion of cognition as distributed in commonplace nowadays. Nevertheless, we are not aware of many systematic research efforts to explore, apply, and evaluate distributed cognition ideas. All of the articles in this issue provide an account of cognition as distributed among people and artifacts, present evidence regarding this distribution, and address the implications of this distribution for certain facets of the teaching and learning practice.

In the opening article, Ilias Karasavvidis provides an introduction and overview of the ideas related to the distribution of cognition. Karasavvidis begins with tracing the contemporary image of mind as the locus of all cognition and intelligence back to Plato. This image of the mind as disembodied and disembedded is subsequently discussed in terms of its impact on current psychological and educational practice. The notion of cognition as distributed has proponents in two traditions, cognitive science and educational psychology, and Karasavvidis presents an integrative account of the ideas within each respective tradition. The article continues with a specific reference to cultural-historical psychology and then critically appraises the distribution of cognition ideas in cognitive science and educational psychology so as to highlight similarities and differences. Karasavvidis concludes his article with a discussion of the implications of distributed cognition ideas for the teaching and learning practice by e xamining how the incorporation of a computer tool in the solution of a correlational problem substantially transformed the problem solution.

Mariette de Haan focuses on the cultural nature of guidance models and considers how the distributed cognition perspective can inform them. De Haan begins her article by discussing how non-western learning practices provide certain guidance models that have become a source of inspiration for school reform in the western world. De Haan examines what the distribution of cognition means for models of guidance and argues that treating cognition as socially and materially distributed entails a view of instruction which portrays learning as intertwined with the social and material context within which it takes place. The article continues with a description of a study on Mazahua learning practices which shows that Mazahua people view knowledge as socially distributed and, furthermore, that their guidance model is based on a distributed cognition perspective. In the second part of her article, De Haan examines comparatively distributed cognition, Mazahua shared competence, and cognitive apprenticeship models and de termines that the most salient difference relates to the issue of task authenticity. The article concludes with a discussion of the transformations that nonwestern cultural models of learning undergo when adopted in the western schooling practices.

In examining ways of conceptualizing the teaching and Learning of thinking, Rupert Wegerif finds Vygotsky's model of internalization incomplete and puts forward the implication model as a promising alternative. Wegerif begins his article by discussing two images of teaching and thinking, offered by Kant and Nietzsche respectively. The article continues with the detailed presentation of two studies aimed to teach nine and ten-year-old children a set of practical ground rules. Wegerif analyses evidence from the first study conducted, which supports a conception of learning that is clearly compatible with Vygotsky's model of internalization, as the students internalized the ground rules introduced and could employ them during solo posttest performance. Subsequently, the second study is presented and Wegerif points out that Vygotsky's internalization model cannot provide an explanation for the changes effected in classroom culture. Wegerif introduces the model of implication to account for this finding regarding changes in classroom culture. In the last section of the article, Wegerif provides an example of implication and discusses implication and subjectivity.

Sean Courtney focuses on an educational innovation, "The Dig," and examines it from the perspective of distributed cognition. The article begins with information about the film which features "The Dig" and the teacher who set up artifacts and then directed the instructional activities. Courtney identifies five key elements as essential for understanding pedagogical innovations and contrast them to traditional forms of teaching and learning: space and time, identity and motivation, power and control, knowledge and text, work and integration, and tools and technology. The article continues with an elaborate account of "The Dig": lesson and artifact preparation, class orientation, archeological site expedition, three-day excavation, hypothesis testing, data collection, and interpretation of findings. In the second part of the article, Courtney discusses "The Dig" in terms of the five key elements identified at the outset in an attempt to demonstrate the innovation as a case of "distributed pedagogy."

Hitendra Pillay and Robert Elliott examine how the distributed cognition model helps determine the cognitive attributes, which would enable individuals to function in a complex, changing world. The article begins with a discussion of the emerging workplace where Pillay and Elliot address the changing social and economic conditions which in turn call for different educational systems. The article continues with a description of the assumptions underlying the distributed cognition model. In the second part of the article, Pillay and Elliott discuss in detail the distributed nature of critical thinking, suggesting that, much like other social and cognitive activities, critical thinking should also be distributed. The paper concludes with an elaborate account of the proposed critical thinking model, which is comprised of four main factors: (a) cultural dispositions, (b) tools, (c) content knowledge, and (d) strategies. Pillay and Elliott identify and discuss these factors as important for promoting and fostering critical thinking.

Neli Stoyanova and Piet Kommers studied the effectiveness of concept mapping in computer-supported collaborative problem-solving. Their article presents an experimental study aimed at investigating the learning effectiveness of concept mapping for computer-supported collaborative problem-solving. The main assumption underlying their research is that distributed cognition is substantial for cognitive construction and reconstruction and that concept mapping is an effective tool for mediating computer-supported collaboration. Three scenarios for "mediated group interaction" by concept mapping were designed-Distributed, moderated and shared. They are based on the assumption that the form in which knowledge is shared strongly influences the process of shaping shared cognition and subsequently influences the effectiveness of collaborative learning. The three scenarios demonstrate differential effects towards various aspects of learning effectiveness both at the group and at the individual level. It is concluded tha t both the mode of sharing and the representation of knowledge as expressed by students are more important than the access to the distributed resources itself. The sharing scenarios showed to be most appropriate for establishing a supportive learning environment.

Thanasis Daradoumis and Joan Manuel Marques address the issue of the distribution of cognition in small virtual group learning. In the first part of the article, Daradoumis and Marques describe an experimental collaborative problem-solving situation, which takes place in a virtual learning environment, providing information about the particular technologies employed in their study. The article continues with an account and examples of the approach used in analysing student-student interactions: Negotiation Linguistic Exchange model, Model of Discourse Contributions, types of learning activities underlying a participant turn and Rhetorical Structure Theory. Daradoumis and Marques subsequently discuss how discourse can be used as a medium and means through which cognition is distributed. In the final section of the article, preliminary results from the study are reported, which suggest certain cognitive factors affecting the learning process such as type and purpose of dialogues as well as type of activities in which the students were involved.

The development of a task-based framework for providing learning within the workplace using networked multimedia constitutes the focus of the article by Patrick McAndrew, Lachlan MacKinnon, and Roger Rist. The article begins with a description of the ASTEP project, which was aiming to create multimedia learning environments to facilitate distance learning. McAndrew, MacKinnon and Rist present the four main learning principles upon which the framework was based. The article continues with an analysis of the tasks and a description of the course model and concludes with a review of the developed framework from a distributed cognition perspective.

In the final article, John Cuthell considers MirandaNet, a learning community, from the point of view of distributed cognition. The article begins with an introduction to the concept of MirandaNet, a forum for innovation and continuing professional development of educators with more than 10000 users. Cuthell gives an account of what a learning community is and describes learning within the content of an online community. Using a series of posts by MirandaNet users on two topics, namely an online learning environment used by the MirandaNet members and lurking, Cuthell provides an illustration of how cognition is distributed among the system users.

Given the lack of research on issues related to the distribution of cognition, it is hoped that the articles of the current special issue will constitute a significant contribution in that direction.