users to upload or select materials (e.g. pictures, music files, texts, websites) and associate tags with these materials. Tags can be chosen freely, and are similar to keywords. Other users can then browse through tags; a click on a tag connects a user to similarly tagged materials. Tags furthermore enable tag clouds, which graphically represent the popularity of tags, demonstrating co-occurrence relations between tags and thus jump from one tag to another. Dcog has also been used to understand learning and communication in clinical settings and to obtain an integrated view of clinical workplace learning. It has been observed how medical actors use and connect gestural practices, along with visual and haptic structures of their own bodies and of artifacts such as technological instruments and computational devices. In so doing they co-construct complex, multimodal representations that go beyond the mental representations usually studied from a cognitive perspective of learning. Distributed cognition can also be seen through cultures and communities. Learning certain habits or following certain traditions is seen as cognition distributed over a group of people. Exploring distributed cognition through community and culture is one way to understand how it may work. With the new research that is emerging in this field, the overarching concept of distributed cognition enhances the understanding of interactions between individual human beings and artifacts such as technologies and machines, and complex external environments. This concept has been applied to educational research in the areas of distributed leadership and distributed instruction. Distributed cognition between internal and external processing has also been used to study problem-solving and Bayesian reasoning. For example, it has been observed that the use of external manipulable materials such as cards and tokens can help improve performance and reduce cognitive bias such as the base-rate fallacy, even among adult problem-solvers, as long as they physically interact with these artefacts. It has also been reported that interacting with tokens can reduce the impact of mathematical anxiety on mental calculation performance and supports insight although the evidence is mixed with regards to the impact of distributing cognition between internal and external processing with regards to insight. Metaphors and examples Distributed cognition is seen when using paper and pencil to do a complicated arithmetic problem. The person doing the problem may talk with a friend to clarify the problem, and then must write the partial answers on the paper in order to be able to keep