Stahl, G. (2013). Theories of cognition in collaborative learning. In C. E. Hmelo-Silver, C. A. Chinn, C. Chan, & A. M. O'Donnell (Eds. ), The international handbook of collaborative learning (pp.74-90). New York: Routledge.

The reading of the history of theory presented here is itself reflective of one theoretical stance among many held, implicitly or explicitly, by collaborative learning researchers.
Through history, the analysis of cognition has broadened, from a focus on single concepts (Platonic ideas) or isolated responses to stimulae (behaviorism), to a concern with mental models (cognitivism) and representational artifacts (post-cognitivism). Theories that are more recent encompass cognition distributed across people and tools, situated in contexts, spanning small groups, involved in larger activities and across communities of practice. 

The history of theory can be tracked in terms of the following issue: At what unit of analysis should one study though (cognition)? 
P 76 Figure 4.1  Adapted from Stahl, 2006, p. 289, Fig 14.1

Theories of individual cognition in CSCL:
Work within CSCL certainly acknowledges the importance of the larger social, historical, and cultural context. However, it often treats this context as a set of environmental variables that may influence the outcomes of individual student cognition, but are separable from that cognition. In this way, cognition is still treated as a function of an individual mind. This approach may be called sociocognitive. It acknowledges social influences but tries to isolate the individual mind as a cognitive unit of analysis by controlling for these external influence.
Followers of Vygotsky, by contrast, are considered sociocultural. They recognize  that cognition is mediated by cultural factors. Yet, they still generally focus on their individual as the unit of analysis. They investigate how individual cognition is affected by cultural mediations, such as representational artifacts or even by collaborative interactions. Vygotsky was trying to demonstrate that individual cognition was derivative of social or intersubjective experiences of the individual, and so his focus was on the individual rather than explicitly on the social or intersubjective processes in which the individual was involved.
In this sense, much CSCL research investigates individual cognition in settings of collaboration. In fact, if the research is based on testing of the individual before and after a collaborative interaction and does not actually analyze the intervening interaction itself, then it is purely an analysis at the individual unit of analysis, where the collaboration is merely an external intervention measured by presumably independent variables.

Theories of community cognition in CSCL
In striking contrast to the steadfast focus on the individual as the unit of analysis is the social science perspective on social processes. Lave and Wenger (1991) borrowed Marx's approach to educational theory, showing for instance how an apprenticeship training system reproduces itself as novices are transformed into experts, mentors, and masters. Learning is seen as situated or embedded in this process of the production and reproduction of structures of socially defined knowledge and power.
Levels of description or unit of analysis in CSCL

Hakkarainen, K., Paavola, S., Kangas, K., Seitamaa-Hakkarainen, P. (2013). Sociocultural perspectives on collaborative learning: Toward collaborative knowledge creation. In C. E. Hmelo-Silver, C. A. Chinn, C. Chan, & A. M. O'Donnell (Eds. ), The international handbook of collaborative learning (pp. 57-73). New York: Routledge.

Three basic metaphors of learning: as individualistically oriented acquisition, as participation, and as collaborative knowledge creation. 

• The knowledge acquisition metaphor: examines how knowledge as a property or characteristic of an individual mind (Sfard, 1998); based on traditional assumption of the transmission of knowledge to student;
• The participation metaphor for learning examines learning as a process of growing up and socializing in a community, and learning to function according to its socially negotiated norms (Brown, Collins, & Duguid, 1989; Lave & Wenger, 1991); learning is the process of growing to become a full member of a community, in which there gradually occurs a shift from peripheral to full participation. From this perspective, knowledge is not a thing in the world itself or within the mind of an individual, it is simply an aspect of cultural perspectives.
• The knowledge creation metaphor (Hakkarainen, Palonen, Paavola, & Lehtinen, 2004; Paavola, Lipponen, & Hakkarainen, 2004) suggests, that despite clear differences, several theories of collaborative learning have a common aim of explicating collaborative processes involved in the creation or development of something new. As representative theorists of knowledge creation metaphor, we ourselves have analyzed especially Bereiter's (2002) knowledge building, Engestrom's (1987) expansive learning, and Nonaka and Takeuchi's (1995) organizational knowledge creation (Paavola et al., 2004). The knowledge creation metaphor is not meant to be a specific theory of collaborative learning, but more like an umbrella term for otherwise quite different theories and approaches to collaborative learning. 

A forerunner of knowledge creation is the theory of knowledge building. Knowledge building is a pedagogical approach that is focused on transforming school classes to inquiry communities focused on improving their shared ideas understood as conceptual artifacts with the assistance of collaborative technologies (Scardamalia & Bereiter, 2006).

In order to elicit knowledge creation process, it is essential to build an inquiry community that structures and directs the participants' collaborative epistemic activities. Collaborative inquiry learning appears to prepresent a special kind of cultural practice that can be appropriated by learners through organizing classrooms as inquiry communities (Brown, Ash, et al., 1993; Scardamalia & Bereiter, 2006). 

Establishing an educational learning community is essential because it carries or bears social structures and practices critical for knowledge creating approaches to collaborative learning. In order to make CL work, it is essential to create and cultivate shared knowledge practices that guide participants' activities in a way that elicits a pursuit of shared inquiry. The term knowledge practices is used by the present investigators to refer to personal and social practices related to epistemic activities that include creating, sharing, and elaborating epistemic artifacts, such as written texts (Hakkarainen, 2009). Such practice refer to relatively stable but dynamically evolving shared routines and established procedures, such as question generation, explication of working theories, search for information, and contributing notes to KF, which have deliberately been cultivated within a learning community. 

One basic tenet of the knowledge creation approach to collaborative learning is that innovation and pursuit of novelty are special kinds of social practices cultivated in epistemic communities and their networks (Hakkarainen et al., 2004; Knorr Cetina, 2001). A successful learning community deliberately aims at "reinventing" prevailing practices so as to elicit knowledge-creating inquiry (Knorr Cetina, 2001, p. 178).

Roschelle, J. (1992). Learning by collaborating: Convergent conceptual change. Journal of the Learning Sciences, 3(2), 235-276.