Introduction
In a landmark article on culture and intelligence, the collective of the Laboratory of Comparative Human Cognition (1982) pointed out that a context-specific account of the cultural basis of intelligence is crucially dependent on the formulation and employment of an adequate unit of analysis.
Concerned as we are with specifying how the outside influences the inside and vice versa, we cannot proceed leaving these two systems as independent entities. Somehow, we must deal with the problem of inside and outside together, as mutually influencing systems [p. 695].
The authors of that paper suggested the concept of activity, and the closely related notion of cultural practice, as the most promising candidates for such a unit. Object-oriented, artifact-mediated activity is the central concept of the cultural-historical approach to higher mental functions, initiated by Vygotsky (1978), Leont'ev (1978), and Luria (1978).
Activity is a molar, not an additive unit of the life of the physical material subject. In a narrower sense, that is, at the psychological level, it is a unit of life, mediated by psychic reflection, the real function of which is that it orients the subject in the objective world. In other words, activity is not a reaction and not a totality of reactions but a system that has structure, its own internal transitions and transformations, its own development
[Leont'ev, 1978, p. 50; also Wertsch, 1981; Smirnov, 1994].