How are we to characterize the reasoning processes of the individual actor as she works her way through a conventional joint activity with a partner?
The actors in MW reason pragmatically about their shared tasks. By pragmatic, it is meant reasoning that originates in the historic, is contingent on circumstances, and is obtained only through action or practice. This is in contrast to analytic models of reasoning where the modus operandi are general and rules of inference are syntactic. The pragmatic view reasons that Dick and Jane achieve passage through the doorway because they help one another and become familiar with the task and the task environment. Whatever `analysis' the individual actor makes about the predicament in which she finds herself falls short of uniquely determining the course of joint action.
There are two critical features to a pragmatic account of reasoning and acting: help from others and the home task environment [7]. Helping one another is the key to keeping co-participants on-track and in-synch as they work their way through a joint activity. Each actor has expectations about the direction a conventional activity will take, but to realize these expectations the actors must work together. As they proceed with their conventionalized behavior, they must continue to keep-in-time; verbal and non-verbal communication signal the phases of their joint actions.
A home task environment is an island of skill that emerges for the individual actor because of the re-occurrence of particular tasks within semi-permanent task environments. What makes for a home task environment is the continuation, the semi-permanence, of sets of co-participants, artifacts, and locations. In the FLOABN project, several benefits of home task environments were shown. For example, it was shown that tieing memory function to home task environments reduces the information-processing load and the amount of perceptual effort on the part of an individual actor for future related activities within the home task environment.
In MW, individual actors also become more familiar with the artifacts and objects of their domain; this is modeled through the operator probability trees. The characteristics of the specific objects that are moved and the specific features (e.g., layout) of the task environment change from problem to problem, but these objects and task environments are similar to prior objects and environments that participating actors have used and acted in. When a lifter attempts to lift a box of a certain size, her prior activity at lifting boxes with similar dimensions creates expectations that predispose the individual lifter to work with the box in one or another manner.
In MW, individual actors also become more familiar with behaviors of their co-participants; this is reflected in the bias of memory towards remembering the points of coordination in prior activities. As one actor becomes more familiar with the behaviors of other actors in the community, her expectations about the shape of the activity become more closely attuned to those of her co-participants. This is the basis from which conventions of behavior develop.