Representing the Social Practices of Communities
as the Basis for Agent-based Simulation
This paper presents a new approach, the Human Community Model
(HCM), to simulating complex human systems. Rather than treat human
actions in a manner analogous to biological processes, such as the predator-prey
model, we consider all human behavior to be a case of an actor engaging in
a practice of a community, and use formal articulations of the concepts of
community and practice. The rigorous articulations allow us to represent,
in machine-usable form, a variety of human action in human communities, without
doing violence to the fundamental realities of human choice and values.
The paper explains the model and how it differs from other approaches, and
shows how it can be used in agent-based simulations of human communities.
The practices of a community, which are the possible behaviors
a member of the community can engage in, have a complex logical structure
including: a) Other, smaller, practices; b) Choices the actor can or
must make in carrying out a practice; c) Choice Principles that govern the
choices a member makes; and d) Individual preferences. Each practice has
versions, allowable sets of steps for carrying out the practice. (“Allowable”
not in the physical sense but in the sense of being known to community members
as ways of doing that practice.) An actor engages in a behavior by carrying
out a version of a practice. Each step is itself a practice, and is
carried out by engaging in one of its versions, down to the level of detail
at which there are no behaviorally significant variations (behaviorally significant
in that community). The practices of a community thus form a hierarchically
organized set of logically complex units representing what can be done, incorporating
actions, choices, community values, and individual values. The formal
model we employ allows us to represent these structures, and build software
based on them.
Carrying out a practice is rarely, if ever, analogous
to a machine carrying out an algorithm; a key aspect of human practices is
that, in the paradigm case, there are several kinds of choices to be made:
which practice to carry out; which of the steps, or options for a step, to
do; and which actual individuals, objects, or materials to use for the logical
roles in the steps of the version of the practice.
This model has been used to build a number of software
systems in different communities of practice, including several question-answering
systems (employing from 50 to 150 practice descriptions) and a system to
actually carry out practices in a large multi-office bank. A number
of the applications were to practices not usually considered to be formally
describable, such as the practice of a manager attempting to improve a subordinate’s
performance by appealing the subordinate’s intrinsic motivations.
Since carrying out an action is a case of carrying out
a set of steps, and each of the steps is itself done by carrying out a set
of sub-steps, it is easy to see how HCM-based simulation can proceed:
Each actor carries out Step 1 of the version of the practice he/she has chosen;
completion of that Stage is some outcome (by definition), so the facts known
to the actor are now changed; Each actor now re-assesses the situation (the
known facts) and again chooses what to do, based on the new facts, which
include (the fact that) the actor has engaged part of the version of the
practice and therefore has behavioral reason to continue it. Theories
about an actor, a kind of actor, or even whole societies, can be tested by
representing them as priorities for making choices among behaviors, and observing
the results of the choices.
The complex logical structure of each practice, combined
with the explicit representation of both the “values” or “preferences” related
to the practice and the precise places in the practice where the choices
reflect the values, provides a rich set of resources for modeling the varieties
of human action. Since the formulation of community has been deliberately
created to cover a wide range of organized human groups, from work teams
and businesses to societies and whole cultures, the applicability seems widespread.
In the paper, we present the full formal structure of
Communities and Practices, and give examples of descriptions of practices.
In addition, we discuss limitations of the current work with the model, and
several planned applications.
Joe Jeffrey
Northern Illinois University
Department of Computer Science
jeffrey@cs.niu.edu