Decision Chemistry Part II: The Emergence of
Routines
Alessandro
Lomi
Stefano
Cacciaguerra
Last
Updated September 2003
Description
-----------------
In the second part of the “Decision chemistry”
model series, the objects that populate the stylized organizational world that
we have designed are computationally more sophisticated than the objects in the
first model. In particular, participants, problems, solutions and opportunities
are now all endowed with communication capabilities and sensory mechanisms that
allow more complex rules of search and motion, and hence induce more complex
patterns of interaction. Objects communicate by leaving “information trails”
that other objects can then sense and follow. In order to be followed,
information trails must be (i) sufficiently strong, i.e., they must be above a
certain sensitivity threshold, and (ii) visible, i.e., they must be within the
angle of vision of the various objects.
Information trails are diffused in local
neighbourhoods that are defined around individual objects. In the movie of the
model’s behavior, the information trails can be seen as green a “halo” visible
around each object. Information trails slowly disappear - or “evaporate” - if
they are not followed. But if they are followed, they become stronger thus
attracting more objects in the corresponding local neighbourhood. This
(strictly local) mechanism of positive feed-back induces “routines” –
relatively stable clusters of problems, solutions, opportunities, and
participants. In the movie of the model’s behavior, routines can be seen as
white areas of varying size.
As in part one – and in keeping with the
original model of Cohen, March and Olsen - the objects that populate this more
complex organizational world are: problems (yellow triangles), participants
(blue squares) and solutions (red circles). The collision rules among the
objects are those defined in the first model (Decision chemistry on a lattice
part one). In particular, we recall that the collision between a “problem” and
a “solution” generates an “opportunity.” Collisions between opportunities and
participants may then give rise to different types of decisions depending on
the relative energy level of individual objects. In the first version of the
model the entities followed a random walk though the lattice.
The basic motivation behind this second and
more advanced model is to show how aggregate entities called “routines” may
emerge, grow, change and disappear as a consequence of simple rules of
interaction among objects that are defined at lower levels. The main analytical
insight offered by our modelling exercise is that conditions can be defined
whereby garbage can-like decision processes evolve to ordered global states.
Finally, from a theoretical point of view, the value of our model is to provide
a structured context in which the implications of the mobility of agents for
the structure of social systems can be discussed and explored.
Visualizing the model
-----------------------------
The following are links to an AVI movie of an
illustrative run of the second model in the “Decision Chemistry” model series The movie is obtained by sampling one state change every
second in order to save space. The underlying model produces a significantly
less discrete behavior. The files large.avi (about 7.8MB) and small.avi (about
3.4MB) contain AVI movies of the model that can be viewed directly with any
standard video player. The files large.zip (about 3.4MB) and small.zip (about
1.7 MB) contain zipped versions of the same movies.
Netlogo
------------
The model
described in “Decision
Chemistry Part II: The Emergence of Routines” is programmed in Netlogo. The
NetLogo User Manual reads: “NetLogo is a programmable modeling environment for simulating natural
and social phenomena. It is particularly well suited for modeling complex
systems developing over time. Modelers can give instructions to hundreds or
thousands of independent "agents" all operating in parallel. This
makes it possible to explore the connection between the micro-level behavior of
individuals and the macro-level patterns that emerge from the interaction of
many individuals.” The
NetLogo software, models and documentation are distributed free of charge for
use by the public to explore and construct models. The most recent version of
NetLogo can be downloaded from: http://ccl.northwestern.edu/netlogo/
Cite
-------
To refer to the present work in academic publications,
please cite as:
Lomi, A., Cacciaguerra, S. 2003. Organizational
decision chemistry on a lattice. Part II: The Emergence of Routines. Working Paper. Department
of Computer Science. University of Bologna.
Acknowledgements
-------------------------
This work was supported in part by the Italian
National Research Council (CNR) (grant number CNRC004195_001, and Grant Ex-60%,
Scientific Committee number 13)