Mella, Piero - Types of Combinatory Systems

The Structure of Concern Project compares many theoretical models from many disciplines to the Adizes PAEI model, arguing that they must all be reflecting the same underlying phenomenon. One concern structure model is described below.

Mella develops a model of the social or collective behavior of interacting autonomous agents, in order to investigate what he calls combinatory effects. Combinatory effects occur when micro-level interactions drive macro-level system behavior, and macro behavior determines, conditions or directs the micro behavior, reciprocally and simultaneously. The concept thus has similarities with ecological concepts such as hierarchical causation (Mella, 2003a; Mella, 2003b).

The goal of Mella’s project is to shed light on a set of problems involving non-linear collective state changes and the individual interactions that cause and are affected by them, including: “…the voice-noise effect in organizations; the clustering and swarming effects in economics; the unjustified raising of retail prices; the stock exchange dynamics deriving from the micro-macro feedback between stockbroker decisions and the stock index…”. All of these are phenomena involving crossed micro-macro level feedback.

In the development of his model, Mella introduces a typology of combinatory systems that instantiates the structure of concern. It is a five-category typology, with two of the elements falling into the “I” bucket. This is unsurprising, given the social focus of the model. The system types in PAEI order are:

P – Systems of Pursuit: The system gradually seems to be orienting itself towards a “goal” or “objective”. The contextually driven shared goals of members of the collective emerge at the macro level as the “goal” of the whole combinatory system. Examples include all kinds of mob behavior, including escape from disasters, lynch mobs, non-violent non-cooperative political resistance, holiday shopping, looting mobs and the floor of the stock market.

A – Systems of Order: The behavior of individuals becomes ordered or has its order amplified by the further-ordered condition of the macro level. The circulating stadium “wave” is a clear example, as are the shifts and turns executed by flocks of small birds or herds on the move. On crowded city streets and dance floors, tacit or explicit “right of way” conventions can give rise to ordered flows of units at the macro level, without such macro behavior being specifically indicated. Footpath formation is another system of order.

E – Systems of Improvement and Progress: This is a subclass of Pursuit, where individual achievements increase the status of the parameter that measures collective performance. They “raise the bar”. This creates positive gaps (being ahead of the crowd) and negative gaps (being behind in the race) along with the motivation for individuals to increase positive and eliminate negative gaps. Standards of comparison are needed that track the overall rising standards of the group so individuals can determine their standing. Races, world record-holding and the progress of science are just some of the many systems of progress.

I – Systems of Accumulation and Diffusion: Systems of accumulation gather together or focalize social responses of a certain type. After the death of Princess Diana, several sites in the UK became foci for the accumulation of flowers from mourners. Emerging neighborhood identities, such as heavy industries in one part of a city, boutiques in another, and various clusterings of ethnically-specific businesses are also systems of accumulation. There can be foci for the accumulation of graffiti or garbage, for the breaking out of applause or laughter and for the reintegration and mobilization of flocks, herds and schools.

Systems of diffusion are contagion-like dynamics where some trait, behavior, quality or state spread from a few members to many members of the collective. Fashion trends of every kind utilize systems of diffusion, as does the spread and preservation of national languages and customs. Religious and political ideologies and mass hysteria also spread in this fashion.

1. Mella, P. (2003a). “Order and Chaos in Combinatory Systems: A Different Approach to Collective Behaviour.” INSC 2003: International Nonlinear Sciences Conference - Research and Applications in the Life Sciences.
2. Mella, P. (2003b) “Synchronization and Self-Organization in Organizations: The Combinatory Systems View” [Web Page]. URL [2005, May 9].
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