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Z. Bonen

April 1979

#1056- 7*9






Z. Bonen

April 1979 /#! 056-79

Evolutionary Behavior of Complex Sociotechnical Systems

Z. Bonen


A complex sociotechnical system (STS) is composed of many people and
many types of equipment interacting together to perform some tasks. A
product/machine evolves by generations; a STS, on the other hand evolves
gradually and incrementaly. Patterns of evolution are described for
product, a single STS and tandem STS. A mature, inflexible STS acts as a
filter blocking radical change proposals and accepting only incremental
changes which cause minimum disruption to its present state. Hence,
radical change is usually championed by newcomers penetrating via empty
niches. Radical change is much more difficult in an area covered by tandem
interlocking inflexible sociotechnical systems.

n ^^^n I

1 . Introduction

A model of the process of evolution of a sociotechnical system (STS)
was described in a previous paper (1). This model stressed the general
impact of system properties on future evolution. It turns out that STSs
act as filters, tending to accept changes congenial to their present state
and to reject radical changes threatening STS disruption. In this paper we
shall classify various types of systems and describe the processes of
evolution associated with them. This detailed discussion supports the
conclusions of the above model.

2. Classification of Complex Sociotechnical Systems

Systems are usually described as small, medium or large with no
precise definition. Here, we shall try to define and classify systems by
categories convenient for the study of the process of evolution.

First of all, we shall differentiate between a inanimate system, i.e.
a product or a piece of equipment, and a complex sociotechnical system
(complex STS) which contains many people and inanimate systems interacting
together to perform a set of functions/missions. A product has a finite
life time and evolves by successive generations (car, airplane, typewriter,
refrigerator). Though a current product generation may be improved by
various modifications during its lifetime, sooner or later it becomes
obsolete and is replaced in toto by a new generation distinguished by some
novel features.

Complex sociotechnical systems, on the other hand, are not built in
one piece. They evolve gradually, mostly through incremental changes

STS state is defined by the following attributes: Values and
objectives, structure: the set of roles and relationships among STS
members, equipment and technological processes, personnel specific
skills and training.


(addition/subtraction/ substitution/fusion) of equipment, personnel,
organization and operating methods. Hence, at any point of time they may
contain incongruous constituents of various ages and levels of development.
Systems do not have a definite lifetime like products, indeed they may
exist for a long time. There is a great variety of sociotechnical systems,
for example: Production line in a factory, newspaper printing press, rail
network, R&D group, an army tank company, ground to air missile battery.
In general, a STS may be as small as a small workshop or as large as a big
societal system.

The basic difference in evolution between a product and a complex STS,
evolution through generation change versus gradual evolution, is pertinent
to all stages of system work: analysis and problem definition, synthesis
and design, development, testing and operations. Thus a real issue posed .
by complex sociotechnical systems to system theory is not how to design and
optimize a large scale system from scratch, but rather how to understand,
facilitate and perhaps optimize their process of evolution.

Products/inanimate systems may be divided into two categories:

1. Separate/stand alone products which can perform specified

functions independently (digital watch, hand calculator,

dishwasher ).

2. Embedded products which operate within a STS (traffic control
equipment, communications transceiver, instrument landing system).
Their performance is tied to the functioning of other system
constituents. The evolution of an embedded product is obviously
connected with the evolution of the system in which it is


A dishwasher does require a supply of electricity and water. However,
these are widely available with common standards and place little
constraint on dishwasher evolution.

Complex sociotechnical systems may be classified by:

1. Equipment/Personnel relative weight.

2. Spatial dispersion.

3. Decision structure.

The relative weight of equipment versus personnel, ranges from social
systems which contain no or little technology (schools) to (almost) fully
automatic systems (power grid, telephone network). At one extreme,
evolution means changing roles and relations between people, at the other
end it means substitution of and changing interactions between pieces of
equipment. Here we shall concentrate on labor intensive, medium to high
technology complex sociotechnical systems where evolution unfolds through
combined technological and social change.

Spatially, we can distinguish between a local compact STS and a
dispersed STS. The constituents of a compact STS interact functionally to
perform a combined task in a limited area (e.g production line, a tank
company, local airport control). Decisions in a compact STS are concerned
mostly with detailed functional coordination.

The constituents of a dispersed STS, usually many compact systems that
are dispersed over a large area, interact mostly through transfer of
material and data (e.g. airline reservation system, military command and
control system, railway system). Compact systems are often small and
dispersed systems are often large, but this is not always the case.

The evolution of a dispersed system includes the evolution of three
distinct but interacting components:

1. Local compact systems.

2. Higher management structure.

3. Interconnecting network structure.

The management structure of a large dispersed STS may vary from strong
central management to no management at all (e.g. an ecological system with
no conscious direction) . Here we shall deal mostly with systems which have
at least some management. Hence, they are capable of purposive evolution.

The above classification is summarized in Figure 1


Relative weight














Figure 1

Following section will deal with the evolution of a product (sec.
3.1), compact STS (sec. 3.2) and tandem STS (sec. 3-3). Specific problems
connected with the evolution of dispersed systems will be dealt with in
a later paper.

3. Evolution of Various Systems
3. 1 Product Evolution

Our main interest is in complex sociotechnical system evolution.
Hence, our discussion of product evolution will be brief and limited to
some aspects relevant to STS evolution. In general, product evolution is
connected with the evolution of the two sociotechnical systems involved in
its production and its use and should be discussed in that context (Figure



Figure 2

In this section we shall deal with the separable case of a stand alone
product. Thus, there is no using STS, only independent users. As for the
productive STS, it is easy for it to accomodate and introduce apparently
promising new stand alone products matched with its existing structure and
technologies. Here, there is no threat of disruptive structure change (1)
and few problems with well known technologies.

On the other hand, new stand alone products based on new technologies
are usually introduced by fluid flexible productive STSs (2) which are
receptive to radical technical innovations. These new products serve as a
vehicle for transfering the latest technology from the laboratory into the

As mentioned above a product evolves through successive generations.
The first generation is concerned mostly with feasibility proof and initial

market acceptance. If the product survives this test, the direction of

evolution of later generations depends strongly on user demands . These

ranging from mostly cost oriented demands (most consumer goods) to mostly

performance oriented demands (military weapons, technical instruments).

The first case is described by Abernathy and Utterback (2). Here, once a

dominant design is established, product innovation and improvement

declines, production process innovations become dominant, volume increases

rapidly and unit cost decreases.

1 . .
Products for which the benefit-cost estimates appear to be promising.

2 Indeed, as shown by von Hippel (3), users may even create the first
generation of the product, especially in industrial equipment.

3 This is a typical case of adaptive specialization (1) which may lead the
productive unit to a dead end if the product becomes rapidly obsolete for
some reason.

Evolution of Product

time >

Consumer Goods Pattern
(Taken from J. Utterback)

time >

Military Systems Pattern

Figure 3


In the performance oriented case, provided there are technological
opportunities for product improvement, considerable performance changes
occur between generations. Volume remains small or medium and cost
increases from one generation to the next. This is a typical situation in
military weapon systems.

These two different patterns are shown in Figure 3. These processes
may cause in the long run large changes in either or both the productive
and the using systems or even the creation of new using systems. This is
apparently in contradiction with our assumption in the beginning of this
section. However, it is in these cases, where the entry of a new product
does not initially disturb the existing order that a Trojan horse effect,
as described by Schon (M, p. 107) is often observed, i.e., long term radical
change entering unobtrusively via apparently innocuous products. The car
is probably one of the best examples of this type (sec. 3.3). Another one
is, perhaps, the present introduction of microprocessors into various
products in many fields.

The barriers to entry for embedded products and/or for products which
are mismatched with present productive systems are much higher and their
evolution is connected intimately to the evolution of the systems in which
they are located.
3. 2 Evolution of Compact Sociotechnical Systems

This section deals with the evolution of compact using systems. A
large part of the discussion applies to other system types too.

1 It is doubtful whether DOD design to cost procedures to counter this
tendency will be very successful if the military push for maximum
performance improvement in each generation.


A complex STS evolves through changes in either or both its
constituents and its structure. System constituents include its personnel
and equipment ("hardware"). System structure is only partially defined by
its formal organization. Indeed, there is considerable flexibility in
roles and relationships among STS constituents which amounts to a variable
structure visible externally by all the operating modes of the system
("software"). This variable structure enables the STS to possess a
repertoire of operating modes ("software" programs) selected according to
the tasks at hand.

The evolution of a compact STS may proceed via the following paths:

1. Improving present system performance - fastest process.

2. Introducing new operating modes - creation of new "software".

3. Substitution and addition of equipment without structural change -
"hardware" change; common path for introducing new technology.

U. Restructuring of the system, including further substitution and
addition of equipment - this process is very slow.

5. Radical structural change without change of equipment-rapid
response to crisis conditions.

6. Combined radical change - radical "hardware" and "software"
changes. This path is rare.

1 . Improving Performance

Performance using present operating modes may be improved by training,
incentives, improved maintenance, etc. All this can take place without
change in operating methods, equipment or personnel. Hence, it is the
fastest process.


2. Introducing New Operating Methods - "Software Change"

A STS has a repertoire of operating modes, selected according to the
task. This adaptability is due to flexibility both in interpersonal
relationships and in personnel-equipment interactions. New operating
methods can be introduced easily within the system flexibility range.
This range depends on:

1. Range of personnel skills and easily acceptable roles and
relationships changes.

2. Range of externally available equipment capabilities
(multi-purpose equipment) .

Within this range new methods assimiliation time depends on required
and available training time.

3. Substitution of Equipment Without Structural Change

The substitution of equipment in a STS is a lengthy process stretching
over the many years required for development, production and full
incorporation. Because of this delay, as well as risk aversion behavior
common in older rigid systems, new equipment will often be based on second
generation technologies, i.e. on technologies which have already been
proven in stand-alone products.

Moreover, this new equipment, even if based on latest technology, must
conform to and function within the existing STS and its operating modes;
these are determined by the bulk of older equipment and, last but not
least, personnel accustomed to the old methods, equipment and social
structure. Their natural inclination is to make the new equipment fit the

If the equipment is internally capable of additional uses but these are
not available at the interface with the user, lengthy modifications may
be required in order to make this capability available.


well known and tried, i.e. the old methods. Hence, no or minimal
"software" changes will be introduced. Thus the STS operates as a filter
which prefers changes causing minimum disruption (1). It is also in the
interest of the producers, who want to introduce new equipment as fast and
as smoothly as possible, to tailor it to the present using STS and to avoid
riskier, more radical innovation.

This process was just described by Morrison (5) investigating problems
of chanfee in the United States Navy in the early 1900 's.

Two more recent examples from two completely different fields will be
cited here. When the first generation of air to air missiles was
introduced into service they were designed to be fired similarly to guns,
i.e. using the same dog fight tactics (tactics are the "software" in this
case) .

The second example is the incorporation of computers in business which
in the beginning followed closely the path of mechanizing and copying
existing routine administrative operations. In both cases system structure
changes (see next section) took place much later.

In summary, this is normal change (1), using new equipment to perform
present tasks more efficiently, while avoiding uncertainties and resistance
involved in structure ("software") change.
4. Restructuring and Further Substitution of Equipment

Making full use of the new technologies may require radical
re-structuring of the STS. This will be achieved, if at all, much later
(possibly a few decades) after the "new" (by now old) equipment has been
thoroughly assimilated by the STS. Hence, a novel STS structure may appear
many years after the maturation of the underlying technology, via a lengthy
process of accumulation of normal incremental "hardware" and "software"


changes thus limiting uncertainty and resistance at each step. This is
illustrated in Figure 4 which shows the long delay in the application of
new technologies in existing systems.

Present STS


Stand Alone Product

I Appearance

1 of New Technology

■**~tFirst Generation Technology

in the Present STS


Second Generations Technology

Qualitative Change
in the STS


Third Generation Technology

Figure 4

The introduction of computers (Electronic Data Processing) into
banking illustrates this two-stage process. EDP was introduced for
mechanizing account handling and other routine banking operations in the
late 50 's. However, radical innovative uses of EDP in banking, involving
electronic fund transfer and automatic tellers, which may lead to radical
changes in banking, have only been introduced during the last few years

This slow transformation process may succeed if the environment
changes slowly. Even so, in many cases the combined effect of many small,
consensus oriented, normal changes does not necessarily add up to a
coherent large scale radical change. On the contrary, it could bring the
mature STS to a dead end (1) (going out of business, defeat in war).

The introduction of the tank into military use illustrates this
lengthy and uneven process. After initial success in WWI technical
improvement in the tank itself proceeded leading to improved and dominant
(produced in large volume) designs in various countries (for example, the
American WWII M4 Sherman tank. However, the required re-structuring needed
to make effective use of the tank, i.e. the formation of independent
armored forces supported by aircraft designed to fight a blitzkrieg was
only acnieved in Germany (7). France and England dispersed their tanks in
the infantry divisions, incorporating them merely as support units for the
infantry. This led directly to their defeat in ig'^O. Thus the
introduction of new equipment constrained by the old battlefield systems
led to a dead end. The German case is an example of combined radical
change described in section 6.
5. Radical Structural Change

In times of crisis, when the environment changes rapidly and system
inadequacies become evident suddenly, the situation is basically different,
requiring fast adaptation. Under this condition radical structural change
which involves radical changes in the set of roles and relationships
between STS members, may occur rapidly. An effective decision collective
is necessary to make and implement the risky and controversial decisions.
Even so, it may fail because in a specific case structural ("software")
change alone may not be sufficient to deal with the situation.

The decision collective includes all people involved in making the
decision, formally or informally, inside as well as outside the formal
boundaries of the system.


This case may be illustrated by the very rapid change (days) in the
composition and tactics of the Israeli forces during the Yom Kippur war in
response to the suddenly revealed threat of anti tank guided missiles. The
belief that tanks alone could break through the defense was shattered; it
was quickly recognized that coordinated combined arms teams composed of
tanks, artillery and infantry were required to deal with the situations.
Note that this innovation was characterized by:

1. Revival of WWII doctrine adapted to the needs of the moment. It
was not necessary to invent and trust a completely new idea in a
risky situation.

2. Only existing hardware was used. Obviously, it was impossible to
change equipment within a few days.

6. Combined Radical Change

In this process qualitative changes in equipment (technology) and
structure (organization, operating methods and procedures) of the STS are
designed and developed together.

Two main factors making this approach difficult are

1. The resistance of mature inflexible systems to radical and
disruptive change, as described previously (1).

2. Multiple uncertainties involved in the combined change of
equipment and structure.

The difficulties of multiple uncertainties may be clarified by looking
at the interconnected development cycles of a complex STS and its equipment
(Fig. 5). We have here two processes, equipment development and system
development, each one of which comprises development cycles due to the
uncerainties involved in new and unknown technology and structure. In the
normal change process (sees. 3-2.3,3.2.4) these two occur in tandem (Fig.


5). First, the equipment is developed to completion, eliminating
technological uncertainties and risk. After that, it is very often
introduced into the system on a full scale (switch //I) without changes in
system structure. Only then begins (switch #2) the long process of
structure modifications leading back (switch //3) to demands for equipment
modifications or even demands for complete new equipment.

Tandem Evolution of a STS



♦-♦ o

for Equipment

Full Scale
in STS




Figure 5

In the combined change process (Fig. 6) the development of structural
changes begins much earlier, by experimenting with new structures and
methods on a pilot STS, sometimes even before the equipment is built. This
is the case when low technological risk in new equipment is combined with
large radical structure change. In general, the proper meshing of
equipment and STS structure development cycles depends on the location of
the major uncertainties, these determine what should be tested at an early

The planning of this experimental process will be described in a later
paper. Difficult as it is to plan this process on paper it is even more
difficult to implement it in a change resistant mature system.

Combined Evolution of a STS







1 *

^ c '




Full Scale

Figure 6
The various system evolution routes which may occur following the
appearance of a new technology are shown in Figure 7. The normal
conservative route 1 involving slow change and large technological gap has
already been described (paragraph 3.2.4). An innovative system may evolve
in two different ways:

1. Implantation of new equipment into an existing STS (Route 2)
combined with radical changes in structure.

2. Creation of a new STS through a novel combination of various
constituents, including new equipment. Here we must distinguish
between a combination of inanimate systems taken from various
sources (route 3) and combinations of parts of different
man-machine systems, i.e. teams of personnel and equipment, taken
from different STSs (route 4). .

The deterrent effect of uncertainties and knowledge gaps renders an
innovative evolution of an existing system more difficult, hence route 1 as
described above is usually perferred to route 2. Creation of a novel
complex sociotechnical system by combining individual inanimate systems
(route 3) or parts of existing STSs (route 4) is usually even more
difficult and slower process. Combination of various inanimate systems

frequently requires a long period of engineering and industrial work. Only
after this work has been completed, is it possible to test the entire
system concept in the field. Such testing may require several development
cycles, which may lead to updating both the overall structure and the form
of constituents' integration. These normal development difficulties are
compounded by the opposition of well established systems operating in the
same area. On the other hand, in an empty area where there is little or no
opposition and/or competition, an attractive technological opportunity can
lead to rapid radical change (i.e. international communication satellite
system) by the creation of a new STS uninhibited by an old structure.

The development of a novel system by combining parts of different
existing systems (route 4) is also a trial-and-error process which requires
several development cycles, i.e., prolonged testing by actual operation in
the field. To do this, parts of different systems must be combined or, in
other words, parts of different organizations (units) must be integrated
into a new pilot system. Such a process will probably encounter strong


Online LibraryZeev BonenEvolutionary behavior of complex sociotechnical systems → online text (page 1 of 2)