User:Dedehayi/reverse salient

Hughes proposes that technological systems pass through particular phases during the system’s evolution. The first of these phases sees the invention and development of the system, owed greatly to the efforts of inventors and entrepreneurs. Considering the initial phase of the electric technological system, for example, Hughes highlights the imperative role played by individuals such as Thomas Edison. The second stage is the era of technological transfer from one region or society to others. Hughes exemplifies such technological transfer through the dissemination of Edison’s electric system from New York City to other cities such as London and Berlin. The third phase of systemic evolution is marked by a period of system growth. This is the time of expansion when the technological system strives to improve its performance, for instance with respect to economic outcomes or output efficiency. Hughes explicates that in this developmental phase, technological systems are dependent on the satisfactory evolution of all system components’ performance. Within the hierarchically nestled system, the development of technological systems is therefore reliant on the reciprocated and interdependent cause and effect processes amongst social and technical components. More accurately, the modus operandi of such developmental change may be described as co-evolutionary, where the balanced co-evolution of system components carries significance in establishing desired system progress (Hughes, 1983). In other words, components of the system which evolve at a sufficient pace contribute positively to the collective development. Conversely, a sub-system which does not develop sufficiently prevents the technology system achieving its targeted development. Hughes (1983) names these problematic sub-systems reverse salients.

A reverse salient is the inverse of a salient that depicts the forward protrusion along an object’s profile or a line of battle (Hughes, 1987). Hence, reverse salients are the backward projections along similar, continuous lines. With respect to technological system development, reverse salients refer to the components of that system which have strayed behind the advancing performance frontier of the system (Hughes, 1983). They are therefore the underperforming components which hamper the progress or which prevent the fulfillment of potential development of the collective system. In line with the socio-technical standpoint, reverse salients can be technical elements such as motors and capacitors of an electric system, or social elements such as organizations or productive units.

Because reverse salients establish the limited pace of system development, it is imperative that they are corrected, where correction is attained through incremental or radical inventions (Hughes, 1987). Consequently, the reverse salient forms a nexus or focusing device (Rosenberg, 1969) for technological system stakeholders, in particular innovators and organizations, which congregate around the retardant and strive to remove it through innovation processes. If the reverse salient is not able to be corrected within the bounds of the existing technological system through incremental innovations, then only radical innovations can successfully resolve the problematic sub-system. The outcome of radical innovations is the creation of a new and different technological system, as witnessed through the innovation of the alternating-current system which overcame the low cost distribution hurdle of the electric technological system, where the direct-current system could not (Hughes, 1983).

The reverse salient is a useful concept for analyzing technological system evolution. This is because quite often the loci of interest in scientific analyses of technological systems are the factors which limit system development. Furthermore, these limiting factors may be more than merely technical components, and at times, quite importantly, may be social components as well. In this way the conceptualization of system performance hindering factors as reverse salients can be more applicable in certain contexts in contrast to similar or overlapping concepts such as bottleneck and technological imbalance (Rosenberg, 1976).

Although the reverse salient and bottleneck can be used interchangeably in particular contexts (see for example: Fransman, 2001; Geels, 2006; Geyer & Davies, 2000; Markard & Truffer, 2006) often the reverse salient refers to the sub-system that not only curbs the performance or output of the collective system but also requires correction because of its limiting affect. This is not necessarily the case with bottlenecks. For instance, a particular system’s output performance may be compromised due to a bottleneck sub-system but the bottleneck will not require improvement if the overall system’s current output performance is satisfactory. If, on the other hand, higher performance would be required of the same system, the bottleneck may emerge as a reverse salient that holds the system back from attaining that higher output performance.

A similar overlap exists between the reverse salient and technological imbalance concepts (see for example: den Hond, 1998; Fransman, 2001; Takeishi & Lee, 2005). Rosenberg’s (1976) imbalance arises from the comparison of technological components of complex machines or operations, which reveal that at any point in time machine component parts will vary in their ability to exceed their existing performance levels, attributable to some limiting component. This condition results in the disequilibrium of technologies within the same system. Rosenberg illustrates this disequilibrium effect through the example of a machining operation in the manufacturing of bicycle hubs. In this example, despite performance improvements which quicken the sub-process of hub forming, the overall pace of hub production remains unchanged. Benefits from the forming process improvement are not realized until the interdependent drilling sub-process quickens its speed of production as well. A condition of disequilibrium therefore emerges between two processes, embedded within the same complex operation. Hence, the technological imbalance described by Rosenberg can equally be seen as a state of reverse salience in a technological system when studying only its technical components. However, the reverse salient concept differs in that it can be used to study imbalances not only between different technical components, but also social components.

Historical developments in a variety of technological systems have been used in the literature to illustrate reverse salience. In his seminal work, Hughes (1983) gives account of the development of Edison’s direct-current electric system towards the objective of supplying electricity within a defined region of distribution. Sub-systems such as the direct-current generator were identified as reverse salients and corrected. However, perhaps the most notable limitation of the direct-current system was its low voltage transmission distance. The reverse salience in this case was the cost of distributing electricity beyond a certain range. To reduce costs, Edison introduced a three-wire system to replace the previously installed two-wire alternative and trialed different configuration of generators, as well as the usage of storage batteries. While these had a positive impact, they did not correct the reverse salient completely. The satisfactory resolution of the problem of costly transmission and distribution of low voltage electricity was eventually provided by the radical innovation of the alternating-current system (Hughes, 1983).

Numerous authors have since offered their accounts based on the analysis of different technological systems. MacKenzie (1987) has pinpointed the gyroscope sub-system as a technical reverse salient in the ballistic missile technological development, where the systemic objective has been to increase missile accuracy. With the objective of proliferating  mobile   music   throughout   the   end-user market, Takeishi and Lee (2005) have argued that music copyright managing institutions have acted as a social reverse salient in the evolution of the mobile music technology system in Japan and Korea. According to Mulder and Knot (2001), the development of the PVC (polyvinyl chloride) plastic technology system has been sequentially hampered by several states of reverse salience, including: difficulty to process PVC material, quality of manufactured products, health concerns for individuals exposed to effluent from PVC manufacturing facilities, and finally the carcinogenetic nature of vinyl chloride.