Technology Life Cycles The world of technology is full of biological metaphors: for example, evolution, mutation, selection, and growth. Some are more appropriate than others. The clearest metaphor is between biological and technological growth or life cycles, and it is one that is widely used in the technological, management, and marketing literature.14 The appeal of the life cycle model lies primarily in its considerable success as, rst, an empirically descriptive tool and, second, as a heuristic device capturing the essential changing nature of technologies, products, markets, and industries. The essence of the technology life cycle model (like that of other growth models in biology) is that growth is nonlinear, and especially not unlimited. Typically growth in biology and 14For an excellent (and also critical) survey, see Ayres (1987). Technology and Global Change e c n a m r o f r e p f o r o t a c d n I i , e r a h s t e k r a m , t e k r a m l

g . e ( Embryonic, chaotic "snake pit" Time Figure 2.5: A stylized technology life cycle model. of technologies alike proceeds along an S-shaped pattern: slow growth at the beginning, followed by accelerating growth that ultimately slows down leading to saturation. However, the S-curve or life cycle model is not an explanatory one. It does not explain why things evolve as they do.

The technology life cycle model (see Figure 2.5) classies the phases of technology development into three phases: childhood, adolescence, and maturity. Subsequently, decline or senescence (and ultimate death) may follow. These correspond to a technologys introduction, growth, saturation, and eventual decline. Typically a technologys life cycle is described by indicators such as output volumes, market share, product characteristics (performance), sources of technological change, and the structure of industry. Most important with the last three of these is whether a life cycle phase is characterized by diversity or standardization. Associated with each of the three phases of the life cycle is a stylized pattern15 as described below. Introduction/childhood. The rst phase is characterized by low production volumes and market shares and is the period with the greatest technological

15These patterns are stylized in that they represent a simplied summary of a large number of product and industry studies. In many individual cases deviations from these stylized patterns can occur. 51 52 Arnulf Grubler and market diversity. Many possible technological designs are explored, development focuses on product innovations, and numerous rms try to gain a footing in the market. Emphasis is on demonstration of technical viability, and costs are of secondary importance. Learning eects and technology improvements derive primarily from experimentation and R&D. Overall the market is highly volatile and uncertain, characterized by a large number of drop-outs, both of design alternatives and rms.