How and why do technologies spread when and where they do? What are the implications and consequences for the structure, wealth, and management of human organizations? Social and industrial evolutionary processes follow a sequence of replacements or substitutions: new ideas for old, new labor patterns for old, new technologies for old. The diffusion of new technologies follows common patterns that guide the selection of technologies and their rate of adoption in the human environment.
We are all accustomed to the idea of growth to a limit, for example, the number of people becoming ill in an epidemic that grows rapidly before eventually reaching a plateau. In fact, observers have recorded thousands of examples of such S-shaped growth in settings as diverse as animal populations, energy and transport infrastructures, language acquisition, and technological performance. Typically, the variable representing a population or system development and diffusion (species population, plant height, engine power, microchip capacity) grows exponentially at the outset. However, such systems whether natural or man-made cannot sustain exponential growth indefinitely. Negative feedback mechanisms or signals from the environment slow the growth, producing the S-shaped curve.
For a single growth process, a single sigmoidal curve is often a useful model. In niches or markets in which several populations or technologies compete, the growth and decline of each entry also often exhibit logistic behavior. This behavior depends on interactions among the competitors. Namely, if a technology's market share grows, it comes at the cost of shares of others. This process is well-described by the so-called "logistic substitution model."
The logistic model also finds applications in demography, notably to model transitions in fertility. For example, in 2009 PHE researchers conducted a demographic study projecting population for the globe as well as individual countries in the year 2050 based on a logistic model of fertility. See 'Implosions, explosions: Population projections to 2050 based simply on a logistic model of fertility'
To offer guidance for considering the diffusion of technologies that affect the human environment, the PHE explores the factors determining when socio-technical diffusion succeeds and how its speed and extent change over time. As part of this effort to advance and ease analyses of logistic behavior in time-series data, the PHE has developed the "LogletLab" software package to fit logistic curves and apply the logistic substitution model to single as well as multiple time-series data sets.
Click here for the LogletLab page
1177 . The Potato and the Prius (PDF). 2018 Keynote address to the 2018 Potato Business Summit of the United Potato Growers of America, Orlando, FL, 10 January 2018. The Potato and the Prius,
1161 . Jews in Time and Space (PDF). International Journal of Anthropology 31(1-2): 93-109, 2016 Jews in Time and Space,
1142 . Quantitative Dynamics of Human Empires [Color Booklet Version, 52 pages] (PDF). Adapted from Marchetti and Ausubel, International Journal of Anthropology 27(1-2):1-62, 2012. 2013 Quantitative Dynamics of Human Empires [Color Booklet Version, 52 pages],
1135 . Quantitative Dynamics of Human Empires (PDF). International Journal of Anthropology 27(1-2): 1-62, 2012 Quantitative Dynamics of Human Empires, Empires; territory; logistic growth; testosterone; progesterone
0096 . Will the rest of the world live like America? (PDF). Technology in Society 26(2004): 343-360, 2004 Will the rest of the world live like America?,
0089 . DRAMs as a model organism for study for technological evolution (PDF). Technological Forecasting and Social Change 69(3): 243-262, 2002 DRAMs as a model organism for study for technological evolution, Technological substitution; Learning curves
0084 . Death and the human environment: The United States in the 20th century (PDF). Technology in Society 23(2): 131-146, 2001 Death and the human environment: The United States in the 20th century, Mortality, epidemiological transition, morbidity
0072 . A primer on logistic growth and substitution: The mathematics of the Loglet Lab software. Technological Forecasting and Social Change 61(3): 247-271, 1999 A primer on logistic growth and substitution: The mathematics of the Loglet Lab software, Logistic curve model
0071 . The Loglet Lab software: A tutorial. Technological Forecasting and Social Change 61(3): 273-295, 1999 The Loglet Lab software: A tutorial, Logistic curve model
0070 . Carrying capacity: A model with logistically varying limits (PDF). Technological Forecasting and Social Change 61(3): 209-214, 1999 Carrying capacity: A model with logistically varying limits, Carrying Capacity, Growth Models, Logistic Model
0062 . Elektron: Electrical systems in retrospect and prospect. Technological Trajectories and the Human Environment 110-134, 1997 Also appeared inÂ DaedalusÂ 125(3):139-169, Summer 1996.Elektron: Electrical systems in retrospect and prospect, energy, electric power
0048 . Human population dynamics revisited with the logistic model: How much can be modeled and predicted?. Technological Forecasting and Social Change 53: 1-30, 1996 Human population dynamics revisited with the logistic model: How much can be modeled and predicted?, Logistic curve model, population
0035 . Bi-logistic growth. Technological Forecasting and Social Change 47: 89-102, 1994 Bi-logistic growth, Logistic curve model
0034 . Graphical representation of the world population growth (PDF). Human Dimensions Quarterly 1(2): 17-19, 1994 Graphical representation of the world population growth, population, logistic curve model
0018 . Rat race dynamics and crazy companies: The diffusion of technologies and social behavior. Technological Forecasting and Social Change 39: 11-22, 1991 Rat race dynamics and crazy companies: The diffusion of technologies and social behavior, technology diffusion
0015 . Regularities in technological development: An environmental view [external link]. Pp 70-91 in Technology and Environment, National Academy, Washington DC 70-91, 1989 Regularities in technological development: An environmental view, technology diffusion, logistic model curve