The first chapter is a laundry list of definitions, summed up by the definition of diffusion itself: "the process in which an innovation is communicated through certain channels over time among the members of a social system." Innovations can be optional, agreed upon collectively, or mandated by authority, and can be described by their relative advantage, compatibility, complexity, trialability, and observability. The number of adopters generally follows an S-curve, something obvious to me now but unknown before the field of diffusion research existed.
The second chapter outlines the history of diffusion research, including a meta-diffusion study on diffusion research activity and publications over time in various fields of (mostly) behavioral science.
Diffusion research began in anthropology (mostly in the form of participant observation) and with the birth of sociology as practiced by Gabriel Tarde (who called adoption "imitation"), Georg Simmel, and others. The first formal study on the diffusion of innovations, which laid the quantitative framework for the field, was in 1943 by rural sociologists at an agrictultural university. This study was soon followed by others both domestic and abroad, and rural sociology the dominant contributing field for diffusion studies until the 1970's. Diffusion research continues in the field of general sociology.
The field of communications began in the 1960's, and is now one of the biggest contributors to diffusion research. Many communications researchers study the diffusion of news events, which is different than other diffusions in that there is nothing to adopt, just a "meme" to hear about. Since news events spread and are gone so quickly, these researchers do what is called "firehouse research," where they are ready to survey people about any news event as it comes up.
Marketing is another big contributor to diffusion research, though many marketing diffusion studies are proprietary information, are biased, or are trivial. Marketing includes social marketing, which uses marketing techniques for nonprofit, socially positive products and services. Social marketing campaigns include audience segmentation (identifying a subaudience to target), formative research (audience orientation), positioning (e.g. choosing a name or icon with the right connotations), pricing (very low but not free, by "conventional wisdom"), and using communication channels.
<aside> Rogers includes a paragraph on the negative connotations of marketing on which Papanek rants at length in Design for the Real World. Rogers maintains neutrality, saying that while some see marketing as manipulation for commercial advantage, marketers - especially those who are successful over time - see themselves as "providing a useful contribution to society" by identifying and filling real needs in an appropriate and affordable way. My bias lies with those against marketing, though I'm not as extreme as Papanek.</aside>
The field of education has been a small contributor of diffusion studies, as have the fields of public health and medical sociology. "KAP" (Knowledge, Attitudes, Practice) surveys were developed in public health diffusion studies in developing countries. Many public health innovations are preventative and thus are especially difficult to spread. Geography is another small contributor to diffusion research, emphasizing location and distances as a factor in diffusion ("the neighborhood effect").
Diffusion research today can be divided into the following areas (this is separate from the disciplines listed above):
- how people learn about innovations
- rate of adoption of different innovations in a particular social system
- what makes some people/organizations innovative (this constitutes 58% of diffusion research, an order of magnitude more than others listed)
- opinion leaders and innovations
- structure of diffusion networks
- rate of adoption in different social systems
- communication channel usage in diffusion