The Diffusion of Innovation, 5th ed by Everett Rogers

In 1994, the Ghanaian government outlawed female circumcision. By 1998 only one forth of the females 15 to 19 in the area studied were circumcised. This change was accompanied by increasing female education, growing freedom from parental control, and the development of a money economy. It led to an increase in adolescent childbirths to unmarried mothers, abortion, and maternal mortality in first childbirths to young mothers. Ending what may seem to be a bad tradition can lead to new problems.

Old Ideas as Tools

Old ideas are the main mental tools that individuals use to assess new ideas and give them meaning. Individuals cannot deal with an innovation except on the basis of the familiar. The previous practice provides a standard against which an innovation can be interpreted, thus decreasing its uncertainty.If an innovation fits with an old idea it has a better chance of adoption.

Examples

Colombian peasant farmers placed pesticide and fertilizer on plants in excessive quantities as if they were water or manure.
Farmers in the Punjab region or India were more likely to cover there new tractors with a blanket as if it was a cow than change the oil.
Pueblos Indians which patrilineal and father-oriented culture accepted Catholicism. Those with mother-centered beliefs did not/

Technology Clusters

Sometimes adoption is more likely if a number of innovations are clustered. In India, new rice varieties, chemical fertilizers, and other chemicals came together. Similar examples can be found in farming in the United States. Using email and having a personal computer is another example.

Empty Vessel Fallacy

Change agents assume that potential adopters are blank slates or empty vessels who lack any relevant experience with which to associate the new idea. This denies the idea that compatibility is important. Change agents often overlook the fact that every innovation is evaluated by clients in terms of their prior experience with something similar.

Complexity

This is the degree to which an innovation is perceived to be relatively difficult to understand and use. The more complex a social system sees an innovation, the less likely it is to be adopted. It is mostly a barrier to adoption. At first home computers were so complex that only the most technically proficient people could deal with them. As of 2002 50% of homes in the U.S. had them.

Trialability

This is the degree to which an innovation can be experimented with on a limited basis. An idea that he tried on the installment plan is generally adopted more rapidly. Early adopters perceive trialability as more important than do later adopters. More innovative individuals have no precedent available to follow when they adopt, while later adopters are surrounded by peers who have already adopted the innovation.

Observeability

This is the degree to which the results of an innovation are visible to others. The idea of safe sex is hard to observe which explains why it has spread slowly. The more observable an innovation is the more likely that it will be adopted.