The paper critically examines the agricultural extension theories and practice in sub-Saharan Africa, and gives a typology of extension theories and technology acceptance model. Over the years, a number of models have been used to enhance the effectiveness of extension services and service delivery. However, the function of theory in research is to identify the starting point of the research problem and to establish the vision to which the problem is directed. Extension science evolved from rural sociology and overtime extension has become more and more associated with social psychology and communication. Consequently, extension theory helps us to comprehensively understand the contextual factors of the innovation process and provides valuable insights into the factors that influence adoption and decision-making amongst smallholder farmers. The paper reviewed and analyzed the most accepted theories/models being used historically and currently for studying technology adoption decisions amongst smallholder farmers. These theories/models include: Cognitive Dissonance Theory, Diffusion of Innovation Theory, Task Technology Fit Model, Expectation Disconfirmation Theory or Expectation Confirmation Theory, Theory of Planned Behaviour, Social Cognitive Theory, Technology Acceptance Model, Model of PC Utilization, Decomposed Theory of Planned Behaviour, The Unified Theory of Acceptance and Use of Technology.
Keywords:Adoption, diffusion, extension, models, practice, technology, theory.