Abstract
Increasingly, it is accepted wisdom for agricultural scientists to get feedback from indigenous peoples—peasants—about new improved seeds and biotechnologies before their official release from the experiment station. What is not yet accepted wisdom is the importance of cognitive science to research on farmer decision making, especially of the type “Why don't they adopt.” In this paper, the impact of the cognitive revolution on models of farmer decision making is described, and decision making models before and after the cognitive revolution are contrasted. An example of a decision model after the cognitive revolution is given by the Malawi farmer's decision whether to use chemical fertilizers or organic fertilizers or both. Results of testing the model show that in Malawi, smallholders' lack of capital and credit are more important factors constraining use of chemical fertilizers than are indigenous beliefs in organic fertilizers or fears of a future dependency on chemicals