Researchers report finding correlational data to identify a positive relationship between nuclear knowledge and positive attitudes toward the use of nuclear energy. This study investigated the relationship between nuclear knowledge and nuclear attitudes and to the understanding of Science-Technology-Society attitudes involving technological attitude objects. This quasi-experimental study tested the causal relationship between knowledge about nuclear power plants and attitudes toward their use in electrical generation. Subjects were presented with systematically designed communications developed to change either their knowledge about or attitude toward nuclear plants. The Standard Events of Instruction was the basis of the knowledge instruction, whereas the Learning Theory Approach and the Theory of Reasoned Action were the theoretical bases of the persuasive communication. The principal finding was that nuclear knowledge and nuclear attitude each can be changed independently of the other. Although knowledge and attitudes are correlationally linked, this study shows no evidence of a cause-effect relationship.