By questioning assumptions that people make, you can get a research idea. These assumptions are expressed in old sayings, editorials, self-help books, cartoons, songs, popular magazines, and television commercials. Box 3.1 (p. 75) shows you how to question those assumptions to get research ideas.
Scientists like good theories. If you find a good theory, you can use it to generate hypotheses. For example, you could try to apply the theory to solve a practical problem or to understand a real life situation. If you don't like the theory, you could look for moderator variables that the theory hasn't accounted for ("The theory doesn't hold when ..."), try to prove that the theory is wrong about its claims concerning mediating variables ("people don't really feel an unpleasant arousal called dissonance"), or try to show that another theory makes more accurate predictions in certain situations.
An easy way to generate research hypotheses is to look at studies that have already been published. Because no study is perfect, you can usually do something to improve the internal, external, or construct validity of a published study.
There is a difference between a research idea and a research hypothesis. The research hypothesis must be testable (if it's wrong, you find out that it's wrong). In addition, you shouldn't make predictions "out of thin air." That is, you should have a reason for making the prediction that you made. If you answer "yes" to the questions in Box 3.3 (page 105), your hypothesis is probably pretty good.