First of all, the title is misleading. Negative results are not the same thing as unfavorable results. Second, as a person involved in biomedical research, I am very familiar with the bias toward publishing positive results, and leaving the negative results buried in a lab notebook somewhere. There are two root causes for this:<p>1. Funding agencies reward positive results. Of course, the biggest funding agency in the U.S. is the U.S. gov't. The gov't must answer to the people, and the people only want to hear about positive results. Show some interest or at least concern for negative findings (and learn, or teach kids in school, why negative findings are important), and you'll find more scientists publishing negative findings.<p>2. Funding, especially in the U.S., is a competition. Why would you tell your competitors all the things that didn't work? Why give them that strategic advantage? Would you expect Google to tell Yahoo which search algorithms don't work? Reward scientists based on consistent good work, and not based on their ability to beat out competitors, and you'll find more scientists publishing negative findings.