dr. margaret hamburg is the f.d.a. commissioner, and she joins me now. >> thank you. >> so these are some pretty horrifying images. what's the theory behind them, behind using them? >> well, as you note, smoking is our leading cause of preventible death in this country. it's a pretty horrifying medical and public health problem, and we need to address it aggressively. these graphicmoking health warnings really are designed to help make sure that people are aware of the risks of smoking, that they are encouraged to stop smoking, if they do smoke. and importantly, to discourage people who are just trying a cigarette or two for the first time, from ever taking up this deadly habit. >> is there solid research data showing that a graphic photo image like these is more effective in deterring behavior, than say a very bold text warning like smoking kills or smoking causes cancer? >> well, there is information from the experience of other countries that have already implemented graphic health warning labels, that it does incre