Hanson and Balan aren't the only sharp tacks at Overcoming Bias:
Politicians want voters to have a positively-biased view of themselves. Consequently, voters learn more about politicians from their failings than from their good deeds.
Barack Obama, for example, smokes. If being known as a smoker was politically beneficial to a candidate then we couldn’t know if Obama really enjoyed smoking or if he was just pretending to enjoy smoking to appeal to voters. But because being known as a smoker will probably hinder Obama’s political career, we know that he really wants to smoke. Consequently, Obama’s smoking reveals something about his character. Perhaps, for example, it shows he is not very future oriented and is willing to suffer long-term harm for a short term benefit.
[...]
Finally, it was recently revealed that Al Gore’s mansion uses 20 times as much energy as the average American’s home does. If Gore personally used much less energy than most Americans did we couldn’t be sure if he was doing this because he genuinely cared about the environment or if he merely wanted people to think he cared about the environment. In contrast, since his large energy use harms him politically, we can be sure that he didn’t use vast amounts of energy just to help his political image.
Politicians are legendary for their hypocrisy. Journalists are legendary for their superficiality. So who would have thought that journalism about politicians' hypocrisy could be so informative?
Neither example explains the behavior, though. Is Gore "addicted" to spending huge amounts of money on energy costs? Or does he just like it and is either stupid or arrogant enough to think it won't harm his public image enough to matter? Same with Obama. Is he unable to stop smoking, or does he just like tobacco and figures he can get away with it?
Maybe by displaying his weakness, Obama is signaling his strength. That is to say, he and his supporters think he is such a strong candidate, that he doesn't have to give up smoking in order to succeed in the 2008 presidential race.
Maybe Gore is signaling ... well, I guess in Gore's case his energy use is signaling he is wealthier than 99.9 percent of the world's population and he can burn the energy to prove it.
Obama has been a smoker for a long time -- smoking is a recurrent theme in his autobiography. I was three years ahead of him in similar colleges to the ones he attended and only about 1-2% of the guys smoked cigarettes. And black youths (which he always wanted to be) have very low smoking rates in recent decades.
So, his smoking is pretty unusual. I would suggest that it may mean he's a more conflicted personality than the suave politician we see on TV, which is the same message you find in his first autobiography.