What's the Latest Development?

Rats who receive a pleasurable sensation when they press a lever quickly become addicted to that lever, neurologists at Johns Hopkins University have found. So strong was the rats' desire for gratification that male rats ignored female rats in heat and mother rats abandoned their children. The good feeling was delivered by an electrode implanted into the rats' brains, which scientists had to disconnect before they starved themselves—even eating became less important than getting their fix. 

What's the Big Idea?

So strong is our drive for pleasure that activities which give us that good feeling are ones we could become addicted to, which are not limited to ingesting drugs or drinking alcohol. Altruism, too, creates positive emotion and activates pleasure-sensitive areas of the brain, the same ones which cocaine addicts enjoy. It turns out that our conception of vice and virtue, while not incorrect, are not as simple as we believe. Our brains compel us toward good behavior and bad behavior often for the same reason.