What Vietnam Tells Us About Addiction And Bad Habits

It's a tradition as old as New Year's: making resolutions. We will not smoke, or sojourn with the bucket of mint chocolate chip. In fact, we will resist sweets generally, including the bowl of M&M's that our co-worker has helpfully positioned on the aisle corner of his desk. There will be exercise, and the learning of a new language. It is resolved.
 So what does science know about translating our resolve into actual changes in behavior?
 The answer to this question brings us — strangely enough — to a story about heroin use in Vietnam.