He invited drug users into his lab. What he discovered is changing what we know about addiction.

What were you taught about drugs?

GIF via Partnership for a Drug-Free America.

Remember hearing about how even just trying an addictive drug once would mean you were hooked for good?

GIF via The Meth Project.

Well that's what Columbia University professor Carl Hart learned in school too.

So imagine his surprise when his own research into drug addiction revealed something very, very different.

Working with others, Hart revisited some long-standing research on lab rats that showed that rats would self-administer drugs until death. He learned that rats that live in sterile cages with nothing else to do chose to take drugs until they effectively committed suicide. But those offered alternatives to drugs — like sweets or some hanky-panky — often chose the alternatives. In other words, the addictive behavior was caused by the environment, not some attribute of the drug itself.

Then Hart did something unusual. He invited human drug users into his lab. He set up an experiment where he offered regular meth users a choice between drugs or money.

When presented with an attractive alternative ($20), even people who regularly use a drug like meth still chose the alternative.

GIF by jgmarcelino/Flickr.

Clearly, we need to change how we think about what drugs do to our brains.

Most drug users are not addicts, Hart says. Not even close.

So, why do people keep taking drugs, even when side effects are so damaging?

It's how people end up with lives of crime and poverty, right? Wrong.

Hart grew up in Miami, in a neighborhood where he saw and experienced a lot of drug use and crime. He went to school in order to understand drug addiction and to try to stop the crisis of drugs driving people into a life of crime and poverty. But now he believes most users are not addicts; they are recreational users. He's also shown that if people have good alternatives to drugs, they will choose the alternatives most of the time. So the "cycle" of drugs, crime, and poverty isn't really a cycle.

Drugs are a symptom of a society where people don't feel they have good options, Hart theorizes. They aren't the cause.

"What I now know is that the drugs themselves are not the real problem. The real problems are: poverty, unemployment, selective drug law enforcement, ignorance, and the dismissal of science surrounding these drugs." — Carl Hart

The real injustice here, Hart wants us to understand, is that even though most users are white, over 80% of people convicted of drug crimes are black. 1 in 3 black males can expect to spend time in prison. Whites? 1 in 20.

This issue is of paramount importance to Hart. He's personally invested as a scientist, but also as a father. Hart knows his two sons are especially vulnerable in a society where black people are targeted by police in the enforcement of drug laws and where drug policies severely punish even occasional users as if they were serious criminals.

This is the kind of thinking — and science — that U.S. drug policy really needs.

He shares lots more good ideas in this talk at TEDMED.