To answer that question, scientists have turned to rats.
为了解答这个问题，科学家们用老鼠来做实验。
Their brain chemistry is similar to ours, but unlike humans.
它们的脑部结构和我们人类很相似，但与人类又不同。
It's possible to give them cannabis in controlled amounts to see if this increases their taste for heroin.
你可以给老鼠一定量的大麻，然后看它们会不会增加对海洛因的需要。
Dr. Steve Goldberg has been measuring the effects.
史蒂夫·高尔伯格博士正在测量这个影响。
Well, in this room, we've got two groups of chambers, one either side.
我们在这个房间里放了两组笼子，分别放房子的两端。
We're working with rats on this side that have had a previous exposure to cannabis.
我们正在研究的是接触过大麻的老鼠，他们在这边。
On the other side, the animals are control animals that have not had the exposure to cannabis.
另一边的控制组，是没有接触过大麻的。
And we're looking at the differences between these two groups in terms of how much heroin they take and how hard they work for it.
我们要了解这两组老鼠的差别，对于海洛因的需求量，以及渴求程度。
So what does this individual rat have to do here?
那这只老鼠在笼里做什么呢？
Dr. Steve Goldberg: He's in a test situation, a light comes on, tells him that heroin's available.
它正在实验当中，当灯亮的时候，就意味着可以获得海洛因了。
In order to get the heroin, he has to poke his nose through a hole, and he gets a dose of heroin.
为了得到海洛因，它必须把鼻子伸出一个洞外面，然后它就能得到一定的海洛因了。
The flashing light is now him receiving a dose of heroin.
要是灯开始闪，那就是它已经得到海洛因了。
He's just had a dose of heroin?
所以这只刚吃过吧？
Yes.
是的。
Each group of rats, those who have been exposed to THC and the control group who haven't,
不管是用过THC的老鼠，还是没用过的，这两组老鼠都有机会吃海洛因，
have the opportunity to take heroin by poking their noses against a dispenser.
只要它们把鼻子顶一下分配器就行。
The number of nose-pokes or doses that each rat takes is measured automatically.
每只老鼠顶的次数和使用的剂量都会被自动的记录。
Steve then compares the results to see whether the past exposure to THC makes the rats more likely to take more frequent doses of heroin.
之后，史蒂夫会比较这些结果，看使用过THC的老鼠会不会更易频繁使用海洛因。
So what results have you found for this rat and for other rats in his group?
所以，通过对比这两组老鼠，你从中发现了什么？
We found that rats that had exposure to cannabis in the past will work for and obtain more heroin each session than the control rats that didn't have the cannabis exposure.
我们发现，在一定的时间内，曾经接触过大麻的老鼠比那些没接触过的，会更加努力地得到更多的海洛因。
