What if scientists knew what you would do before you even knew? What if they could read out your feelings, your preferences and your inclinations even if you weren’t aware of them?

It’s not so much science fiction anymore. A team of researchers headed by John-Dylan Haynes at the Bernstein Center for Computational Neuroscience has developed a technique that can read out people’s intentions before they actually act on them, by analysing patterns of brain activity during the decision making process.

In a series of tests, subjects were given the option of adding or subtracting numbers. Haynes says he could clearly distinguish the brain pattern for adding from the pattern for subtracting before the subjects had actually performed the action. And he says soon, science will go even further: Determining actions, feelings and preferences long before people even know they are thinking of them. A trip deep into the sub-conscience.

"They wouldn’t even know. For them it was unconscious. So they have the impression that they haven’t even made up their mind yet. So it seems that their brain seems to be determining something before they themselves even become aware of it," John-Dylan Haynes says about his research.

Haynes says widespread use of mind reading devices and total observation are still a thing of the future, but he does believe, he tells me, that science has reached a point where society needs to debate and decide how far it wants researchers to go. He says the potential benefits are huge.

Mind reading technology could drive the development of brain-controled computers that would help people with disabilities manage their lives just by using their minds, and the technology could revolutionize crime fighting as the perfect lie detector and even help in the battle against terrorism, Haynes says.

"We might be able to tell from a brain activity pattern if someone has been in a specific place before, such as an al Qaeda terrorist camp. That’s something that we should be able to do within the next couple of years."

But what if a company could make the perfect cigarette, or food, or another product that perfectly targets reward systems in the human mind or if all your secrets were laid out to authorities on a regular basis? Haynes says that’s where he would draw the line, the only question at that point: Will scientists then still have the power to draw the line?

Watch my report

-- From CNN Berlin Bureau Chief Frederik Pleitgen