Current Affairs Journal: Ninth Entry

Listen up guys, there is news in the world of forensic sciences. The future we talk about all the time might already be just around the corner, ready to arrive. A new, seemingly revolutionary, lie detector has been developed. In comparison to the old polygraph it is supposed to work much more accurately because it does not use your physical response, but the blood flow to your brain to prove that you're being dishonest. But let's not get our hopes up yet and look at all the facts first.

Now, first things first. What is a polygraph?? Some of you might have already heard about this machine. Still, for those who are unfamiliar with this term, I am going to explain to you what it is I am talking about.
A polygraph is basically a lie detector. By attaching between four and six sensor to a subject's body, he/she is monitored so the examiner can look at the persons vitals, which is important for the next step. The examiner asks the subject some "control questions". These questions are chosen to include questions that the subject might lie about to seem honest. If the subject really lies to a question like "Have you  ever lied to get out of a difficult situation" the examiner should be able to see the lie by a change in your body functions (perspiration, breathing rate, pulse and blood pressure).When the examiner starts asking the questions that are really important it should become apparent if the subject tells a lie or not. By comparing your physiological responses to lying with your usual vitals the subject should be caught lying. Well...should be...

If you start your research on the polygraph, you actually find more pages on how to cheat a polygraph test than pages that simply tell you how a polygraph works. I think this fact is already prove enough to convince someone that this machine is not very reliable at what it does.

The following things are very common among the different things people suggest to do to cheat a polygraph test.

- Cause yourself pain by e.g. twisting your finger or biting your tongue. By doing that WHEN YOU'RE ASKED A CONTROL QUESTION, your body functions change and a truthful answer will seem like a lie. How are people supposed to know if you're lying about relevant questions if  truthful answers to control questions appear to be wrong.
- Change your breathing pattern. This might be a more difficult step to take (for me, at least). When you're asked a control question, change your breathing pattern. Hold your breath, breathe faster or slower. This will change your pulse or even cause you to sweat. Only do it for a couple of seconds  ,though, and then change back to your usual breathing pattern. If the examiner switches to asking relevant questions, control your breathing. Be calm and don't try to breathe too deeply. "A breathing rate of 15-30 breaths per minute" should be maintained but I seriously doubt that trying to remember that or trying to do it doesn't stress you (which will, then again, show on the graph).
If you think changing your breathing pattern would be too obvious, try thinking about something scary or stressful ..and hope that it'll work.


Clearly, a polygraph is not yet the kind of technology forensic scientists might be hoping for. Recently, though, one new method has claimed to be able to identify lies with a success rate of 90% (some sources claim 97%). This new method is called fmRI (functional magnetic resonance imaging) which, as opposed to the polygraph, tries to identify lies by looking at your brain. Researchers claim that if an individual is being dishonest, some regions of his/her brain need more oxygenated blood than usual. Lying is a decision that the individual makes and for that reason the part of the brain that is responsible for decisions (prefrontal cortex) should get more blood. A fmRI scan should show this increased blood flow to the brain.

Sounds pretty damn convincing, right? Well, apparently there are still some things that most of us overlook, like the following: the people tested so far have been healthy individuals only. What if someone takes drugs that affect their blood pressure? What about people that have a blockage in an artery? And in fact, there has been some research done that showed that increased activity in the prefrontal cortex may actually represent truth-telling.Okay, now I  guess we can all see why it has not yet been allowed to use fmRI in court. To my mind, that is a good thing. Just think about the polygraph. We can't use some technology that is not yet fully developed. The risk we'd take is just too big.

Well then, sorry to disappoint you all. It seems like we will have to wait a little longer for someone to create or perfect a lie detector with a success rate of 99.9999 %.