INTERROGATION CHAIR: Can "truth serum" make criminals fess up?
© iStockPhoto / Stefan Klein

The baby-faced gunman of Mumbai, Azam Amir Kasab,  now in the custody of Indian police, is the sole surviving attacker in the three-day rampage that began on the night of November 26 and left more than 170 people dead and scores of others injured.

After the attacks, Indian officials immediately began pointing fingers at longtime rival, Pakistan, as the source of the 10 militants—a charge that Pakistan President Asif Ali Zardari disputed last night on CNN. During police interrogations, Kasab himself claimed to hail from the Punjab region of Pakistan and to have trained with the Pakistan-based extremist group, Lashkar-e-Taiba.

Of course, Kasab could be making this all up. The only way that interrogators can tap a man's memory is to ask him. But what if the person is unwilling to spill the beans or, at least, the real ones? If only there were only a way to plug a USB cable to the back of Kasab's head and just download the experiences.

While such technology may be the stuff of science fiction, Indian government officials have announced they will employ another technique that seems to leap from the pages of a 1940s pulp novel: truth serum. Also known as narcoanalysis, administering psychoactive drugs for interrogation purposes has been around for just under a century, but it has been viewed with skepticism from the start. Indeed, the practice is banned in most democracies, and evidence obtained from such an interrogation would have a hard time making it into an American court. 

But could "truth serum" reliably extract the truth from this man and other criminal targets? We asked Alison Winter, a science historian at the University of Chicago, who has studied the origins and applications of truth serum.

What does the term "truth serum" mean?
That's a term that was used to describe the use of certain drugs, most commonly barbiturates like sodium amytal and sodium pentothal, to try to extract truthful statements from people about their past experiences.  What the term really meant was that the people who used the serum believed that it made people unable to censor themselves and they would just empty their memories into a narrative statement.

Who discovered these effects?
In the mid-1910s, Dr. Robert House was an obstetrician who noticed that the popular obstetric anesthetic drug, scopolamine, also known as twilight sleep, would put his patients into a state where they would deliver information in a way that seemed automatic.

He didn't want to use it in interrogation, for the purpose of getting people to admit to criminal acts, so this is a quite different beginning from the association we have now. At the time, he wanted to use it to provide support for claims people made about their innocence -- not their guilt.  If somebody said 'I wasn't at the crime, I was in the library but nobody saw me,' then, perhaps, this would give support for the claim, because you would think they could not lie under the drug's influence.

It was only later when other people used these drugs that they got the reputation for having the power to force people to provide information against their will.

How did they begin to be used for interrogation?
In the 1930s, there were these committees to evaluate corruption in American policing, and it first came out that police were using these drugs in interrogations to get suspects to incriminate themselves. But there's not a lot of documentation of that.