I just found this fascinating photo in a 1932 book on forensic psychology in the Universidad de Antioquia’s history of medicine section. It pictures the inventor of the truth serum, Dr House, administering the drug to an arrested man in a Texas jail.

The book is called Manual de Psicolog√≠a Jur√≠dica (literally ‘manual of legal psychology’) by the pioneering forensic psychiatrist Emilio Mira y L√≥pez and is a curious mixture of psychological theory, mental tests and descriptions of what seem like strange lie-detecting contraptions.

The history of the ‘truth serum’ is recounted in a fantastic article by medical historian Alice Winter from Bulletin of the History of Medicine which describes the Dr House’s invention and the influence it had on society of the time.

Truth serum was the creation of a rural Texas physician, Robert House. House claimed that the drug scopolamine hydrobromide, which was known for erasing the knowledge of painful events, could actually be used to extract intact information. His announcement was seized upon by journalists, police, and forensic scientists as heralding a potentially transformative new technology, and was just as robustly rejected by the legal community. Scopolamine’s identity as an extractor of “truth” was indebted to certain earlier conventions‚Äînotably, research into altered psychic states such as mesmerism and hypnotism, which sometimes were said to create a confessional state. Scopolamine, in turn, created the shoes that other chemical agents would come to fill when, later in the decade and in the 1930s, the new barbiturates sodium amytal and sodium pentothal were said to have the potential to extract “truthful” memories.

These drugs largely act by reducing inhibition, with the hope that the person will speak more freely, but they have never been found to reliably make anyone more truthful.

Alice Winter was also recently interviewed on SciAm’s Mind Matters blog, in light of rumours that one of the men involved in the Mumbai attacks had been subjected to interrogation under ‘truth serum’.

Link to Winter’s article The Making of ‘Truth Serum’.

Link to ‘What is truth serum?’ from SciAm.