Brain Imaging and Lie Detection

Langleben, D. D., & Moriarty, J. C. (2012). Using brain imaging for lie detection: Where science, law, and policy collide. Psychology, Public Policy, and Law, 30, Advance online publication.

Previous research has pointed to the inability of humans to reliably detect lies in others. Studies have demonstrated that polygraph data is also frequently inaccurate and unreliable, and it is generally prohibited as admissible evidence in courtrooms in the U.S. Thus, new forms of technology have been sought as an objective method of lie detection. Advances in the use of functional magnetic resonance imaging (fMRI) of the brain have led to interest in its use for the purpose of lie detection. According to Langleben and Moriarty (2012), these images show differences between lying and truth-telling in the lateral and inferior prefrontal and posterior parietal cortices and do not appear to vary with gender, handedness, or language. After several studies demonstrated the ability to correctly distinguish (more than 75% or the time) between research participants’ truthful statements and deception, start-up firms began to file patents to license this technology. Critics of the use of fMRI lie detection have focused on legal and ethical issues as well as the accuracy of fMRI evidence, and to date courts have disallowed requests to admit fMRI tests of truthfulness. A significant concern is that studies of fMRI lie detection have used laboratory settings, “normal” participants, and designs in which the investigators directed the participants to lie. This latter component makes it difficult to determine whether the brain images obtained indicate deception or task compliance. Langleben and Moriarty have suggested that additional clinical trials are needed to determine error rates. They identified several components of the research design that deserve attention. These include (1) the deception task scenario – for example, participants may be asked to commit a mock crime or misrepresent autobiographical information, (2) the fMRI paradigm – that is, whether the fMRI scan is based on time intervals or the presence of stimuli, and (3) the experimental deception model – that is, the method of eliciting deception, such as having the participant conceal knowledge during questioning. The authors view fMRI lie detection as a promising technology, but caution against its use without additional scientific proof of reliability and validity.

Making Connections

Brain imaging
External validity
Lie Detection
Reliability and validity

Media Supplement

In this video, Neuroscientist Carrie Brumback Peltz demonstrates Event-Related Optical Signal (EROS) technology, a ground-breaking technique that allows researchers to use light to get a nearly real-time look at the neuronal activity inside the human brain. [5 min]