News reports yesterday and today tout a study that suggests one can learn whether a subject is lying by using a functional MRI to scan their brain while the person is testifying. According to the study led by Dr. Scott Faro of Temple, seven "deception areas" of the brain were identified.
Jim Lindgren at the Volokh Conspiracy quotes a news account which seemed to reveal a fundamental design flaw in the experiment. The key passage in the Reuters story is:
Faro and colleagues tested 10 volunteers. Six of them were asked to shoot a toy gun and then lie and say they didn't do it. Three others who watched told the truth about what happened. One volunteer dropped out of the study.
As even Lindgren's high school-age daughter identified, there are two variables when there should be only one -- whether one is shooting the gun, and whether one is lying about the gun being shot. One would expect that the activity of shooting a gun would have an effect on the activation of brain centers and not just the lying about it.
Curious, I decided to see whether the study really was this poorly designed. What I noticed, however, is how poorly it was reported. Some stories said there were ten volunteers, other stories said eleven. Some, clearly cribbing off this Reuters story, described the three who watched, while others said simply that six were told to lie about firing the gun and the others were told to tell the truth, eliding what those others were doing in the experiment.
A Daily Bulletin from the RSNA conference (hey, why doesn't APSA release Daily Bulletins?) reveals a crucial level of detail:
The research group used 11 volunteers and asked six to shoot a toy gun with blank bullets. Five other participants did not shoot the gun.
In two experiments, both shooters and non-shooters were asked to alternately lie and tell the truth about their participation. Scientists then examined the individuals with fMRI, while simultaneously administering a polygraph exam.
This sets my mind more at ease, because with two rounds of experiments and switching roles presumably they were careful enough to distinguish the act of lying from the act of shooting. I say this, of course, without having seen how they performed their tests, which were not included in the press release, naturally.
This is a line of research going back several years. Here is a July press release from the American Psychological Association on one study which involved leaving money on a table rather than firing a gun. A study from two years ago had identified four deception centers in the brain, though this research sounds like it had a needlessly complex research design. I have not read any of these papers yet and I am not a specialist in this field, but it does appear to be an active line of research.
Which leads to a question: Why is this, possibly flawed, Temple study getting so much play in the media? One possibility is that the RSNA and/or Temple Medical School have much more aggressive public relations officers than the other institutions where the research has been conducted. Another is that it took the presence of (toy) guns in the study, rather than money on the table, to get the attention of reporters. In any case, rather than a bold shot out of the blue as the reports imply (no pun intended), this is an incremental contribution to an ongoing line of work. As so much of scholarship is.
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