Monday, January 30, 2006

Brain Scans and Lie Detection: True or False?

Now this is a rapidly expanding area of research (and one that's quite well-funded by the DOD). Wired did a piece on this recently (Don't Even Think About Lying), and there's an AP story that appeared in papers around the country (e.g., the Boston Globe). The Neurocritic was going to weigh in on the topic, suggesting that someone should do an experiment to relate the fMRI findings to the peripheral psychophysiological measures taken by a polygraph.

Now there is such a study:

Mohamed FB, Faro SH, Gordon NJ, Platek SM, Ahmad H, Williams JM.
Brain Mapping of Deception and Truth Telling about an Ecologically Valid Situation: Functional MR Imaging and Polygraph Investigation--Initial Experience.
Radiology. 2006 Feb;238(2):679-688.

Purpose: To examine the neural correlates during deception and truth telling by using a functional magnetic resonance (MR) imaging technique and an ecologically valid task and to compare the results with those of a standard polygraph examination. Materials and Methods: All subjects gave written informed consent for this HIPAA-approved study, which was approved by the institutional review board of Drexel University. Eleven healthy subjects (five female and six male subjects; mean age, 28.9 years) were randomly assigned to the group of guilty subjects or the group of nonguilty subjects. Each group consisted of two separate functional MR imaging conditions: "lie-only condition" and "truth-only condition." The lie-only condition was used to compare brain activity during a known lie to control questions and a subjective lie to relevant questions. The truth-only condition was used to compare brain activity during a known truthful response to control questions and a subjective truthful response to relevant questions. Functional MR images were acquired with an echo-planar sequence, and statistical analysis was performed. Physiologic responses were measured with a standard four-channel polygraph instrument. Results: During the deception process, specific areas of the frontal lobe (left medial and left inferior frontal lobes), temporal lobe (right hippocampus and right middle temporal gyrus), occipital lobe (left lingual gyrus), anterior cingulate, right fusiform gyrus, and right sublobar insula were significantly active. During the truth telling process, specific areas of the frontal (left subcallosal gyrus or lentiform nucleus) and temporal (left inferior temporal gyrus) lobes were significantly active. The polygraph examination revealed 92% accuracy in deceptive subjects and 70% accuracy in truthful subjects. Conclusion: Specific areas of the brain involved in deception or truth telling can be depicted with functional MR imaging. (c) RSNA, 2006.

Unfortunately, The Neurocritic does not have online access to the journal, Radiology, and so cannot provide a critique of this article. More commentary on fMRI and lie detection will be forthcoming...

Subscribe to Post Comments [Atom]

Friday, January 27, 2006

Men are Torturers, Women are Nurturers...

...tell it to Lynndie England!!

All right, let's start at the beginning. My sound-byte-worthy headline was derived from a paper published this week in Nature:

Singer T, Seymour B, O'doherty JP, Stephan KE, Dolan RJ, Frith CD.
Empathic neural responses are modulated by the perceived fairness of others.
Nature. 2006 Jan 26; 439:466-9.

The neural processes underlying empathy are a subject of intense interest within the social neurosciences. However, very little is known about how brain empathic responses are modulated by the affective link between individuals. We show here that empathic responses are modulated by learned preferences, a result consistent with economic models of social preferences. We engaged male and female volunteers in an economic game, in which two confederates played fairly or unfairly, and then measured brain activity with functional magnetic resonance imaging while these same volunteers observed the confederates receiving pain. Both sexes exhibited empathy-related activation in pain-related brain areas (fronto-insular and anterior cingulate cortices) towards fair players. However, these empathy-related responses were significantly reduced in males when observing an unfair person receiving pain. This effect was accompanied by increased activation in reward-related areas, correlated with an expressed desire for revenge. We conclude that in men (at least) empathic responses are shaped by valuation of other people's social behaviour, such that they empathize with fair opponents while favouring the physical punishment of unfair opponents, a finding that echoes recent evidence for altruistic punishment.

Unfortunately, this article has unleased an avalanche of what is called "BAD Neuro-Journalism" by the James S. McDonnell foundation, starting with the Editor's Summary :

I feel your pain

Humans have the capacity to empathize with the pain of others, but we don't empathize in all circumstances. An experiment on human volunteers playing an economic game looked at the conditional nature of our sympathy, and the results show that fairness of social interactions is key to the empathic neural response. Both men and women empathized with the pain of cooperative people. But if people are selfish, empathic responses were absent, at least in men. And it seems that physical harm might even be considered a good outcome — perhaps the first neuroscientific evidence for schadenfreude.

Next, this dish, best served cold:

Revenge: Why men are better at it than women

[tell that one to the proverbial "woman scorned"]

...and about 9,490 other hits.

Empathic neural responses are modulated by the perceived fairness of others

"This investigation would seem to indicate there is a predominant role for men in maintaining justice and issuing punishment."

-- Lead researcher Dr Tania Singer

Well then, that explains why the public outrage directed at Lynndie England was so much greater than that directed at the Abu Ghraib ringleader (and father of Ms. England's child), former prison guard Charles A. Graner.

Lyndie England, the Right and Feminism
Equal Opportunity Torture


Right wing pundits have been seeking to draw special notice to Private Lynndie England. Though only one of many sadistic individuals involved in the horrific acts at the prison who were photographed, England has been on the receiving end of the most invective. Though her fellow sadists were just as cruel, England is getting all of this extra attention because she is an easier target. England is an easier target because she is a woman.

OK, back to Nature. One of the most serious problems with this article is the extrapolation from a small group of students in London to the evolution of neural machinery that implements differential sex roles.

MORE words of wisdom from Dr. Singer:

"Men expressed more desire for revenge and seemed to feel satisfaction when unfair people were given what they perceived as deserved physical punishment.

"This type of behaviour has probably been crucial in the evolution of society as the majority of people in a group are motivated to punish those who cheat on the rest.

"This altruistic behaviour means that people tend to protect each other against being exploited by society's free-loaders, and evolution has probably seeded this sense of justice and moral duty into our brains."

And don't get me started on their methodology -- a priori regions of interest (ROIs) for pain-related empathy in fronto-insular cortex and anterior cingulate cortex (like the relationship between those brain regions and "pain-related empathy" are well-established!) -- and on their pink-and-blue color-coded tables!

SUMMARY from The Neurocritic : Ummm, it's nice they can generalize from 16 male undergrads to the evolution of sex differences that are universally valid in all societies.

As you can tell, this one really bothers me...

Subscribe to Post Comments [Atom]

eXTReMe Tracker