Tag: neuroethics

elsewhere on the net, vacation edition

I’m hanging out in Boston for a few days, so blogging will probably be sporadic or nonexistent. Which is to say, you probably won’t notice any difference.

The last post on the Dunning-Kruger effect somehow managed to rack up 10,000 hits in 48 hours; but that was last week. Today I looked at my stats again, and the blog is back to a more normal 300 hits, so I feel like it’s safe to blog again. Here are some neat (and totally unrelated) links from the past week:

  • OKCupid has another one of those nifty posts showing off all the cool things they can learn from their gigantic userbase (who else gets to say things like “this analysis includes 1.51 million users’ data”???). Apparently, tall people (claim to) have more sex, attractive photos are more likely to be out of date, and most people who claim to be bisexual aren’t really bisexual.
  • After a few months off, my department-mate Chris Chatham is posting furiously again over at Developing Intelligence, with a series of excellent posts reviewing recent work on cognitive control and the perils of fMRI research. I’m not really sure what Chris spent his blogging break doing, but given the frequency with which he’s been posting lately, my suspicion is that he spent it secretly writing blog posts.
  • Mark Liberman points out a fundamental inconsistency in the way we view attributions of authorship: we get appropriately angry at academics who pass someone else’s work off as their own, but think it’s just fine for politicians to pay speechwriters to write for them. It’s an interesting question, and leads to an intimately related, and even more important question–namely, will anyone get mad at me if I pay someone else to write a blog post for me about someone else’s blog post discussing people getting angry at people paying or not paying other people to write material for other people that they do or don’t own the copyright on?
  • I like oohing and aahing over large datasets, and the Guardian’s Data Blog provides a nice interface to some of the most ooh- and aah-able datasets out there. [via R-Chart]
  • Ed Yong has a characteristically excellent write-up about recent work on the magnetic vision of birds. Yong also does link dump posts better than anyone else, so you should probably stop reading this one right now and read his instead.
  • You’ve probably heard about this already, but some time last week, the brain trust at ScienceBlogs made the amazingly clever decision to throw away their integrity by selling PepsiCo its very own “science” blog. Predictably, a lot of the bloggers weren’t happy with the decision, and many have now moved onto greener pastures; Carl Zimmer’s keeping score. Personally, I don’t have anything intelligent to add to everything that’s already been said; I’m literally dumbfounded.
  • Andrew Gelman takes apart an obnoxious letter from pollster John Zogby to Nate Silver of fivethirtyeight.com. I guess now we know that Zogby didn’t get where he is by not being an ass to other people.
  • Vaughan Bell of Mind Hacks points out that neuroplasticity isn’t a new concept, and was discussed seriously in the literature as far back as the 1800s. Apparently our collective views about the malleability of mind are not, themselves, very plastic.
  • NPR ran a three-part story by Barbara Bradley Hagerty on the emerging and somewhat uneasy relationship between neuroscience and the law. The articles are pretty good, but much better, in my opinion, was the Talk of the Nation episode that featured Hagerty as a guest alongside Joshua Greene, Kent Kiehl, and Stephen Morse–people who’ve all contributed in various ways to the emerging discipline of NeuroLaw. It’s a really interesting set of interviews and discussions. For what it’s worth, I think I agree with just about everything Greene has to say about these issues–except that he says things much more eloquently than I think them.
  • Okay, this one’s totally frivolous, but does anyone want to buy me one of these things? I don’t even like dried food; I just think it would be fun to stick random things in there and watch them come out pale, dried husks of their former selves. Is it morbid to enjoy watching the life slowly being sucked out of apples and mushrooms?

fMRI, not coming to a courtroom near you so soon after all

That’s a terribly constructed title, I know, but bear with me. A couple of weeks ago I blogged about a courtroom case in Tennessee where the defense was trying to introduce fMRI to the courtroom as a way of proving the defendant’s innocence (his brain, apparently, showed no signs of guilt). The judge’s verdict is now in, and…. fMRI is out. In United States v. Lorne Semrau, Judge Pham recommended that the government’s motion to exclude fMRI scans from consideration be granted. That’s the outcome I think most respectable cognitive neuroscientists were hoping for; as many people associated with the case or interviewed about it have noted (and as the judge recognized), there just isn’t a shred of evidence to suggest that fMRI has any utility as a lie detector in real-world situations.

The judge’s decision, which you can download in PDF form here (hat-tip: Thomas Nadelhoffer), is really quite elegant, and worth reading (or at least skimming through). He even manages some subtle snark in places. For instance (my italics):

Regarding the existence and maintenance of standards, Dr. Laken testified as to the protocols and controlling standards that he uses for his own exams. Because the use of fMRI-based lie detection is still in its early stages of development, standards controlling the real-life application have not yet been established. Without such standards, a court cannot adequately evaluate the reliability of a particular lie detection examination. Cordoba, 194 F.3d at 1061. Assuming, arguendo, that the standards testified to by Dr. Laken could satisfy Daubert, it appears that Dr. Laken violated his own protocols when he re-scanned Dr. Semrau on the AIMS tests SIQs, after Dr. Semrau was found “deceptive“ on the first AIMS tests scan. None of the studies cited by Dr. Laken involved the subject taking a second exam after being found to have been deceptive on the first exam. His decision to conduct a third test begs the question whether a fourth scan would have revealed Dr. Semrau to be deceptive again.

The absence of real-life error rates, lack of controlling standards in the industry for real-life exams, and Dr. Laken’s apparent deviation from his own protocols are negative factors in the analysis of whether fMRI-based lie detection is scientifically valid. See Bonds, 12 F.3d at 560.

The reference here is to the fact that Laken and his company scanned Semrau (the defendant) on three separate occasions. The first two scans were planned ahead of time, but the third apparently wasn’t:

From the first scan, which included SIQs relating to defrauding the government, the results showed that Dr. Semrau was “not deceptive.“ However, from the second scan, which included SIQs relating to AIMS tests, the results showed that Dr. Semrau was “being deceptive.“ According to Dr. Laken, “testing indicates that a positive test result in a person purporting to tell the truth is accurate only 6% of the time.“ Dr. Laken also believed that the second scan may have been affected by Dr. Semrau’s fatigue. Based on his findings on the second test, Dr. Laken suggested that Dr. Semrau be administered another fMRI test on the AIMS tests topic, but this time with shorter questions and conducted later in the day to reduce the effects of fatigue. … The third scan was conducted on January 12, 2010 at around 7:00 p.m., and according to Dr. Laken, Dr. Semrau tolerated it well and did not express any fatigue. Dr. Laken reviewed this data on January 18, 2010, and concluded that Dr. Semrau was not deceptive. He further stated that based on his prior studies, “a finding such as this is 100% accurate in determining truthfulness from a truthful person.“

I may very well be misunderstanding something here (and so might the judge), but if the positive predictive value of the test is only 6%, I’m guessing that the probability that the test is seriously miscalibrated is somewhat higher than 6%. Especially since the base rate for lying among people who are accused of committing serious fraud is probably reasonably high (this matters, because when base rates are very low, low positive predictive values are not unexpected). But then, no one really knows how to calibrate these tests properly, because the data you’d need to do that simply don’t exist. Serious validation of fMRI as a tool for lie detection would require assembling a large set of brain scans from defendants accused of various crimes (real crimes, not simulated ones) and using that data to predict whether those defendants were ultimately found guilty or not. There really isn’t any substitute for doing a serious study of that sort, but as far as I know, no one’s done it yet. Fortunately, the few judges who’ve had to rule on the courtroom use of fMRI seem to recognize that.

Regarding the existence and maintenance of standards, Dr. Laken testified as to the protocols and controlling standards that he uses for his own exams. Because the use of fMRI-based lie detection is still in its early stages of development, standards controlling the real-life application have not yet been established. Without such standards, a court cannot adequately evaluate the reliability of a particular lie detection examination. Cordoba, 194 F.3d at 1061. Assuming, arguendo, that the standards testified to by Dr. Laken could satisfy Daubert, it appears that Dr. Laken violated his own protocols when he re-scanned Dr. Semrau on the AIMS tests SIQs, after Dr. Semrau was found “deceptive“ on the first AIMS tests scan. None of the studies cited by Dr. Laken involved the subject taking a second exam after being found to have been deceptive on the first exam. His decision to conduct a third test begs the question whether a fourth scan would have revealed Dr. Semrau to be deceptive again.
The absence of real-life error rates, lack of controlling standards in the industry for real-life exams, and Dr. Laken’s apparent deviation from his own protocols are negative factors in the analysis of whether fMRI-based lie detection is scientifically valid. See Bonds, 12 F.3d at 560

fMRI: coming soon to a courtroom near you?

Science magazine has a series of three (1, 2, 3) articles by Greg Miller over the past few days covering an interesting trial in Tennessee. The case itself seems like garden variety fraud, but the novel twist is that the defense is trying to introduce fMRI scans into the courtroom in order to establish the defendant’s innocent. As far as I can tell from Miller’s articles, the only scientists defending the use of fMRI as a lie detector are those employed by Cephos (the company that provides the scanning service); the other expert witnesses (including Marc Raichle!) seem pretty adamant that admitting fMRI scans as evidence would be a colossal mistake. Personally, I think there are several good reasons why it’d be a terrible, terrible, idea to let fMRI scans into the courtroom. In one way or another, they all boil down to the fact that just  isn’t any shred of evidence to support the use of fMRI as a lie detector in real-world (i.e, non-contrived) situations. Greg Miller has a quote from Martha Farah (who’s a spectator at the trial) that sums it up eloquently:

Farah sounds like she would have liked to chime in at this point about some things that weren’t getting enough attention. “No one asked me, but the thing we have not a drop of data on is [the situation] where people have their liberty at stake and have been living with a lie for a long time,” she says. She notes that the only published studies on fMRI lie detection involve people telling trivial lies with no threat of consequences. No peer-reviewed studies exist on real world situations like the case before the Tennessee court. Moreover, subjects in the published studies typically had their brains scanned within a few days of lying about a fake crime, whereas Semrau’s alleged crimes began nearly 10 years before he was scanned.

I’d go even further than this, and point out that even if there were studies that looked at ecologically valid lying, it’s unlikely that we’d be able to make any reasonable determination as to whether or not a particular individual was lying about a particular event. For one thing, most studies deal with group averages and not single-subject prediction; you might think that a highly statistically significant difference between two conditions (e.g., lying and not lying) necessarily implies a reasonable ability to make predictions at the single-subject level, but you’d be surprised. Prediction intervals for individual observations are typically extremely wide even when there’s a clear pattern at the group level. It’s just easier to make general statements about differences between conditions or groups than it is about what state a particular person is likely to be in given a certain set of conditions.

There is, admittedly, an emerging body of literature that uses pattern classification to make predictions about mental states at the level of individual subjects, and accuracy in these types of application can sometimes be quite high. But these studies invariably operate on relatively restrictive sets of stimuli within well-characterized domains (e.g., predicting which word out of a set of 60 subjects are looking at). This really isn’t “mind reading” in the sense that most people (including most judges and jurors) tend to think of it. And of course, even if you could make individual-level predictions reasonably accurately, it’s not clear that that’s good enough for the courtroom. As a scientist, I might be thrilled if I could predict which of 10 words you’re looking at with 80% accuracy (which, to be clear, is currently a pipe dream in the context of studies of ecologically valid lying). But as a lawyer, I’d probably be very skeptical of another lawyer who claimed my predictions vindicated their client. The fact that increased anterior cingulate activation tends to accompany lying on average isn’t a good reason to convict someone unless you can be reasonably certain that increased ACC activation accompanies lying for that person in that context when presented with that bit of information. At the moment, that’s a pretty hard sell.

As an aside, the thing I find perhaps most curious about the whole movement to use fMRI scanners as lie detectors is that there are very few studies that directly pit fMRI against more conventional lie detection techniques–namely, the polygraph. You can say what you like about the polygraph–and many people don’t think polygraph evidence should be admissible in court either–but at least it’s been around for a long time, and people know more or less what to expect from it. It’s easy to forget that it only makes sense to introduce fMRI scans (which are decidedly costly) as evidence if they do substantially better than polygraphs. Otherwise you’re just wasting a lot of money for a fancy brain image, and you could have gotten just as much information by simply measuring someone’s arousal level as you yell at them about that bloodstained Cadillac that was found parked in their driveway on the night of January 7th. But then, maybe that’s the whole point of trying to introduce fMRI to the courtroom; maybe lawyers know that the polygraph has a tainted reputation, and are hoping that fancy new brain scanning techniques that come with pretty pictures don’t carry the same baggage. I hope that’s not true, but I’ve learned to be cynical about these things.

At any rate, the Science articles are well worth a read, and since the judge hasn’t yet decided whether or not to allow fMRI or not, the next couple of weeks should be interesting…

[hat-tip: Thomas Nadelhoffer]