Why brain-based lie detection is not ready for "prime time"

We are in a new and interesting legal world. Although to date, no US court cases have used brain-based lie detection techniques as evidence, several cases have sought such evidence and settled out of court. fMRI is the most frequent type of brain-based lie detection technology, with two companies, Cephos and No Lie MRI providing this service in the legal domain. There have also been attempts made to use EEG for deception detection. Notably, such a technique was used in part to prosecute a young woman for murder in India in 2008.

I am far from the first to point out that this technology is highly exploratory and not accurate enough to be used in the court of law. My goal here is to outline a good number of the reasons this is the case.

9. We do not know how accurate these techniques are. Although the two aforementioned companies boast lie detection accuracy rates of 90%+, these cannot be independently verified by an independent lab as the methods used by these companies are trade secrets. For example, there are few peer-reviewed studies of the putative EEG-based marker of deception, the P300, and most come from the lab that is commercially involved with a company trying to sell the technique as a product. Interestingly, an independent lab studying the effect of countermeasures on the technique found an 82% hit rate in controls (not the 99% accuracy claimed by the company), and this was reduced to 18% when countermeasures were used!

8. In the academic literature, where we do have access to methodology, we are limited to testing typical research participants: undergraduate psychology majors (although see this). For a lie detection method to be valid, it would need to be shown as accurate in a wide variety of populations, varying in age, education, drug use, etc. This population is not likely to be skilled in deception as a career criminal might, and it has been shown that the more often one lies, the easier it is to lie. Most fMRI-based lie detection techniques are based on the assumption that lying is hard to do, and thus requires the brain to use more energy. If frequent lying makes lying easy, then it could be the case that practiced liars don't have this pattern of brain activity.
     Although a fair amount has been made lately about WEIRD subjects, participants in these studies are actually beyond WEIRD: they are almost exclusively right handed, and predominantly male.

7. Along this same line, the "lies" that are told in these studies rarely have an impact on the lives of the student participants. Occasionally, an extra reward is given if the participant is able to "trick" the system, but in the real world, with reputations and civil liberties at stake, one might imagine that one might do a better job at tricking the scanner. However, being instructed to lie about a low-stakes laboratory situation is not the same as the high-stress situations where this technology would be used in real-life. Occasionally, a study will try to ameliorate this situation by using a mock crime (such as a theft) as the deceptive stimuli. However, these are also of limited use as participants know that the situation is contrived.

6. Like traditional polygraph tests, it is possible to fool brain-based lie detection systems with countermeasures. Indeed, in an article in press at NeuroImage, Ganis and colleagues found that deliberate countermeasures on the part of their participants dropped deception detection from 100% to 30%. Most studies of fMRI lie detection have found more brain activation for lies than truth, suggesting that it is more difficult for participants to lie. However, is this still the case with well-rehearsed lies? What about subjects performing mental arithmetic during truth to fool the scanner?
    
5. A general lack of consistency in the findings in the academic literature. To date, there are ~25 published, peer-reviewed studies of deception and fMRI. Of these studies there are at least as many brain areas implicated in deception, including the anterior prefrontal area, ventromedial prefrontal area, dorsolateral prefrontal area, parahippocampal areas, anterior cingulate, left posterior cingulate, temporal and subcortical caudate, right precuneous, left cerebellum, insula, putamen, caudate, thalamus, and various regions of temporal cortex! Of course, we know better than to believe that there is some dedicated "lying region" of the brain, and given the diversity of deception tasks (everything from "lie about this playing card" to "lie about things you typically do during the day"), the diversity of regions is not surprising. However, the lack of replication is a cause for concern, particularly when we are applying science to issues of civil liberties.

4. An additional issue surrounds the fact that many of these studies are not properly balanced. In other words, participants are instructed to lie more or less often than they are instructed to tell the truth.

3. There is a large difference between group averages and finding deception within an individual. Knowing that on average, brain region X is significantly more active in a group of subjects during deception than during truth does not tell you than for subject 2 on trial 9 than deception was likely to occur due to the differences in activation. Of course, some studies are trying to study this level of analysis, but right now they are the majority.

2. Some things that we think that are not true are not necessarily lies. Most of us believe we are above-average drivers, and smarter and more attractive than most even when these beliefs are not true. Memories, even so-called "flash-bulb" memories are not fool proof.

1. Are all lies equivalent to the brain?  Are lies about knowledge of a crime the same in the brain as white lies such as "no, honey those pants don't make you look fat" or lies of omission or self-deceiving lies?

My picks for the top studies of 2010

Presented in no particular order, here are the ten studies of 2010 that I found the most interesting. Enjoy!

1. A Wandering Mind is an Unhappy Mind
I wrote about this study here. Authors used an iPhone app to obtain "what are you doing?", "what are you thinking about?" and "how happy are you right now?" data. It turns out that we are thinking about something other than what we are doing about half of the time, and these are the times we are least happy.

2. Electrical Enhancement of Mathematical Ability.
I wrote about it here. The authors used transcranial direct-current stimulation as participants were learning an novel digit vocabulary. The stimulation (if done in the proper direction) facilitated this type of learning.

3. Ego Depletion only Happens if you Believe it will Happen.
I wrote about it here. Ego depletion is the idea that self-control is like a muscle, and if you use too much of it, you need to rest it like a muscle. The authors show here that people who believed in ego depletion had depleted continuous self-control, whereas people who believed that self-control was not a limited resource did not. Critically, giving people one of the two beliefs also changed behavior in the predicted direction.

4. Habit Formation in the Real World.
Have you heard that it takes 28 days to form a new habit? This is a very common notion, but is it true? The authors found that it can take up to 60 days for people to report a new behavior feeling automatic.

5. Vollenweider's Review of Psychadelic Drugs
Everything you ever wanted to know about psychedelics, but were afraid to ask. Good review of neurobiology of these drugs and their potential therapeutic uses in depression, OCD, anxiety, etc.

6. Eye Position Predicts what Number you have in Mind
When asked to generate "random" numbers, people have a hard time being truly random. In this study, people were asked to generate random numbers while their eye movements were monitored. It was found that the number a person generated could be predicted from the position of the eyes: in particular, that eyes in the lower left part of the visual field predicted small numbers and eyes in the upper right predicted large numbers.

7. Willful Modulation of Brain Activity in Disorders of Consciousness
Until this paper, there had been limited reports of patients in minimally conscious states able to perform mental imagery tasks as measured with fMRI. However, we also know that diagnosis of these states is prone to errors. How common is it for minimally conscious patients to be able to follow mental directions? 54 patients were tested, and it was found that only 5 could perform the tasks.

8. Putting Brain Training to the Test
Making software to "train your brain" into being smarter, more attentive, and less forgetful is a lucrative industry, but there was little evidence for or against this kind of training leading to cognitive enhancement. This massive study used over 11,000 participants and found that although participants got better at the tasks in the games, no improvement was found in non-trained real-world tasks. Save your money, folks.

9. Outcome Reporting Among Drug Trials
All clinical trials need to be registered through the NIH at clinicaltrials.gov. This policy was designed to prevent Big Pharma from running near-infinite numbers of trials on a drug, then only reporting ones with positive results. This study examines differences between studies funded by industry, by government and by private organizations. Industry-funded trials had 85% positive results, while government-funded trials had 50% positive results. Humph.
 
10. Prediction of Individual Brain Maturity
 Human brains mature rather late and at different rates. The issue of brain maturity has been key to policy decisions about how to punish adolescent criminals and how to insure adolescent drivers. This study uses fMRI to show how mature an individual brain is. 

Killingsworth MA, & Gilbert DT (2010). A wandering mind is an unhappy mind. Science (New York, N.Y.), 330 (6006) PMID: 21071660

Cohen Kadosh R, Soskic S, Iuculano T, Kanai R, & Walsh V (2010). Modulating neuronal activity produces specific and long-lasting changes in numerical competence. Current biology : CB, 20 (22), 2016-20 PMID: 21055945

Job V, Dweck CS, & Walton GM (2010). Ego depletion--is it all in your head?: implicit theories about willpower affect self-regulation. Psychological science : a journal of the American Psychological Society / APS, 21 (11), 1686-93 PMID: 20876879

Vollenweider FX, & Kometer M (2010). The neurobiology of psychedelic drugs: implications for the treatment of mood disorders. Nature reviews. Neuroscience, 11 (9), 642-51 PMID: 20717121

Loetscher, T., Bockisch, C., Nicholls, M., & Brugger, P. (2010). Eye position predicts what number you have in mind Current Biology, 20 (6) DOI: 10.1016/j.cub.2010.01.015

Monti, M., Vanhaudenhuyse, A., Coleman, M., Boly, M., Pickard, J., Tshibanda, L., Owen, A., & Laureys, S. (2010). Willful Modulation of Brain Activity in Disorders of Consciousness New England Journal of Medicine, 362 (7), 579-589 DOI: 10.1056/NEJMoa0905370

Owen, A., Hampshire, A., Grahn, J., Stenton, R., Dajani, S., Burns, A., Howard, R., & Ballard, C. (2010). Putting brain training to the test Nature, 465 (7299), 775-778 DOI: 10.1038/nature09042

Bourgeois FT, Murthy S, & Mandl KD (2010). Outcome reporting among drug trials registered in ClinicalTrials.gov. Annals of internal medicine, 153 (3), 158-66 PMID: 20679560

Dosenbach NU, Nardos B, Cohen AL, Fair DA, Power JD, Church JA, Nelson SM, Wig GS, Vogel AC, Lessov-Schlaggar CN, Barnes KA, Dubis JW, Feczko E, Coalson RS, Pruett JR Jr, Barch DM, Petersen SE, & Schlaggar BL (2010). Prediction of individual brain maturity using fMRI. Science (New York, N.Y.), 329 (5997), 1358-61 PMID: 20829489

Sunday soundbites: Happy Boxing Day!

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Here is an article I wish I'd written: links between the disease semantic dementia and the insomniac memory loss in Gabriel Garcia Marquez' One Hundred Years of Solitude.

PLoS ONE publishes a study flying in the face of placebo theory showing that patients aware of placebo treatment still show a placebo effect. Study is here, and skeptical analysis found here and here.

Andrew Gelman has a great analysis of why summary plots don't show the whole story.

Nature shows the value of networking in science.

Counting calories? You can blame Lavoisier for first understanding the body as a combustion engine, according to Nature's history of nutrition information.

The journal Biology Letters published this paper by a group of 8th graders. It will be freely available online until the New Year.

How much are those Nature papers really worth? A new study examines citation rates of Nature and Psychological Review.

Bad Science has a great "Year in Nonsense" article for the cynical.

Have some fun doing recreational probability with Understanding Uncertainty.

The science of a good first impression, over at Pop Economics.

Why no one bats .299 in late September

This paper shows that people strive for round-number goals, showing evidence from Major League baseball players, high school students taking the SAT, and from laboratory subjects answering hypothetical surveys of behavior.

As can be seen in the figure, baseball players are 4 times more likely to end the season with a 0.300 batting average than a 0.299 average! How does this happen? Players that are at 0.298 or 0.299 are more likely to have at-bats (rather than having a pinch hitter), they are slightly more likely to have hits at those at bats, and once a batter hits the magic 0.300 point, batters often take walks and sit out for pinch hitters.

The SAT takers were 10-20 percentage points more likely to re-take the test if they had an exam ending in -90 (e.g. 1190) than one ending in -00 (e.g. 1200).

Last, the authors gathered laboratory participants and asked them how they would react given certain situations. To give an example situation, imagine running laps around a track and you are getting tired. You have run either 28, 29, 30 or 31 laps (depending on what condition you are in). Do you want to run one more lap? They found that participants in the just under a round number condition (29 laps) were more likely to run one more, and participants in the just over the round number (31) were less likely to do one more.

Are these round number goals rational? In other words, is a baseball player more likely to get a lucrative contract with a 0.300 batting average than a 0.299? Do highly selective colleges have round number cut-offs for admissions? The authors examined data from university admissions that showed no discontinuities in the probability of admission as a function of SAT score, suggesting that such round number goals are not, in fact, rational.

Pope D, & Simonsohn U (2010). Round Numbers as Goals: Evidence From Baseball, SAT Takers, and the Lab. Psychological science : a journal of the American Psychological Society / APS PMID: 21148460

Sunday soundbites: Rocky Mountain High edition

Not neuro-related, but terrifying: 5% of Boston high school students report carrying guns to school, and think that more people carry guns than actually do.

Nature recognizes the role (they don't seem sure what kind, though) of blogs in scientific discourse.

The New York Times has a nice review of Antonio Damasio's new book The Self Comes to Mind.

Psychology Today has a top ten psychology studies of the year article.

In the spirit of top tens, ScienceNow also has a top ten stories of the year.

Nate Silver of the enviably-fantastic Five Thirty Eight, and himself an orthodox Bayesian, gives a Bayesian take on WikiLeaks' Jullian Assange.

Taking advantage of the open scanner hours now that people are leaving for winter break? Neuroskeptic has the prayer for you.

105 Major League Baseball players have theraputic exemptions for ADHD drugs.

Accelerometers on smart phones used to train prosthetic limbs.

Barking up the Wrong Tree presents an article showing that the Flynn effect (the phenomenon of population IQs rising over time) makes it difficult to have an objective standard for retardation when it comes to capital punishment cases.

Roundup of epic visualizations

A map of the world revealed by networks of Facebook friendships.

Play with the New York Times' tool for visualizing census data.

Spatial distributions of tourists and locals in various cities.

How did your schools compare with others within district, state, country?

Asteroid discoveries from the last 30 years.

Sunday soundbites

Weekly fun dataset for hobby-statisticians.

More statistical goodness on diabetes rates and state lines.

Neurophilosophy has an interview with Suzanne Corkin about HM.

Visualize yourself eating to lose weight? A good review of a recent study at NPR.

The Chronicle of Higher Education has a short piece reviewing a paper showing that we find bearded salesmen more trustworthy. (I dunno... facial hair freaks me out....)

Barking up the Wrong Tree reviews a study showing that narcissism scores are on the rise.

Maybe it's because parents are giving their children more unique names.

The Economist has a good interview with Oliver Sacks. (Though shame on the Economist for mixing up "affect" and "effect").

The Neurocritic has a great article on how blogging and peer review interact (or not).

Cool interview with author of recent paper on visual hallucinations.

A good analysis of the "slut gene".

Book review: Addiction: A Disorder of Choice by Gene Heyman

I was apprehensive about reading this book. I was worried that it was going to be a hyper-conservative and moralizing tome. What I found instead was a provocative and well-researched book that I highly recommend to anyone interested in addiction, public policy or psychiatry.

As is clear from the book’s title, Heyman asserts that the dominant paradigm of drug addiction (that it is a “chronic and relapsing brain disease”) is not correct, and that by viewing addiction as the result of a series of willful actions, we have a better understanding of the course of drug addiction and its treatment.

Why is this view controversial? It strikes at the heart of the paradoxical way that we view drugs and drug addiction in the modern US. Heyman explains: “The reasoning behind this view is that if addiction is a disease, then science will soon find an effective treatment for it, as had been the case for many other diseases, but if that addiction is a matter of choice, then the appropriate response is punishment… The core assumption of this viewpoint is that there are but two possible responses to addiction: treatment or punishment”. As a good liberal, I was uncomfortable starting the book because I was worried that Heyman would be blaming the victims of addiction, and potentially creating policy that would take away treatment options, leaving them worse off.

Heyman remains unfortunately agnostic on what ought to be done about drug abuse, but focuses instead on the science and history of drug abuse and drug policy. Here are his central arguments for addiction being a choice:

The same drugs have different effects on people that depend on cultural context

Across time, culture and place, the reactions to the same drug are markedly different. If drug abuse were a biological reflex, this would not be the case. Of course, some of the “cultural contexts” listed by Heyman (smoking versus injecting heroin, for example) can dramatically influence the metabolism of the drug, which is a biological context that can influence receptor binding, etc.

The more interesting piece of this argument was that studying only those in treatment for drug addiction biases many studies of drug addicts. These people have higher co-morbidity with other mental illnesses and are more likely to relapse. For most people, a drug habit runs a natural course, beginning in a person’s late teens to early twenties and ending by age 30. Heyman profiles the majority population of invisible “successful addicts” who start and end drug-taking behavior as free choices.

The right motivations get just about anyone to quit

When people are given enough motivation, nearly all can quit taking drugs. 85% of drug addicted doctors and airline pilots faced with the possibility of passing all future random drug tests or losing their jobs will quit taking drugs. “Change your incentives, change your behavior, change your brain”.

The genetic basis for addiction is not compelling.

Heyman uses religiosity and twin studies to prove this point. Religion is a learned and voluntary behavior, and twins tend to have similar degrees of religiosity. However, the religiosity data only show a 0.3-0.4 correlation between even identical twins, so I agree with Heyman that the argument is a little weak.

The book misses a great opportunity to go into the neuroscience of addiction, as strengthening neural circuits associated with habit, and down-regulating neurotransmitter systems affected by the drugs could be very potent reasons why drug taking is so difficult to stop.

Near the end of the book is an argument of choice behavior, largely based on the very cool research of Drazen Prelec and colleagues. While it takes Heyman a while to set up the background, it is worth following as it has a lot of explanatory power for habitual behavior of all kinds, not just drug addictions. In brief, as the negative consequences of taking drugs accumulate slowly while the positive feeling of taking drugs is immediate (albeit diminishing over time), it takes a long-term perspective to see that drug-taking is a losing prospect in the long-term. The same goes with any bad habit: while just one cupcake will not cause you to gain 20 pounds, the habit of eating cupcakes over time will accumulate those 20 pounds. It takes a strong future orientation to see that the immediate deliciousness of the cupcake is not worth the long-term metabolic cost of the cupcake. Heyman refines his argument here by pointing out that while it is silly to say that someone would choose to be an addict, one becomes an addict from the accumulation of choices. “The point is that one day of heroin does not mean addiction, just as eating desert once does not make one fat. Of course as the days accumulate, the characteristics of addiction emerge, and as the deserts accumulate, fat cells get bigger”

One disappointment is the frequent straw-man argument along the lines of “It is not likely that anyone ever referred to recovery from obsessive compulsive disorder or schizophrenia as ‘going cold turkey’”.  These arguments seem to appeal to the emotions behind addiction rather than the science. Also, cognitive behavioral therapy, which involves the willful changing of one’s beliefs and behaviors, is an effective strategy for combatting other mental illnesses such as OCD, only showing how nuanced the idea of will in mental illness really is.

Sunday soundbites

Does kicking back and watching TV make you happier? Absolutely not. In fact, scheduling your free time might make you happier.

A very pretty statistical visualization.

Interesting Google talk on industry scientists hired by corporations to sow seeds of doubt in the public's mind about science.

Speaking of evil corporate interests, The New York Times has an article about the increasing boldness of ghostwriting in the pharmaceutical industry.

And more Big Pharma shenanigans here.

Nature has a short-but-sweet quip on the value of basic research.

I think that this guy should read that last one.

Freakonomics blog has a piece on how the same study can lead to opposite-sounding headlines in different papers.

This would surely be nominated for an IgNoble if not for the null result: do dogs get contagious yawns from people? Unclear.

More IgNoble fodder: this might actually be the most inspiring paper I've ever read!

Science reviews two feminist critiques of neuroscience.

PLoS has this article about D4 variants associated with sexual promiscuity. I can't wait to see what kind of headlines we see about this one.

What is the real value of effective writing?

This shocking article, written by a man who makes a living writing college papers for other people, has had a lot of mileage around the web lately.

I had two immediate reactions to the essay: “I would love to invite this guy to a dinner party, he sounds really interesting” and “this is just another example of the profoundly broken economics of the American higher educational system”

“In the midst of this great recession, business is booming. At busy times, during midterms and finals, my company's staff of roughly 50 writers is not large enough to satisfy the demands of students who will pay for our work and claim it as their own.”  Stated the pseudonymous Mr. Dante.

Alex Reid wrote about some economic observations from the article. “… it's a little sad that people who are clearly accomplished writers (to be able to produce quickly good academic material across the disciplines) are willing to work for such little pay.”  This is in stark opposition to my own reaction, which was along the lines of “wow, I could increase my post-doc salary by a substantial margin by doing this!”  And recall that despite my whining, my salary is quite reasonable when compared to my adjunct peers in the humanities.  I whole-heartedly agree with Mr. Reid’s assertion that we should really start questioning our paradigms about college education.

To review: our students can’t afford not to get a college degree, and end up paying smart individuals who might otherwise be teaching them if it wasn’t more worth their while economically to pass them through the system. These students are in college because it’s just “what you do” to get a job that doesn’t involve flipping burgers.  What kind of education do people need to have for a typical job? How do we best scale this to the largest number of people?

Of course, this ghostwriting problem is far from limited to the college population. This week’s Nature had this article about “editorial services” that help with everything from experimental logic to type setting that help researchers get work published.  Such a service operates in a massive ethical gray area of authorship ethics – if a service organizes your ideas and suggests a critical control experiment, is that not a unique intellectual contribution?

Although both cases are very different, it is evident that the inability to clearly communicate one’s ideas is a primary barrier to academic and life success, and although we do not compensate teachers for this skill, its value is shown on the black market.

Sunday soundbites

The Neuroskeptic has the 9 circles of academic hell.

Speaking of academic hell, it looks like the 2011-2012 science funding prospects are very slim, especially with the latest tea-party-style Republicans.

Also, the Neuroskeptic has an excellent post on the rise of fMRI research with 7-Tesla magnets. Now, we  have more power to detect artifacts!

NPR wonders why people can't walk straight. Apparently, the problem isn't limited to post-alcohol consumption walking.

"Your brain has more connections than every computer on Earth combined" claims Gizmodo.

Over at Science is a review of a paper claiming that these connections are the latest reason that human brains are "special".

Does early exposure to pornography turn people into porn addicts? Barking up the Wrong Tree reviews a new study saying "No".

Jonah Lehrer has a timely piece on overeating in the Wall Street Journal.

For the statistically obsessed, this will keep you busy for hours.

Sunday soundbites

In defense of perfectionism.

Over at Nature, Melanie Stefan argues that scientists should keep a CV of failures. You know, to keep perspective. The perspective of wanting to drink heavily at 10am?

On the other hand, Frank Furedi argues that civic-minded activities should be recognized as accomplishments on one's CV.

Freakonomics blog has a review of a new novel on romance and data mining. Sounds like my kind of book!

A great description of a very depressing study on the media's representation of female scientists.

Also in the category of gender inequality, the recommendation letters women receive might do more harm than good.

Excellent article on the "privatization of neuroscience" and the shift away from basic research.

OK. Now to solve your depression from the previous links.

OK. Enough feeling good. Big Pharma really is as evil as you think they are.

Ah, the magic of.... placebo

Placebos are incredibly neat. This is why I am disappointed that they are typically described in undergraduate classrooms simply as a type of control. While they are certainly critical research controls, they are also a powerful example of how the brain, as much as the external world, creates our reality.

Work on placebos started after World War II, primarily from the work of Henry Beecher. Beecher, who had tended to wounded soldiers during the war, had witnessed saline solutions providing powerful pain relief to wounded soldiers during times when morphine supplies had run out.

Generally, we know that a placebo can provide relief from a variety of symptoms, including pain, Parkinson’s symptoms, ADHD, depression, allergies, epilepsy and more.  The relief from placebo isn’t just from patients telling doctors what they want to hear –when naloxone, a drug that blocks opiate receptors, is given to people who are taking a placebo pain reliever, the pain relief vanishes, suggesting that the placebo was activating some of the same neural systems activated when “real” drugs are taken. Similarly, dopamine is released during a placebo treatment for Parkinson’s, just as with the active treatment. An excellent summary of the neurobiology of placebo research can be found here.

Of course, not all placebos are created equal. For example, placebos that are injected are more effective than pills, and among pills, gelatin capsules are more effective than tablets. The price of the placebo also seems to alter its effectiveness. For example, in a clever 2008 study from Dan Ariely’s research group, participants were given mild electric shocks to their wrists before and after taking a drug they were told was an experimental pain killer that is similar to codeine. The “drug” was, of course, a placebo. Critically, half of the participants were told that the pills cost $2.50 each, while the other half of participants were told that each pill had been discounted to $0.10 each. It turns out that over 85% of participants in the high-priced drug condition experienced pain relief while only 60% of participants in the low-priced drug did.

To further complicate matters, not all people respond to a placebo to the same degree. In general, the more willing you are to expect a good outcome, the more of a placebo effect you will have. This is why children have more of an effect than adults (I mean, they believe in the Tooth Fairy, too!), and severely depressed patients have very little of a placebo effect.

It is crucial to consider studies such as these when considering clinical trials for new drugs. The gold standard for such trials is to compare the new drug to a placebo. If the drug has a greater effect than placebo and has an acceptable level of negative side effects, then it is typically approved by the FDA. While it is unlikely that clinical researchers are making their placebos intentionally less effective by making them less believable (these studies are done “double blind” meaning that the researchers don’t know which participants are on the drug, and which are on the placebo until the end of the study, so doing this would make the drug less effective too), we do need to consider that the effect size of the same drug is going to vary widely as a function of the placebo used, and the type of participants in the study.

This speaks directly to the recent controversy over the effectiveness of anti-depressant medication. The media creates headlines such as “The depressing news about anti-depressants”, which hide a rather nuanced issue: if the severity of depression affects the strength of the placebo effect, then not all studies of depressed patients will show a statistically significant effect of anti-depressants. This is shown graphically in this figure from a 2008 meta-analysis of antidepressant effects: while the effect size of the anti-depressants (red triangles) were more or less constant over a wide-range of depression levels, the effect size of the placebo (gray circles) decreased as the severity of depression increased. This means that in only the most depressed patients is there a significant effect of the antidepressant, but not because the drug is less effective in less depressed people.

…And placebos are not just limited to drugs. It turns out that most building thermostats and city street crosswalk buttons don’t actually do anything other than give you a sense of control! And I’m just about the biggest jerk on the planet as the placebo effect goes away once you know about it, so you can blame me when you are sitting in your office freezing and knowing that you can’t do a thing about it! Sorry.

EDIT: 1-1-11
And the movement of your progress bar might also be another placebo!

Sunday soundbites

Should be get rid of university libraries?  Um.... hell no!

How will the US elections affect science funding? According to Nature, the outlook is a little grim. See also the analysis in Science.

Virtual Mentor has a fairly lucid article on potential concerns of using fMRI to determine the reliability of eye-witness testimony.

The Dana Foundation is updating its list of great books about the brain.

A great example of bad science journalism criticism can be found here, writing about media's response to new "computational marathoning" paper.

The Neurocritic sets the record straight on the Tetris-as-PTSD-prevention garbage.

Beautiful brain pictures over at The New Scientist.

Wired is "celebrating" the 75th anniversary of the lobotomy.

More on what makes you happy

One problem that has previously limited happiness research is that asking people to imagine how happy they are doing something might not yield the same results as asking them how happy they are when they are actually doing this activity. However, a paper in today’s Science shows just this kind of data. The authors developed an iPhone application that would randomly “ping” participants and ask them what they were doing, how happy they were doing it, and whether they were currently thinking about what they were doing or something else. After getting over a quarter of a million responses from over 2000 participants, they noticed the following trends:

-         Except for when you are having sex, your mind is often on 

      something other than what you are doing. Nearly half of the samples reported mind wandering.

-         You are generally more unhappy when your mind is wandering, 

      albeit less so when you are thinking pleasant thoughts.

-         Happiness was better predicted from what you are thinking about than what you are doing.

I also really like their data representation: the location of the bubble 

indicates how happy you are (unhappy on the left to happy on the right), 

and the size of the bubble shows how many samples were from each activity. From this, I conclude that we consistently under-rate how happy exercise makes us, and that we need to have more sex!

Killingsworth, M., & Gilbert, D. (2010). A Wandering Mind Is an Unhappy Mind Science, 330 (6006), 932-932 DOI: 10.1126/science.1192439

Electrical enhancement of mathematical ability

Mathematical ability is highly linked to earning power and career success.  A new paper  in Current Biology demonstrates that six days of 20 minute sessions of electrical stimulation over the parietal lobe can increase some numerical literacy tasks, even six months after the stimulation was applied!

The electrical stimulation is called transcranial direct-current stimulation (TDCS). In this paradigm, electrodes are placed on the scalp as in EEG, and then a small amount of current (1-2 mA) is applied. In this paper, electrodes were applied to the parietal lobe as injuries to this region can lead to numerical difficulties. Three groups of participants were tested: two experimental groups who received stimulation, with the current going in each direction, and a control group who had electrodes applied, but without electrical stimulation (sham stimulation).

During the stimulation, participants were presented with pairs of novel symbols that stood for digits. Participants would learn the value of these symbols by indicating which symbol represented the larger value.

 As you can see from this figure, all three groups learned the task over the six experimental sessions.

Following the learning task, participants would then be given a "numerical Stroop" task to determine the automaticity of the symbol-value relationships. In this task, pairs of symbols are presented with one larger than the other. The larger symbol could be the symbol representing the larger value (congruent condition), could be the same value as the smaller value (neutral condition), or the larger symbol could represent the smaller value (incongruent condition). If the newly learned symbols were being processed as numbers, then the reaction times in the incongruent condition should be longer than neutral while congruent trials should lead to faster reaction times.

 It turns out that the stimulation did lead to an increased congruity effect, but only when the current was going in one direction (right-annode, left-cathode). In fact, current in the opposite direction seemed to decrease the learning of the symbols!

As illustrated in the left-hand figure, sham stimulation led to a ~65ms congruency effect (because even without stimulation, the participants were still learning the task). However, in the right-annode, left-cathode stimulation, the effect was about twice as large, while the opposite stimulation provided no learning at all.

Over at Practical Ethics, this paper is being discussed in terms of the societal benefit that could come from increased mathematical ability. Indeed, increasing numerical literacy could indeed decrease poverty and lead to increased innovation as they suggest. I also agree with their general unease about the possibility of "anti-enhancement" of mathematical abilities that is suggested from the right-cathode stimulation condition.

Cohen Kadosh, R., Soskic, S., Iuculano, T., Kanai, R., & Walsh, V. (2010). Modulating Neuronal Activity Produces Specific and Long-Lasting Changes in Numerical Competence Current Biology DOI: 10.1016/j.cub.2010.10.007

Sunday soundbites

Will my neurotic personality negatively affect my career? No, but my current academic salary will not decrease my neuroticism over time.

Is the university dead? We have no idea. In other depressing news, here's the state of tenure according to Nature.

Also in Nature are the results on one journal's experiment with making peer review transparent.... followed by some hand-wringing about its high rate of retractions.

The Simpson's take on grad students and PhDs.

The ability to imagine the future seems independent of the hippocampus.

An excellent review of the (in)famous Little Albert experiment over at The History of Psychology.

More good history: Bering in Mind has a great article on the history of obesity.

The great Facebook Oracle of data mining can predict when romantic breakup are most likely to happen.

Vogue-it til you make it: power posing your way to success.

Data-driven dieting

The interesting thing about dieting is that while everyone knows what you need to do to lose weight (eat less and move more), very few people know much about how to get yourself to do these things.

So, how do you increase your willpower? 

1. Don’t get too hungry.

It seems that there is a link between blood sugar and self control. For example, this study showed that when you perform an act requiring self-control, your blood sugar drops, and that when you have low blood sugar, your performance on subsequent self-control tasks decreases. This is a good reason to heed the oft-quoted diet advice to eat small meals 5-6 times a day as this stabilizes the blood sugar and keeps the cookie monster at bay.

2. Use your imagination.

Tempting treats are nearly everywhere around us at this time of year: leftover Halloween candy, holiday parties, home-baked treats, etc. How should you respond to a tempting, but fattening treat in your vicinity? According to this study, try to imagine it in non-food context. Instead of seeing brownies, see chocolate door stops. Instead of candies, checkers pieces. Just try to think of as many non-food uses for the item. Researchers found that subjects who were told to think of non-food uses for tempting chocolate rated chocolate as less appealing than those who were instructed to think of chocolate as delicious.

3. Adjust your mental model.

Earlier, I wrote about a recent paper refuting a long-held model of self-control that asserted that self-control is a limited resource that gets depleted with use. This paper demonstrated that not believing in this model led to higher performance on a self-control task.

Gailliot, M., Baumeister, R., DeWall, C., Maner, J., Plant, E., Tice, D., Brewer, L., & Schmeichel, B. (2007). Self-control relies on glucose as a limited energy source: Willpower is more than a metaphor. Journal of Personality and Social Psychology, 92 (2), 325-336 DOI: 10.1037/0022-3514.92.2.325


Hofmann, W., Deutsch, R., Lancaster, K., & Banaji, M. (2009). Cooling the heat of temptation: Mental self-control and the automatic evaluation of tempting stimuli European Journal of Social Psychology DOI: 10.1002/ejsp.708

Funny stats video

But what is your p value???

Getting Savage on evolutionary psychology

Now, I love sex advice columnist Dan Savage. I have been a faithful purveyor of his columns, podcasts and blogs for some time now. And sure, I don’t agree with him on every bit of advice, but he bats a solid .900 and articulately calls out many forms of B.S. But right now, I have a beef with Mr. Savage over his love affair with the new evolutionary psychology-inspired book Sex at Dawn by Christopher Ryan and Cacilda Jethá. This is an example of the all-too-common use of science-y thinking as justification for a particular belief, in this case, the use of evolutionary psychology to endorse the “naturalness” of polyamory.

My contentions are the following: 1. while I am all for the promotion of reading and scientific literacy, we need to be especially vigilant against accepting poor science that confirms what we already believe; 2. that we need to critically examine whether science can inform social policy discussions; and 3. we need to divorce the notion that the “naturalness” of an act means that the act is desirable.

Problems with evolutionary psychology

I need to point out in the spirit of full-disclosure that I have not read Sex at Dawn. However, from Mr. Savage’s multiple interviews with Dr. Ryan, it is evident that the apple of this book does not fall far from the tree of Buss and Baker.

Evolutionary psychology offers only post-hoc fits of theory to data

            In evolutionary psychology, one asks how human evolutionary history can explain aspects of current human behavior. Functionally, it amounts to doing thought experiments on questions such as “how did a cave man’s life influence the shape of the human penis”? The problem with this kind of problem statement is that you are looking at some data (in this case the shape of human penises) and looking for a model that fits this data. You can come up with many such models, because you are fitting the data after the fact, but you have no guarantee that your model is correct.

Let’s take a case in point of an issue brought up in the latest interview with Dr. Ryan on the Savage Lovecast. The question: why are human penises larger than gorilla penises when gorillas are larger than men? The given answer: because they were designed as plungers to remove the semen of rival males from the reproductive tract of a female. The larger theory behind this answer lies in the idea of sperm competition, the notion that females practice selective non-monogamy as a means of maximizing genetic quality in the offspring. The male, worried that he might be cuckolded into investing resources into offspring not genetically related to him needs adaptations to keep his partner from being impregnated by rivals. Therefore, it is to his advantage to have a “plunger penis” that will reduce the probability of pregnancy from a rival.

           

It’s kind of like an intellectual Rube-Goldberg machine, isn’t it? Or perhaps more fittingly, like one of Kipling’s “just-so stories”.

The “scientific data” for this claim come from this paper, which might be the most hilarious scientific study I’ve ever read (and this includes the smoking pot in the fMRI scanner study). From the abstract:

Inanimate models were used to assess the possibility that certain features of the human penis evolved to displace semen left by other males in the female reproductive tract. Displacement of artificial semen in simulated vaginas varied as a function of glans/coronal ridge morphology, semen viscosity, and depth of thrusting. Results obtained by modifying an artificial penis suggest that the coronal ridge is an important morphological feature mediating semen displacement.

 

Yes, kids… this is research with dildos and masturbation sleeves. Other great sound bites from the article include the “recipe” for artificial semen: 

Simulated semen was created by mixing 7 ml of water at room temperature with 7.16 g of cornstarch and stirring for 5 min. After trying different mixtures of cornstarch and water, this recipe was judged by three sexually experienced males to best approximate the viscosity and texture of human seminal fluid.

And in addressing limitations of the current paradigm:

A limitation of our attempts to model semen displacement was the greater rigidity of the prosthetic as compared to real genitals. The artificial vaginas did not expand as readily as real vaginal tissue nor did the phalluses compress, and, as a result, semen displacement was assessed on the basis of a single insertion. The effects, however, were robust and generalized across different artificial phalluses, different artificial vaginas, different types of simulated semen, and different semen viscosities.

…Sigh…. My own research seems so vanilla in comparison! But in all seriousness, extraordinary claims require extraordinary evidence, and this is not that evidence.

 

Evolutionary psychology does not make uniquely falsifiable claims

The hallmark of actual science is that it makes predictions that can be falsified and separated from other possible explanations. Evolutionary psychology does not do this. For example, the fact that men who have spent more time away from their partners find their partners more attractive and desirable, and ejaculate semen with higher sperm counts during copulation are taken as evidence for the sperm competition hypothesis. The argument is that as the man has not observed his partner, he is threatened by sperm competition, so it is to his advantage to copulate often and with… uh, greater virility. Although these studies control for time since last copulation, it doesn’t take much creativity to come up with alternative explanations.

Another example: the sperm competition hypothesis would predict that men would be more concerned with sexual infidelities of a partner (as this could result in cuckoldry) and women would be more concerned with emotional infidelities (as this could result in him leaving her without resources, or diverting resources into another partner). To test this prediction, David Buss conducted many surveys with many different groups asking them whether they would theoretically be more upset by a sexual or emotional infidelity. As nicely shown in David Buller’s critique of evolutionary psychology, although more men than women say that sexual infidelity is more upsetting, half of the men are still choosing emotional infidelity as more upsetting, so this model is far from complete.

Evolutionary psychology assumes that we know what psychological pressures existed for our ancestors in the Pleistocene.

We don’t. 

A closely related problem is that evolutionary psychology assumes that the mind evolved to the problems of the Pleistocene and then remained static for over 12,000 years. This seems implausible as large species-wide shifts have been observed in as little as 18 generations (less than 500 years for human generations).

However, many people who hate evolutionary psychology do so for irrational reasons

Evolutionary psychology is fine for intellectual masturbation, but we should strongly question its place as an actual science. However, many of its loudest critiques are based on emotional and political responses, rather than on the quality of the academic content.

Consider Megan McArdle’s critique of Sex at Dawn for The Atlantic. She writes:

“For example, like a lot of evolutionary biology critiques, this one leans heavily on bonobos (at least so far).  Here's the thing:  humans aren't like bonobos. And do you know how I know that we are not like bonobos?  Because we're not like bonobos.”

(Emphasis in original). 

Although I am sure Ms. McArdle is more articulate in other matters, it is true that when our beliefs are challenged, we are quick to say that scientific inquiry into the matter in question is useless.

Evolutionary psychology stirs up a political hornet’s nest. If we believe that our minds evolved to solve problems of the Pleistocene and have remained largely unchanged, this suggests that our minds have little capacity to change. Therefore, we can do little about real social problems such as war, racism and rape.

As Steven Pinker points out, ignoble tendencies do not have to lead to ignoble behavior. In other words, what “is” is not the same as what “ought”. The confusion between these two concepts comes from a fallacy confounding what is natural with what is good. Which leads me to my last problem with Dan Savage’s promotion of this book…..

Things that are natural are not necessarily desirable

Let’s step back and assume for a moment that the science of evolutionary psychology was solid, and that Ryan’s hypothesis about the polyamorous nature of humans was true. There would still be a major problem with Dan Savage’s use of this book to endorse polyamorous relationships: just because some behavior is fundamental to the nature of human beings does not mean that it’s a desirable state for current human beings.

Let me be clear on this point - I am not saying that humans shouldn’t be polyamorous. I believe consenting adults should do whatever they like. However, I am saying that the “naturalness” of polyamory does not inform its desirability.

Savage and Ryan are implicitly stating that since polyamory occurs throughout animal species and in human evolutionary history, it is natural. OK, but so are war, conquest, exploitation and rape and we do not condone these.

Dan, you are a smart guy…. Don’t get sucked in to poor science just because it tells a compelling story that you want to believe!