William M. Briggs

Statistician to the Stars!

Page 395 of 707

Brain Atrophy Responsible For Religious Belief?

Hippo's campusReaders can help me choose the best metaphor. (1) A snowball which starts the size of a pea but gains in strength and speed as it rolls downhill, mindlessly consuming all in its path; or (2) An avalanche, a furious, powerful deluge which is set off by some small thing, mindlessly consuming all in its path.

The application is to fMRI and other imaging studies of the brain which show that some “aberrant” (i.e. non-leftist) behavior can be pinned to some small region inside the skull. These statistical studies, which were nonexistent just a short while ago, now pop up weekly. Each works cites the others, and in so doing hopes to convince by sheer mass. Like a snowball or avalanche. Call it Death by Correlation, or Attack of the P-Value.

We have seen dark triads, enjoyment of custom, faith, and many, many others, all said to be caused by quirks in the brains of conservatives and theists. Today’s example is “Being ‘Born-Again’ Linked to More Brain Atrophy.” Well, at least this is clear enough. Rotting, shriveling brains “linked” to faith.

The abstract of the peer-reviewed paper by Amy Owen et alia is instructive. It opens,

Despite a growing interest in the ways spiritual beliefs and practices are reflected in brain activity, there have been relatively few studies using neuroimaging data to assess potential relationships between religious factors and structural neuroanatomy.

That sentence is paradigmatic: “Despite interest in X, we have not yet seen work in subgroup Y” opens many papers. It suggests a bandwagon groaning under the weight of scientists with hyperactive pituitaries, or whatever cranial organ is responsible for copycat research—and according to these folks some such organ must exist.

As depressing as this beginning is, let’s push on. Our data-mining discovery-of-the-day comes from comparing “religious factors and hippocampal volume change using high-resolution MRI data of a sample of 268 older adults.” Main claim: “Significantly greater hippocampal atrophy was observed for participants reporting a life-changing religious experience.” And there you have it: withered brains produce faith. In case the connotation wasn’t obvious, the press article reminds, “Shrinkage of the hippocampus is also associated with depression, dementia and Alzheimer’s disease.”

(You know, it’s not often I brag or boast or plead, but I should receive some kind of humanitarian award for reading these papers so you don’t have to.)

Participants, with double the number of women, mean age near 70, were measured twice, a baseline and follow-up—follow-ups were not consistent: times “ranged from 2—8 years.” Participants were “those meeting DSM-IV criteria for major depressive disorder” and those “never-depressed”. They never tell us how many in this study were depressed and how many not. Ah, who needs rigor? This is statistics!

Affiliation was queried: non-born-again, born-again Protestant, Catholic, and Other. Only 19—just 19; a mere 19; 7%—listed no religion. Those claiming not to be born again were asked whether they had had “life-changing religious experiences” (LCRE).

Now, over the course of follow-up, twenty-two—that is, 22, which is 1 more than 21—people were newly born again and 23 others had new LCREs. That is 55 total, folks, which is nearly three times as many who claimed no religion prior to the study. That must mean that many people merely reported switching their religious label. How did the researchers handle this ambiguity in their statistical models?

(I really am going to have to devise a graphic which indicates crickets chirping.)

Understand, dear reader: the evidence for this study is entirely statistical, the result of regression models producing publishable p-values. They created two models for change in (falsely assumed error-free) measures of the left and right hippocampus. For the LH model, every measure of religion, pre or post, gave negative model coefficients except “Other” (but that had an unacceptable p-value). This includes “None,” which I remind us means no religion. Same for the RH model, except “Other” was negative here; “None” was still negative. Negative means the item shrank the hippocampus.

Unfortunately for consistency in reporting, newly born-again status was not significant in either model; neither were new LCREs (baseline for both was). And do you know what? The authors did not report any kind of baseline comparison of hippocampus size and religious belief. Must have slipped their minds—which cranial organ was responsible for this error we do not yet know; further studies might tell us.

Now, participants were old. Yet, somehow, the model coefficient for “Duration in study” was positive for the LH model and negative for the RH model. How can this be? Aging causes the left but not the right hippocampus to grow? By golly, Owen has discovered that enrollment in fMRI studies encourages hippocampus growth! On the left side only, alas; the p-values aren’t there yet, but this is early days: more research is needed. Send donations.

As always, the most fun is had by reading the discussion, where authors allow their minds to range freely over possible explanations of the data. I was going to summarize these curious cogitations, but I quailed after reading, “Research on temporal lobe epilepsy indicates that features of hyper-religiosity may be positively associated with hippocampal atrophy, but findings are mixed.” Good grief. I had not the strength to continue.

But I did check: they hadn’t even an inkling that their results were a statistical artifact or due to a sloppy experimental protocol and even sloppier analysis. I blame myself and other statisticians for this. I really do.

Wearing A New Hat At JP Research

JP ResearchI am now a member of JP Research. What does this mean to you, my loyal readers? Little, except that my contact information for consulting has changed. New telephone and email: 650-559-5999, william@jpresearch.com. These are also listed on my Hire Me and Contact pages.

Story tips, personal correspondence, missives that begin “Briggs, you fool…”, and so forth still come to matt@wmbriggs.com.

At JP I’ll be doing the same kind of work, traveling to the same places and then some, and meeting new people. My locus in quo is unchanged. My teaching gig at Cornell remains. This blog will continue unmodified. I’ll almost certainly, however, be buying a new light grey Borcalino snap-brim fedora (teardrop crease). My collection of brown headgear is just-the-thing, except these chapeaux don’t always “go” with certain shades of blue, a major concern.

Rest assured that I have given this change serious consideration. Never, indeed, have I pondered longer or harder. There was even, at one point, actual hand wringing. But I came to the conclusion that the addition of a new hat to my stable is a necessity.

I know what you’re thinking: why grey and not blue? Well, blue hats are limiting. You can’t wear a blue hat with a brown, white, or tan suit. And you can’t even wear it with all shades of blue, especially darker ones. A blue hat is too jaunty: it is not a serious hat. Whereas a grey can be sombre or gay with the simple switch of the band. Borsalino

Not the stingy brim, either. These are Borsalino’s attempt to cash in on the hipster hat fad. And since all fads are doomed by definition, it is best to avoid them and save your money. Hipster hats are, I suppose, a gentle introduction to the world of adulthood, and so in this sense they can be encouraged. They are orders of magnitude better than a golf or baseball cap. And I believe that wearing a hipster hat might even increase the probability of wearing better clothes.

But if you’re going to spend the money, don’t blow it on a head covering that will look dated after one season. Which brings us to the well known men’s fashion rule: never skimp on shoes or hats. Nothing, but nothing, ruins the look of an outfit, no matter how carefully chosen or expensive, than to see it topped by a cheap hat or bottomed by rubber soles.

Incidentally a good, but expensive, pair of shoes, properly cared for will last forever, especially if they are a member of a rotation (try not to wear the same pair every day). Hats too can be Methuselan, as long as you don’t make a habit of doffing one by pinching the peak.

Speaking of homburgs: yes, but not for me. I am yet too young and anyway too long-faced. I want a derby, but I also want a moustache. The Powers That Be deny me both, sadly.

All these things and more will be on my mind as I begin my new life at JP.

Don’t Drive On Tax Day! You Might Die

Tax day crashesThis is it. The day to traipse to the post office and mail in your income tax papers. In farm lingo, this is the time swill the pigs. To feed the beasts. To oil the machine. To encourage the greedy sons-of-you-know-whats. To unwilling fork over what the politicians think belongs to them.

Unless you’re one of the lucky few—and by “few” I mean half of all Americans—who don’t have to pay federal income taxes, today is the day you’ll have to donate over a large chunk of your income to insatiable Washington bureaucrats. This can lead to a certain amount of “stress.” And that modern malady can cause you to drive distractedly. Which in turn can cause you to die in a bloody, fiery crash.

Or so says Donald Redelmeier and Christopher Yarnell who published a peer-reviewed research letter in JAMA which claims to have statistical proof that traffic accidents increase on Tax Day.

Taxes, our pair says, “influence the long-term health of the economy,” but how do taxes affect the health of people?

We investigated the number of individuals involved in a fatal road crash on tax day under the prespecified hypothesis that stressful deadlines might increase the risk of road trauma by impairing drivers or by compromising surrounding individuals from making compensatory adjustments.

They looked at each Tax Day from 1980 to 2009 (30 years; though the data extend to 1975; why leave it out?), and the two days a week before and after Tax Day, and counted the number of fatal crashes, defined as at least one person crapping out because of and within 30 days of the crash. There were 6,738 fatal crashes on tax day and 12,758 fatal crashes on the other two days. Conclusion?

Comparisons of tax days with control days yielded an odds ratio of 1.06 (95% CI, 1.03-1.10; P < .001), equivalent to an absolute increase of 404 individuals in fatal road crashes on tax days over the study interval or about 13 individuals during the average tax day.

So if Redelmeier is right, driving to the post office in a state of high dudgeon on Tax Day kills about 13 Americans each year. As the good doctor said in a news report on this study, “Who looks to tax day in a joyful way? Even those who are getting refunds are stressed. Refunds are never as big as they thought and there is always the chance they could be reviewed at a later date.”

That 1.06 appears to arise from ( 6738/30 ) / ( 12758/60 ), incidentally. Ignore the p-value, because with sample sizes this large publishable p-values are free for the asking. Focus instead on the reasons our researchers gave:

One explanation is that stressful deadlines distract drivers and contribute to human error (a national poll suggested that tax day was the second most stressful day in 2011)…Driving patterns may be altered on tax day. Although
electronic submissions might be expected to lessen driving on tax day, we observed an increase rather than a decrease in fatal crashes in recent decades.

Now isn’t that odd. E-filing—that is, the non-necessity of driving to the post office—accentuates the effect. Somehow. Who knows how. But, as the saying goes, the numbers don’t prevaricate.

Redelmeier says,

We always knew road crashes destroyed the lives of thousands of people each year in the U.S., and driver error contributes to 93% of the crashes. Stress is often speculated to contribute to driver error, but stress is usually impossible to study, [but] tax day is synchronized, repeated, and tremendously onerous…

Almost every one of these fatal crashes could have been avoided by a small change in driver behavior.

Tax Day isn’t the only danger, no sir. The good doctor, who is a kind of crash aficionado, has in other work also identified Super Bowl Sunday and Election Day1 as killers. Yes, I know what you’re thinking, but you’re wrong: the risk of crashing on Election day “was similar, regardless of whether a Democrat or Republican was elected.” His research also “does not indicate which candidate could best help save the 100 lives lost each day in fatal crashes in the United States.”

Redelmeier has also, in the same statistical manner, “discovered” that emergency department visits decreased during an Olympic gold medal television broadcast. This reminds me of the apocryphal story I used to hear as a kid: that water use surged during commercials in the I Love Lucy program.

The way to criticize these studies is so obvious that I leave it as a homework exercise in the comments. (Plus, I may shortly have a way to investigate the numbers.)


Thanks to DAV for suggesting this topic.

1This paper was published with Rob Tibshirani, a good statistician and aggressive if not unskilled basketball player. But nobody bats 1.000.

Obama Doesn’t Have A Chance

Barack ObamaI have returned from a week away from the computer. Announcements to follow tomorrow.

I am going to tell you of several conversations in which I took part over the last week, talks which, taken together, indicate that Barack Obama has almost no chance of winning re-election.

Of course, given my political views, it is always possible that I have misinterpreted the evidence and twisted it so that it conforms to my desires, i.e. that I am wishcasting. Too, I publicly predicted (in January) that Obama would lose, and nobody likes to make a mistake. You may thus want to discount what I tell you accordingly. Or you may want to listen and so back a winning forecast.

I was off from San Francisco to Las Vegas to attend a conference, and then back to the Bay Area for a certain project. This travel produced four cab rides: three of the four cabbies started conversations about politics (the last lectured me why Japanese cars were better than American). I say “started” to indicate that I did not begin any of these chats, nor did I actively direct their courses.

First cabbie (in SF) was Chinese by birth, now (I later learned) American. He apologized for not having a computer (it was busted), which meant I had to pay cash. But it also meant, he said, that he could not pick up riders who the city of San Francisco gave a kind of cab credit card which allowed them to charge rides to the city. This privileged class were “the poor” and those who met a broad (he claimed) definition of “disabled” (“The [last guy] didn’t have problems!”). The cabbie told me he was tired of so many people getting so much for free when he had to work so hard.

Second cabbie (in Vegas) was German by birth, now American. He brought up politics by way of a joke at Mr Obama’s expense, then nervously laughed and said he hoped it wouldn’t bother me. He was thinking of his tip, of course, but I put him at his ease by telling him that I agreed with his quip. He too mentioned having to work while others did not.

Third cabbie (in Vegas) was American by birth, a Hispanic thirty-something ex-civil engineer. He couldn’t stand office confinement. I asked how was business, and he said it was better now. Now? He said that since the mayor had acted in response to some disparaging comments Mr Obama made about ceasing business trips to Vegas, things were better. Cabbie said he used to like Obama, but “he shouldn’t say things like that.”

The conference itself contained a number of lawyers whose practices involve them with the government. I heard from and talked with several. I apologize that I must be vague about details.

One lawyer related a tale in which his company had settled a certain suit with opposition lawyers, only to see the government, unbidden, step in at the last moment and invalidate the settlement. The government then imposed its own settlement, mandating that a much larger sum be paid to it instead of to customers and opposition lawyers. The government would “manage” this fund and dispense monies to customers who wrote with claims. Few customers did, but the government got to keep the extra monies.

This, many said, was not the first incident, and all thought it would be far from the last. One important lawyer—Jewish (a big block for Obama last election; lawyer mentioned his son’s Bar Mitzvah), self-labeled Democrat—said, “If you think it’s bad now, just wait until after the election. They’re holding things back now until after they come back. It’s gonna be worse.”

Discussion agreed that the government was now staffed by “activists” whose reward system was based on “How big of a penalty can we get? How big of a fine?” Another said, “It’s going to be a regulating and political onslaught.” This was from a gentleman who said, “You know, I’m what’s called a knee-jerk Democrat…” Another person said she had actually worked for Mr Obama during the last election, but said (jokingly?) she was considering working for Mr Romney. And there was much much more.

Mr Obama has, and will keep, the far left. But this will harm him with the so-called “independents” and “Reagan Democrats.” The political elites are saying “It’s Obama in a romp”, but these are the same elites who were blindsided by the recent Supreme Court oral arguments.

Mr Obama also has the “promises” and words of the old Left—but he won’t have their votes. Obama hasn’t a chance.

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