Cost Benefit Analysis Applied to Neti Pot Use

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Link to the article shown just above

I have nonallergic rhinitis. I have had great success keeping it under control with 10 milligrams of Cetirizine (one brand is Zyrtec) every night and using a neti pot to wash out my nasal passages twice a day, night and morning. My neti pot ritual has been pretty simple: use the little spoon provided with certain brands of neti pots to measure out and stir non-iodized salt into warm tap water. (Iodized salt burns and isn’t a good idea.) Then tip my head and pour the salted water into one nose and out the other. Blow my nose as needed—which is a lot. Reverse directions and repeat. Stop when the water is gone. Then I’m done.

But with the latest report of a woman dying from a freshwater amoeba infection (see above), I am being urged by those close to me, as well as by authorities to use only distilled or boiled water instead of tap water. (Of course, the boiled water needs to be allowed to cool before use!)

I’m not the only one using a neti pot and having to think about whether it is worth the trouble to use distilled or boiled water. Neti pots became fairly popular after Oprah touted them. On that, see “Yahoo! Reveals Oprah’s Effect on Web Searches” and the academic article below:

Let me approach my decision using the tools of cost-benefit analysis. Over a number of years’ time, there have been 4 widely publicized reports of brain-eating amoebae cases in the United States attributed to neti pot use by doctors. There are two types of brain-eating amoebae that have been blamed: Naegleria fowleri and now Balamuthia mandrillaris. (Technically, Naegleria fowleri is a “shapeshifting amoeboflagellate excavata,” not an amoeba.) Wikipedia currently says that Naegleria fowleri “is typically found in bodies of warm freshwater, such as ponds, lakes, rivers, and hot springs.” Balamuthia mandrillarisis believed to be distributed throughout the temperate regions of the world” in the soil and water.

In order to get a number for the annual risk of neti-pot use with salted tap water, I need to guess number of people using neti pots with salted tap water, the number of brain-eating amoeba cases per year due to neti pots, and the fraction of those brain-eating amoeba cases from neti pot use that are due to people using unsalted tap water. This distinction matters because, salt might kill or weaken freshwater amoebae. From “Is My Neti Pot Going to Kill Me?” shown above:

It’s not just about avoiding irritation, either—achieving the proper salinity protects you from microorganisms that can’t survive in saltwater, like Naegleria fowleri. “It's a freshwater thing,” says Iaquinta.

Brain-eating amoeba cases due to neti pot usage are sensational news, so let me assume that most such cases are well-reported. To lean on the high side, let’s suppose there are on average 3.25 such cases per year in the US. Unfortunately, I can’t find any numbers on neti-pot usage by googling around. And the number of people who use tap water instead of distilled water will be even harder to find out. (I’d be glad for help!) Let me suppose that 1% of the US population is using neti pots with tap water. That is about 3.25 million people. And since doing neti pot without using salt is very unpleasant (I’ve made the mistake a few times), let me simplify by imagining that all neti pot users put salt in. That last assumption makes the risk estimate higher than it would otherwise be. One last assumption that makes the incremental risk estimate higher than it otherwise be is to assume that someone who uses a neti pot with distilled or boiled water faces no risk. Putting all of that together gets me to a literal one-in-a-million risk annually. And you can see how changing the assumptions would change the incremental risk estimate.

How bad is a one-in-a-million annual risk? Economists use a concept called “the value of a statistical life” to turn such a tiny risk into dollars. $10 million is a relatively high number for the value of a statistical life. (See various estimates down at the bottom of the Wikipedia article “Value of life.”) A one-in-a-million annual chance of a $10 million hit is a cost of $10 per year. Think of that $10 million value of a statistical life as applying to someone with a US median level of income. Then whether someone at the median level of income should take the trouble to use distilled or boiled water should depend on whether they assess the time, money and trouble of using distilled or boiled water as more or less than the $10 per year cost from brain-eating amoeba risk of not using distilled or boiled water. I suspect that most people at a US median income would judge the time, money and trouble cost of using distilled or boiled water instead of tap water to be greater than $10 a year. So it is a reasonable decision to use tap water (with salt, of course, since it is very unpleasant not to use salt). Note that since the risk is entirely to oneself, some of the ethical concerns with using the value of a statistical life for cost-benefit analysis that show up in contexts where one is making a decision for others are muted in this context.

Getting the cost-benefit calculations right is important not only because many people may be making unwarranted expenditures of money, time and trouble, but also because some people who could benefit from using a neti pot may be discouraged from doing so because they think they have to used distilled or boiled water.

Those who are above the median income could reasonably think that they can afford to pay more for probabilities of their own survival at more than $10 million for a life (= $100,000 for each 1% chance). But the time and trouble costs of using distilled or boiled water would also be higher for those at higher incomes who also have higher hourly wages or a higher hourly dollar valuation of time for any other reason. Theoretically, if the marginal utility of a dollar declines faster than 1% for every 1% increase in consumption (as I believe it does), then the value of a statistical life should go up more-than-proportionately with the level of consumption. (The total util value of a life should go up some with a higher level of consumption; and likely much more importantly quantitatively, one then converts utils into dollars using the reciprocal of the marginal utility of consumption.) On average, a more-than-proportionate increase in the value of a statistical life with the level of consumption should make the dollar value of a statistical life go up faster with income than the value of time. And some of the cost of using boiled or distilled water is a cost in money. So among neti-pot users, if people are somewhat rational, I would expect more high-income folks to go to the trouble of using boiled or distilled water than moderate-income folks. (A tendency toward following the average practice within a society would reduce this effect, but shouldn’t eliminate it.) The ultra-rich who also have ultra-high levels of consumption could have their employees take on almost all of the extra time and trouble cost of using distilled or boiled water instead of tap water, and so should probably use boiled or distilled water.

All of that makes it a nonobvious decision for me, personally, whether to go to the trouble of using boiled or distilled water. It all depends on how easy and fast the procedure can be made when using boiled or distilled water. But what is obvious is that I shouldn’t stress myself out about this decision. It’s not a big deal either way. (On the costs of decision-making, see “Cognitive Economics.”)

Let me note that doing the cost-benefit analysis I sketch out above more carefully would be a great senior-thesis project of an undergraduate in economics. But it would take some legwork.

For annotated links to other posts on diet and health, see:

Miles Kimball on `The 7 Principles of Unitarian Universalism'

Note: This is a major update of my November 18, 2012 blog post “The 7 Principles of Unitarian Universalism,” adding my own take on things. I will implement this update at the original location as well.

I have mentioned on this blog that I am a Unitarian Universalist. The website for the Unitarian Universalist Association has a nice summary of the principles and sources of Unitarian Universalism. Let me reflect on what each one means to me. I’ll give the official statement uninterrupted, then comment. I hope that in, some measure, my blog reflects these principles.

There are seven principles which Unitarian Universalist congregations affirm and promote:

The inherent worth and dignity of every person;Justice, equity and compassion in human relations;Acceptance of one another and encouragement to spiritual growth in our congregations;A free and responsible search for truth and meaning;The right of conscience and the use of the democratic process within our congregations and in society at large;The goal of world community with peace, liberty, and justice for all;Respect for the interdependent web of all existence of which we are a part.

Unitarian Universalism (UU) draws from many sources:

Direct experience of that transcending mystery and wonder, affirmed in all cultures, which moves us to a renewal of the spirit and an openness to the forces which create and uphold life;Words and deeds of prophetic women and men which challenge us to confront powers and structures of evil with justice, compassion, and the transforming power of love;Wisdom from the world’s religions which inspires us in our ethical and spiritual life;Jewish and Christian teachings which call us to respond to God’s love by loving our neighbors as ourselves;Humanist teachings which counsel us to heed the guidance of reason and the results of science, and warn us against idolatries of the mind and spirit;Spiritual teachings of earth-centered traditions which celebrate the sacred circle of life and instruct us to live in harmony with the rhythms of nature.

These principles and sources of faith are the backbone of our religious community.

Let me discuss each principle in turn.

1. The inherent worth and dignity of every person: These days I feel keenly the denial from many quarters of full humanity to those born elsewhere, particularly if they are poor and don’t yet speak English well. One of my best statements about immigration is “"The Hunger Games" Is Hardly Our Future--It's Already Here.” I also have a sermon on the general tendency to divide the world into “Us and Them.”

For economists, a routine way of denying the inherent worth and dignity of each person is to do a cost-benefit or welfare analysis, that without comment, puts a weight of zero on non-citizens. My alternative is “The Aluminum Rule”:

When acting collectively–or considering collective actions–put a weight on the welfare of human beings outside the in-group at least one-hundredth as much as the welfare of those in the in-group.

Because of the rampant poverty in the world, the Aluminum Rule would lead to dramatically different policies than putting a weight of zero on the out-group.

2. Justice, equity and compassion in human relationships: When I read the words “justice,” and “equity,” I think of John Rawls’s book A Theory of Justice, which to me points toward the broader class of mathematically formal social welfare functions—which is a serious research interest of mine in my work with Dan Benjamin, Ori Heffetz and Kristen Cooper toward building national well-being indexes.

Beyond that, “justice” to me means this principle, distilled from blogging my way through on liberty and John Locke’s 2d Treatise—see “John Stuart Mill’s Defense of Freedom” and also “Miles Kimball on John Locke's Second Treatise,” from which the following quotation is taken:

… no government action that clearly both reduces freedom and lowers overall social welfare is legitimate, regardless of what procedural rules have been followed in its enactment.

When, as is often the case, freedom is abridged in order to enrich the lives of the rich and impoverish the lives of the poor, it makes me burn with indignation. I give some examples of policies in this category that treated by all too many people as innocent in “‘Keep the Riffraff Out!’

The word “compassion” makes me think of my own behavior much closer to home. Do I care about the people I deal with every day as much as I should? Do I strive to understand where they are coming from and what matters to them? (See “Liberty and the Golden Rule.”) Do I treat them right, both in doing my duty and looking for cases in which a modest effort on my part could benefit them greatly? Am I fulfilling my long-run duty to develop my social skills to the extent I reasonably can in order to be a warmer and more positive presence for others?

3. Acceptance of one another and encouragement to spiritual growth in our congregations: Each of us is different. Each of us has something that can be made fun of. Each of us could be made an outcast. I have my own stories of being treated at times as less than fully human because of my nerdly leanings. Those remembered moments still hurt, even decades later. Other people have their own stories of being made to feel less than fully human. To me “acceptance of one another” means a lot less of that happening.

To me, the interesting thing about “spiritual growth” is that I don’t know what it means. But that’s OK. As I wrote in “An Agnostic Grace”:

Religion is the “everything else” category in our existence in human societies and as individuals after parceling out the things people understand fairly well about human life—just as “natural philosophy” used to be the “everything else” category after parceling out as natural sciences the things people were beginning to understand fairly well about the natural world.

The same can be said for “spiritual” in the way it is used by nonsupernaturalists: “spiritual” refers to important things—many of them very, very positive—that we don’t fully understand yet. Spiritual growth is coming to a somewhat better understanding of those things and using that understanding to better our lives. To encourage one another in spiritual growth requires a sensitivity to things others are striving for or struggling with that may be hard for them to articulate. Let’s respect the things that people feel in their gut but can’t yet express very well, and give time for words to be put to those things.

4. A free and responsible search for truth and meaning: One of the glories of the U.S. Constitution is that it guarantees freedom of religion. (One of its shames was that it winked at slavery.) What is rare and precious beyond that is to have freedom of religious belief within the walls of a house of worship. I have that in Unitarian Universalism. I can believe as I believe and it is OK with everyone within a UU congregation. And I accord the same privilege to others. For example, I was fascinated rather than distressed to have Wiccan believers as full fellow members of the First Unitarian Universalist Congregation of Ann Arbor.

Truth is a sacred word to me. I left my previous religion in large measure because I felt my religious leaders (including very high-ranking leaders) had lied to me. In my career as an economist, the sacredness of truth shows up in a strong desire to urge statistical practices that put the truth ahead of careerist scientific advancement or confirmation of an ideology.

“Meaning” suggest to me both deep introspection into my own values and “Leaving a Legacy” by doing good that extends beyond one’s immediate circle. But “meaning,” like “spiritual” also points to the transcendent things that I don’t understand very well. I would like more transcendence in my life, and I don’t have much of a clue what that means. But I think the quest for transcendence, in balance with my other values, will lead to something bright and beautiful.

5. The right of conscience and the use of the democratic process within our congregations and in society at large: To me democratic values, and “the right of conscience,” means that I don’t have to bow the knee to anyone (unless I choose to do so out of freely-arrived at, deeply-felt respect). Human beings have evolved adaptations for hierarchy. But it is possible for each of us to insist on being treated as an equal and to treat others as equals. There are many intellectually interesting issues—not all of them resolved—on the question of in what sense should we be treating one another as equals. But what I am sure of is that we can and should be insisting on equality and treating others as equal to a greater extent than we do.

6. The goal of world community with peace, liberty, and justice for all: War is hell. Slavery is hell. Poverty is hell. They are hell when they happen in other countries just as much as if they happen in ours. Working to make war, slavery and poverty much rarer than they are in the world is a noble goal. And having the world sliced up into pieces with a majority of the world’s people only allowed to go into a few of those pieces is truly unfortunate.

7. Respect for the interdependent web of all existence of which we are a part. As I get older, plants and nonhuman animals intrigue me more and more. Some of our quest for meaning is likely to run through a contemplation and appreciation of plants and other animals.

Now, our planet is in danger of getting distressingly hot due to human action. We should take that seriously with serious measures (such as a carbon tax or a worldwide ban on burning coal) that go far beyond the symbolic. This doesn’t mean that we need to turn against capitalism. The best ways to take care of our precious planet, with plants, other animals, and us on it, is by using the price system and the creative potential of capitalist institutions, along with appropriate government measures.

To me, “the interdependent web of all existence” also includes the rest of the universe beyond our planet. Particularly valuable for contemplation are the many planets now being discovered beyond our solar system. (See “Exoplanets and Faith.”)

Conclusion: Besides being repelled by lies, I left my previous religion for Unitarian Universalism because its theological underpinnings felt too small. I felt the universe, and even our still tentative understanding of the universe, had a grandeur missing from what I was taught in that Church. When I was still a believer in Mormonism, I resolved (in the abstract) that I would only leave it for something that was bigger and better. Although Unitarian Universalism has a certain minimalism to it, it not only allows, but encourages the freedom of thought that allows all the best and and most wonderful thinking that has been done throughout human history in. That is truly grand.

Don’t miss these Unitarian-Universalist sermons by Miles:

By self-identification, I left Mormonism for Unitarian Universalism in 2000, at the age of 40. I have had the good fortune to be a lay preacher in Unitarian Universalism. I have posted many of my Unitarian-Universalist sermons on this blog.

Also, you can see other posts on religion, philosophy, humanities, culture and science by clicking on this link:

Nik Martin Interviews Miles Kimball: Trump Wants to Go Negative, but Does the Fed?

On August 19, 2019, Nik Martin interviewed me for the Deutsche Welle on Donald Trump now being an advocate for negative interest rates. You can see the results in the October 29, 2019 article shown above: “Interest rates: Trump wants to go negative, but does the Fed?

Here are the quotations from me that Nik used in the article:

  • “The severity of the Great Recession was almost entirely due to the fact that we were not yet used to a negative interest rate policy," economist Miles Kimball from the University of Colorado Boulder, told DW. "If rates had been cut to -5% early in 2009, we would have had a strong recovery by mid-2010." Kimball added that a negative rate policy by the Fed would be "a really good guarantee that we wouldn't get into another terrible recession.”

  • "You need to have ways to protect small savers from negative rates. If people know that negative rates won't affect them, they're going to be a lot less riled up." To avoid political blowback, Kimball told DW that Fed subsidies could be used to "make sure small checking and saving accounts never see negative rates and also ensure that bank profits are protected."

  • "It's not like a cut of 10 basis points suddenly becomes magically powerful," Kimball told DW. "But a cut of 600 basis points has always been powerful and it continues to be very powerful in the negative region."

  • Like many of his peers, the University of Colorado Boulder economist doesn't think negative rates will happen before the US election. If the next recession is mild, a negative rate of -1% may be enough to boost demand, he said. In the meantime, he says Trump could do the Fed a favor and continue to champion the benefits of negative rates on social media.

    "Now that he has done a series of favorable tweets, it could dramatically change the attitude of some folks with Republican leanings. Since most Democrats are likely to defer to the Fed in a situation where negative interest rates are needed, that should make policymakers a lot more comfortable."

Here are some quotations that Nik didn’t use:

  • There are no big technical problems with negative interest rate policy, just details that need to be worked out. The big concern is really about political blowback, specifically from folks with more of a leaning towards the Republican Party.

  • If people know that negative rates are not going to happen to regular people in their checking account, then people are going to be a lot less riled up.

  • I think the Fed is making some pre-emptive moves and you know it's not doing everything that Trump says he wants, but it's actually not coming from too different a place than Trump's latest tweet.

  • There are many many other things that President Donald Trump is doing that people should judge him on, come election time. But the business cycle is not one of them.

  • President Trump may actually be accomplishing something that generations' worth of of economics professors never accomplished: to get people to realize that the business cycle is the Fed's responsibility, not the president's.

  • If Donald Trump continues to speak favorably about negative interest rate policy I think it is enormously helpful.

  • A willingness to use deep negative rates would be an excellent guarantee that we wouldn't get into a terrible recession.

  • The severity of the Great Recession was almost entirely due to the fact that we were not yet used to negative interest rate policy.

  • If rates had been cut to -5% early in 2009, we would have had a strong recovery by mid 2010.

  • People are a little silly saying 'If negative interest rate policy is so great why didn't it do more for Japan?' Well a basis point is still a basis point.

  • The same subsidies from the Fed that would incentivize banks to make sure small checking and saving accounts never see negative rates also ensure that bank profits are fine, since negative rates are good for bank balance sheets other than the difficulty banks would have in passing on negative rates to checking and savings accounts. If banks don't need to pass on negative rates to small checking and saving accounts because of this Fed support, there is no more bank profits problem.

  • It all depends on how bad things get. The next recession is most likely to be mild. If it is, minus 100 basis points might well be enough. But the basic rule is that interest rates should be cut as far as needed, or raised as far as needed to get the desired level of aggregate demand.

  • Down to something like -1%, no change in paper currency policy is needed.

    Between -1% and something like -3%, it is important that banks be penalized for excess paper currency withdrawal at the cash window of the central bank (similar to current policy at the Swiss National Bank and the Bank of Japan, though loopholes would have to be closed).

    Below something like -3%, it becomes important to take paper currency off par.

    … the lower the interest rate is, the more costly it becomes to subsidize the provision of zero instead of negative rates in small checking and saving accounts. At some point the fiscal authority may need to help the central bank afford that cost. However, the central bank can probably go ahead and do it and—if necessary—get recapitalized by the fiscal authority later. Some discussions with the fiscal authority about whether they are (a) OK with a lower ceiling on the amount that can get the zero rate, (b) would rather pony up some money, or (c) would rather face some chance of having to recapitalize later could be appropriate.

I referenced many blog posts for Nik:

Of course, I also referenced my aggregator post for negative interest rate policy:

Mental Retirement: Use It or Lose It—Susan Rohwedder and Robert Willis

I am now 59 years old. (I was born in 1960.) Like many people my age, I am terrified of cognitive decline with advancing age. In “Hints About What Can Be Done to Reduce Alzheimer's Risk,” I discussed what little can be done about one source of cognitive decline. But there are other sources of cognitive decline with advancing age. In their Journal of Economic Perspectives article “Mental Retirement,” Susann Rohwedder and Bob Willis provide the best available evidence for the welcome idea that continued, strenuous mental activity can stave off cognitive decline. They describe the hypothesis they are testing this way:

The phrase “use it or lose it” reflects a hypothesis contained in a large popular and scholarly literature to the effect that a person can stave off normal cognitive aging— the decline of reasoning ability and speed of mental processing with age—or even dementia by engaging in cognitively demanding activities that exercise the mind. Conversely, this hypothesis holds that an undemanding environment will fail to impede and may even accelerate the process of cognitive decline.

The big problem with trying to find evidence for the idea that strenuous mental activity can slow down cognitive decline in old age is that cognitive decline—or simply a lower level of cognitive acumen—can lead people to pursue less strenuous mental activity. That is, a positive correlation between strenuous mental activity and cognitive status doesn’t tell one whether strenuous mental activity improves cognitive status or good cognitive status leads to more mental activity. (Cue the phrase “reverse causality.”)

I know both Bob and Susann well. (Bob Willis is my coauthor for the paper “Utility and Happiness,” which I mention in “My Experiences with Gary Becker.”) The way they identify the effect of strenuous mental activity on cognitive status is to look at differences in age of retirement across countries that are due to differences in the social security/public pension systems in those countries. Working is more strenuous mental activity than many other things one might do. And there are many plausible political reasons social security/public pension systems differ across countries that have nothing to do with dealing with a country’s especially high or low level of cognitive decline in old age. In their abstract, they write:

We investigate the effect of retirement on cognition empirically using cross-nationally comparable surveys [the Health and Retirement Study (HRS) and its clones] of older persons in the United States, England, and 11 European countries in 2004. We find that early retirement has a significant negative impact on the cognitive ability of people in their early 60s that is both quantitatively important and causal. Identification is achieved using national pension policies as instruments for endogenous retirement.

Susann and Bob argue as follows. First, there is a correlation between early retirement and cognitive decline across countries. The horizontal axis of their graph below shows change in employment rate comparing ages 60-64 to ages 50-54 in each country, while the vertical axis shows change in “a cognitive test of immediate and delayed word recall” between those same two age ranges.

Second, they argue that most of the variation in the age-related change in employment on the horizontal axis is exogenous:

The literature on the determinants of cross-country differences in retirement behavior provides strong evidence that these differences are primarily driven by differences in national pension, tax, and disability policies. As a result, most of the cross-country variation in the relative labor supplies of 60-64 year-olds relative to 50-54 year-olds depicted in Figure 1 is a result of national policies. Because it is highly unlikely that these policies have been set in response to observed age patterns in cognitive performance in the respective country’s population, we argue that these policies provide valid instruments to identify the causal effect of retirement on cognition even in micro-data, where problems of reverse causation tend to have rendered identification difficult.

Third, they pursue an explicit instrumental variables strategy using the micro data in the HRS and its sister surveys:

Our instrumental variables estimation, as always, can be viewed as a two-stage process. In the first stage, we use retirement status as our dependent variable and national pension policies as the explanatory variables: whether the individual has reached the age of eligibility for early retirement benefits in the public pension system and whether the individual has reached the age of eligibility for full retirement benefits. We also investigate specifications that use as additional instruments the number of years to or since reaching the age of eligibility for early retirement benefits (eligibility age minus current age); and the number of years to or since reaching the age of eligibility for full retirement benefits.

Susann and Bob find large effects:

We find a large and significant effect of retirement (or more precisely of “not working for pay”) suggesting that retirement is associated with a reduction in the memory score of about 4.7 points on a scale from 0 to 20 compared to those who continue working. The average score in the sample is just under 10 and the standard deviation is 3.3. So the estimated effect amounts to just under 1.5 times the standard deviation of the cognitive score in our analytical sample.

“Significant” in this case means a p-value of below .05%, which meets the standard I advocate in “Let's Set Half a Percent as the Standard for Statistical Significance.”

Note that this doesn’t mean that brain-exercise apps will do a lot of good. The dosage is much larger from having a job than from doing a brain app for 15 minutes a day. Susann and Bob make that point:

As we discussed at the beginning of the paper, Salthouse (2006) offers reasons to be skeptical of evidence purporting to demonstrate that mental exercise reduces the rate of cognitive decline. Nonetheless, we believe that the unengaged lifestyle hypothesis may be a plausible explanation for the mental retirement effect for several reasons. First, unlike many of the interventions discussed by Salthouse, like crossword puzzles and card games, retirement represents a major change in a person’s lifestyle and activities and thus affords the potential for a large effect. Second, the range of cross-country variation in age of retirement due to differences in policy is also large. Finally, the ten-year span between ages 50-54 and 60-64 in Figure 1 is long enough to indicate that the mental retirement effect represents a change in the rate of cognitive decline, rather than a short-term effect of retirement itself.

I don’t think it has to be a job to be strenuous enough mental activity to keep one mentally sharp, but it has to be something big.

Susann and Bob propose two mechanisms for why having a job or something just as cognitively taxing might help stave off cognitive decline [numbering added]:

  1. For many people retirement leads to a less stimulating daily environment. In addition, …

  2. … the prospect of retirement reduces the incentive to engage in mentally stimulating activities on the job.

Susann and Bob end on a cheery note:

There is evidence that older Americans have reversed a century-long trend toward early retirement and, during the past decade, have been increasing their labor force participation rates, especially beyond age 65. This is good news for the standard of living of elderly Americans, as well as for the fiscal balance of the Social Security and Medicare systems. Our paper suggests that it may also be good news for the cognitive capacities of our aging nation.

I should say that there are other interesting things in the paper. For one thing, distinction between “fluid intelligence” and “crystallized intelligence” and their different time paths is worth knowing. For another, Susann and Bob have a nice summary of Kerwin Charles’s paper on retirement. (Kerwin Charles is a former University of Michigan colleague of mine.) Here is their description of Kerwin’s paper:

The problem of endogenous retirement makes it difficult to interpret many of the published estimates of the effect of retirement on various measures of health. In an interesting exception, Charles (2002) addresses the question “Is Retirement Depressing?” Reviewing the literature, he notes that there is often a positive correlation in cross-sectional data between symptoms of depression and retirement status—the retired are more depressed. However, using longitudinal data from the HRS and instrumental variable techniques, Charles finds that people who are depressed tend to select into retirement and, more surprisingly, once retired, their depression lessens, a causal effect that is opposite in sign to the correlation. His identification strategy uses policy variations concerning mandatory retirement and Social Security benefits that influence retirement incentives by age and cohort.

Conclusion: I plan to do everything I can to stay cognitively sharp in old age. To begin with, I don’t plan to officially retire until around age 72, and maybe later. (This will help a lot financially, too.) Then, I plan to keep doing research, learning more cool math, reading, and blogging (and maybe writing a book or two) after I officially retire. I won’t give up on making mental exertions, even if I suffer the grief from outliving near and dear friends and loved ones.

For annotated links to other posts on diet and health, see:

The Federalist Papers #1: Alexander Hamilton's Plea for Reasoned Debate

For most of the time I have been blogging, I have been blogging every other Sunday on political philosophy. At a paragraph or a few paragraphs per blog post, so far I have blogged my way through John Stuart Mill’s On Liberty and John Locke’s Second Treatise on Government. Here are the two aggregator posts leading to the relevant links:

Today is my first post on The Federalist Papers, which is where I am turning next.

#1 in The Federalist Papers is a plea by Alexander Hamilton (using his pen-name Publius) for reasoned debate. In our own time of heightened political passions, it has a great deal of wisdom for us. Alexander Hamilton proffers the following ideas. (I draw the text below from this website.) Before each passage (indented) I put in bold my brief summary of that passage and in italics a representative excerpt from the passage.

A. Great good for the world (and honor for those deciding) will accompany a good decision: “… whether societies of men are really capable or not of establishing good government from reflection and choice …”

To the People of the State of New York:

AFTER an unequivocal experience of the inefficiency of the subsisting federal government, you are called upon to deliberate on a new Constitution for the United States of America. The subject speaks its own importance; comprehending in its consequences nothing less than the existence of the UNION, the safety and welfare of the parts of which it is composed, the fate of an empire in many respects the most interesting in the world. It has been frequently remarked that it seems to have been reserved to the people of this country, by their conduct and example, to decide the important question, whether societies of men are really capable or not of establishing good government from reflection and choice, or whether they are forever destined to depend for their political constitutions on accident and force. If there be any truth in the remark, the crisis at which we are arrived may with propriety be regarded as the era in which that decision is to be made; and a wrong election of the part we shall act may, in this view, deserve to be considered as the general misfortune of mankind.

This idea will add the inducements of philanthropy to those of patriotism, to heighten the solicitude which all considerate and good men must feel for the event….

B. Collectively making a reasoned choice is difficult: The plan offered to our deliberations affects too many particular interests … not to involve … views, passions and prejudices little favorable to the discovery of truth.

… Happy will it be if our choice should be directed by a judicious estimate of our true interests, unperplexed and unbiased by considerations not connected with the public good. But this is a thing more ardently to be wished than seriously to be expected. The plan offered to our deliberations affects too many particular interests, innovates upon too many local institutions, not to involve in its discussion a variety of objects foreign to its merits, and of views, passions and prejudices little favorable to the discovery of truth.

C. Power-hungry men whose power is furthered by a weak federal government will oppose the proposed Constitution: the perverted ambition … of men, who … flatter themselves with fairer prospects of elevation from the subdivision of the empire”

Among the most formidable of the obstacles which the new Constitution will have to encounter may readily be distinguished the obvious interest of a certain class of men in every State to resist all changes which may hazard a diminution of the power, emolument, and consequence of the offices they hold under the State establishments; and the perverted ambition of another class of men, who will either hope to aggrandize themselves by the confusions of their country, or will flatter themselves with fairer prospects of elevation from the subdivision of the empire into several partial confederacies than from its union under one government.

D. However, many people will hold the wrong opinion honestly, and others will hold the correct opinion for impure motives: “… much of the opposition … will spring from … the honest errors of minds led astray by preconceived jealousies and fears”

It is not, however, my design to dwell upon observations of this nature. I am well aware that it would be disingenuous to resolve indiscriminately the opposition of any set of men (merely because their situations might subject them to suspicion) into interested or ambitious views. Candor will oblige us to admit that even such men may be actuated by upright intentions; and it cannot be doubted that much of the opposition which has made its appearance, or may hereafter make its appearance, will spring from sources, blameless at least, if not respectable--the honest errors of minds led astray by preconceived jealousies and fears. So numerous indeed and so powerful are the causes which serve to give a false bias to the judgment, that we, upon many occasions, see wise and good men on the wrong as well as on the right side of questions of the first magnitude to society. This circumstance, if duly attended to, would furnish a lesson of moderation to those who are ever so much persuaded of their being in the right in any controversy. And a further reason for caution, in this respect, might be drawn from the reflection that we are not always sure that those who advocate the truth are influenced by purer principles than their antagonists. Ambition, avarice, personal animosity, party opposition, and many other motives not more laudable than these, are apt to operate as well upon those who support as those who oppose the right side of a question. Were there not even these inducements to moderation, nothing could be more ill-judged than that intolerant spirit which has, at all times, characterized political parties. For in politics, as in religion, it is equally absurd to aim at making proselytes by fire and sword. Heresies in either can rarely be cured by persecution.

E. Generous attitudes toward partisan opponents are unlikely to prevail: A torrent of angry and malignant passions will be let loose…. to increase the number of their converts by the loudness of their declamations and the bitterness of their invectives.

And yet, however just these sentiments will be allowed to be, we have already sufficient indications that it will happen in this as in all former cases of great national discussion. A torrent of angry and malignant passions will be let loose. To judge from the conduct of the opposite parties, we shall be led to conclude that they will mutually hope to evince the justness of their opinions, and to increase the number of their converts by the loudness of their declamations and the bitterness of their invectives. An enlightened zeal for the energy and efficiency of government will be stigmatized as the offspring of a temper fond of despotic power and hostile to the principles of liberty. An over-scrupulous jealousy of danger to the rights of the people, which is more commonly the fault of the head than of the heart, will be represented as mere pretense and artifice, the stale bait for popularity at the expense of the public good. It will be forgotten, on the one hand, that jealousy is the usual concomitant of love, and that the noble enthusiasm of liberty is apt to be infected with a spirit of narrow and illiberal distrust….

F. Populism is a greater danger to liberty than a strong central government: “… a dangerous ambition more often lurks behind the specious mask of zeal for the rights of the people than under the forbidden appearance of zeal for the firmness and efficiency of government.”

On the other hand, it will be equally forgotten that the vigor of government is essential to the security of liberty; that, in the contemplation of a sound and well-informed judgment, their interest can never be separated; and that a dangerous ambition more often lurks behind the specious mask of zeal for the rights of the people than under the forbidden appearance of zeal for the firmness and efficiency of government. History will teach us that the former has been found a much more certain road to the introduction of despotism than the latter, and that of those men who have overturned the liberties of republics, the greatest number have begun their career by paying an obsequious court to the people; commencing demagogues, and ending tyrants.

G. I am, indeed, in favor of the proposed Constitution; let me spell out my arguments: “I frankly acknowledge to you my convictions, and I will freely lay before you the reasons on which they are founded.”

In the course of the preceding observations, I have had an eye, my fellow-citizens, to putting you upon your guard against all attempts, from whatever quarter, to influence your decision in a matter of the utmost moment to your welfare, by any impressions other than those which may result from the evidence of truth. You will, no doubt, at the same time, have collected from the general scope of them, that they proceed from a source not unfriendly to the new Constitution. Yes, my countrymen, I own to you that, after having given it an attentive consideration, I am clearly of opinion it is your interest to adopt it. I am convinced that this is the safest course for your liberty, your dignity, and your happiness. I affect not reserves which I do not feel. I will not amuse you with an appearance of deliberation when I have decided. I frankly acknowledge to you my convictions, and I will freely lay before you the reasons on which they are founded. The consciousness of good intentions disdains ambiguity. I shall not, however, multiply professions on this head. My motives must remain in the depository of my own breast. My arguments will be open to all, and may be judged of by all. They shall at least be offered in a spirit which will not disgrace the cause of truth.

I propose, in a series of papers, to discuss the following interesting particulars [bullet formatting added; all-caps in original]:







H. Although few argue directly against the Union of the thirteen states, those against the proposed Constitution must downplay the importance of striving to preserve the Union. “we already hear it whispered in the private circles of those who oppose the new Constitution, that the thirteen States are of too great extent for any general system, and that we must of necessity resort to separate confederacies of distinct portions of the whole.”

In the progress of this discussion I shall endeavor to give a satisfactory answer to all the objections which shall have made their appearance, that may seem to have any claim to your attention.

It may perhaps be thought superfluous to offer arguments to prove the utility of the UNION, a point, no doubt, deeply engraved on the hearts of the great body of the people in every State, and one, which it may be imagined, has no adversaries. But the fact is, that we already hear it whispered in the private circles of those who oppose the new Constitution, that the thirteen States are of too great extent for any general system, and that we must of necessity resort to separate confederacies of distinct portions of the whole. [1] This doctrine will, in all probability, be gradually propagated, till it has votaries enough to countenance an open avowal of it. For nothing can be more evident, to those who are able to take an enlarged view of the subject, than the alternative of an adoption of the new Constitution or a dismemberment of the Union. It will therefore be of use to begin by examining the advantages of that Union, the certain evils, and the probable dangers, to which every State will be exposed from its dissolution. This shall accordingly constitute the subject of my next address.


1. The same idea, tracing the arguments to their consequences, is held out in several of the late publications against the new Constitution.


It is easy to notice that, under the guise of a general introduction, table of contents and exhortation to give a fair hearing, Alexander Hamilton has already inserted many substantive arguments for the Constitution, as well as characterizations of opponents to the Constitution that are less kind than his characterizations of the advocates of the Constitution. Nevertheless, his call to reasonableness and extensive lip service to the idea that his opponents are not all entirely evil is refreshing.

That is not to say that The Federalist Papers #1 has no villains: the final paragraph about division of the Union into pieces being “whispered in private circles” presents the clear picture of an evil conspiracy.

To my mind, the restraint Alexander Hamilton has in attacking his opponents makes those attacks more powerful to those who actually read them than the more brazen political attacks of our day. But in our day, brazenness of political attacks is crucial for getting an attack to spread virally; and it is considered OK if those virally-spread attacks are only heard by those who already lean against those attacked: solidifying one’s base is worth a lot, politically.

One might claim that the expansion of the franchise to all citizens 18 an up means that political appeals need to be dumbed down in our day. That may be. But a wonderful thing about the high intellectual register of the political appeals in The Federalist Papers is that they can still speak to us today. I doubt that the political diatribes of the early 21st century will stand the test of time anywhere near as well.

Update November 10, 2019: Greg Ransom had these comments on Twitter.

All Hallows' Eve

Link to the poem shown above  , (which includes quite a bit in a Scottish dialect).     Link to the Wikipedia article “Halloween.”

Link to the poem shown above, (which includes quite a bit in a Scottish dialect).

Link to the Wikipedia article “Halloween.”

As a child, I remember watching the Peanuts Christmas special, in which Linus talks about the religious meaning of Christmas. What about the religious meaning of Halloween? Despite Linus’s insistence in the importance of the Great Pumpkin, the Wikipedia article “Halloween” says that liturgically,

It begins the three-day observance of Allhallowtide, the time in the liturgical year dedicated to remembering the dead, including saints (hallows), martyrs, and all the faithful departed.

From the tenor of many Halloween costumes, it seems that Halloween is a time to remember not only the dead but also death itself. But, intriguingly, Halloween comes at death in a light-hearted way—as if to say: yes, we’ll all die, but what of it?

Should we fear death? As an if-then statement, those convinced they will go to hell should fear death. Those convinced they will go to heaven shouldn’t fear death much.

What about those convinced that death is nonexistence? In his essay “Immortality and the Fear of Death” Jack Sherefkin discuses the ancient symmetry argument that one shouldn’t fear death if it is simple nonexistence:

A more powerful argument used by the Epicureans against the fear of death is the “symmetry” argument. This was probably first used by Lucretius, a Roman disciple of Epicurus. Lucretius argued since we do not feel horror at our past non-existence, the time before we were born, it is irrational to feel horror at our future non-existence, the time after our death, since they are the same. Or as Seneca expressed it: “Would you not think him an utter fool who wept because he was not alive a thousand years ago? And is he not just as much a fool who weeps because he will not be alive a thousand years from now? It is all the same; you will not be and you were not. Neither of these periods of time belongs to you.”

Some version of the symmetry argument has been put forth by Cicero, Plutarch, Seneca, Schopenhauer and Hume. Hume cited Lucretius’ argument to Boswell, Dr. Johnson’s biographer, when he interviewed Hume on his death bed. “I asked him if the thought of Annihilation never gave him any uneasiness. He said not the least; no more than the thought than he had not been as Lucretius observes.”

If not fear, I think there is a reason to hate death. Death is a key part of the time budget constraint we face. Facing death is like not being richer in time than we are. Among other things, I am annoyed with my own death in the way I am annoyed with having only 24 hours in a day, of which almost a third go to sleep.

We may fear or hate our own death, but some of the sharpest experiences in our lives are likely to be the deaths of others. Most people see the deaths of their own parents—an experience that typically hits them like a ton of bricks. You can sense some of that in my posts about the deaths of my parents:

I have also seen the deaths of my father-in-law, mother-in-law. And, unfortunately, I have seen the deaths of three of our children, which my wife Gail talks about in a guest post:

In the public realm, I have become very much aware of eminent economists important to my own thinking who have died. I have not written posts about all of the economists important to me who have died in the last few years, for example, I was very distressed when Julio Rotemberg died. But I do have some posts on economists important to me who have died:

But Halloween takes even our grief and looks at the bright side. The Mexican counterpart of Halloween is “The Day of the Dead” when the dead come back to visit. But even if the dead are simply remembered, it is a demonstration that death has not sundered our connection utterly. The connection between two human beings is badly, badly frayed when one of them dies. But the connection is not gone. It is still there.

The connection to those who have gone before us is an important one. On the Norlin Library here at the University of Colorado Boulder is the inscription “Who knows only his own generation remains always a child,” which is a tweak on something Cicero wrote. We grow stronger by strengthening our connection to those who are dead.

Let me leave you with my “Daily Devotional for the Not-Yet,” which has a line about our ancestors and others who have died before us. Let us not forget them.

In this moment, as in all the moments I have, may the image of the God or Gods Who May Be burn brightly in my heart.

Let faith give me a felt assurance that what must be done to bring the Day of Awakening and the Day of Fulfilment closer can be done in a spirit of joy and contentment.

Let the gathering powers of heaven be at my left hand and my right. Let there be many heroes and saints to blaze the trail in front of me. Let the younger generations who will follow discern the truth and wield it to strengthen good and weaken evil. Let the grandeur of the Universe above inspire noble thoughts that lead to noble plans and noble deeds. Let the Earth beneath be a remembrance of the wisdom of our ancestors and of others who have died before us. And may the light within be an ocean of conscious and unconscious being to sustain me and those who are with me through all the trials we must go through.

In this moment, I am. And I am grateful that I am. May others be, now and for all time.

Another Problem with Processed Food: Propionate

In “The Problem with Processed Food” I point out 3 problems with highly processed food:

  1. Most food processing makes food easier to eat and enhances digestibility [which can increase the speed with which it boosts insulin].

  2. The newer the type of food processing, the less tested it is by time.

  3. Food companies have a different objective function than you do—or at least a different objective function than your long-run self does.

Under the category of things “untested by time” is propionate. The article shown above reports on recent research:

Consumption of propionate, an ingredient that’s widely used in baked goods, animal feeds, and artificial flavorings, appears to increase levels of several hormones that are associated with risk of obesity and diabetes …

The study, which combined data from a randomized placebo-controlled trial in humans and mouse studies, indicated that propionate can trigger a cascade of metabolic events that leads to insulin resistance and hyperinsulinemia — a condition marked by excessive levels of insulin. The findings also showed that in mice, chronic exposure to propionate resulted in weight gain and insulin resistance.

Additional details strengthen the story—except for the limitation of the human trials to short-run effects on only 14 people. However, that was enough to show that the mouse results seem relevant to humans:

For this study, the researchers focused on propionate, a naturally occurring short-chain fatty acid that helps prevent mold from forming on foods. They first administered it to mice and found that it rapidly activated the sympathetic nervous system, which led to a surge in hormones, including glucagon, norepinephrine, and a newly discovered gluconeogenic hormone called fatty acid-binding protein 4 (FABP4). This in turn led the mice to produce more glucose from their liver cells, leading to hyperglycemia — a defining trait of diabetes. Moreover, the researchers found that chronic treatment of mice with a dose of propionate equivalent to the amount typically consumed by humans led to significant weight gain in the mice, as well as insulin resistance.

To determine how the findings in mice may translate to humans, the researchers established a double-blinded, placebo-controlled study that included 14 healthy participants. The participants were randomized into two groups: One group received a meal that contained one gram of propionate as an additive and the other was given a meal that contained a placebo. Blood samples were collected before the meal, within 15 minutes of eating, and every 30 minutes thereafter for four hours.

The researchers found that people who consumed the meal containing propionate had significant increases in norepinephrine as well as increases in glucagon and FABP4 soon after eating. 

Although I have recommended that the first thing you should do to make your diet healthier is to go off sugar (see for example “3 Achievable Resolutions for Weight Loss” and “Letting Go of Sugar”) I have been careful to point out that as things stand it is hard to distinguish between going off sugar and going off highly processed food, because almost all highly processed food has sugar as an important ingredient. There really could be reasons other than sugar that make processed food bad for you, but if you go off sugar, you will avoid those problems too, because you will be going off most processed food as well.

One claim I have made is that an insulin spike will make someone hungry again. Note that for the producers of processed food, that would typically seem like a plus: there is a reasonable chance that the person eating their food would decide that they were hungry for that particular food, or that, being hungry, it was again most convenient to eat that food. So even if the producer of that processed food were only looking at the sales numbers, they might gravitate toward producing types of processed food that caused insulin spikes. Thus, even without any conscious bad intent, the process of engineering food that people will eat a lot of has some tendency to result in bad outcomes. And that engineering of food happens much, much faster than any human evolution that could blunt bad effects.

Michael Pollan famously said “Eat food, not too much, mostly plants.” This post on Michael Pollan’s statement gives several criteria for something being real food instead of just a food-like substance. If it is real food:

  • Your great grandmother would recognize it as food.

  • It doesn’t come out of a container with a long list of ingredients.

  • It will rot or go bad, and so tends to be on the outer perimeter of grocery stores where it is easier to bring in fresh food of that type.

The biggest two limitations of Michael Pollan’s dictum is that (a) not all plant food is created equal in terms of its health effects, and (b) eating all the time, from morning til night, is problematic. See “Forget Calorie Counting; It's the Insulin Index, Stupid,” “Stop Counting Calories; It's the Clock that Counts” and “Jason Fung's Single Best Weight Loss Tip: Don't Eat All the Time.”

For annotated links to other posts on diet and health, see:

Job Posting for a Full-Time Research Assistant with a Bachelor's Degree to Help with the Research Needed to Build a National Well-Being Index, Starting Late Summer 2020

Our team—Dan Benjamin, Ori Heffetz, Kristen Cooper and I, plus the continuing research assistants Hannah Solheim and Arshia Hashemi—are looking for someone interested in being a research assistant for a couple of years (most likely before going on to a PhD program in Economics) to help us hammer out the principles needed to construct a national well-being index as carefully as GDP is constructed, so that it can stand as a full coequal to GDP. Here is the link telling how to apply:

I am also involved in work on genoeconomics, for which we also need a full-time research assistant at the same stage:

We advertised both positions on Twitter:

Tushar Kundu was our research assistant 2017–2019. Here is what he has to say:

Hannah Solheim is not on Twitter, but Arshia Hashemi is, and has this to say about his experience so far as a research assistant:

If you are on Twitter yourself, you can ask me questions there: But the official postings at the links above should make clear what to do next.

Dan, Ori and I, with various coauthors, have published 6 papers in the American Economic Review (3 full-size papers and 3 “Papers and Proceedings” papers) and two in other journals based on our research in the Economics of Happiness, as you can see from my CV.

Update, October 30, 2019: Mark Fabian gives this vote of confidence:

The Virtual Reality Theory of Dualism

Link to the Wikipedia article “Mind-body dualism”

Link to the Wikipedia article “Mind-body dualism”

In “On Being a Copy of Someone's Mind” I argued as follows:

… my problem with hardcore dualism is this:

  1. If a spirit or soul influences any of my decisions, then it has enough effect on particles in the brain that it should be detectable by physics with the sensitivity of instruments we have now.

  2. If a spirit or soul is affected by the body but does not itself have any effect on the body (Epiphenomenalism), then it is not through any causality from that spirit or soul the spirit or soul that we talk about because it has no causal pathway to move our mouths. God might make our bodies so they talk about our epiphenominal spirits or souls. But our spirits or souls in this case are not talking about themselves on their own behalf.

However, since then, I have been thinking of a type of dualism that is not particularly unlikely: the idea that the world I and others see all around us is a virtual reality videogame—except that this game involves all of our senses and a clouded memory of our lives outside of the videogame. In such a case, it might be that our avatars (which we think of as our whole selves) do a lot of the routine thinking, but the minds of our true selves who entered the videogame are instantiated in substrates beyond and outside of the familiar quarks, leptons, force particles and Higgs bosons that are part of the warp and woof of the programming of the videogame.

If we are indeed in a suped-up virtual reality videogame, our true selves might only intervene in what our avatars are doing once every few seconds, once every few minutes, once every few ours, or even only once every few days if we choose to mostly go along for the ride, treating the videogame as if it were a movie.

These interventions would, indeed, violate the laws of physics, but it could be relatively hard to set up instruments to successfully detect them. Let me assume for the moment that it is seen as making a more fun virtual reality videogame if it is possible to detect that one is inside a videogame. That is, let me suppose that the videogame isn’t set up to hide from a determined experimenter the fact that one is in a videogame. Still, it would require finding a small (but serious) localized violation of the laws of physics we know (which are the default of the videogame we are in), in a hard-to-predict microscopic location in the brain. That is, supposed that someplace in the brain, every minute or so, as our true selves make a choice about what general direction to go in the game, there is a violation of the laws of physics we know.

There might be a moral dimension to you and I being in a virtual reality videogame. One can just play the game for fun, or one can play the game as a character-building exercise. Having fun during the game might feel good afterward and having tried hard to do good during the game might feel very rewarding once the game is over.

Discussing this, I notice an oddity: many accounts of dualism have one’s spirit or soul that “inside” one’s body. Why can’t one’s spirit or soul be outside the universe, as it is if I and others are in a virtual reality videogame?

One possibly pernicious aspect of the idea that you and I are in a virtuality reality videogame is that we might make a mistake thinking someone is a computer-generated character who is a real person, and fail to treat them with the care they deserve. On the other hand, someone who seems of low status within the videogame might be a very high status real person outside the videogame; that is a reason to treat everyone well—a little like the way the Greeks said gods would come in disguise to test out people’s hospitality.

One thing I want to insist on is that, although some other versions of duality are more traditional, that carefully considered, any type of duality is at least as odd as the idea that we are inside of a virtual reality videogame.

Related Posts:

Where is Social Science Genetics Headed?

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Social science genetics is on the rise. The article shown above is a recent triumph. By knowing someone’s genes alone, it is possible to predict 11–13% of the number of years of schooling they have. Such a prediction comes from adding up tiny effects of many, many genes.

Since a substantial fraction of my readers are economists, let me mention that some of the important movers and shakers in social science genetics are economists. For example, behind some of the recent successes is a key insight, which David Laibson among others had to defend vigorously to government research funders: large sample sizes were so important in accurately measuring the effects of genes that it was worth sacrificing quality of an outcome variable if that would allow a much larger sample size. Hence, when they were doing the kind of research illustrated by the article shown above, it was a better strategy to put the lion’s share of effort into genetic prediction of number of years of education than genetic prediction of intelligence, simply because number of years of education was a variable collected along with genetic data for many more people than intelligence was.

One useful bit of terminology for genetics is that other non-genetic information about an individual, such as years of education or blood pressure are called “phenotypes.” Another is that linear combinations of data across many genes intended to be best linear predictors of a particular phenotype are called “polygenic scores.” Polygenic scores have known signal-to-noise ratios, making it possible to do measurement-error corrections for their effects. (See “Adding a Variable Measured with Error to a Regression Only Partially Controls for that Variable” and “Statistically Controlling for Confounding Constructs is Harder than You Think—Jacob Westfall and Tal Yarkoni.”)

Both private companies and government-supported initiatives around the world are rapidly increasing the amount of human genotype data linked to other data (with a growing appreciation of the need for large samples of people over the full range of ethnic origins). For common variations (SNPs) that have well-known short-range correlations, genotyping using a chip now costs about $25 per person when done in bulk, while “sequencing” to measure all variations, including rare ones, costs about $100 per person, with the costs rapidly coming down. Sample sizes are already above a million individuals, with concrete plans for several million more that will be data sets that are quite accessible to researchers. 

In this post, I want to forecast where social science genetics is headed in the next few years. I don’t think I am sticking my neck out very much with these forecasts about cool things people will be doing. Those in the field might say “Duh. Of course!” Here are some types of research I think will be big:

Genetic Causality from Own Genes and Sibling Effects. Besides increasing the amount of data on non-European ethnic groups, a key direction data collection will move in the future is to collect genetic data on mother-father-self trios and mother-father-self-sibling quartets. (For example, the PSID is now in the process of collecting genetic data.) Conditional on the mother’s and father’s genes, both one’s own genes and the genes of a full sibling are as random as a coin toss. As a result, given such data, one can get clean causal estimates of the effects of one’s own genes on one’s outcomes and the effects of one’s sibling’s genes on one’s outcomes.

Genetic Nurturance. By looking at the genes of the mother and father that were not transmitted to self, one can also get important evidence on the effects of parental genes on the environment parents are providing. (Here, the evidence is not quite as clean. Everything the non-transmitted parental genes are correlated with could be having a nurture effect on self.) Effects of nontransmitted parental genes are interesting because most things that parents can do other than passing on their genes are things a policy intervention could imitate. That is, the effects of non-transmitted parental genes reflect nurture.

Recognizing Faulty Identification Claims that Involve Genetic Data. One reason expertise in social science genetics is valuable is that questionable identification claims will be made and are being made involving genetic data. While the emerging data will allow very clean identification of causal effects of genes on a wide range of outcomes, the pathway by which genes have their effects can be quite unclear. People will make claims that genes are good instruments. This is seldom true, because the exclusion restriction that genes only act through a specified set of right-hand side variables is seldom satisfied. Also, it is important to realize that large parts of the causal chain are likely to go through the social realm outside an individual’s body. 

Treatment Effects that Vary by Polygenic Score. One interesting finding from research so far is that treatment effects often differ quite a bit when the sample is split by a relevant polygenic score. For example, effects of parental income on years of schooling are more important for women who have low polygenic scores for educational attainment. That is, women who have genes predicting a lot of education will get a lot of education even if parental income is low, but women whose genes predict less education will get a lot of education only if parental income is high. The patterns are different for men.

Note that treatment effects varying by polygenic score has obvious policy implications. For example, suppose we could identify kids in very bad environments who had genes suggesting they would really succeed if only they were given true equality of opportunity. This would sharpen the social justice criticism of the lack of opportunity they currently have. Notice that many of the policy implications based on treatment effects that vary by polygenic score would be highly controversial, so knowledge of the ins and outs of ethical debates about the use of genetic data in this way becomes quite important.  

Enhanced Power to Test Prevention Strategies. One unusual aspect of genes is that the genetic data, with all the predictive power that provides, are available from the moment of birth and even before. This means that prevention strategies (say for teen pregnancy, teen suicide, teen drug addiction or being a high school dropout) can be tested on populations whose genes indicated elevated risk, which could dramatically increase power for field experiments.

The Option Value of Genetic Data. Suppose one is doing a lab experiment with a few hundred participants. With a few thousand dollars, one could collect genetic data. With that data, one could immediately begin to control for genetic differences that contribute to standard errors and look at differences in treatment effects on experimental subjects who have different polygenic scores. But with the same data, one would also be able to do a new analysis four years later using more accurate polygenic scores or using polygenic scores that did not exist earlier. In this sense, genetic data grows in value over time.

The example above was with genetic data in a computer file that can be combined with coefficient vectors to get improved or new linear combinations. If one is willing to hold back some of the genetic material for later genetic analysis with future technologies (as the HRS did), totally new measurements are possible. For example, many researchers have become interested in epigenetics—the methylation marks on genes that help control expression of genes.

Assortative Mating. Ways of using genetic data that are not about polygenic scores in a regression will emerge. My own genetic research—working closely with Patrick Turley and Rosie Li—has been about using genetic data on unrelated individuals to look at the history of assortative mating. Genetic assortative mating for a polygenic score is defined as a positive covariance between the polygenic scores of co-parents. But one need not have direct covariance evidence. A difference equation indicates that a positive covariance between the polygenic scores of co-parents shows up in a higher variance of the polygenic scores of the children. Hence, data on unrelated individuals shows the assortative mating covariance among the parents’ generation in the birth-year of those on whom one has data. One can go further. When a large fraction of a population is genotyped, the genetic data can, itself, identify cousins. This makes it possible to partition people’s genetic data in a way that allows one to measure assortative mating in even earlier generations.

Conclusion: Why More and Better Data Will Make Amazing Things Possible in Social Science Genetics. One interesting thing about genetic data is that, there is a critical sample size at which it is possible to get good accuracy on the genes for any particular outcome variable. Why is that? after multiple-hypothesis-testing correction for the fact that there are many, many genes being tested, “genome-wide significance” requires a z-score of 5.45. (Note that, with large sample sizes, the z-score is essentially equal to the t-statistic.) But a characteristic of the normal distribution is that at such high z-score, even a small change in z-score can make a huge difference in p-value. A t-score of 5.03 has a p-value ten times as big, and a score of 5.85 has a p-value ten times smaller. That means that in this region, for a given coefficient estimate an 18% increase in sample size is guaranteed to change a p-value by an order of magnitude. Thinking about things the other way around, if there are genes with different sizes of effects distributed normally, if to start with, one can only reliably detect things far out on the normal distribution of effect sizes, then a modest percentage increase in sample size will make a bigger slice of the normal distribution of effect sizes reliably detectable, which will mean identifying many times as many genes as genome-wide significant.

The critical sample size depends on what phenotype one is looking at. Most importantly, power is lower for diseases or other conditions that are relatively rare. The critical sample size at which we will get a good polygenic score for anorexia is much larger than the sample size at which one can get a good polygenic score for educational attainment. But as sample sizes continue to increase, at some point, relatively suddenly, we will be there with a good polygenic score for anorexia. Just imagine if parents knew in advance that one of their children was at particularly high risk for anorexia. They’d be likely to do things differently and might be able to avert that problem.

I am sure there are many cool things in the future of social science genetics that I can’t imagine. It is an exciting field. I am delighted to be along for the ride!

Here are some other posts on genetic research: