A week of links

Links this week:

  1. Eugenics, ready or not. A good long read.
  2. Tort reform preventing people from suing for “weight related harms” may increase attempts to lose weight. HT: Ryan Murphy
  3. What does behavioural economics mean for income distribution? The argument ignores most the interesting subtleties, as there are questions around what the reference point is, how you could redistribute while avoiding loss frames etc., but the idea is still worth considering.
  4. Cholesterol is OK.
  5. The number of childless women in their 40s is falling, particularly among the most educated.
  6. If you’re in Sydney on June 17, Rob Brooks is presenting on the price of sex.
  7. Some coverage of my new paper in the Daily Mail and (for those who can get through the paywall) The Times.

And if you missed them, my posts this week:

  1. The thinking behind my newly published paper.
  2. Fifty years of twin studies.

Fifty years of twin studies

If you’re familiar with the literature, this is unsurprising. A meta-analysis in Nature Genetics of 2,748 twin study publications points to the strong role of genetics and the weak role of family influence (a major component of “shared environment”) in shaping human traits. The abstract:

Despite a century of research on complex traits in humans, the relative importance and specific nature of the influences of genes and environment on human traits remain controversial. We report a meta-analysis of twin correlations and reported variance components for 17,804 traits from 2,748 publications including 14,558,903 partly dependent twin pairs, virtually all published twin studies of complex traits. Estimates of heritability cluster strongly within functional domains, and across all traits the reported heritability is 49%. For a majority (69%) of traits, the observed twin correlations are consistent with a simple and parsimonious model where twin resemblance is solely due to additive genetic variation. The data are inconsistent with substantial influences from shared environment or non-additive genetic variation. This study provides the most comprehensive analysis of the causes of individual differences in human traits thus far and will guide future gene-mapping efforts. All the results can be visualized using the MaTCH webtool.

Also of interest, most of the resemblance between twins is due to additive genetic variation. This is a positive sign for plans to identify the causal variants behind complex traits. It’s just a matter of getting those sample sizes up in genome-wide association studies.

Amusingly, in one case this study has been flagged as a tie between nature and nurture. But the “nurture” we are talking about here isn’t reading to your kids.

Conspicuous consumption and economic growth

A paper of mine has just been published in the Journal of Bioeconomics – Sexual selection, conspicuous consumption and economic growth.

I posted about this article when the working paper was first released, and that post still does a good job of explaining the motivation behind the paper. In that post I wrote:

Around ten years ago, I was rummaging through books in a bargain bookshop under Sydney’s Central Station when I came across a $2 copy of Geoffrey Miller’s The Mating Mind. It turned out to be a good use of my $2, as The Mating Mind is one of the most important books in shaping my thinking, and it was one of the first books I put on my economics and evolutionary biology reading list.

Miller’s basic argument was that sexual selection shaped the human mind. Whether through runaway selection or the brain acting as a fitness indicator, female choice led to increasing mental capacity and shaped our propensity to be humorous, create art or engage in other displays of mental fitness.

As I read the Mating Mind, it occurred to me that the growing mental capability and tendency to display it would have direct economic effects. It would be possible to argue that sexual selection shapes economic growth. Ten years after that idea, my latest working paper (co-authored with my supervisors Boris Baer and Juerg Weber) seeks to flesh out one element of it. The working paper provides a theoretical model for the hypothesis that sexual selection and the resulting propensity to engage in conspicuous consumption has economic effects, and in particular, the desire to engage in conspicuous consumption is one of the pillars underlying the emergence of modern economic growth.

The concept behind the hypothesis is relatively simple. Men who signal their quality through conspicuous consumption have higher reproductive success, as the conspicuous consumption provides a reliable signal of their quality to potential mates. To engage in conspicuous consumption takes effort by the men – whether in the form of art, humour or entering the labour force to acquire resources to consume conspicuously. As the prevalence of males who conspicuously consume increases, the total level of these activities also increases. The increased participation in productive activities results in a scale effect, whereby the greater number of people involved in creative and productive activities results in increased technological progress, which underlies economic growth.

The evolutionary part of the model is more interesting than the economic as there is minimal feedback from the economy back into the evolutionary dynamics. The lack of feedback also means that it is not very representative of modern society, as conspicuous consumption in modern societies is of limited threat to survival. Still, the model provides a starting point and I have a few ideas to take it further.

I have been introducing my talks on the paper with an example from Robert Frank’sLuxury Fever, in which Frank held up Patek Philippe’s Calibre 89 watch as an example of conspicuous consumption. Only four were made, with the first selling for $2.5 million and the latest auction price being over $5 million. Frank mocks the watch for its need for a tourbillon, a mechanism to account for the earth’s rotation, when his cheap quartz watch does not require such a mechanism, as gravity does not affect the vibrations of the crystal.

Now consider the innovation and thought that went into the Patek Philippe watch, including that tourbillon. This watch has 1728 components, gives you the date of Easter each year, and unlike most mechanical watches, will not record the years 2100, 2200 and 2300 as leap years while still recording 2400 as one (as per the order of Pope Gregory XIII in 1582). If you look at Patek Philippe’s list of patents, you get a feel for the innovation involved in making watches for what is largely conspicuous consumption.

When you also consider the innovation undertaken by the potential buyers as they seek to amass the wealth necessary to obtain such a watch, the positive angle to conspicuous consumption grows. As a result, curbing conspicuous consumption may have costs (although, I still prefer taxing consumption to income). If nothing else, we should appreciate the historical role of conspicuous consumption – competition for sexual partners is a driving force for many productive activities, and one generation’s conspicuous consumption is another generation’s day-to-day tool.

In its life as a working paper over the last few years the paper has received a variety of comments, including from Matt Ridley in The Wall Street Journal, Rob Brooks in The Huffington Post and Chris Dillow at Stumbling and Mumbling.

If you want a copy of the paper and can’t get through the Journal of Bioeconomics paywall, you can download the working paper version or drop me a line. The major difference between the two versions are that the simulations have been shunted into the electronic supplementary material for final publication.

A week of links

Links this week (or more like two weeks):

  1. Another favourite behavioural science story bites the dust.
  2. Three schools of thought on decision making.
  3. Better teachers receive worse evaluations.
  4. An attempt to reduce bias backfires.
  5. Biased scientists.
  6. Hayek and business management.
  7. More highly educated women are having children.

Life continues to be busy, so posting will continue to be sparse for at least another couple of weeks.

A week of links

Links this week:

  1. On the misplaced politics of behavioral policy interventions. And hawkish biases.
  2. Noah Smith v Bryan Caplan on education signalling – 1, 2 and 3. I believe signalling is an important part of the education story, but Smith’s argument about costly signalling is on point.
  3. Robert Trivers on his friends and enemies. HT: Razib

And if you missed it, my one post this last week:

  1. Bad nudges toward organ donation.

Life continues to be busy, so posting will continue to be sparse.

Bad nudges – organ donation edition

It’s a favourite behavioural science story. Countries that have opt-in organ donation have lower rates of organ donation than countries where you have to opt out of being an organ donor. If we change the way the choice is framed from opt in to opt out, we can dramatically increase the rate of organ donation.

Except, it’s not that simple. For countries where there is an opt-out system, there is no simple point where the choice is presented to them as the default and they can easily tick the box to be removed from the organ donation register. Instead, they need to find and fill out forms or call various government agencies to overcome a presumed consent.

Further, although opt-out countries tend to have higher donation rates, some countries with opt-in systems have higher donation rates than those with opt-out. The high numbers that get reported – 99.98% of Austrians are organ donors – are the numbers who haven’t opted out, not the number who donate. When it comes to the point of donation, other issues become more relevant, including the wishes of the family. It’s no surprise that the family might wish to intervene, particularly given that in an opt-out system there is no moment where the donor is required to express their wish.

It seems to have been on the cards for a while now, but I’ve just realised Wales is shifting to being an opt-out country. The rolling out of this nudge is lazy.

Instead of trying to design a system where they actually determine the wishes of the person and their family, they rely on the inconvenience of having to opt out to boost registered numbers. At the time of death, the family will have no sense of what the deceased wished for- after all, the number of people who choose to opt out is far less than the number who than indicate in surveys that they do not wish to donate.

There is no shortage of alternative approaches that don’t rely on granting (or attempting to grant) the right to organs through omission. Active choice is one option – when people get a driver’s licence or tax file number, ask them to choose whether they wish to be an organ donor or not. It will likely increase the number of registered organ donors over an opt-in system, while proving some indication of people’s wishes. An active choice also indicates these wishes to the family, with those wishes one of the major factors in families agreeing to donation.

Then there are the more interesting options that could be tested – markets for organs, preferential treatment for those on registers (as occurs in Israel), or systems to match donors. These options are often prohibited.

Instead of increasing the freedom to develop new solutions, we have a misunderstood story about a nudge gaining momentum, inadvertently placing the burden on family members at the time of death.

As an aside, I’m still hunting for examples of nudges introduced explicitly to increase freedom by allowing a hard requirement to be relaxed. Current count remains at zero.

*Searching around for information on the changes in Wales, I came across another perspective from Eric Crampton.

A week of links

Links this week (or more like two weeks):

  1. The problem with satisfied patients.
  2. Happiness inequality.
  3. Explaining the growth mindset.
  4. Gender-blind economists.
  5. Logical versus ecological rationality.
  6. Slaughter scientific peer review. HT: Christopher Snowdon.
  7. Poor children have smaller brains.

And if you missed them, my posts from the last two weeks:

  1. Unemployment and self control.
  2. Uncertainty and understanding behaviour.

Life is busy at the moment, so posting will continue to be sparse over the next month.

Returns to self control – unemployment edition

A new paper in Psychological Science by Michael Daly and friends:

Childhood Self-Control and Unemployment Throughout the Life Span: Evidence From Two British Cohort Studies

The capacity for self-control may underlie successful labor-force entry and job retention, particularly in times of economic uncertainty. Analyzing unemployment data from two nationally representative British cohorts (N = 16,780), we found that low self-control in childhood was associated with the emergence and persistence of unemployment across four decades. On average, a 1-SD increase in self-control was associated with a reduction in the probability of unemployment of 1.4 percentage points after adjustment for intelligence, social class, and gender. From labor-market entry to middle age, individuals with low self-control experienced 1.6 times as many months of unemployment as those with high self-control. Analysis of monthly unemployment data before and during the 1980s recession showed that individuals with low self-control experienced the greatest increases in unemployment during the recession. Our results underscore the critical role of self-control in shaping life-span trajectories of occupational success and in affecting how macroeconomic conditions affect unemployment levels in the population.

HT: Stirling Behavioural Science Blog

Uncertainty and understanding behaviour

From Cameron Murray on the trolley problem:

In Scenario A a trolley is barreling down the tacks toward five people who will be killed unless the trolley is stopped. Luckily, there is a fork in the tracks, and by simply pulling a lever, the trolley can be diverted onto a second set of tracks. Unfortunately there is a single person in the path of the tolled on this track who will be killed if you pull the lever.

The dilemma is whether you should pull the lever and save five people by sacrificing one? In surveys most people say they would.

In Scenario B you find yourself on a bridge next to a fat man where below the same dilemma is playing out, with a trolley hurtling down the tracks towards five people. The question here is whether it is permissible to pushing the person next to you onto the tracks if you knew it would stop the trolley and save the five people.

Most people in this scenario would not push the man off the bridge, even though the same welfare gains in terms of lives saved would be the same as Scenario A (so you know, 68.2% of philosophers would push the man to save the five). …

Fundamentally the incompatibility of these two outcomes arises because we are presented with a dilemma in terms of risk, or knowable probabilities. …

Let us now look at the question in terms of uncertainty. For a start, how do we know the trolley is out of control? Is it possible to delay the decision to get more information?

… [I]n Scenario A, switching the tracks leads to a new situation that opens up the set of possible choices … while eliminating others. Switching the trolley onto the side track buys time and keeps options open without killing anyone.

In Scenario B, most people choose not to push the fat man. Here what the are doing is buying time before anyone gets killed. Even after the decision is made not to push the man, there will be time available for many other as-yet-unknowable situations to arise. …

The whole rationale of making decisions in a world of uncertainty revolves around keeping options for desirable outcomes open, and often this involves buying time by not making a decision at all.

A couple of practical examples:

In criminal behaviour, Becker’s expected utility framework has been called into question due to the radical difference between human behaviour in a world of uncertainty versus a world of risk. Increasing chances of being caught and increasing punishment if caught are substitute methods for changing probability distributions of expected outcomes in a world of risk, but in a world of uncertainty they will have far different effect on criminal decisions.

The same logic of uncertainty can be applied in social psychology to understand the bystander effect. The bystander effect is the label given to the occasionally observed inverse relationship between the number of people witnessing a victim in need, and the number of people offering help. Various reasons for this empirical phenomena have emerged, with the idea of a diffusion of responsibility dominating explanations.

But when we dig a little deeper we can see the logic of uncertainty at play. Repeated experiments on the bystander effect show that the degree of ambiguity is a crucial determinant of the willingness to assist, with reaction times being much slower in the presence of more ambiguous situations.

Read his full post.

A week of links

Links this week:

  1. Behavioral Public Choice: The Behavioral Paradox of Government Policy. HT: Ryan Murphy
  2. Happiness and growth.
  3. The genetic component of sex offending.
  4. “[I]is growth mindset the one concept in psychology which throws up gigantic effect sizes and always works? Or did Carol Dweck really, honest-to-goodness, make a pact with the Devil in which she offered her eternal soul in exchange for spectacular study results?”
  5. A new Charles Murray book – By the People: Rebuilding Liberty Without Permission
  6. Evolution continues.
  7. The weird belief that people follow dietary guidelines. A question – to what extent do food manufacturers respond to the guidelines, especially to earn “heart smart” certifications and the like?
  8. Economics melts the brain. One alternative which I’ve often seen is, because the model assumptions simply don’t work, they throw every bit of economics they’ve ever learnt out the window and revert to storytelling.

And if you missed it, my one post this week:

  1. Predicting replication.

And a blast from the past: Why isn’t economics evolutionary?