Arhiiv kuude lõikes: August 2019

Privacy reduces cooperation, may be countered by free speech

Cooperation relies on reputation. For example, fraud in online markets is deterred by the threat of bad reviews, which reduce future trading with the defector. Data protection, specifically the “right to be forgotten” allows those with a bad reputation to erase their records from the market provider’s database and create new accounts with a clean slate. Bayesian participants of the market then rationally attach a bad reputation to any new account (“guilty until proven innocent”). If new entrants are penalised, then entry and competition decrease.

One way to counter this abusing of data protection laws to escape the consequences of one’s past misdeeds is to use free speech laws. Allow market participants to comment on or rate others, protecting such comments as a civil liberty. If other traders can identify a bad actor, for example using his or her government-issued ID, then any future account by the same individual can be penalised by attaching the previous bad comments from the start.

Of course, comments could be abused to destroy competitors’ reputations, so leaving a bad comment should have a cost. For example, the comments are numerical ratings and the average rating given by a person is subtracted from all ratings given by that person. Dividing by the standard deviation is helpful for making the ratings of those with extreme opinions comparable to the scores given by moderates. Normalising by the mean and standard deviation makes ratings relative, so pulling down someone’s reputation pushes up those of others.

However, if a single entity can control multiple accounts (create fake profiles or use company accounts), then he or she can exchange positive ratings between his or her own profiles and rate others badly. Without being able to distinguish new accounts from fake profiles, any rating system has to either penalise entrants or allow sock-puppet accounts to operate unchecked. Again, official ID requirements may deter multiple account creation, but privacy laws impede this deterrence. There is always the following trilemma: either some form of un-erasable web activity history is kept, or entrants are punished, or fake accounts go unpunished.

Kardina täiendamine papist aknapalistusega

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Kui ruloo on läbimõtlematult väike ja kinnitatud akna ülaservast madalamale, nii et valgus paistab ruloo kohalt ja külgedelt öösel tuppa, siis oleks hea kas parem kardin paigaldada või vähemalt akna ülaservale ja külgedele varjav riideriba kinnitada. Kui aga üürikorteris kardinat vahetada ega seina ega akna külge midagi kleepida, kruvida ega naelutada ei tohi, siis on akna palistamine raskendatud.

Üks lahendus on riputada palistus aknapiida külge nii, et see püsib vaid hõõrdejõu abil. Pappkarpide sisenurgad sobituvad hästi aknapiida ülaserva välisnurkadega, nagu juuresoleval pildil.

Karbinurkadest lõigatud tükid saab tasapinnaliste papiristkülikutega omavahel ühendada. Kui selline papist aknaääristusriba kleeplindi abil piisavalt pingule tõmmata, siis ei libise see ka tuulise ilma ja lahtise aknaga aknapiidalt maha. Pinge ei tohi muidugi nii suur olla, et pappkarpide nurgad rebenevad või laiali painduvad.

Painduv materjal nagu riie kipub aknapiidalt maha libisema, aga tõenäoliselt saaks ka riidest sarnase palistuse teha kui see piisava pinge all on. Üks variant on jäika mittevenivasse riidetükki „nurgad” õmmelda, mille saab sarnaselt pappkarbinurkadele aknapiidale venitada. Kaugus õmmeldud „nurkade” vahel peab täpselt aknapiida laiusega sobituma, muidu kas ei lähe riie piidale või on lõtv ja libiseb maha. Teine variant on elastne riie või kummipael, millel venitamisruumi rohkem. Selle probleem on, et „nurgad” venivad ja painduvad, mis soodustab mahalibisemist.

Püksisäärte kitsamaks õmblemine

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Pikkade pükste allservad kipuvad jalgrattaga sõites keti ja hammasratta vahele jääma. Lahendusi on mitu: püksisäär soki sisse toppida või klambri või kummipaelaga jala välisküljelt kokku tõmmata. Sokist kipub säär vändates välja tulema, jala liikumise tõttu. Pika sooniva säärega sokid lahendavad selle probleemi, aga on ebamugavad. Klambrit või kummipaela peab kaasas kandma ja meeles pidama, aga mälu mul vananedes halveneb.

Veel üks lahendus on püksisäärte kitsamaks õmblemine, nagu juuresoleval pildil.Sirge toru asemel on säär tiputa koonuse kujuline.

Pükste allserva kitsendades peaks hoolitsema, et kand ikka läbi mahuks. Kitsamaks tasub õmmelda eestpoolt, et põlve painutust mitte takistada.

Committing to an experimental design without revealing it

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Pre-registering an experiment in a public registry of clinical trials keeps the experimenters honest (avoids ex post modifications of hypotheses to fit the data and “cherry-picking” the data by removing “outliers”), but unfortunately reveals information to competing research groups. This is an especially relevant concern in commercial R&D.

The same verifiability of honesty could be achieved without revealing scientific details by initially publicly distributing an encrypted description of the experiment, and after finishing the research, publishing the encryption key. Ex post, everyone can check that the specified experimental design was followed and all variables reported (no p-hacking). Ex ante, competitors do not know the trial details, so cannot copy it or infer the research direction.

Salati söömise mehaanika

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Salatit on keeruline süüa, sest seda lamedalt taldrikult torkides ei jää see hästi kahvli otsa ja kahvlit labidana selle alla nihutades kalduvad ebakorrapärase kujuga lehetükid küljele, mitte ei jää tasakaalu. Mõlemal juhul kipub salat tõstes kahvlilt maha kukkuma. Kausist salati kurku kallutamine ka ei toimi, sest lehed kleepuvad kausi külge, on liiga suured või kukuvad ebakorrapärase kuju tõttu raskestiennustatavas suunas suust mööda.

Paar lahendust, mida ma pole kasutatavat näinud, on salati blenderis joodavaks püreeks tegemine või batooniks kokkupressimine. Mõlemad variandid on mehaaniliselt lihtsamad juua-süüa kui tavaline salat. Näppudega söömine on lihtsam kui kahvliga, aga kaugel ideaalsest. Juurviljamahl või smuuti on pisut sarnased salatipüreele, aga neist on kiudained (viljaliha) eemaldatud.

Üks võimalus salatit mugavalt püstijalu süüa oleks muu salat ühe suure salatilehe sisse rullida ja sushisarnaselt kinni siduda. Kahjuks oleks selline salatirull üsna ebastabiilne ja lekkiv, sest salat kipub rebenema, on elastne pinna normaali suunas ehk püüab end lahti kerida, vedelikku mitteimav, seega laseb kastmel lihtsasti lekkida. Salatileht ei kleepu enda külge, mis takistaks lahtirullumist.

Aasia köögis on probleemile lahendus leitud, kuigi ma pole seda laialt kasutuses näinud. Nimelt rullitakse salat (või ka muu toit) riisipaberi sisse, mis on lihtsalt õhuke taignakiht. See on pinna normaali suunas plastne, mitte elastne, seega ei keri end lahti. Pinnaga paralleelselt on aga veniv ja elastne, nii et ei rebene. Riisipaber on pisut niiske ja kleepub enda külge nagu iga tainas, mis takistab rulli lagunemist ja hoiab vedeliku selle sees. Pisut imab riisipaber ka vedelikku, aga see pole oluline omadus.

Avoiding the Bulow and Rogoff 1988 result on the impossibility of borrowing

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Bulow and Rogoff 1988 NBER working paper 2623 proves that countries cannot borrow, due to their inability to credibly commit to repay, if after default they can still buy insurance. The punishment of defaulting on debt is being excluded from future borrowing. This punishment is not severe enough to motivate a country to repay, by the following argument. A country has two reasons to borrow: it is less patient than the lenders (values current consumption or investment opportunities relatively more) and it is risk-averse (either because the utility of consumption is concave, or because good investment opportunities appear randomly). Debt can be used to smooth consumption or take advantage of temporary opportunities for high-return investment: borrow when consumption would otherwise be low, pay back when relatively wealthy.

After the impatient country has run up its debt to the maximum level the creditors are willing to tolerate, the impatience motive to borrow disappears, because the lenders do not allow more consumption to be transferred from the future to the present. Only the insurance motive to borrow remains. The punishment for default is the inability to insure via debt, because in a low-consumption or valuable-investment state of affairs, no more can be borrowed. Bulow and Rogoff assume that the country can still save or buy insurance by paying in advance, so “one-sided” risk-sharing (pay back when relatively wealthy, or when investment opportunities are unavailable) is possible. This seemingly one-sided risk-sharing becomes standard two-sided risk-sharing upon default, because the country can essentially “borrow” from itself the amount that it would have spent repaying debt. This amount can be used to consume or invest in the state of the world where these activities are attractive, or to buy insurance if consumption and investment are currently unattractive. Thus full risk-sharing is achieved.

More generally, if the country can avoid the punishment that creditors impose upon default (evade trade sanctions by smuggling, use alternate lenders if current creditors exclude it), then the country has no incentive to repay, in which case lenders have no incentive to lend.

The creditors know that once the country has run up debt to the maximum level they allow, it will default. Thus rational lenders set the maximum debt to zero. In other words, borrowing is impossible.

A way around the no-borrowing theorem of Bulow and Rogoff is to change one or more assumptions. In an infinite horizon game, Hellwig and Lorenzoni allow the country to run a Ponzi scheme on the creditors, thus effectively “borrow from time period infinity”, which permits a positive level of debt. Sometimes even an infinite level of debt.

Another assumption that could realistically be removed is that the country can buy insurance after defaulting. Restricting insurance need not be due to an explicit legal ban. The insurers are paid in advance, thus do not exclude the country out of fear of default. Instead, the country’s debt contract could allow creditors to seize the country’s financial assets abroad, specifically in creditor countries, and these assets could be defined to include insurance premiums already paid, or the payments from insurers to the country. The creditors have no effective recourse against the sovereign debtor, but they may be able to enforce claims against insurance firms outside the defaulting country.

Seizing premiums to or payments from insurers would result in negative profits to insurers or restrict the defaulter to one-sided risk-sharing, without the abovementioned possibility of making it two-sided. Seizing premiums makes insurers unwilling to insure, and seizing payments from insurers removes the country’s incentive to purchase insurance. Either way, the country’s benefit from risk-sharing after default is eliminated. This punishment would motivate loan repayment, in turn motivating lending.

Asking questions of yourself

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To make better decisions, ask about all your activities “Am I doing this right? Is there a better way?” I would have benefited from considering such questions about many everyday tasks. For example, I brushed my teeth wrong (sawing at the roots) until late teens, brushed my teeth at the wrong time (right after a meal when the enamel is soft) until my 30s. I only learned to cut my own hair in my mid-20s, and this was the highest-return investment I ever made, because a hair clipper costs as much as a haircut, so pays for itself with the first use.

Peeling a kiwi with a spoon is far easier than slicing with a knife. All it took to learn this was one web search, but it required asking myself the question of whether I was peeling fruit optimally. Same for extracting the seed from an avocado.

Cracking the shell of a hard-boiled egg, making two holes at the ends and blowing air under the membrane before peeling is another trick I wish I had known earlier.

Microwaved food is cooler in the centre, so to avoid scalding one’s mouth, it is helpful to start eating it from the middle. Cooked food left in a covered cooking pot or transferred to a storage container while still mildly hot does not go bad at room temperature for several days – doing this experiment required posing this hypothesis. Drinking without touching the bottle with one’s mouth turns out to be quite easy and is widespread in India.

Only after learning to drive did I start meaningfully using gears on a bicycle, and it took about 15 years more to start shifting approximately correctly (pedalling cadence 60-100 rotations per minute, downshifting before stopping, avoiding cross-geared riding). Similarly for basic bike maintenance like cleaning and oiling the chain, selecting the appropriate front and rear tire pressure given one’s weight and tire widths. Seat height is one thing I figured out early, but not handlebar height.

As a teenager, I would have benefited from asking myself whether I was overtraining, whether my nutrition was reasonable, how soon to return to training after various injuries and whether to seek medical assistance with these. Questioning the competence of coaches and doing a simple web search for sports medicine resources would have prevented following some of their mistaken advice.

Sometimes asking yourself the question reveals that you are already doing the task correctly. On the internet, people claim that they do not use shampoo, just water, and their hair stays clean-smelling and more lush than using detergent. An experiment not to use shampoo was a failure for me, causing greasy hair and lots of dandruff after a few days. The optimality of shampoo may depend on individual scalp and hair characteristics. On the other hand, a single-blade disposable razor and cold water give me a better shave than multi-bladed fancy brands with foam (that get clogged), and the disposable razor stays sharp enough for a month or two of everyday shaving.

When going to teach, it may be worth asking whether the room is the correct one, even if some students show up and the room is free, because once in this situation I was in a room with the right label, but in the wrong building.

On the other hand, constantly doubting oneself is unhealthy and unhelpful. If enough evidence points one way, then it is time to make up one’s mind.

Putting your money where your mouth is in policy debates

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Climate change deniers should put their money where their mouth is by buying property in low-lying coastal areas or investing in drought-prone farmland. Symmetrically, those who believe the Earth is warming as a result of pollution should short sell climate-vulnerable assets. Then everyone eventually receives the financial consequences of their decisions and claimed beliefs. The sincere would be happy to bet on their beliefs, anticipating positive profit. Of course, the beliefs have to be somewhat dogmatic or the individuals in question risk-loving, otherwise the no-agreeing-to-disagree theorem would preclude speculative trade (opposite bets on a common event).

Governments tend to compensate people for widespread damage from natural disasters, because distributing aid is politically popular and there is strong lobbying for this free insurance. This insulates climate change deniers against the downside risk of buying flood- or wildfire-prone property. To prevent the cost of the damages from being passed to the taxpayers, the deniers should be required to buy insurance against disaster risk, or to sign contracts with (representatives of) the rest of society agreeing to transfer to others the amount of any government compensation they receive after flood, drought or wildfire. Similarly, those who short sell assets that lose value under a warming climate (or buy property that appreciates, like Arctic ports, under-ice mining and drilling rights) should not be compensated for the lost profit if the warming does not take place.

In general, forcing people to put their money where their mouth is would avoid wasting time on long useless debates (e.g. do high taxes reduce economic growth, does a high minimum wage raise unemployment, do tough punishments deter crime). Approximately rational people would doubt the sincerity of anyone who is not willing to bet on her or his beliefs, so one’s credibility would be tied to one’s skin in the game: a stake in the claim signals sincerity. Currently, it costs pundits almost nothing to make various claims in the media – past wrong statements are quickly forgotten, not impacting the reputation for accuracy much.

The bets on beliefs need to be legally enforceable, so have to be made on objectively measurable events, such as the value of a publicly traded asset. By contrast, it is difficult to verify whether government funding for the arts benefits culture, or whether free public education is good for civil society, therefore bets on such claims would lead to legal battles. The lack of enforceability would reduce the penalty for making false statements, thus would not deter lying or shorten debates much.

An additional benefit from betting on (claimed) beliefs is to provide insurance to those harmed by the actions driven by these beliefs. For example, climate change deniers claim small harm from air pollution. Their purchases of property that will be damaged by a warming world allows climate change believers to short sell such assets. If the Earth then warms, then the deniers lose money and the believers gain at their expense. This at least partially compensates the believers for the damage caused by the actions of the deniers.

Book-like screen arrangement

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Office computer screens are mostly kept in the landscape orientation, but are usually used for documents, which are in the portrait format. Modern screens can be rotated to portrait mode, which makes reading print-view documents easier, or at least allows a larger fraction of the document to be displayed. Taking this one step further, for markup languages (XML, LaTeX) or programming, it is often helpful to see both the code and the compiled output side by side. This may be displayed on one large split screen in landscape orientation or two vertically oriented screens in a book-like arrangement, as in the following image.

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Why princesses and princes are described as attractive

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The bards and scribes who recorded events for posterity received their income essentially in the form of tips from the rulers and the rich, so had an incentive to flatter, describing their patrons as more attractive, virtuous, brave, etc than they really were.

In addition to the exaggeration of their actual attractiveness in reports that have reached us, the children of the wealthy probably really were more beautiful than the poor. Richer youth were better fed and cared for, thus had fewer developmental abnormalities (e.g. bent legs from calcium deficiency) and diseases. The poor were malnourished, lived in dirty conditions and were subject to violence, therefore were more likely stunted, stank and had skin diseases, missing teeth and scars. The latter two distinctions in looks have to a lesser extent lasted to the present day, for the same reason.

Attractiveness consists of the visual, audible and olfactory signals of a fit mate (healthy, fertile conspecific), because organisms evolved to consider fit mates attractive. In times when most people were malnourished and diseased, a well fed and healthy rich person would have been much fitter than most, thus a preferred sexual partner for others.

On the other hand, conditional on surviving to adulthood, the poor likely had better immune-related genes, because they were under stronger selection pressure. Poorer people also experienced more infections, thus acquired stronger immunity to more diseases if they survived. Then conditional on equal looks, a person from a poorer background would have been a fitter mate. Also, the ruling class intermarried to keep wealth in the family, so were inbred (hereditary diseases among European royalty are an example consequence). For these two reasons, it is not surprising that the rulers and the rich found some poor people sexually attractive, specifically the outwardly healthiest-appearing among those who reached maturity.