Autoriarhiiv: sanhei

Platform providers fake being popular

Crowdfunding platforms, stock exchanges and other providers of two-sided markets want to appear popular, because having more buyers attracts more sellers and vice versa. The platform’s revenue is usually proportional to the number of users, because it charges a commission fee on trades or advertisers pay it to show ads to users. The exchange’s marginal cost of a user is close to zero, giving it an incentive to fake a high volume of trades, a large limit order book and a small bid-ask spread.

The platform’s cost of posting a great volume of outstanding buy and sell orders at a small spread is that many investors try to trade at these favourable bid and ask prices. Either the market maker has to take the other side of these attempted transactions or is found fraudulent. Taking the other side results in a large loss if some investors are better informed than the exchange.

The platform could falsely display a large trading volume, but keep the order book honestly small by adding fake trades at prices between the bid and the ask only, so no investor’s real limit order is ignored. This seems difficult to detect, unless one side of the limit order book is empty (e.g. no buyers) and at least one at-market order on the other side (e.g. a sell) is outstanding. In this case, any trades occurring would have to satisfy the at-market order. However, the platform or real investors can then take the other side of the at-market order at a very favourable price to themselves, which discourages at-market orders. A large trading volume with a thin order book is still slightly suspicious, because it requires that crossing buy and sell orders between the bid and ask prices arrive almost simultaneously, in order to be matched without appearing on the order book for long, and without triggering the real limit orders. Displaying the fake buys and sells on the order book risks attracting actual matching trades, which the platform would have to honour (at a cost).

Without automated quote matching, there are no at-market orders, for example on the Funderbeam crowdfunding platform. Instead, everyone either posts a limit order or picks an order from the other side to trade with, e.g. a buyer chooses a sell. Investors can pick an order with a worse price (higher sell or lower buy) on the other side, which frequently occurs on Funderbeam. Choosing a worse price is irrational, unless the traders in question are colluding, so the asset is effectively not changing ownership. Reasons to carry out such seemingly irrational trades are to manipulate price and volume, e.g. price can be raised or reduced by targeted trades outside the bid-ask interval. Volume can only increase after added trades, rational or not, but such seemingly greater activity is exactly what benefits the stakeholders of the platform. The employees of the market maker have a natural motive to fake-trade between themselves to make their firm look good, even without any inappropriate pressure from their boss.

Another way to attract issuers and investors is to demonstrate successful initial public offerings, meaning that the funds are raised quickly (good for issuers) and the price of the newly listed stock (or other asset) goes up, which benefits investors. Adding fake capital-raisers is difficult, because potential investors will check the background of the supposed issuer. Inserting spoof investors into an actual funding campaign is costly, because real money would have to be invested. One way to manipulate popularity upward is to simultaneously add a fake issuer and fake investors who satisfy its funding need. The idea is to not leave time for real investors to participate in the campaign, by pretending that the capital-raiser achieved its target funding level before most investors could react. This is easier in markets with a small number of real investors and without an auto-invest feature. However, the real investors who were supposedly pre-empted may still research the supposedly very popular issuer.

A costless way to briefly boost the popularity of a real fundraising campaign is to add fake investors after the target funding is achieved, and forbid issuers from increasing the target or accepting funds from those who subscribed after the goal was reached. Any campaign meeting its target can then be made to look heavily oversubscribed. However, if the issuers are informed in advance of the restriction not to increase the target, then they may find an alternative unrestricted platform to raise funds. On the other hand, if the restriction is not mentioned beforehand, then it will likely anger the issuers who will then create negative publicity for the platform. Competition between exchanges thus curtails their manipulation incentives.

The platform can motivate real investors to raise their bids when the campaign reaches its target by rationing demand: bidders in an oversubscribed share issue get only a fraction of what they wanted to buy. Anticipating this, buyers will increase their requested quantities so that the fraction of their new bid equals their actual demand. This makes the campaign look oversubscribed and creates a feedback loop: if other investors increase their quantities, then rationing reduces the fraction of a given investor’s demand that will be satisfied, so this investor raises her or his requested amount, which in turn makes others increase theirs.

If investors know of the bid rationing in advance, then they may select a rival market provider without this restriction, but if rationing takes them by surprise, then they may leave and publicly criticise the platform. Capital-raisers compare exchanges, so if many market providers inflate demand and the issuers pay attention to the level of oversubscription (instead of the fraction of campaigns reaching the target, which is what should matter to the capital-raiser), then the biggest inflator wins. Of course, platforms may not want to reveal unsuccessful campaigns (e.g. Funderbeam does not), so public data on the fraction of issuers who achieved their funding goal is unlikely to exist.

Theoretically, the feedback from bid rationing to increased quantity demanded could lead to infinite amounts requested. A countervailing incentive is that with positive probability, other investors do not honour their commitment to buy, in which case a given investor may be required to buy the amount (s)he demanded, instead of the lower amount (s)he actually wanted. If there is no commitment to buy (for example, on Funderbeam the bids are only non-binding indications of interest), then the danger of overcommitting is absent, so the rational choice seems to be requesting an infinite amount. Investors do not indicate infinite interest, so either they are irrational or some other penalty exists for outbidding one’s capability to pay.

Star job candidates benefit from appearing to be worse

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Employers have a cost of making a job offer: filling out forms, getting approval, not being able to make other offers simultaneously in case too many job candidates accept, etc. A company who believes that it is not the top choice of candidates would want to avoid making an offer to a star applicant (one who is likely to receive better alternative offers from top employers, thus turn down the lower-ranked company’s offer).

If the star job-seeker is uncertain about the offers she or he will get, or wants a bargaining chip to use with the most preferred company, then (s)he prefers to obtain the lower-ranked employer’s offer, even when planning to reject it. A way to entice the company into offering a job is to pretend to be more attainable (have a worse outside option) by faking lower talent and potential when interviewing with lower-ranked employers. For this pretence to be (partly) credible, it must have a cost for the job-seeker, otherwise all the best candidates would pretend to be worse and increase their chance of obtaining offers from their backup employers. Then the next-best candidates would have to fake being less good to receive jobs, etc. This race to the bottom would only end once all candidates look like the worst possible, which does not seem realistic.

One potential cost is that faking lower talent has a random outcome, which may be so bad that the employer does not want to offer a job at all. This would temper the incentive to appear worse. Another cost is information leakage – if bad performance at a less desirable interview becomes known to higher-ranked employers, then the candidate may forfeit her or his most preferred interviews and jobs. It could also be that the top job-seekers cannot hide their quality, for example because their genius shines out despite their best effort, or employers base offers solely on recommendation letters, which the candidate cannot see or affect around the time of applying.

Why rational agents may react negatively to honesty

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Emotional people may of course dislike an honest person, just because his truthful opinion hurt their feelings. In contrast, rational agents’ payoff cannot decrease when they get additional information, so they always benefit from honest feedback. However, rational decision makers may still adjust their attitude to be more negative towards a person making truthful, informative statements. The reason is Bayesian updating about two dimensions: the honesty of the person and how much the person cares about the audience’s feelings. Both dimensions of belief positively affect attitude towards the person. His truthful statements increase rational listeners’ belief about his honesty, but may reduce belief in his tactfulness, which may shift rational agents’ opinions strongly enough in the negative direction to outweigh the benefit from honesty.

The relative effect of information about how much the person cares, compared to news about his honesty, is greater when the latter is relatively more certain. In the limit, if the audience is completely convinced that the person is honest (or certain of his dishonesty), then the belief about his honesty stays constant no matter what he does, and only the belief about tact moves. Then telling an unpleasant truth unambiguously worsens the audience’s attitude. Thus if a reasonably rational listener accuses a speaker of „brutal honesty” or tactlessness, then it signals that the listener is relatively convinced either that the speaker is a liar or that he is a trustworthy type. Therefore an accusation of tactlessness may be taken as an insult or a compliment, depending on one’s belief about the accuser’s belief about one’s honesty.

If tact takes effort, and the cost of this effort is lower for those who care about the audience’s emotions, then pleasant comments are an informative signal (in the Spence signalling sense) that the speaker cares about the feelings of others. In that case the inference that brutal honesty implies an uncaring nature is correct.

On the other hand, if the utility of rational agents only depends on the information content of statements, not directly on their positive or negative emotional tone, then the rational agents should not care about the tact of the speaker. In this case, there is neither a direct reason for the speaker to avoid unpleasant truths (out of altruism towards the audience), nor an indirect benefit from signalling tactfulness. Attitudes would only depend on one dimension of belief: the one about honesty. Then truthfulness cannot have a negative effect.

Higher order beliefs may still cause honesty to be interpreted negatively even when rational agents’ utility does not depend on the emotional content of statements. The rational listeners may believe that the speaker believes that the audience’s feelings would be hurt by negative comments (for example, the speaker puts positive probability on irrational listeners, or on their utility directly depending on the tone of the statements they hear), in which case tactless truthtelling still signals not caring about others’ emotions.

Social welfare functions derived from revealed preference

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The social welfare functions used in policy evaluation typically put more weight on poorer people, justifying redistribution from the rich to the poor. The reasoning is that the marginal benefit of a unit of money is greater for the poor than the rich. However, people with a greater marginal value of money are more motivated to earn and save, other things equal, so more likely to become rich. In this case, the rich have on average a higher marginal benefit of money than the poor, or a lower marginal cost of accumulating it. If the justification for redistribution is an interpersonal utility comparison, then revealed preference suggests a greater Pareto weight for richer people, thus redistribution in the opposite direction to the usual.

If the marginal utility of money decreases in wealth or income, then people earn until the marginal benefit equals the marginal cost, so the comparison between the rich and the poor depends on their marginal cost of earning, evaluated at their current wealth and income. The cost and benefit of earning may both be higher or lower for richer people. In a one-shot model, whoever has a greater benefit should receive redistributive transfers to maximise a utilitarian welfare criterion. Dynamic indirect effects sometimes reverse this conclusion, because incentives for future work are reduced by taxation.

Those with a high marginal utility of money are more motivated to convince the public that their marginal utility is high and that they should receive a subsidy. The marginal utility is the difference between a benefit and a cost, which determine whether the poor or the rich have a greater incentive to lobby for redistributive transfers. The marginal cost of an hour of persuasion equals the person’s hourly wage, so depends on whether her income is derived mostly from capital or from labour. For example, both rentiers and low-wage workers have a low opportunity cost of time, so optimally lobby more than high-wage workers. If lobbying influences policy (which is empirically plausible), then the tax system resulting from the persuasion competition burdens the high-wage workers the heaviest and leaves loopholes and low rates for capital income and low wages. This seems to be the case in most countries.

A tax system based on lobbying is inefficient, because it is not the people with the greatest benefit that receive the subsidies (which equal the value of government services minus the taxes), but those with the largest difference between the benefit and the lobbying cost. However, the resulting taxation is constrained efficient under the restriction that the social planner cannot condition policy on people’s marginal costs of lobbying.

Harjumus võib eesmärgile vastu töötada

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Harjumus aitab laiskusega võidelda, sest muudab käitumise automaatseks, jätab otsustamise vahele. Vahel kaob käitumise harjumuspäraseks muutumisel silmist selle algne eesmärk, näiteks trenni puhul tervis, hambapesul ilusad terved hambad. Harjunud tegevus võib muutunud olukorras osutuda kahjulikuks, mida mõtlemist vahele jättes ei märka – teetööde tõttu võib tavapärane kiireim marsruut alternatiivist oluliselt aeglasem olla, aga inimene pöörab ikka automaatselt samale teele nagu alati. Samuti võib käitumine ise tasapisi teiseneda, näiteks rutiinses trennis harjutuste tehnika lihtsama vastupanu teed minna.

Harjumus regulaarselt hambaid pesta teeb pisut halba kui viimane toidukord enne pesu satub hambapesuajale liiga lähedale. Hammaste harjamine kohe peale sööki kahjustab hambaemaili, sest see on pehmenenud, eriti magusa või hapu toidu järgselt. Sellepärast soovitas hambaarst mul vältida hambapesu tunni aja jooksul peale sööki ja selle asemel happekahjustuse vähendamiseks suukeskkond neutraliseerida piima, suuloputusvedeliku või veega. Samuti peaks hambaid pesema õige harjamistehnikaga, mitte „juurt saagides” ega ka mitte liiga kaua, jällegi emailiabrasiooni piiramiseks. Ajapikku kipub harjamistehnika valeks muutuma, mida inimene rutiinis olles tähele ei pane.

Trenniharjumus takistab laisklemist, aga väljaspool trenni tehtud kehalise pingutuse või haigestumise järgselt võib tavaline trenn kahjulik olla. Ületreening (näiteks sama lihase jõutrenn järjestikustel päevadel) tekitab stressihormoone, soodustab vigastusi ja võib füüsilist suutlikkust vähendada, nii et algsele eesmärgile vastu töötada sarnaselt liigkiire või liigpika hambapesuga. Vilets harjamistehnika kahjustab igemeid ja hambajuuri, analoogselt viletsa trennitehnika tekitatud vigastuste ja piiratud ja tasakaalustamata kehalise arenguga.

Food calories are not directly related to obesity

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It seems that the change in bodyweight should be a strictly increasing function of calories eaten minus calories spent. The first caveat to this claim is that calories in the food eaten do not equal the calories absorbed, which is what matters for weight gain. People differ in the efficiency of their digestion – that is what bariatric surgery relies on. Also, food labels use calories measured by the burn method (dry the food, burn it, measure the heat output), which ignores for example that coarsely chewed food chunks pass through the digestive tract relatively unchanged, thus contribute few nutrients to the organism. An extreme example is wholegrain flax (linseeds) that remain undigested due to a waxy coating. In nature, seed dispersal by birds relies on the indigestibility of the seeds.

Even if calories absorbed could be accurately measured, the type of food eaten would still matter for weight gain due to imperfect willpower. Some foods are more addictive than others, notably those rich in refined carbohydrates – an easy example is drinks that are essentially sugar-water. Consuming a given amount of calories from high-glycaemic-load sucrose makes people eat more sooner on average than ingesting the same calories from slowly digested whole grains or unsaturated fat. Similarly, ignoring willpower limitations is why abstinence-based programs to prevent sexually transmitted infections, which naively might be expected to be 100% effective, are in fact ineffective (Underhill et al 2007, doi:10.1136/bmj.39245.446586.BE).

There are various tricks to circumvent limited willpower to win the game against one’s future tempted self. To reduce temptation, food should be out of sight outside mealtimes (in cupboards, drawers, fridge) and unhealthy snacks should not be bought at all. Even seeing dishes and cutlery may trigger cravings, in which case these too should be placed out of sight when not in use.

Avoiding grocery shopping while hungry is an old piece of advice, which may be taken further by having someone else buy your food. Two people can even agree to grocery-shop for each other according to shopping lists exchanged beforehand. Online ordering may be a solution, but of course the merchants want customers to buy more, so advertise tempting foods with photos on their website. These ads can be blocked with some effort. A more sophisticated solution is to have one’s own user interface (front end) interact with the merchant’s website – scrape the data on inventory and prices, send commands to buy.

Democracy may be the best system due to political economy constraints

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Democracy picks the leader who is best at getting elected, not necessarily the best at leading the country. The ability to become a leader differs from the ability to lead. For example, populism and overconfidence in oneself may help one’s election prospects but harm performance at governing.

Even if there was some very accurate way to select the best leader (e.g. test their honesty, intelligence, work ethic, in addition to electability), it may be not be feasible in practice to make this person govern for long. The reason is the political economy constraint that someone better at obtaining power can depose the best leader (one whose government would maximise social welfare, however defined). The disruption resulting from the coup may even harm society more than the difference between being governed by the best leader as opposed to the best power-grabber. In this case, the leadership of the most electable person may maximise welfare, subject to assumptions like „the best power-grabber is also good enough at retaining power, preventing coups once in government”.

The skills of getting elected and organising a revolution probably differ, so an elected government has some of the same vulnerability as the best leader. The political economy constraint of preventing a coup may then favour making the strongest dictator or the most dangerous revolutionary lead the country. However, this may not be the best system for selecting leaders due to a tradeoff between the ability to govern and the ability to overthrow a government. The welfare-maximising selection system subject to the political economy constraint would pick the person who is best at governing among those who can successfully resist a coup. Democracy may be such a compromise, choosing reasonably popular leaders who have a low probability of being overthrown and are adequate at governing. On the one hand, democracy may avoid a ruthless dictator whose rule is very stable, but harmful, and on the other hand a saintly leader who would be deposed quickly.

Elatustaseme võrdlus ei võta arvesse kvaliteeti

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Põhja-Euroopa tomatid on vesised, hapukad ja seest roosakashallid, aga Lõuna-Euroopa omad magusad maitseplahvatused, seest punased. Samuti Gruusias värskelt puu otsast võetud küpsed virsikud ja muud puuviljad on palju maitsvamad kui need, mis on toorelt ekspordiks korjatud ja merekonteineris järelküpseda lastud. Samanimeline restoranitoit Itaalias on palju parem kui Põhja-Ameerikas või Eestis. Erinevate riikide ostukorvi kalliduse arvutamisel loeb aga ainult toodete hind, mitte neist saadav heaolu, nii et elatustase annab heaolutasemest vildaka pildi.

Kui kvaliteet erineks ainult väikse osa ostude puhul (restoranitoit ja puuviljad on keskmise leibkonna kuludes pisike protsent), siis see heaolutaseme võrdlust eriti ei mõjutaks. Üks oluline kululiik, mille puhul kvaliteet riigiti märgatavalt erineb, on majutus. USAs on ka uute kallihinnaliste kortermajade põrandad lainelised, mida kõndides märkab, dušikabiinis jookseb vesi nurka, mitte keskele äravoolu, akna ümber on tuntava tuulega praod ja tänavamüra kostab selgesti. Vanadel ja eramajadel on samad murekohad. Tartus euroremonditud ühiselamus selliseid probleeme polnud, kuigi see oli odav majutus. USAs on ka tippülikoolide hoonetes prussakad ja närilised, Tartus minu teada mitte. Tänavatel on USAs tihti näha kahjuritõrjefirmade siltidega mikrobusse, järelikult selle teenuse nõudlust on. Austraalias on enamik maju soojustamata ka piirkondades, kus kolm kuud aastas on hommikul härmatis maas. Soojustuse puudumisel langes seal mu kütmata kontori temperatuur 12 kraadini ja korteris 10,5ni. Elatustaseme arvutus aga kvaliteediprobleeme ei kajasta, võtab arvesse vaid pinda ja hinda.

Avalike teenuste pakutavat väärtust on statistikas keeruline hinnata, nii et vahel peab piirduma nendele kulutatava rahaga, mis on sisend, mitte väljund. Avaliku ruumi kvaliteet kindlasti riigiti kõigub – tänavate puhtus ja siledus USAs ja Singapuris on nagu öö ja päev.

Kvaliteedierinevuste põhjustatud kallakut ei saa korrigeerida ka avaldatud eelistusi kasutades (Dowrick ja Quiggin 1994 https://www.jstor.org/stable/2117988: kui ühe riigi keskmine elanik saaks teise riigi keskmist ostukorvi endale lubada, aga teise elanik esimese ostukorvi mitte, siis on esimene riik rikkam ja selle elanikud paremas olukorras). Probleemiks on jällegi, et need avaldatud eelistused on ainult hinnapõhised, seega kvaliteeti ei arvesta.

Heaolu sõltub mitte ainult tarbimisest, vaid palju otsesemalt eelistustest. Keskmise elaniku kasulikkusfunktsioon võib riigiti erineda, igatahes stereotüübid sellele vihjavad. Hüpotees eelistuste varieeruvuse kohta on kontrollitav ja Dowrick ja Quiggin 1994 lükkavad selle ümber (erinevusi ei leia), aga nende test sõltub kvaliteedi samasusest riikide vahel. Test seisneb järgnevas ostukorvide võrdluses: kui mõlema riigi keskmine elanik saab endale lubada mõlema riigi keskmist tarbitavate toodete ja teenuste komplekti, aga valitud ostukorvid riigiti erinevad, siis järelikult eelistused kokku ei lange. Eeldus, et mõlema elanikud suudavad osta mõlemat komplekti, on oluline selleks, et sissetulek valikut ei piiraks. Selline rahaline piirang viiks erinevale tarbimisele ehk näilisele erinevusele eelistustes.

Kui mõndade toodete ja teenuste kvaliteet on parem ühes riigis, teistel teises, siis oleks loogiline, et inimesed valivad riigiti erinevad ostukorvid isegi täpselt sama sissetuleku ja eelistuste puhul. Üks võimalik põhjus, miks Dowrick ja Quiggin 1994 sellist erinevust ei leidnud, on et kvaliteetsemad tooted on kallimad ka riikide lõikes, misjuhul hinnapõhine elatustaseme võrdlus kajastab heaoluerinevusi hästi (sarnaseid eelistusi eeldades). Toidu puhul ei tundu, et hind kvaliteediühiku kohta riigiti sama on – näiteks troopilised puuviljad on troopikas nii odavamad kui ka värskemad kui nende eksporditurgudel.

Ostukorvierinevuste puudumise teine võimalik põhjus on, et riigis, kus antud toode hinna-kvaliteedi suhtelt halvem on, eelistavad inimesed seda toodet. Kui kasulikkusfunktsiooni erinevus tasakaalustab kvaliteedierinevuse, siis on tarbitav komplekt sama hindadeprofiiliga riikides sarnane. Esmapilgul tundub imelik, et parema tootega riigis huvitab see toode inimesi vähem ja täpselt kvaliteedierinevuse võrra. Seletus on harjumine antud toote keskmise kvaliteeditasemega oma elukohas: veini või juustu, mis eestlastele kõlbab, ei võtaks prantslased suu sissegi, samas head ja halba verivorsti või leiba pranslased eristada ei suudaks, aga eestlased valiksid peaaegu ühehäälselt hea.

Harjumust saab modelleerida näiteks nii, et inimese heaolu on kasvav funktsioon tarbitavatest kogustest ja suhtelistest kvaliteetidest (praegune kvaliteet miinus varem kogetud keskmine kvaliteet). Kui selline kasulikkusfunktsioon on inimestel sama, siis samade hindade korral tarbivad nad harjumuspärase kvaliteediga tooteid samas koguses. Varem kogetud kvaliteedid võivad inimeste vahel palju erineda, aga kui varasem kvaliteet võrdub praegusega, siis on ostukorv ühesuguse varandusliku ja hinnatasemega riikides sarnane. Harjumine võrdsustab heaolutaseme riikide vahel, neutraliseerides kvaliteedierinevused. Kui elatustasemega tahta mõõta heaolu, siis harjumise korral polegi tarbitav kvaliteet oluline, nii et selle eiramine elatustaseme võrdluses on õigustatud.

Odavamat toodet tarbitakse alguses rohkem, mis võib vähendada edasist heaolu sellest tootest, seega tarbimist. See tasakaalustab parema ja odavama kauba esialgset rohkem ostmist riikide võrdluses, muutes ostukorvid aja jooksul sarnasemaks. Taas muudab tasakaalustumine hinna- ja kvaliteedierinevused heaolu jaoks vähem oluliseks.

Äpp, mis ennustab kohaletulijate arvu

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On palju veebilehti ja äppe, mis aitavad kohtumisi kokku leppida ja üritustele minekut koordineerida, näiteks meetup.com. Minu kogemuse põhjal umbes pooled internetis tulla lubajatest ei ilmu kohale, lisaks mõned tühistavad viimasel hetkel või hilinevad. See tekitab vahel ürituse korraldajale probleeme, näiteks kui ta on lubanud teatud arvu osalejaid organiseerida ja sellest sõltub kohaletulnute piletihind (grupisoodustus) või on minimaalne arv inimesi vajalik spordivõistkonna kokkusaamiseks. Lisaks sunnivad hilinejad ja teadmata kaduvad tulla lubajad teisi ootama, mis on tüütu.

Selleks, et motiveerida inimesi ausalt oma tulekuplaane teatama, lubadusi pidama ja õigeaegselt kohale tulema on vaja käitumisele vastavaid tasusid ja karistusi. Üks lahendus on, et osalejaks registreerujad peavad osalustasu ette maksma ja mitteilmumise korral seda tagasi ei saa. Tasuta või odavate ürituste puhul sellest ei piisa.

Hilinemise vältimise motiiv tekiks ka siis, kui on üldteada, et hilinejaid ei oodata, vaid transport väljasõidule läheb minuti pealt õigel ajal. Enamik inimesi ei taha aga hilinejaid maha jätta ja nii venib ooteaeg tihti pool tundi või rohkemgi, kusjuures paljude ootajate heaolukaotus kokku on tõenäoliselt suurem kui hilinejate võit mittemahajäämisest. Paljude ürituste kuulutusel kirjutatakse, et väljasõiduaeg on punktipealt täpne, aga seda lubadust murtakse peaaegu alati – ma pole veel kogenud üritust, kus keegi maha jäeti, et õigel ajal lahkuda.

Õige motivatsiooni tekitamiseks peaks hilineja või mitteilmuja maksma teistele piisavat kompensatsiooni, aga sotsiaalse sündmuse kontekstis on sellist nõuet keeruline jõustada. Mitteilmujalt on raske midagi sisse nõuda ja ka hilineja võib väita, et tal hetkel raha kaasas pole. Kui tahta trahvi teha vastavalt hilinetud minutite ja ootama sunnitud osalejate arvule, siis läheb ka arvutus enamiku inimeste jaoks keeruliseks. Lahenduseks on äpp, mis tuvastab telefoni asukoha põhjal, kes on kokkusaamiskohas õigel ajal ja kes mitte. Kohaletuleku registreerimiseks võib kasutada ka telefonide omavahelist lähisuhtlust (bluetooth, NFC). Äpp saab automaatselt välja arvutada hilinejate ja mitteilmujate kompensatsiooni ootajatele, selle äpiga seotud pangakontolt või krediitkaardilt maha võtta ja ootajatele kanda. Kes ei nõustu selliste tingimustega, võib kasutada muid ürituste koordineerimise vahendeid. Mittenõustumine signaliseerib ka teatud määral, et inimene ei plaani lubadusi pidada.

Sõltumata sellest, kas äpi kaudu nõuda mitteilmujate kompensatsiooni kohaletulijatele või mitte, on äpil veel see hea külg, et andmed inimeste varasemate registreerumiste ja asukoha kohta lasevad ennustada, kes lubajatest ilmub ja millise hilinemisega. Seega äpp saab automaatselt arvutada kohaletulijate arvu tõenäosusjaotuse, mis on korraldajale abiks planeerimisel. Samuti saab kroonilised mitteilmujad tulevastelt üritustelt välja jätta, näiteks neile mitte teavitusi saata – ka selle saab äpp automatiseerida.

Väga piiratud ulatuses on sarnane funktsionaalsus praegustel kokkusaamisveebilehtedel olemas, näiteks meetup.comi grupiadministraatorid saavad registreerida mitteilmujad ja programmeerida reegli, et kolm mitteilmumist eemaldab inimese grupist. Vajadus mitteilmujad käsitsi registreerida on praeguste äppide üks piirang. Ka ei erista praegused veebilehed tulekulubaduse tühistamise aega (viimasel minutil registreerumise tühistamine on sarnane mitteilmumisele) ega hilinemise kestust. Hea oleks ka arvestada lisaks inimese mitteilmumiste arvule tema õigeaegsete kohaletulekute arvu, mis aitaks paremini ennustada ta tulevast osalemistõenäosust.

Seasonings may reduce the variety of diet

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Animals may evolve a preference for a varied diet in order to get the many nutrients they need. A test of this on mice would be whether their preference for different grains is negatively autocorrelated, i.e. they are less likely to choose a food if they have eaten more of it recently.

Variety is perceived mainly through taste, so the mechanism via which the preference for a varied diet probably operates is that consuming a substance repeatedly makes its taste less pleasant for the next meal. Spices and other flavourings can make the same food seem different, so may interfere with variety-seeking, essentially by deceiving the taste. A test of this on mice would flavour the same grain differently and check whether this attenuates the negative autocorrelation of consumption, both when other grains are available and when not.

If seasonings reduce variety-seeking, then access to spices may lead people to consume a more monotonous diet, which may be less healthy. A test of this hypothesis is whether increased access to flavourings leads to more obesity, especially among those constrained to eat similar foods over time. The constraint may be poverty (only a few cheap foods are affordable) or physical access (living in a remote, unpopulated area).

A preference for variety explains why monotonous diets, such as Atkins, may help lose weight: eating similar food repeatedly gets boring, so the dieter eats less.