Search engines as modern oracles, by Andrei Z. Broder & Preston McAfee

 Among the costs of visiting Mt. Parnassus to consult the Oracle at Delphi was that it was difficult to interpret the answers received, particularly if the questions were posed too casually.  Modern search engines are a bit like ancient oracles that way, and the resemblance may become greater as generative AI chatbots based on Large Language Models (LLMs) become part of search.

Here is some advice about how to think about all that.

Delphic Costs and Benefits in Web Search: A utilitarian and historical analysis. by Andrei Z. Broder & Preston McAfee, Google Research, August 16, 2023

Abstract: "We present a new framework to conceptualize and operationalize the total user experience of search, by studying the entirety of a search journey from an utilitarian point of view.

"Web search engines are widely perceived as “free”. But search requires time and effort: in reality there are many intermingled nonmonetary costs (e.g. time costs, cognitive costs, interactivity costs) and the benefits may be marred by various impairments, such as misunderstanding and misinformation. This characterization of costs and benefits appears to be inherent to the human search for information within the pursuit of some larger task: most of the costs and impairments can be identified in interactions with any web search engine, interactions with public libraries, and even in interactions with ancient oracles. To emphasize this innate connection, we call these costs and benefits Delphic, in contrast to explicitly financial costs and benefits.

"Our main thesis is that users’ satisfaction with a search engine mostly depends on their experience of Delphic cost and benefits, in other words on their utility. The consumer utility is correlated with classic measures of search engine quality, such as ranking, precision, recall, etc., but is not completely determined by them. To argue our thesis, we catalog the Delphic costs and benefits and show how the development of search engines over the last quarter century, from classic Information Retrieval roots to the integration of Large Language Models, was driven to a great extent by the quest of decreasing Delphic costs and increasing Delphic benefits.

"We hope that the Delphic costs framework will engender new ideas and new research for evaluating and improving the web experience for everyone."

And here's the final paragraph:

"We hope that this paper will engender new ideas for Delphic costs assessments, the measurement of Delphic costs, and means of reducing these costs. We would like to see the evaluation of web search engines move away from assessing the quality of ranking in isolation of the users’ overall search experience and personal context towards a holistic evaluation of user utility from using search engines. Moreover, this “utilitarian analysis” approach, rather than pure relevance analysis, could and should be applied to situations that do not involve explicit search, such as content feeds and recommender systems."

Return to the Econ by Joshua Gans

 Joshua Gans indulges his inner anthropologist:

Return to the Econ  by Joshua S. Gans,  August 20, 2023

Abstract: This paper revisits the Econ tribe famously documented by Leijonhufvud (1973). In half a century, the Econ have had their practices upended by technology and, for all but a few pockets of stasis, have changed their status hierarchy with new icons that are the focus of societal energy.

"In conversations with other members of the Econ, about 30 years ago, some rogue elements of Math-Econ, despite having achieved the highest levels of modl carving, made an attempt to carve modls that were actually useful and see if they “worked.” Rumour has it that they did, in fact, work and became useful in all of all things, the allocation of empty space and body parts. These elements were expelled by the Math-Econ as unworthy and left the sect with nothing but their Nobs."

Kidney disease in war-torn Sudan

 The Lancet brings us this news from Sudan.

Kidney failure in Sudan: thousands of lives at risk by Hatim A Hassan, Mohamed Hany Hafez, Valerie A Luyckx, Serhan Tuğlular, and Ali K Abu-Alfa, The Lancet, August 09, 2023DOI:https://doi.org/10.1016/S0140-6736(23)01370-3

"Sudan is one of few countries in Africa that has provided dialysis and transplantation under universal health coverage for several decades.2 Before the war, around 8000 patients required ongoing dialysis and around 4500 were living with kidney transplants (appendix). Haemodialysis was provided twice per week instead of three times per week to permit access to more patients within budget constraints.3

Haemodialysis requires continuous water, electricity, staffing, and disposable supplies. Since fighting began, dialysis services, which are mostly located in Khartoum, have been severely disrupted (appendix). Patients who can, have fled to dialysis units in other cities. Despite some units reducing haemodialysis frequency to once weekly, shortening sessions at times to 2 h, and offering appointments all day and all night, they are struggling to cope with demand. Most haemodialysis staff continue to work without being paid and are at high risk of burn-out. Egypt is accepting patients needing dialysis, but the cost and risk of the journey are prohibitively high for most.

Dialysis supplies have mostly run out by early August, 2023, despite dialysis sessions being reduced to weekly. A donation of supplies for a third of the patients for 3 weeks was obtained from one company. Reliance on donations of the large quantities of dialysis supplies needed for around 8000 patients is unrealistic. Dialysis supplies are not only expensive, but are bulky and costly to transport. Patients with kidney transplants are experiencing dangerous interruptions in their access to immunosuppressive medication. A reliable source of financing is urgently required to meet the needs of patients requiring dialysis and people with kidney transplants.

Support is needed to prevent adding a further layer of tragedy to this war if dialysis services cannot continue and transplant medication is not provided. Wars elsewhere pose similar threats to dialysis provision. The global health agenda must address the urgent need for transparent decision making and affordable access to vital treatments such as dialysis and transplantation during crises. Finding solutions to meet the needs of patients with kidney failure who depend on these therapies in low-resource settings in times of peace is also long overdue."

Calligraphy fan: OR and Game Theory

 Haibo Wang visited and brought me a fan, with calligraphy from his dad in Chinese characters.

Alex Chan translates:

"What is written is “運籌帷幄 博弈天下”.   運籌 is logistics (運籌學 is operations research) 博弈is gaming (and 博弈論 is  game theory)." 

"And the translation for the whole phrase is something like: strategizing and gaming the world - this is how you might describe a general." 

Kidney exchange between Portugal and Italy

 Italy-Portugal cross transplants. that click that saved two

"Thanks to a complex work of intervention planning and logistics, managed by the National Transplant Center, the Veneto Regional Transplant Center and the Portuguese institutions, the kidney of the Italian donor was removed in Vicenza and transplanted in Porto in a 41-year-old man while the Italian patient was transplanted with a kidney donated by a 36-year-old woman. The organs were harvested in the two centers simultaneously on the morning of 20 July. The Portuguese kidney arrived at Treviso airport at 2.10 pm on board a Lusitanian Air Force flight: the military delivered the organ to the regional transplant coordinator of the Veneto, Dr. Giuseppe Feltrin, receiving the Italian kidney in exchange. The 118 of Vicenza immediately transported the organ to San Bortolo where the transplantation began immediately. Both surgeries were successful and all recipients and donors went home in excellent condition."

Organ transplants between Hong Kong and mainland China: the promise and the politics

 This is a followup post to an earlier post# about the first cross border transplant in China between the mainland and Hong Kong. That's been followed by some political tensions, as reported in this forthcoming article in the American Journal of Transplantation.

A plan to save lives: Hong Kong–mainland China second-tier mutual assistance allocation. The new program between the transplant communities plays out on a backdrop of controversy and historical tension  by Lara C. Pullen, PhD, Published:July 28, 2023DOI:https://doi.org/10.1016/j.ajt.2023.07.015

"Key points:

"The transplant communities of Hong Kong and mainland China have proposed a second-tier mutual assistance allocation program that some find controversial.

• Tensions between Hong Kong and mainland China have a long and deep history.

• In 2014, the Chinese government announced a stop to obtaining organs from executed prisoners.

• Transplantation in mainland China has rapidly evolved, and people monitoring the change report that data from 10 to 15 years ago does not reflect the country’s current system."

**********

The background:

In December, the South China Morning Post carried this story about a transplant involving an organ recovered on the mainland and transplanted into a baby in Hong Kong, which was apparently the first such  transplant to cross that border:

4-month-old Hong Kong girl suffering from heart failure receives successful transplant with donated organ from mainland China, in city’s first such arrangement by Cannix Yau

One of the subheadlines is "Health Bureau notes importation of organ met relevant regulations, and hospital officials say arrangement involving mainland might be repeated in future"

***

And here's the story in the China Daily:

Securing a new lease of life By Li Bingcun | HK EDITION | Updated: 2023-03-31 15:10

"Hong Kong and the Chinese mainland have successfully carried out the first-ever cross-boundary organ-sharing operation, saving the life of an infant. The feat caps the city’s strenuous efforts to create a standing mechanism in organ sharing with the mainland to save more lives. Li Bingcun reports from Hong Kong."

***

Apparently the discussion of closer cooperation between transplant authorities in Hong Kong and the mainland is politically fraught. 

Here's a story from the Global Times that refers to some pushback from the mainland:

First organ donation between mainland and HK saves 4-month old baby By Wan Hengyi

"the acceptable heart donation for Cleo requires a donor weighing between 4.5 kilograms and 13 kilograms, and the chances of a suitable donor appearing in Hong Kong are slim to none. 

...

"COTRS initiated the allocation of a donated heart of a child with brain death due to brain trauma in the mainland on December 15. As a very low-weight donor, no suitable recipients were found after multiple rounds of automatic matching with 1,153 patients on a national waiting list for heart transplants in the COTRS system. In the end, the medical assistance human organ-sharing plan between the Chinese mainland and Hong Kong was launched.

"Some netizens from the Chinese mainland asked why a baby from Hong Kong who has not lined up in the COTRS system can get a donated heart when there is a huge shortage of donated organs in the mainland.

"In response, the organ coordinator told the Global Times that the requirements for organ donation are extremely high, noting that all the prerequisites including the conditions of the donor and recipient, the time for the organ to be transported on the road and the preparation for surgery must reach the standards before the donation can be completed.

"The COTRS system has already gone through several rounds of matching, which is done automatically by computer without human intervention, said the organ coordinator. "

...

"As of the end of October 2022, a total of 42,500 donors had donated more than 126,300 large organs in China, according to Guo Yanhong, director of the medical emergency department of the NHC."

******

Here's a story from the Guardian, about political concerns on the Hong Kong side:

Hongkongers opt out of organ registry ‘amid fear of Chinese donations’      by Amy Hawkins

"Thousands of Hongkongers have opted out of the city’s organ donor registry, seemingly as a form of subtle protest against proposals to establish deeper medical ties with mainland China.

...

"The trigger appears to have been a life-saving operation carried out in December on a four-month-old baby girl in Hong Kong, who was in need of a heart transplant. When a local match could not be found, a heart was transferred from a child who had suffered brainstem death in mainland China.

...

"Since the baby’s heart transplant, authorities have discussed the idea of establishing a mutual assistance registry with mainland China to facilitate future donations. That would be yet another erosion of the boundary between China and Hong Kong, which was supposed to remain largely autonomous from Beijing until 2047.

"Earlier this month, local news outlet Ming Pao reported that there had been discussion on social media among Hongkongers who did not want their organs donated to patients in mainland China."

********

China has a population approaching 1.5 Billion people, and Hong Kong is a city of about 7.5 Million people, so my guess is that HK is too small to have an efficient self-contained transplant system, and could benefit from being integrated into the mainland's system.

********

#Here's my earlier (contemporaneous) post:

Tuesday, January 10, 2023

Cross-border transplantation between China and Hong Kong

Argentine presidential politics, and monetary markets for kidneys

 The Financial Times reports on the surprising primary election performance of a far right candidate, Javier Milei.

Argentina radical rightwinger shakes up presidential race with primary win. by Ciara Nugent

"Javier Milei, a radical libertarian economist and outsider candidate, unexpectedly won Argentina’s primary poll, indicating a strong shift to the right as the South American country prepares to vote in a presidential election.

"Milei, a former television personality and one-term congressional representative who has called for extreme austerity and dollarising Argentina’s economy, won 30.1 per cent of the vote on Sunday, surpassing pollsters’ average forecast of 20 per cent, with 96 per cent of votes counted.

"That put his Freedom Advances party ahead of centre-right force Together for Change, with 28.3 per cent, and the ruling populist coalition Union for the Homeland, whose candidate is centrist economy minister Sergio Massa, which earned 27.2 per cent."

**********

I'm not a close follower of Argentine politics, but his name rang a bell, and reminded me that I had blogged about him in connection of his support for markets for kidneys. (There's no indication that was an issue in the presidential primaries...)

Wednesday, June 15, 2022

An unusual Argentine presidential candidate supports a monetary market for kidneys

Affirmative action in Brazilian universities: guest post by Inácio Bó

 Recent legislation in Brazil addresses university admissions with affirmative action that targets multiple characteristics that individuals may have (in different combinations), namely income, ethnicity, and the type of institution at which they studied. Early attempts to implement such a system produced undesirable outcomes, but recent legislation, informed by market design, is on the path to correcting this. Below, Inácio Bó brings us up to date:

Guest blog post by Inácio Bó

For many decades, Brazilian’s federal universities were—and still are— the top higher education institutions in the country. They had, however, a contradictory combination of circumstances: all of them were public-funded and tuition-free, but their students were overwhelmingly from a minority white higher socio-economic class. In response to that, in 2012 congress passed legislation mandating affirmative action in the access of all such institutions.

Orhan Aygün and I were at that time classmates pursuing our PhD in economics at Boston College. We spent days and weeks looking at the details of the structure of the rules for implementing the law, trying to better understand it. While working on some examples, we noticed that there could in principle be situations that were at odds with the intended objective of the law. Under some circumstances, black and low-income candidates would be rejected from positions where white and high-income candidates would be accepted, despite the former having higher entry-level exam grades than the latter. This  would be an outcome that goes in the opposite direction from the intended objective of helping black and low-income students attend these institutions.

The reason for this problem lies on the method used for implement the affirmative action law in the universities. Seats in each program in each university were split into groups of seats, including “open seats”, “black candidates”, “low-income candidates”, and “black and low-income candidates”. When applying for a program, a candidate would choose one of the alternatives for which she is eligible. The top candidates among those applying for each set of seats, ranked by their grade in a national exam, would be accepted. This method might, however, result in different levels of competition for different seats in the same program, resulting for example in tougher requirements for acceptance for “black and low-income” candidates than for “black” candidates, even if on average low-income candidates have lower grades overall.

In a paper published in the AEJ:Micro in 2021 (Aygün, Orhan, and Inácio Bó. 2021. "College Admission with Multidimensional Privileges: The Brazilian Affirmative Action Case." American Economic Journal: Microeconomics, 13 (3): 1-28.), we showed how this problem can be solved while still satisfying the text and spirit of the affirmative action law in Brazil with small changes in the way by which candidates are selected. (The idea is to order slot-specific priorities so that candidates with protected characteristics can compete for all of those slots for which their characteristics qualify them.) The paper also shows “smoking gun” evidence that these “unfair rejections” were taking place, showing that programs where the cutoff grades for acceptance for each subset of seats were compatible with these rejections constituted almost half of the programs offered across the nation.

While the article gained praise in the academic economic community, our hopes that it would reach the policymakers in Brazil were initially dashed. Despite having the chance of personally visiting the Ministry of Education in 2015 for two weeks, my attempts to talk with those in power were unsuccessful, and people to whom I explained some of our findings deemed its contents “critical of the government”.

 Especially in light of the political developments that took place in Brazil in the years that followed, I had mostly moved on from my hopes of seeing the changes we proposed being implemented.

Things started to change, however, around May of 2022. The staff from the office of representative Tábata Amaral, who is a prominent young politician with a focus on education, were having talks with Ursula Mello, now a professor at the Department of Economics at PUC-Rio in Rio de Janeiro, about some aspects of the affirmative action law related to her work. Given her knowledge about the AEJ:Micro paper, Ursula suggested that I join the discussions. A meeting where this happened even ended up in the press (https://www1.folha.uol.com.br/educacao/2022/05/pesquisadores-defendem-novo-algoritmo-no-sisu-para-nao-prejudicar-cotistas.shtml).

Adriano Senkevics, her co-author in related papers who works at the INEP—an agency connected to the Brazilian Ministry of Education in charge of evaluating educational systems—also joined.

In these discussions, it became clear that if we wanted our ideas to have any chance of gaining traction, we needed to write a policy-oriented paper, focused on the current Brazilian specifics, in Portuguese, and with policy-makers as the audience—not academics.

Adriano and I worked together in that project, now with a much more detailed dataset. We tailored the proposal to the updated law, which also included reservations for candidates with disabilities, and were finally able to quantify the negative impact of the failures we identified. Our estimates indicate that, in the selection process of 2019, at least ten thousand students were “unfairly rejected” from their applications, with more than 8 thousand being left unmatched to any university despite having an exam grade high enough to be accepted for less restrictive reserved seats. These numbers greatly exceeded our expectations, and made a clear political case for a change. The working paper went out in January of 2023 (“Proposal to change the rules for the occupation of quotas in the student entrance to federal institutions of higher education,” by Inácio Bó and Adriano Souza Senkevics).

While the theoretical arguments were already in the AEJ:Micro paper, the proposal had a greater and faster impact in the corridors of the Brazilian capital. Articles in the main newspapers in the country reported on the findings and the proposal (https://oglobo.globo.com/brasil/educacao/enem-e-vestibular/noticia/2023/03/quase-650-candidatos-para-uma-vaga-maiores-concorrencia-do-sisu-estao-entre-os-alunos-cotistas.ghtml

, https://oglobo.globo.com/brasil/antonio-gois/coluna/2023/02/reformar-o-sisu.ghtml

, https://www1.folha.uol.com.br/colunas/rodrigo-zeidan/2023/04/desenhando-mercados.shtml )

People were openly sharing the article on twitter with members of the ministry of education

(https://twitter.com/thiamparo/status/1621189953785839617?s=20 ,

https://twitter.com/mgaldino/status/1621008428763332612?s=20 ). We could feel the momentum.

In the months that followed, I started having regular interactions with members of the Ministry of Education. The text and zoom discussions involved technical and political aspects of changes in the law, which extended beyond the specific changes we suggested.

Different variations of the changes and some alternative proposals were considered. I had to run simulations while flying to deliver them before a meeting that the secretary had with the minister. I also had the incredible experience of joining a meeting at the “Casa Civil”—a department somewhat comparable to the prime minister in a parliamentary system—with the presence of secretaries from multiple ministries , where I presented our proposal and discussed some details and scenarios. Around that time, and without our knowledge, a senator presented a bill explicitly based on our proposal (https://www25.senado.leg.br/web/atividade/materias/-/materia/156995 ).

By the end of June, our belief that the changes would be implemented became stronger. Since our proposal was (by design) already compatible with the quotas law, its implementation could be done even in the absence of new legislation, and there was clear interest on the part of those in charge for making it happen.

A momentous event in this journey, however, took place on August 9th.

Because of a series of political circumstances, an urge to pass a renewed law for the affirmative action led to a bill proposed by Representative Dandara—the first member of congress who herself benefitted from the quotas law—to be brought to the floor for a vote.

Among other changes, it made the affirmative action policy permanent, changed the order in which seats are filled, and included text that should, in the following secondary legislation, include text that describes our proposal. As if emotions were not high enough, we had urgent calls to send the text of our proposal to members in the floor of congress minutes before the vote took place. And this resulted in the photo below, showing Dandara giving a speech before the vote, with a page from our paper in her hand.

The journey is not yet over. The bill must still pass the senate, and the legislation with the implementation details will follow. But I learned that these changes are made of so many steps that one has to choose one as the turning point. We believe that this is a good one.

The INEP (National Institute of Educational Studies and Research) thinks so too: (https://www.gov.br/inep/pt-br/assuntos/noticias/linha-editorial/inep-contribui-com-atualizacao-da-lei-de-cotas)

The high out-of-pocket cost of donating a kidney. By Martha Gershun

 Martha Gershun continues to write eloquently about the obstacles to kidney donation.  

Here she is in Stat:

The high out-of-pocket cost of donating a kidney. By Martha Gershun 

"Five years have now passed since I donated my kidney, and both Deb and I are doing well....

"My husband and I are comfortable financially. We could afford the $5,000 in gasoline, hotels, and food for the 19 nights we spent travelling to the Mayo Clinic for my medical evaluation, surgery, recovery, and six-month follow-up visit. Our children are grown and our parents are gone, so we had no child care or elder care expenses (though we did have to pay a cat sitter for the time we travelled). And neither of us had to forgo any wages: At 61, I had already retired from paid work, and the generous PTO policy at the nonprofit where my husband was CEO covered the 128 hours of work he missed to travel with me and help with my recovery.

 "We did not qualify for assistance from the National Living Donor Assistance Center (NLDAC), because my recipient’s income was more than 300% of the current Health and Human Services (HHS) Poverty Guidelines (this has recently been raised to 350%). In fact, my recipient generously insisted on reimbursing us for our out-of-pocket expenses. This is not considered direct compensation for an organ, so is legal under the National Organ Transplant Act (NOTA).

But all of that was just our good fortune. What about potential organ donors without our resources? It is very easy to imagine someone in a low-wage hourly job who wants to donate a kidney to their sister, a married mother of two, who, along with her spouse, has an annual household income slightly above $105,000, which is 350% of the current HHS Poverty Guidelines. That potential donor, unable to access help from NLDAC, would be unable to afford the out-of-pocket expenses or lost wages. There would be no living donation; the patient would remain on the kidney transplant waiting list, along with 93,000 others.

Every living kidney donor saves private insurance or Medicare significant expense — experts estimate between $250,000 and $500,000 over the lifetime cost of dialysis for each kidney patient they help. Every living kidney donor enables the hospital and the surgeons, nephrologists, nurses, and other staff who work there to earn money for their transplant work. But the kidney donor — the one person who gives away a part of their body to make this miracle possible — is forced to incur financial losses to participate.

Recognizing this problem, New York state recently passed the Living Donor Support Act, the first law that provides living organ donors in the United States reimbursement for donation-related expenses, including lost wages, travel, lodging, and child care.

"Congress just revised the 1984 law that set up the United Network for Organ Sharing (UNOS) as the sole contract holder to run the country’s organ transplant system. Hopefully, this will have a tremendous impact on the way the system procures, allocates, and distributes organs from deceased donors. A better functioning transplant system, with improved technology and a better process for wait list management, could help living donors, but this legislation does nothing to help living donors overcome the financial barriers to organ donation.

...

"Individuals should not have to pay out of their own pocket to save someone else’s life."

Fall workshops in Mathematics and Computer Science of Market and Mechanism Design

 Here's an update on the three scheduled workshops connected to the SLMath (formerly MSRI) semester focus on market and mechanism design. (There will be two in September and one in November.)

"Mathematics and Computer Science of Market and Mechanism Design" Register for Fall 2023 Workshops at SLMath (MSRI) in Berkeley, California and Online     In recent years, economists and computer scientists have collaborated with mathematicians, operations research experts, and practitioners to improve the design and operations of real-world marketplaces. Such work relies on robust feedback between theory and practice, inspiring new mathematics closely linked – and directly applicable – to market and mechanism design questions. Established researchers, postdoctoral fellows, and graduate students are invited to join world-renowned mathematicians, computer scientists, economists, and other experts at these hybrid events at the Simons Laufer Mathematical Sciences Institute (SLMath, formerly MSRI) in Berkeley, California.   September 7-8, 2023: Connections Workshop Organizers: Michal Feldman (Tel-Aviv University), Nicole Immorlica* (Microsoft Research) The Connections Workshop will consist of invited talks from leading researchers at all career stages in the field of market design. Particular attention will be paid to real-world applications. There will also be an AMA (Ask Me Anything) session focused on career paths with highly visible individuals in the field, and a social event intended to help workshop attendees network with each other.   Register for the Connections Workshop   September 11-15, 2023: Introductory Workshop Organizers: Scott Kominers (Harvard Business School), Paul Milgrom (Stanford University), Alvin Roth (Stanford University), Eva Tardos (Cornell University) The workshop will open with overview/perspective talks on algorithmic game theory and the theory and practice of market design; the afternoon will feature a panel on active research areas in the field (again, at the overview level). The next 2 days will consist of introductory mini-course and tutorials, on topics such as game theory, matching, auctions, and mechanism design. The following day will focus on applicable tools and technology, such as lattice theory, limit methods, continuous optimization, and extremal graph theory. The workshop will conclude with a panel discussion on major open problems.   Register for the Introductory Workshop   November 6-9, 2023: Algorithms, Approximation, and Learning in Market and Mechanism Design Organizers: Martin Bichler (Technical University of Munich), Péter Biró* (KRTK, Eotvos Lorand Research Network) The workshop is aimed at exploring core subjects in the field of market and mechanism design, such as the design of non-convex auction markets, the design of matching markets with preferences, algorithmic mechanism design, and learning in games and markets. These topics are interrelated and deeply rooted in mathematics and computer science. Each day of the 4-day workshop is devoted to one of these topics with talks by leading scholars in the field and panel discussions on major open problems.    Register for the November Workshop   Registration is open for both in-person and online-only attendees through each workshop's scheduled dates. Those who plan to attend via Zoom will receive workshop links in advance of the event. For assistance with registration questions, contact coord@slmath.org. SLMath workshops are free of charge to attend, thanks to the generous support of our funders, including the National Science Foundation and the Alfred P. Sloan Foundation.

Repugnance watch: British satire considers cellular agriculture in human meat

In The Conversation:

The British Miracle Meat: how banning repugnant choices obscures the real issue of poverty  by Renaud Foucart

"A provocative Channel 4 satirical programme, The British Miracle Meat, has led to hundreds of complaints to media regulator Ofcom. The mockumentary depicts ordinary Britons facing the cost of living crisis selling thin slices of their tissue to an innovative factory that uses it to grow lab meat.

The show was inspired by Jonathan Swift’s satire A Modest Proposal (1726), in which the author of Gulliver’s Travels suggests poor Irish people sell their children for food. The Channel 4 show’s creators wanted to make viewers think about the effects of the cost of living crisis, as well as the future of food.

Viewers were left baffled, however, seeing the show as promoting cannibalism. In the UK, it is illegal to sell human organs and other tissues. But in economics, we teach our students the theory of “repugnant markets” – those in which disgust or distaste lead governments to ban certain transactions rather than tackling the underlying economic reasons for them."

Freezing (and then carefully warming) donor organs breaks the organ transplant time barrier (for rats, for the time being)

 Here's a note in Nature Reviews Nephrology pointing out the longer term promise of the recent successful freezing, thawing, and transplantation of rat kidneys.

Cryopreservation breaks the organ transplant time barrier by Marlon J. A. de Haan & Ton J. Rabelink, in Nature Reviews Nephrology (2023)

"The pressing issue of organ shortages for transplantation is fuelled by the rising incidence of kidney failure and the declining quality of organs from an ageing donor pool. However, the main bottleneck in organ transplantation is time; indeed, the current clinical standard for kidney preservation necessitates immediate transplantation following organ recovery1. This urgency often results in suboptimal matches between donors and recipients. Cryopreservation has emerged as a potential solution to this challenge. Such an approach would enable organs to be preserved in a suspended state for extended periods and ready for transplantation on demand. The prospect of long-term banking of cryopreserved organs holds promise for transforming organ transplantation into an elective procedure, thereby enhancing donor–recipient matching, improving equity in access, optimizing patient preparation, refining transplant tolerance protocols, increasing organ utilization and improving graft and patient survival. However, even though cryopreservation has successfully been used to store human embryos, extending the process to preserve whole organs has remained a scientific aspiration — until now. A study by Han et al. introduces an approach to cryopreservation that seemingly extends the shelf life of organs indefinitely2."

...

"By rapidly cooling rat kidneys to –150°C, Han et al. were able to halt the biological clock of the organs, effectively inducing a glass-like state — a process known as vitrification2 (Fig. 1). Specifically, the researchers perfused a cocktail of cryoprotective agents (CPAs) and iron oxide nanoparticles into the organ’s vasculature, which they followed by rapid cooling to ultralow temperatures to achieve a state of vitrification. This vitrified kidney, with its hard, smooth, glasslike appearance, was then transferred to a –150°C freezer for long-term banking. When these kidneys were later rewarmed and transplanted into nephrectomized recipients, they regained life-sustaining renal function. The rewarming stage poses more challenges to the process of cryopreservation: it requires both speed to avoid ice formation during devitrification and uniformity to prevent thermal stresses and mechanical cracks. Here, the iron oxide nanoparticles had a crucial role. Placing the vitrified kidney in a coil that generates electromagnetic fields activates these nanoparticles, generating heat. This innovative approach enabled rapid rewarming at an impressive rate of approximately 72 °C per minute throughout the entire organ, ensuring uniform warming rather than limiting warming to the organs’ surface. This ground-breaking milestone marks an extraordinary achievement in ‘reviving’ a complex organ like the kidney and is the culmination of decades of research into methods to prevent the destructive formation of ice during the cooling process, minimize toxicity from CPAs, and enable fast and uniform rewarming3.

***********

Recently:

Wednesday, June 28, 2023

Freezing, thawing and transplanting a rat kidney: a first step towards organ banking

Ned Brooks on Coalition to Modify NOTA

Ned Brooks (about whom I've often blogged) is putting his eloquence and organizational skills to the task of increasing organ donation by allowing organ donors to be compensated. Below is a short video of an address he gave to the National Kidney Donation Organization (NKDO) which he founded, about his new effort, the Coalition to Modify NOTA.

 

Here's a copy of the email that came with the video:

To the NKDO Membership:   Thank you for your responses to the survey asking if NKDO should support the Coalition to Modify NOTA (CMN), formed by non-directed donors Ned Brooks, Elaine Perlman and Cody Maynard.   87% of our membership supports the mission statement of CMN as follows:   The Coalition to Modify NOTA (ModifyNOTA.org) is created in response to the inability of the current system to adequately address the crisis of kidney failure in the United States. The National Organ Transplant Act of 1984 prohibits the compensation of organ donors.   The current system of deceased donations and voluntary living donation is grossly inadequate to the task of completely ending the shortage of transplant kidneys and saving the lives of patients in kidney failure who are dying unnecessarily each year.  We believe that the solution to this crisis is to have the government compensate donors in a manner that is neither exploitative nor coercive. The Coalition to Modify NOTA seeks the modification of the National Organ Transplant Act to allow such government compensation.   Watch this presentation on the Coalition to Modify NOTA by Ned Brooks.   To sign your name in support of the Mission Statement, please go to Join the Coalition.   Kind regards,   Matt Cavanaugh, CEO and President

SITE 2023 Session 5: Experimental Economics Thu, Aug 10 - Fri, Aug 11 2023

 SITE 2023 Session 5: Experimental Economics   Thu, Aug 10 2023, 9:00am - Fri, Aug 11 2023, 5:00pm PDT

John A. and Cynthia Fry Gunn Building, 366 Galvez Street, Stanford, CA 94305

ORGANIZED BY Christine Exley, Harvard University  Kirby Nielsen, California Institute of Technology  Muriel Niederle, Stanford University  Alvin Roth, Stanford University  Lise Vesterlund, University of Pittsburgh

This session will be dedicated to advances in experimental economics combining laboratory and field-experimental methodologies with theoretical and psychological insights on decision-making, strategic interaction and policy. We are inviting papers in lab experiments, field experiments and their combination that test theory, demonstrate the importance of psychological phenomena, and explore social and policy issues. In addition to senior faculty members, invited presenters will include junior faculty as well as graduate students.

Thursday, August 10, 2023

9:00 AM - 9:30 AM PDT  Breakfast and Welcome

AUG 10 9:30 AM - 10:00 AM PDT

Information Avoidance and Image Concerns

Presented by: Judd Kessler (The Wharton School)

Co-author(s): Christine L. Exley (Harvard University)

A rich literature finds that individuals avoid information and suggests that avoidance is driven by image concerns. This paper provides the first direct test of whether individuals avoid information because of image concerns. We build off of a classic paradigm, introducing control conditions that make minimal changes to eliminate the role of image concerns while keeping other key features of the environment unchanged. Data from 6,421 experimental subjects shows that image concerns play a role in driving information avoidance, but a role that is substantially smaller than one might have expected.

AUG 10 10:00 AM - 10:30 AM PDT

Transactional Preferences and the Minimum Wage

Presented by: Kristóf Madarász (London School of Economics)

Co-author(s): Anna Becker (Stockholm University), Attila Lindner (University College London), and Heather Sarsons (University of British Columbia)

A growing number of studies suggest that minimum wages have limited disemployment effects while at the same time increasing output prices. This finding contradicts the ”law of demand”, which states that output demand, and therefore employment, should fall whenever prices increase. We propose a simple framework to explain this fact and to highlight some aspects of ethical consumption more generally. Consumers derive extra utility when engaging in transactions that can be associated with positive moral attributes. In the context of the minimum wage, consumers derive a higher marginal utility when they know that the good they are consuming is produced by a worker earning a higher wage. Combined with firms’ inability to credibly commit to higher wages, a mandated minimum wage policy can lead to higher output and positive employment effects simultaneously. We implement an online survey experiment in the U.S. to test for the proposed mechanism. We use our findings to reassess the welfare implications of the policy.

AUG 10 10:30 AM - 11:00 AM PDT

Assessing Behavioral Incentive Compatibility

Presented by: Lise Vesterlund (University of Pittsburgh)

AUG 1011:00 AM - 11:30 AM PDT Break

AUG 10

11:30 AM - 12:00 PM PDT

Connecting Common Ratio and Common Consequence Preferences

Presented by: Charlie D. Sprenger (Caltech)

Co-author(s): Christina McGranaghan (University of Delaware), Kirby Nielsen (California Institute of Technology), Ted O’Donoghue (Cornell University), and Jason Somerville (Federal Reserve Bank of New York)

Many models of decision-making under uncertainty are motivated by two prominent deviations from expected utility (EU): the common consequence effect (CCE) and the common ratio effect (CRE). Both decision problems were originally proposed as thought experiments by Allais (1953), and later popularized by Kahneman & Tversky (1979). The apparent deviations from EU predictions in each problem have motivated a wide body of decision theories in risky choice.

Although the CRE and CCE both represent violations of the EU axiom of independence, they have been studied mostly independently, and using quite different experimental parameters. In fact, however, the two decision problems are closely related: If conducted at a common set of experimental parameters, the two problems would share three out of four possible options. Moreover, the connections between the two problems are relevant for assessing various non-EU models—i.e., different models predict specific patterns.

In this paper, we extend existing empirical tests by (i) explicitly recognizing the connection between the two decision problems; (ii) conducting a large number of experiments covering connected CRE and CCE problems at different experimental parameters; and (iii) implementing experiments using both paired choice tasks (for comparison to the prior literature) and paired valuation tasks (our preferred approach given the inferential challenges outlined in McGranaghan et al (2022)).

Our results provide important insights on the shape of risk preferences. We find small but significant CR preferences, but systematic reverse CC preferences. Through their connection, this pattern implies that individuals violate betweenness by preferring mixtures. These results are inconsistent with leading non-EU models, and we propose a model to rationalize these findings.

AUG 10  12:00 PM - 12:30 PM PDT

Beliefs in a High-Stakes Environment

Presented by: Stephanie Wang (University of Pittsburgh)

Co-author(s): Yiming Liu (Humboldt University of Berlin)

It has been well-documented that people tend to be overconfident. We investigate whether biased beliefs in performance persist in a high-stakes environment. Specifically, we ask whether students are overconfident when estimating their high school entrance exam performance. Students in our environment have strong incentives to accurately assess their exam scores because they need to submit their rank order list under an immediate acceptance mechanism before knowing their exam performance. Combining administrative and survey data on estimated performance and actual performance, we find no evidence for overconfidence in estimation in this high-stakes environment. However, when we remove the high stakes by eliciting students’ recall of their performance in a previous mock exam, they show a strong pattern of overconfidence. Consistent with Benabou and Tirole  ́ (2002)’s theory of the supply of biased beliefs through biased memory, we find suggestive evidence that students rely on their potentially biased memory of past performance to construct their high-stakes estimation.

AUG 11 12:30 PM - 2:0

AUG 10 12:30 PM - 2:00 PM PDT Lunch/Discussion

AUG 10 2:00 PM - 2:15 PM PDT

Procedural Decision-Making in the Face of Complexity

Presented by: Gonzalo Arrieta (Stanford University)

Co-author(s): Kirby Nielsen (California Institute of Technology)

Individuals often change their decision-making in response to complexity, as has been discussed for decades in psychology and economics, but existing literature provides little evidence on the general characteristics of these processes. We introduce an experimental methodology to show that in the face of complexity, individuals resort to “procedural” decision-making, which we categorize as choice processes that are more describable. We elicit accuracy in replicating decision-makers’ choices to experimentally measure and incentivize the choice process’ describability. We show that procedural decision-making increases as we exogenously vary the complexity of the environment, defined by the choice set’s cardinality. This allows for procedural reinterpretations of existing findings in decision-making under complexity, such as in the use of heuristics.

AUG 10 2:15 PM - 2:30 PM PDT

What Drives Violations of the Independence Axiom? The Role of Decision Confidence

Presented by: Aldo Lucia (California Institute of Technology)

Recent theoretical work implicates decision confidence as a central component of decision-making under uncertainty, attributing failures of Expected Utility (EU) to a lack of confidence. We design an experiment testing EU’ central independence axiom and contemporaneously eliciting measures of decision confidence. We find that choices characterized by high self-reported levels of decision confidence and low response times are more likely to com-ply with the independence axiom. Contrary to the common certainty effect rationale for independence violations, we show that subjects predominantly violate EU by choosing risky lotteries over certain amounts when they are unconfident in their choices.

AUG 10 2:30 PM - 2:45 PM PDT

Does Artificial Intelligence Help or Hurt Gender Diversity? Evidence from Two Field Experiments on Recruitment in Tech

Presented by: Mallory Avery (Monash University)

Co-author(s): Andreas Leibbrandt (Monash University) and Joseph Vecci (University of Gothenburg)

The use of Artificial Intelligence (AI) in recruitment is rapidly increasing and drastically changing how people apply to jobs and how applications are reviewed. In this paper, we use two field experiments to study how AI in recruitment impacts gender diversity in the male-dominated technology sector, both overall and separately for labor supply and demand. We find that the use of AI in recruitment changes the gender distribution of potential hires, in some cases more than doubling the fraction of top applicants that are women.This change is generated by better outcomes for women in both supply and demand. On the supply side, we observe that the use of AI reduces the gender gap in application completion rates. Complementary survey evidence suggests that this is driven by female jobseekers believing that there is less bias in recruitment when assessed by AI instead of human evaluators. On the demand side, we find that providing evaluators with applicants’ AI scores closes the gender gap in assessments that otherwise disadvantage female applicants. Finally, we show that the AI tool would have to be substantially biased against women to result in a lower level of gender diversity than found without AI.

AUG 10 2:45 PM - 3:00 PM PDT

Regulation of Organ Transplantation and Procurement: A Market Design Lab Experiment

Presented by: Alex Chan (Harvard University)

Co-author(s): Alvin E. Roth (Stanford University)

We conduct a lab experiment that shows current rules regulating transplant centers (TCs) and organ procurement organizations (OPOs) create perverse incentives that inefficiently reduce both organ recovery and beneficial transplantations. We model the decision environment with a 2-player multi period game between an OPO and a TC. In the condition that simulates current rules, OPOs recover only highest-quality kidneys and forgo valuable recovery opportunities, and TCs decline some beneficial transplants and perform some unnecessary transplants. Alternative regulations that reward TCs and OPOs together for health outcomes in their entire patient pool lead to behaviors that increase organ recovery and appropriate transplants.

AUG 10 3:00 PM - 3:30 PM PDT Break

AUG 10 3:30 PM - 3:45 PM PDT

Memory and the Persistence of Gender Discrimination

Presented by: Francesca Miserocchi (Harvard University)

Standard models of discrimination assume that decision-makers use all the available information about candidates when making their decisions. Based on research in psychology, I test the hypothesis that when decision-makers have a lot of other information in their mind, they are less likely to remember how particular individuals performed and fall back on stereotypes, which disadvantages women in predominantly male-dominated fields. First, in years when teachers need to evaluate a larger number of students – amplifying memory constraints – girls are considerably less likely to be recommended for top-tier scientific high school tracks. On the contrary, the gender gap in students’ objective math ability does not expand during these years. Second, I conduct an experiment in which teachers assign track recommendations for hypothetical student profiles. Teachers are less likely to recommend girls to scientific tracks if they freely recall the information about them than when they can reference the information (proxying a perfect memory benchmark). Third, when asked to remember a candidate’s past performance on a series of trivia questions in sports and pop-culture, participants tend to remember a higher share of correct sports questions when they are answered by a boy than by an identical girl. The opposite is true for pop-culture questions. The results suggest that a significant portion of gender discrimination is driven by imperfect and selective memory of previously observed information, opening up the scope for policy interventions in the form of structured reminders.

AUG 10  3:45 PM - 4:00 PM PDT

Revealed Preference when Attention is Selective and Malleable

Presented by: John Conlon (Stanford University)

I show experimentally that information persuades not only by shifting beliefs but also by redirecting attention. Participants in my experiment decide whether to purchase a multi-attribute good. At baseline, selective attention generates large distortions in how responsive demand is to the values of these attributes. Randomly providing information about the value of one attribute, even when it is already known and transparently redundant, starkly increases responsiveness to that attribute and distracts attention from others. These forces can produce paradoxical responses to correcting beliefs: reducing overoptimism about an attribute can nonetheless boost demand for its associated good. 

AUG 10  4:00 PM - 4:15 PM PDT

Interventionist Preferences and the Welfare state: The Case of In-Kind Nutrition Assistance

Presented by: Tony Q. Fan (Stanford University)

Co-author(s): Sandro Ambuehl (University of Zurich), B. Douglas Bernheim (Stanford University), and Zach Freitas-Groff (Stanford University)

Poverty assistance is often administered in-kind even though cash transfers might raise recipients’ welfare more effectively. We characterize the political economy constraint that paternalistic motives impose on the welfare system. In our experiment, a representative sample of U.S. citizens reveal their motives by deciding whether to constrain real U.S. food stamp recipients’ choices between in-kind donations and cash equivalents we disburse. The modal respondent (40%) imposes the strictest possible constraints, while 30% impose no constraints. Hence, the majority’s behavior is consistent with deontological motives rather than trade-off thinking. Yet, because of biased beliefs about recipient preferences, respondents underestimate the restrictiveness of their interventions, suggesting that they are partly misguided. Overall, respondents’ goal is not to ensure sufficient healthy nutrition, but to prevent consumption of items deemed inappropriate. While respondents reveal racial and gender stereotypes in various survey questions, neither donor nor recipient demographics have substantial effects on restriction decisions, though restrictions increase with respondents’ political conservatism. In-experiment behavior correlates strongly with views about government policy.

AUG 10  5:00 PM - 8:00 PM PDT  Dinner at Muriel’s House

Friday, August 11, 2023

9:00 AM - 9:30 AM PDT Breakfast and Welcome

AUG 11 9:30 AM - 10:00 AM PDT

Sleep: Educational Impact and Habit Formation

Presented by: Silvia Saccardo (Carnegie Mellon University)

Co-author(s): Osea Giuntella (University of Pittsburgh) and Sally Sadoff (University of California San Diego)

In a field experiment among undergraduates, we test the impact of interventions to increase sleep on sleep habits and academic achievement. Offering incentives contingent on sleeping at least 7 hours per night increases sleep during both the four-week treatment period and the one to five-week post-treatment period. The intervention also significantly increases GPA at the end of the semester. Our estimates suggest that causally increasing sleep by an average of 6 - 16 minutes per night improves GPA by 0.12 - 0.14 standard deviations. We additionally examine the role of timing of rewards and reminders and feedback for improving sleep habits. We find that immediate incentives combined with reminders and feedback have the largest impact during treatment, but do not outperform delayed incentives or reminders and feedback alone during the post-intervention period. Our results suggest that interventions targeting sleep are a cost-effective tool for improving educational outcomes.

AUG 11 10:00 AM - 10:30 AM PDT

Describing Deferred Acceptance to Participants: Experimental Analysis

Presented by: Ori Heffetz (Cornell University and Hebrew University)

Co-author(s): Yannai Gonczarowski (Harvard University), Guy Ishai (Hebrew University of Jerusalem), and Clayton Thomas (Princeton University)

Designed markets often rely on carefully crafted descriptions of mechanisms. By and large, these descriptions attempt to convey as directly as possible what the outcome of the market will be. Are there principled, alternative theories of how to construct descriptions to expose different properties of mechanisms? Recently-proposed menu descriptions aim to provide such a theory towards exposing the strategyproofness of real-world mechanisms such as Deferred Acceptance. We design an incentivized experiment to test the ability of a menu description of Deferred Acceptance (compared to a traditional description) to affect participant behavior and their understanding of strategyproofness. We also design treatments conveying the definition of strategyproofness itself rather than the full details of the mechanism, with one treatment inspired by traditional definitions and one inspired by menu descriptions.

AUG 11  10:30 AM - 11:00 AM PDT

Decomposing the Winner’s Curse in Common-Value Auctions: What is the Role of Contingent Thinking?

Presented by: Muriel Niederle (Stanford University)

AUG 11  11:00 AM - 11:30 AM PDT  Break

AUG 11  11:30 AM - 12:00 PM PDT

Stochastic Dominance and Preference for Randomization

Presented by: Séverine Toussaert (University of Oxford)

Decision theorists usually take a normative view on stochastic dominance: a decision maker who chooses a lottery that puts more weight on options he likes less must be making a mistake. In this paper, I argue that stochastic dominance violations may naturally occur in situations where anticipatory utility is high, such as going on a holiday trip. In such a situation, the decision maker may trade the certainty of going to his favorite destination for the excitement of not knowing where he will go. To document this phenomenon, I conduct an experiment in which participants make a series of binary choices between a sure destination and a lottery over holiday trips. The outcome of the lottery is revealed close to the date of travel. I vary the characteristics of the lotteries to understand when violations of stochastic dominance are most likely to occur and analyze their properties. I discuss the implications for the modelling of anticipatory utility.

AUG 11  12:00 PM - 12:30 PM PDT

Insensitive Investors

Presented by: Cary Frydman (University of Southern California)

Co-author(s): Constantin Charles (University of Southern California) and Mete Kilic (University of Southern California)

We experimentally study the transmission of subjective expectations into actions. Subjects in our experiment report valuations that are far too insensitive to their expectations, relative to the prediction from a frictionless model. We propose that the insensitivity is driven by a noisy cognitive process that prevents subjects from precisely computing asset valuations. The empirical link between subjective expectations and actions becomes stronger as subjective expectations approach rational expectations. Our results highlight the importance of incorporating weak transmission into belief-based asset pricing models. Finally, we discuss how cognitive noise can provide a microfoundation for inelastic demand in the stock market.

0 PM PDT  Lunch/Discussion

AUG 11  

2:00 PM - 2:30 PM PDT

The Experimenters' Dilemma: Inferential Preferences over Populations

Presented by: Alistair Wilson (University of Pittsburgh)

Co-author(s): Luca Rigotti (University of Pittsburgh) and Neeraja Gupta (University of Richmond)

We examine the experimenter’s preferences over different populations using statistical power under a fixed budget as the stand-in for the researcher’s utility. We consider five populations commonly used in experiments by economists: undergraduate students at a physical location, undergraduate students in a virtual setting, Amazon MTurk "workers", a filtered MTurk subset from CloudResearch, and Prolific. Focusing on noise due to inattention, observation costs dominate the comparisons, with the larger online population samples superior to the smaller lab samples. However, once we factor in responsiveness to treatment, the lab samples have greater power than either MTurk or Prolific.

AUG 11  2:30 PM - 3:00 PM PDT  Break

AUG 11 3:00 PM - 3:30 PM PDT

Quantifying Lottery Choice Complexity

Presented by: Benjamin Enke (Harvard University)

Co-author(s): Cassidy Shubatt (Harvard University)

We develop indices of the objective and subjective complexity of lottery choice problems that can be computed for any standard dataset. These indices reflect which choice set features increase error rates and cognitive uncertainty in gauging expected values. Using these measures, we study behavioral responses to complexity across one million experimental decisions. In line with a model of heteroscedastic cognitive noise, complexity (i) makes choices more inconsistent and regressive to people’s prior; (ii) predicts when subjects accept unattractive gambles; and (iii) spuriously generates complexity aversion and small-stakes risk aversion. In structural estimations, complexity-dependent heteroscedasticity improves model fit considerably more than prospect theory does.

AUG 11 3:30 PM - 4:00 PM PDT

Competing Causal Interpretations: A Choice Experiment

Presented by: Sandro Ambuehl (University of Zurich)

Co-author(s): Heidi C. Thysen (Norwegian School of Economics)

A central factor when choosing an action is its causal effect on the outcome of interest. Yet, causal information is often lacking. People instead observe correlational or historical data, along with causal interpretations and action recommendations provided by experts who frequently disagree with each other. We use a laboratory experiment to study human choice in such settings. Roughly half of our subjects attempt to determine the fit of the causal interpretations to past data, as the literature on model persuasion assumes, and we outline the limits to their ability to do so. Half the subjects’ choices are co-determined by the interpretations’ promises of future payouts, as the literature on narrative competition assumes, or by the downside these choices entail if they are mistaken. Additionally, subjects commonly employ heuristics such as Occam’s razor, but they usually prefer more complex interpretations to more parsimonious ones. We also study the extent to which behavior is robust to framing and has out-of-sample predictive power, as well as the relation between subjects’ choices and their political attitudes and psychological characteristics. Finally, we will characterize the contexts in which subjects’ behavioral tendencies expose them to the greatest losses and render them most receptive to misleading interpretations.

AUG 11 4:00 PM - 4:30 PM PDT

Extracting Models From Data Sets: An Experiment Using Notes-to-Self

Presented by: Guillaume Fréchette (New York University)

Co-author(s): Emanuel Vespa (University of California, San Diego) and Sevgi Yuksel (University of California, Santa Barbara)

We report results from an experiment designed to study how people extract patterns from their observations. The novel experimental design asks subjects to organize different sets of observations (data) with the goal of making predictions in similar situations. We study whether the predictions subjects make in each environment are consistent with them using some “model” that posits specific statistical relationships between different variables. We find that the predictions of most subjects can be rationalized by some model. Importantly, we find the most commonly used model is the optimal one in that it maximizes prediction accuracy. Deviations from the optimal model often involve use of simpler models that fail to account for statistically relevant correlations in the data. Variation in the set of observations presented to subjects across environments allows us to test whether the way subjects learn from data display a key aspect of causal reasoning: identification of conditional independence between variables. While we find strong evidence for this, we also observe that failures of this increase with the noise in the data. Complemented with ancillary non-choice data that emerges as a by-product of our design, our results provide insights into how people form models of the world by studying data and how they use these models to make predictions.

AUG 11   5:00 PM - 7:00 PM PDT Dinner in Courtyard