Friday, February 27, 2015

Game theory and cool-kidology

It would appear that there’s a substantial academic literature on social groupings amongst adolescents at schools. I learned about this while attending a seminar by Robert Akerlof on Social norm formation: the role of esteem. The paper considers a simplified model of social interaction between adoloscents1 in which (in a 2-player version) each player makes 3 choices: effort at 2 activities (academic achievement versus rock music), which one to value, and whether to interact with the other player. There are exogenous costs of effort and of interaction; the latter may be positive or negative. If both players choose to interact with effort at the same activity, then the weaker player grants esteem to the other player; self-esteem may also be derived from valuing the activity you really prefer. Esteem is what everyone wants. The model is somewhat reminiscent of social network models of opinion adoption, but without an underlying graph and neighbourhood structure.

The paper aims to be “the first model to capture the conflict between conformity and differentiation, which is at the heart of social interaction in many economic settings”. One key feature of the real world that the model aims to capture is the way we give up on activities where there are poor prospects of being competitive; competition for academic achievement is high amongst pupils of similar ability, but a big disparity may cause the weaker ones to switch to something else entirely. Apparently this can be used to explain why Catholic schools have lower drop-out rates; the lower cost of interaction helps (according to the equilibrium of the simultaneous-move game) pupils who are weak academically, and would be most likely to drop out. The model also predicts a “smart set”, and a “cool set” who have high self-esteem, and the middle, who have low self-esteem. That was probably you, if you read this far.

1No jokes now. I’m willing to accept that it’s possible to simplify interaction amongst adolescents.

Thursday, February 19, 2015

Not just a little local difficulty

Last week I attended a debate on a proposal for work to be carried out to improve the appearance of the Castle Mill student residences at Oxford. This article reports the outcome of the debate, and the basics of the background to it. The proposal to remove the top floor of the residences was rejected with 210 votes in favour and 536 votes against. But (as reported here) supporters of the proposal are now requiring a postal vote of all approximately 4500 academics/senior admins who are eligible to vote. I’m glad I went along to the debate, even though my opinion was unchanged; I just became slightly more convinced that it would be daft to remove the top floor of the buildings. I would encourage anyone to read the transcripts of the speeches, that appear in this supplement to the latest issue of the university’s Gazette. I couldn’t give the debate a write-up that would do it justice; it touched on interesting and fundamental issues such as the extent which someone is obliged to remedy an accidentally bad outcome, what’s to be done about the shortage of housing, and the fundamental nature and purpose of Oxford (the city, as much as the university).

The following are a few points I took away. It was pointed out that the cost of implementing the proposal is a very small fraction of the university’s turnover. The counter-argument is that nearly all of the university's turnover (including philanthropic donations) is devoted to specific projects, and is not discretionary income; the cost of work on the residences would have to be met from discretionary funds. That’s a reminder, in turn, that such discretionary funds are very valuable, and should be carefully looked after. It was also pointed out that the 38 student rooms that would be lost by the proposal represents a very small fraction of the university’s estate (and an even smaller fraction of the total amount of student housing in Oxford). The counter-argument is that it is (or ought to be) pretty hard to demolish student rooms (at a substantial cost) at a time when Oxford is the most unaffordable place in the UK. It also occurs to me that due to the inelastic nature of housing demand, it could easily be the case that a small change in student housing availability could have a disproportionate effect on the price of student housing, one that would impact on the cost of living for all Oxford students. (Although Oxford’s absentee-landlords may cite a positive externality.)

I chose the title of this article since it notes the “bigger picture”, which I felt got slightly less attention in the debate than it deserved. It is taken from a speech by one of the supporters of the proposal, who argued that if it did not go ahead, that outcome would make the university appear uncaring about its surroundings, and it would be less favourably regarded by outsiders, including potential benefactors. Against that, the same problem arises with spending a lot of money in getting rid of high-quality student rooms. Another “bigger picture” point was made that the university has to change and evolve in order to maintain its leading position in the wider academic world. The city of Oxford’s raison-d’être has got more to do with an internationally-leading university than a nationally-competitive meadow. Personally I would have liked one or two speakers to emphasise the point that at a time of worsening housing shortage at the national level, decisions to build have to be made in a more hasty manner than may be desirable in an ideal world, and we sometimes have to make certain sacrifices in order to ensure that people have roofs over their head.

As a final note, surely the view of St. Barnabas Church is no great loss. I’m quite a fan of Victorian architecture, but the main reason to preserve St. Barnabas Church is as a reminder that occasionally the Victorians got things badly wrong. That picture on the Wikipedia page speaks more eloquently to that point than I possibly could.

Monday, February 02, 2015

Analysis of REF 2014 results

Here are a couple of recent articles I found interesting at Wonkhe (which as election time approaches deserves to be of interest to UK academics).

The hidden bang-for-buck heroes of UK research presents a (yet another) league table, this one ranking universities according to a measure of their research output, divided by their research income. I like the idea since it sometimes seems like universities and academics get judged by their research inputs more than by their research outputs. On the other hand (“be careful what you wish for”), there’s a downside to the pursuit of value for money: consider the way various airlines have gone low-cost; side-effects have been reductions in quality, reduced profitability, corner-cutting on safety, and they are less attractive as employers than they used to be.

Teaching and research: A zero-sum game? —the title caught my eye— shows a scatter plot of universities with research output on the x-axis, and teaching (National Student Survey) on the y-axis. I was unconvinced by the claimed positive correlation, but agree that there seem to be two clusters, with research output constituting the relevant attribute.

Tuesday, January 27, 2015

Game theory and anger

As a child, I recall learning the Latin tag “Ira furor brevis est” (Anger is a brief madness). It makes the point that anger is irrational; really, as game theorists we ought never to get angry. On the other hand, emotional modelling is important for us as computer scientists: the article Computationally Modeling Human Emotion was highlighted on the front cover of the December issue of the CACM. A recent article, The Commitment Function of Angry Facial Expressions, by Lawrence Ian Reed, Peter DeScioli, and Steven A. Pinker (RDP in what follows), provides a satisfying game-theoretic explanation. The clue is in the Latin tag: you may benefit from being irrational, if you can convince your opponent that you are irrational. This helps you get better payoff in the ultimatum game.

Recall that in the ultimatum game, player 1 gets (provisionally) a sum of money that he is to share with player 2. He does this by offering player 2 some percentage of the money, and if player 2 accepts, the money is divided accordingly, but if player 2 rejects, neither player gets anything. This means that a rational player 2 should accept even a derisory offer from player 1, but in experiments the money tends to be split more evenly. If player 2 can convince player 1 that he is not rational (will reject a derisory offer) he stands to do better.

The RDP paper tested the ultimatum game on several hundred players (over Amazon’s Mechanical Turk), in which player 1 got to see a video clip, purporting to come from player 2, announcing what player 2 would accept, either with or without an angry expression. A one-sentence summary of results is that the angry expression helps player 2 get a better offer from player 1. Player 2 wins by convincing player 1 he is irrational.

As a usage of game theory, does this still fall foul of Ariel Rubinstein’s critique of game theory, in which he says that some of the arguments for game theory do nothing more than attach labels to real life situations? I feel like it does help to justify the study of game theory, e.g. study of the ultimatum game for its own sake, since it would be hard to just devise it on ad ad-hoc basis, in the context of the RDP paper.

Finally, while the RDP paper concentrates on the appearance of anger, as opposed to its reality, it seems like a basis for explaining the existence of anger in the first place. That is, in a world where we worry that undervaluing someone else’s welfare may cause them to succumb to a “furor brevis” and do something you’ll both regret, we all cooperate more. There are articles like this one that seek to explain anger and advise people on how to deal with it, that miss this game-theoretic point. So next time you see someone lose their temper, explain to them that their behaviour is not a bug but a feature, that is against the interest of the individual but in the interest of the tribe. Then duck for cover.

Monday, January 26, 2015

Associate/Full Professor Position at Oxford in Algorithms or Complexity

The Department of Computer Science at the University of Oxford is planning to make an appointment at associate/full professor level with effect from 1 September 2015 or as soon as possible thereafter.

Applicants should hold a PhD in computer science or a related subject and have experience in any area related to algorithms or complexity.

The details are here. Please get in touch if you are thinking of applying, and have questions about the college system and its benefits.

Thursday, January 22, 2015

Microeconomics and machine learning

A couple of recent article in The Economist discuss that in the age of big data, microeconomists may be able to gain some of the prestige that mainly goes to macroeconomists. A long way from dismal: microeconomics is fingered as the way forward in applying large data sets to the challenge of making economic predictions. Quotes:
But technology is lending them [microeconomists] clout. Armed with vast data sets produced by tech firms, microeconomists can produce startlingly good forecasts of human behaviour
The success of micro is its magpie approach, stealing ideas from psychology to artificial intelligence.
Another article: Meet the market shapers discusses examples of Silicon valley firms using microeconomic models to learn from data.

Friday, January 16, 2015

Can the golden triangle learn to share, just a little?

According to The Economist, Cambridge leaves Oxford trailing in its wake. The names refer to the cities rather than the universities. Over the past few years, Cambridge has attracted substantially more highly skilled people and jobs, and has built a lot more houses. It’s the shortage of housing in Oxford, and vested interests that resist building new houses, that are blamed for stifling Oxford’s growth.

I’ve lived in the North of England for long enough to find it repugnant that cities like Oxford and Cambridge should be encouraged to compete with each other to attract highly-skilled jobs. It’s not long ago that Astra Zeneca decided to move its research lab from Cheshire to Cambridge, at a time when there’s a valid concern that London (and the South-East) are sucking the economic life out of the rest of the nation. The article states: “Companies [in Oxford] complain that the exorbitant cost of housing is making it hard to hold onto workers.” The challenge is to translate this market force into action, and move some of these companies northwards.

(added 19.1.15:) See Cities Outlook 2015, newly released by the Centre for Cities, for more details on the importance of addressing the North-South divide, and how bad the problem has become.

(added 22.1.15:) Article with a strange message:
Universities minister Greg Clark has called on leading universities in the Midlands and North of England to do more to tackle a north-south divide in the number of school leavers entering leading universities.
Fine so far.
Analysis of government figures by the Sutton Trust for The Times has shown that all but one of 20 local authorities that send the most pupils to the most selective universities are from the London and the south east of England. The 20 sending the fewest school leavers to top universities are predominantly in the most deprived areas in the north and Midlands regions.
Well, since the selective unis are in London and the SE, to the extent that students are biased by locality, that disparity ought to exist.
Mr Clark said he wanted leading universities, particularly those in areas that send the least pupils into higher education, to work more closely with schools and be more creative in their efforts to raise aspirations among pupils. Citing Sheffield Hallam University as an example of an institution that is providing effective access support to schools and colleges in its region,...
This is the dodgy bit. It seems like Northern unis are supposed to facilitate the process of shipping the top students out to another part of the country. That is equal and opposite to what is needed to tackle the North-South divide.