PWT on KPCC

Today, I'll be talking about People Will Talk on AirTalk with Larry Mantle, KPCC 89.3. It's an NPR station broadcasting to Pasadena, LA, Orange County and the Web. I'm scheduled to be on at around 11.30 a.m. Pacific Time.

Nooooooooooo

I haven't even got copies of People Will Talk yet, and I've found a mistake.

In the last chapter, I talk about reputation on the large scale, between groups and countries. This involves a mention of work by Michael Tomz, an economist at Stanford, on the role of reputation in sovereign debt. Tomz's 2007 book Reputation and International Cooperation looks at several centuries of data from the bond markets, and shows how a country's past behaviour influences how the markets treat it.

All very interesting and relevant stuff. The problem is, I call Tomz 'David' in the text (the reference is correct). Bloody bloody bloody hell. A lesson in the power of embarrassment, something also discussed in the book.

My apologies to Professor Tomz.

People Will Talk in the NY Post

Yesterday's New York Post has an article extracted/adapted from People Will Talk.

It's mostly about gossip, the subject of two of the book's chapters. To go to the source for a lot of what's in the article, check out the work of Ronald Burt at U Chicago. He's found that one's reputation is a product of one's social network, and that the kind of reputation you get depends a lot on the structure of your network - particularly on how closed (cliquey, in which everyone talks to everyone else) or open it is.

In particular, I refer you to these two pdfs:

Gossip and reputation

Closure and Stability: Persistent Reputation and Enduring Relations among Bankers and Analysts

And his 2005 book Brokerage and Closure.

Steering clear of the magic kingdom

In his stylish and thought-provoking book Frozen Desire: An Enquiry into the Meaning of Money, James Buchan argues that one of money's defining properties is that it robs things of their essences by making them comparable.

Pre-money, each thing had a certain thinginess. It was what it was, and could not be otherwise. But once money comes along, a thing can be expressed in terms of its cash value, and so, instead of seeing it as uniquely itself, we see it as more or less valuable than something else, and it loses that essence.

(One reason that men give women chocolates and flowers, Buchan suggests, is that they are perishable, and so, because they cannot be converted back into money, they retain their thinginess, helping to keep money and romance apart.)

Similarly, one feature of social media is that, by making our social lives quantifiable in a way they weren't before, they make them more like money. One can count one's twitter followers and facebook friends, compare them to someone else's, feel inadequate, and change one's behaviour to try and catch up.

Of course, people have always courted popularity, but never before has it been so easy to measure and compare. And, as occurred with money, something is lost in the process.

Or, as Bonnie Stewart puts it: "The peer-to-peer relationality of social media is undermined by the kind of behavior that cultivates status over relationships." (Stewart is writing in Salon, or rather Salon has reproduced one of her blog posts.)

Stewart is discussing Klout, which aims to give you "a single tidy number meant to sum up your influence and engagement in the social media sphere". There have been several attempts in the past to create general online measures of social worth, often with reference to Whuffie, the reputation-based currency imagined by Cory Doctorow in his novel Down and Out in the Magic Kingdom.

In People Will Talk, I'm sceptical about them, for the same reason as Stewart is - because by reducing a narrative to a number, you lose information, but gain a precision and quantifiability that is actually spurious.

But it looks like Klout is taking off. It, Stewart writes: "has established itself as a major arbiter of influence in social media circles...it’s already driving hiring in social media spheres. Its algorithm is being taken up as a factual assessment."

One reason for this is probably that employers have no idea how to decide who to hire, and will clutch at any straw, such as credit scores, that seems to differentiate one candidate from another.

That may be bad for certain types of people trying to get certain types of job. On a self-interested note, I wouldn't be surprised if this type of information were also influencing hiring decisions in journalism.

Whether it means anything, I don't know. Is your Klout score a reflection of anything more than your Klout score? I guess the way to judge that is whether it tells you anything you don't already know, or can't deduce another way - simply by counting their friends/followers, for example. (Given that too many can be a bad thing, in terms of likability and credibility, it'd be interesting to know how Klout treats this.)

Klout, for example, hints that Justin Bieber is famous. I am, however, prepared to believe that these things can be useful, and will probably become more so (even though I don't really want to, because I value the thinginess of things, and doubt that I am the kind of person/writer who will prosper in that kind of world - I don't want to know my Klout, and not just because I suspect it's tiny).

More generally, what's pernicious about this type of quantification is that it infects everyone, not just those who play the game professionally. It encourages us to compare and commodify ourselves - again, not a phenomenon confined to online life, and not a new complaint about online society, but something that seems to be becoming easier to do and more widespread.

One of my favourite lines in a novel comes in Jonathan Franzen's the Corrections, when one character says to another, "what's life about?", and she replies "I don't know, but it's not about winning." And yet, we're being given ever more ways to treat life like a high-score table. And, because we are competitive animals, as well as cooperative ones, we lap it up.

In the process, social information becomes like money, and our social lives become monetized. Stewart again: "We are gradually being directed away from sociality and toward businesslike behaviors by the business interests that design and profit from the platforms we use."

Or, to quote Slavoj Zizek (I know!) in the LRB: "We are often told that privacy is disappearing, that the most intimate secrets are open to public probing. But the reality is the opposite: what is effectively disappearing is public space, with its attendant dignity."

Or to put it a third way, the difference between social interaction and social media is like the difference between a park and a theme park. In the latter, your experience is controlled to commercial ends. Theme parks can be fantastic, but (unlike the hero of Down and Out) I wouldn't want to live in one.

Itetem ta humgopak...Altogether now!...

If you read the paper on musical diversity within and between cultures in todays Proc R Soc, you will search in vain for any idea of what the music actually sounds like. So I had a google. And then I had a totally unrigorous ponder on what I found (I also looked in vain for any proper coverage of this work).

Tom Rzeszutek and his colleagues analyse a corpus of folk songs from '16 Austronesian-speaking aboriginal populations from Taiwan and the northern Philippines'. These include the Paiwan...

Here's a snippet of a rather nice Paiwan love song

What does the fact that this sits so easily on the western ear say about musical diversity - perhaps that the total range of musical possibilities is actually quite small, and that cultures explore musical space (saturate diversity, if you like) quite quickly? Does this also mean that there's a lot of convergent evolution in music, with the same tricks popping up often in different cultures?

Here's another...

Sounds pretty similar to me.

They also analyse the songs of the Ifugao...

What does the fact that the people behind this arrangement can slather their aboriginal song in a jumbo helping of (country and) western cheese, but still recognize it as something Ifugao, say about the features of music that are most important in placing it in a certain culture? And what does the fact that music hybridizes so easily say about the generation and meaning of musical diversity?

The authors quantify the songs using a technique of their own invention called 'CantoCore', based on the cantometrics approach devised in the 1960s by the mighty Alan Lomax. CantoCore 'codes 26 characters related to song structure, including rhythm, pitch, syllable, texture and form'. They than measure the distance between songs by adapting a technique used to measure genetic distance - borrowing the tools of phylogenetics.

When they do this, they find that there's much more musical variation within cultures than between them. Within culture variation accounts for a whopping 98% of the total, in fact.

The 2% difference between cultures is still statistically significant, though. After all, it's easy to distinguish Cuban music from gypsy music, from Indian music, and so on. I'd guess that some aspects of music must be more diagnostic than others to our ears. (I think that CantoCore only analyses songs, so out in the real world you can also throw in instrumentation as a means of recognition.)

What I want to know is if some cultures have more diverse music than others. That's true of genetic diversity, and it reflects our species' history.

So, just as Africans are most genetically diverse, and the rest of us are, give or take, a subset of them, is the same true of music? In Subsaharan Africa, cultural diversity mirrors biodiversity - that is, the places with the most species per square mile also have the highest density of different languages. So perhaps the same goes for tunes.

Eric B and Rakim explain social learning

OK, People Will Talk is creeping onto the shelves (and whatever the electronic equivalent of a shelf is) and we can begin the task of examining the book's themes through the medium of golden-age hiphop.

Finding a tune for Chapter 1 is easy. The chapter's called 'Follow the leader'. (Although, unlike one later chapter, it's not named specifically after the track in question. I did briefly wonder about naming every chapter after an old-school joint, but never really put in the effort to do so.) You can read this chapter for free.

What a fantastic record. Video hasn't aged so well, though, has it?

Social learning occurs when animals make a decision not by direct experience, trial and error, but by copying what others are doing. It's an important aspect of how many species decide where to eat (in, e.g., sticklebacks), where to nest (many birds), and who to mate with (guppies, humans).

Piggybacking on another like this saves the effort and risk of finding something out for yourself, and is an immensely powerful strategy for exploiting your environment. When different learning strategies are set against one another, social learners outcompete individual learners. (On the other hand, it can also lead to information cascades, if everyone copies everyone else blindly without ever looking at the raw data on which decisions are based.)

Animals don't copy willy nilly. Whether they copy depends on their own internal state: animals who know less, because they are young, for example, or because they failed last time, are more likely to copy others. (It makes perfect sense to be young and impressionable, in other words.) And who they copy depends on the models on offer. The mating and foraging choices of big fish are more likely to be copied, for example, because a big fish is old and experienced; the embodiment of its own good decisions.

Humans are the champion social learners. Where did you get your tastes, your politics, your language and accent, your religion, and so on? By sampling the options and picking the one you liked best? Course not, it was by copying your family and friends. Social learning lies at the heart of culture and technology: it allows us to pass things on, and means that instead of reinventing the wheel, you can invent the bicycle.

The ability to observe and copy others is also one of the pillars of reputation. It's not exactly reputation, at least as far as people are concerned: copying someone is not the same as observing them and using that to plan how you treat them. Social learning is, though, how things get reputation - it's what happens when you choose a restaurant or a movie based on someone else's recommendation. It's how brands get built and broken.

Unlike other species, humans also give something back to those from whom they socially learn. Prestige, Joseph Henrich and Francisco Gil-White argue, is the tribute that the copiers pay to the copied. By honouring those who are excellent at something, the rest of us can get up close to them and hope to learn from them.

The evolution of prestige was something new in the world. Previously, displays had been largely repulsive - designed to show dominance and deter challenges. But prestige is an attractive force, which wins people over rather than putting them off. (Prestige and dominance are the equivalents of soft power and hard power in international relations.)

Chapter 2 is about costly signalling - the idea that conspicuous displays of virtue are also displays of intellectual, material or physical wealth. It's hard to imagine that there might be any hiphop records that touch on the subject of showing off, but I'll try and ferret one out. If you've an interest in evolutionary psychology, behavioural economics, fat basslines and lyrical flow, please feel free to make a suggestion. Late 80s/early 90s preferred, but I'm not going to be too dogmatic about this.

Do not trust this post

We've always judged each other by the company we keep, but now, when you meet a stranger via Facebook or Twitter, you can see their social network laid out all at once —how many people they are connected to, and who. And that can form part of the information you use to work out whether you like them, or trust them.

It's like PageRank for people. Unlike websites, however, it seems that people can be too well-connected. In a study published this week, David Westerman and his colleagues showed students mocked up Twitter accounts reporting information on swine flu. They found that tweeters with an intermediate number of followers — 7,000, rather than 70 or 70,000 — were judged as most likely to know what they were talking about and to be telling the truth.

A similar study from 2008 found that strangers on Facebook were ranked as most likeable—and even physically attractive—if they had a middle-ranking number of friends. The sweet spot was around 300, rather than a few tens, or a thousand.

Too few connections, it seems, shows that someone doesn't inspire trust or affection. But too many is the mark of a hoarder, someone who spends their effort on boosting their numbers, not on genuine interaction. It's not hard to estimate from a person's friend or follower count how they spend their online social time, and how much attention you'd get if you joined that person's circle.

Westerman's Twitter study also found that tweeters were rated as most competent when there was a narrow gap between the number of people following them and the number of people they followed. This, the authors suggest, may be a cue that the person behind the account is sociable, inquisitive and a good reciprocator.

Results such as these show how people are adapting to online life — no surprise, given that our species has managed to adapt to every other physical and social environment on the planet. True, the effect of network size on likeability and credibility is pretty small — it's hard to argue that counting someone's followers is a better measure of their credibility than reading their tweets. but then, people have only just begun working out how to parse this information. And as it becomes more common for people's first contacts to be via online social networks, and as networking sites become places people go to for breaking news, this kind of information may become more important.

These findings also hint at what online society might be doing to the size of our social groups. There are various measures and predictions of this, the most famous being 150— Dunbar's number, based on plotting the size of the neocortex against social group size in humans and other primates. (Going by that, a Facebook friend is worth half a real-world friend, which sounds plausible.)

Robin Dunbar's idea (I'm writing off the top of my head here) is that primates without language have to maintain social bonds by grooming. We do so with language, which is less time- and energy- intensive, and can involve more than two people at once. So we can live in larger groups.

But even talking only allows you to connect with so many people at once. In the flesh, large conversational groups fragment naturally, because it's easier than shouting or trying to get a word in edgeways. But online, physical space is not limited, and there's not the same problem with everyone trying to speak at once. It's also much easier, and less awkward, to eavesdrop on an interesting conversation without joining in.

All this should make it possible for people to maintain larger social groups, albeit with weaker connections. On the other hand, a recent study by Dunbar and his colleagues found that people who spent lots of time on social network sites did not have larger offline networks, or closer offline relationships. So maybe what we're seeing is people developing online and offline social worlds that, to a degree, serve different purposes.

These kind of findings also suggests that as norms about online social behaviour develop the upper limit of people we connect to online could be set, not just by the physical demands of keeping in touch, but by the social demands placed on us by the judgment of our peers.

However, my pathetic Twitter numbers (54 followers, 21 following at time of writing) shows that I'm the last person you should trust on this.

Extinction and taxes

There's not actually very much evolution in Robert Frank's The Darwin Economy. Frank takes a big idea from Darwin: the insight that success is relative, and so how much is enough depends on what everyone else is doing. But the deeper you go into the book, the less Darwin is mentioned. (Also, this something that economists must have already realized, because they've got a name for it: positional spending.) Essentially, it's a book about tax policy, and a very good one.

I've got a piece in Slate criticizing his biological examples (and spinning off from there). But I thought the writing about economics was excellent, partly because I'm not an economist and it was all clear to me. Not everything he advocates chimed with my prior prejudices — he argues (convincingly), for example, that goods should be allocated on willingness to pay, even though that might see them go to those we consider less deserving. But it's hard not to think that the world would be a better place if Frank were making tax policy.

Frank makes the point that an arms race and a tragedy of the commons are the same thing. Everyone is better off if everyone shows restraint, but any individual is better off if he or she alone cheats. So the rational thing to do is cheat, and everyone ends up worse off.

This is a connection that biologists have only just begun to make. In particular, Hanna Kokko and her colleagues, including Daniel Rankin, have published a series of papers looking at whether and how a species might evolve itself to death, with selection for individual advantage leading to population collapse. (In a not-very-useful sense, every adaptation beyond being a string of RNA sitting in the primordial soup is a tragedy of the commons, because it diverts resources from reproduction in search of a competitive advantage.)

It's this connection that originally set me thinking about Frank's take on evolution, although, as is the way of these things, nothing of that ended up in the piece.

The main purpose of this post, then, is to make up for that by directing you to this very readable paper published in Oikos early this year, in which Kokko and Katja Heubel draw the link between tragedies of the commons, levels of selection (i.e. individual vs group) and sexual conflict (differing evolutionary interests between males and females).

As an example, they use a fish, the Amazon molly, so called not because of where it lives (Mexico/Texas), but because it's an all-female species. But even though it produces asexually, it still needs to mate with a male of a closely related molly species, to help things along developmentally.

The Amazon molly, then, is a sperm parasite, and the host species would be better off if males could resist the temptation to mate with them. Selection on individual males, however, usually tends towards indiscriminate keenness, because missing out on a genuine mating costs more than mating erroneously. So a tension between group and individual good is created. Can this, Kokko and Heubel ask, lead to prudent males? There's some evidence it can — males from population that coexist with Amazon mollys are choosier than those that don't.

Besides all that cool stuff, another reason I liked this paper is that it says this about the group selection debate:

Our second message is to remind researchers that much of the battle about levels of selection is ultimately about how we teach students about evolution. For some reason, most laymen who accept evolution think of natural selection as something that ensures the survival of a species. Student generation after student generation, bright young minds must be made aware of the flaws lurking in naïve group selection thinking before they can hope to argue clearly about evolution. …The mainstream approach of evolutionary biologists in dealing with this problem is to learn to label all ‘group’ arguments as inherently dodgy.

Given the number of dodgy arguments ever produced, this rule of thumb is often valid. Still, recent theoretical work creates the very valid question by any deeply thinking student: if kin and group selection really are two sides of the same coin, why is one ‘good’ and the other ‘bad’ in our textbooks? The crux of the issue seems to be no particular scientific result, but the fact that for some unknown reason it is much more natural for people to come up with naïve (wrong) group selection arguments than naïve (wrong) kin selection arguments, and evolutionary biologists consequently have to be trained to be very wary of the former. … However, among experts, it might be time to move on from petty semantics to a true appreciation of demographic consequences of cooperation and conflict, and the rich tapestry of evolutionary outcomes that can arise over different time scales, whichever the favoured mathematical method each person chooses to employ.

Which seems a very useful way of looking at it.

How reputation can (help, in a small way, to) save the world

Nature Climate Change has just published a comment piece by me looking at the role reputation can play in achieving some sort of action on climate change. But hey, seeing as it'll cost non-subscribers $18 to read it, why not save yourself 87 cents and pre-order my book instead? Most of it's in there, and you'll get approximately 78,500 other words thrown in at no extra charge.

Reputation is fantastic at solving collective action problems. Climate change is the biggest collective action problem in our species' history. So what can reputation do to address climate change? At an individual level, perhaps a bit - there seem to be reputational rewards from shopping green, and from climate-conscious generosity. That said, conspicuous consumption is always likely to be a more reliable status symbol than conspicuous non-consumption.

But me not taking leisure flights (which I haven't for a few years) is not going to stop China building coal-fired power stations. So how do we get international agreement to limit emissions? The world of international relations has been described as one of anarchy and self-help. And yet, most countries honor most of their treaties, most of the time. In the absence of the world government that isn't going to happen any time soon, concern for their reputations is one of the things that makes them do so. (I am a fan of UC Berkeley law professor Andrew Guzman's papers on this topic.)

Unfortunately, Guzman (I think it was him) has written that reputation seems to work best at encouraging compliance in areas that aren't central to a country's interests, such as nature conservation. I don't think we can really put the transition to a low-carbon economy in that category. The higher the stakes, the greater the temptation to break the rules (I think the Dutch football team's behaviour in the last world cup final is a great example of this.)

And it works best when there's also domestic pressure on the government to behave well. Which is missing at the moment. And unlike people, countries rarely treat each other in one area based on how they behaved in another - rather, they have lots of different reputations.

So in terms of avoiding a global tragedy of the commons, most of what's in our social nature is still pointing the wrong way. I'm still hoping for some moral leadership to come from somewhere. But I'm not hopeful.

Bruce Chatwin's evolutionary biology

I started reading The Songlines in the belief that it was a travel book. And it is, and for a while that's all it is — Bruce Chatwin's book, published in 1987, is primarily about his time in the Australian desert with Aborigines and the people who work with them.

But about a third of the way in, it starts getting evolutionary, with a sudden digression to recall a visit to Konrad Lorenz in 1974 (I think he was interviewing Lorenz for the Sunday Times.). Chatwin goes to Lorenz's family home in Altenberg, just outside Vienna (a place I have visited in its current incarnation as the Konrad Lorenz Institute for Evolution and Cognition Research; I don't think it's appearance has changed much).

The memory is triggered when Chatwin sees an Aborigine act out the travels of the Lizard Ancestor, reminding him of Lorenz's own ability to mimic the animals he studied. For anyone wonkish about animal behaviour, this chapter is worth the price of admission alone. But it is also a jumping off point, from where Chatwin goes into Lorenz's ideas about aggression in and human animal nature. From then on the book is increasingly devoted to Chatwin's own ideas about human evolution.

Chatwin was not a complete amateur in this regard. In the mid 1960s, he abandoned a job as an auctioneer at Sotheby's and went off to do a PhD in archaeology at Edinburgh, which e also dropped out of after two years. There's lots in The Songlines about his visits to important palaeoanthropological sites, especially in South Africa, where he spends time with Raymond Dart and Elisabeth Vrba. He also planned a sort-of-academic book about nomads that he never completed, and large sections of Songlines is given over to fragments from those notebooks, along with quotes, reminiscence, anecdote, and so on (much of which teeters on the verge of outrageous padding).

Chatwin's big idea about human evolution is that predators — or The Beast, as he calls it — provided the selection pressure that made our species smart and social. Out on the savannah, he thinks, the carnivores, especially big cats such as Dinofelis, were so menacing that it was adapt-or-die, and in our case adaptation meant becoming human.

Chatwin runs this idea past Lorenz: "[He] tugged at his beard, gave me a searching look and said, ironically or not I'll ever know:
'What you have just said is totally new'."

I say: baboons*.

Chatwin's ideas about The Beast led him to believe that the violence in our natures arose not for competing with each other, but for defending ourselves against predators. And his travels among nomads lead him to believe that settlements, institutions, states and so on pervert our natures so as to bring out the worst in us. That is to say, he thinks that humanity's natural and good state is to be like Bruce Chatwin.

There's nothing wrong with this just-so-storifying, and he's far from the first or last person to come up with a scientific hypothesis that's comfortingly close to his own temperament. I don't think Chatwin's ideas on human evolution have aged very well —if I had to sum up what evolution has done to human behaviour, I'd say it has made us better at cooperating with members of our own group, the better to compete with members of other groups. (See for example, to pick a couple of examples off the top of my head, the work of Sam Bowles and Robin Dunbar.) And humans seem the most likely culprits for the extinction of Dinofelis, and a host of other large vertebrates, not least in Australia. But this isn't a paper, and he's not an academic, so he doesn't have to meet the standards of academia. (Rather, he shows what you can get away with if you've got a fine prose style and the intellectual confidence that goes with being posh.)

I think Chatwin's 1977 travel book, In Patagonia is more successful, but I'm glad I read the Songlines, particularly for its descriptions (the accuracy of which I'm not qualified to judge) of how songlines work, and how Aboriginal Australians use them. Between the lines, there's also much that speaks to more orthodox ideas about human nature in how these groups coexist with one another, even though they are potential competitors for resources.

And one notebook fragment touched a nerve with me. A much-cited Bedouin proverb goes: "I against my brother, my brothers and me against my cousins, then my cousins and I against strangers." This is often, and correctly, given as an illustration of how people instinctively grasp kin selection.

But Chatwin's version adds another line: I against my brother, I and my brother against our cousin, I my brother and cousin against the neighbours, all of us against the foreigner.

What made me so happy about this is that it shows that social distance and genetic distance are equivalent, because they are both a measure of shared interests, and so influence the benefits of cooperation versus competition. Ideas about social distance are a theme of my reputation book, and one that no doubt/I hope I'll be developing here in future posts

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*That is, a smart-but-not-that-smart level of group solidarity and some nasty canines seem quite adequate for dealing with large carnivores.

Good deeds and big cities

A few months ago, the network researchers Sam Arbesman and Nicholas Christakis published a paper looking at how the frequency of good deeds scales with city size.

This was an extension of work by Luis Bettencourt and his colleagues looking at how all kinds of stuff scales with city size. They found that what you might call social productivity — wealth, wages, patents, but also illness and crime — scales superlinearly. That is, big cities have proportionately more of them than small ones. (Bettencourt and Geoffrey West have an article on this in a recent Scientific American.)

Arbesman and Christakis looked at some things that those guys hadn't: the frequency of altruistic acts. They found a more mixed picture.

Some of the things they looked at did scale superlinearly. They include the size and frequency of political donations, and the number of organ donations by deceased people. But some (the number of people returning a census letter) scale sublinearly; you get less of them per person in bigger cities). And others (living organ donation and voting) show a linear pattern. Jonah Lehrer blogged about the work.

Recently, Sam (who I have interviewed and chatted to once or twice, and whose stuff is always worth reading) was kind enough to mail me the paper, and I finally got round to reading it. Having done that, I think that how a particular type of good deed scales with city size might depend on the motivation that underlies the deed.

There are several theoretical explanations for why people act altruistically: they might be helping relatives who share their genes (kin selection), returning a favour (reciprocal altruism), to improve their reputation with onlookers, who will help them when they need it (indirect reciprocity), or to show how great they are as a way of attracting allies, friends and mates (costly signalling, a.k.a competitive altruism).

City size is particularly relevant to the last two of these. In a larger town, you have a bigger potential audience for your good deeds, but it's also easier to remain anonymous, and harder to keep track of other people, and so to know whether you should cooperate with them or not. To seamlessly introduce the theme of my forthcoming book, it's easier to escape your reputation. This also might account for the bystander effect, where people pass by some hideous crime without intervening. The economist/evolutionary biologist Karthik Panchanathan has been doing some experimental work on this.

I'd guess that as our group size increases, it pushes cooperation away from indirect reciprocity — from behaviours that are based on trust, because trust is harder to build and maintain — and towards costly signalling. This doesn't need trust, because altruists are using conspicuous do-gooding as an advertisement of status, like conspicuous consumption. City size, in other words, influences which types of altruism are rewarded, and so influences people's altruism budgets. They stop building a reputation, and start buying one.

This fits with our stereotype of cities as slippery, brash, places full of sharp practice, and of small-town folk as decent, simple and trusting. It also fits, as far as it goes, with the data: Arbesman and Christakis found that a 'doing your bit' form of altruism, returning a census form, became less common in larger cities, whereas a 'showing off' form of altruism, that's dependent on personal wealth - political donation – became more common. The evo psychologist Henry Lyle and his colleagues have already suggested that blood donation is a costly signal, so the same might go for organ donation.

I ran this idea past Sam, and he said that it was possible, but this sort of data is very hard to come by.

There are also some obvious objections. Live organ donation — a pretty damn costly signal of good health, if ever there was — scales linearly. One possibility is that most of these organs go to family members, and so be the result of kin selection, which you wouldn't expect to respond to city size.

Another issue is whether the psychological mechanisms that people use to decide whether to behave altruistically are really that sensitive to groups above a certain size. Can we sense that London is a bigger, more anonymous city than San Francisco, and adjust our behaviour accordingly? I'm not sure — I've lived in London most of my life, and spent a year a long time ago in the Bay Area. I love London, but it doesn't give a monkey's. The Bay Area seemed more like it buoyed people up. I'll stop before speculation becomes anthropomorphism.

The ecology of babygrows

Spread among young families there is an ocean of baby clothes. When you’re expecting, you toss in a bucket and haul some out. When your child outgrows them, you try and throw them back, along with most of the new clothes you were given, like that hand-knitted jumper that junior refused to wear.

So just like any population, the amount of babyclothes in any house equals recruitment (gifts) plus immigrants (hand-me-downs), minus mortality (things thrown away), minus emigration (stuff you pass on).

What’d be most interesting would be to study the garments’ migratory patterns: Where do they go? How long do they survive? What’s the network structure?

You could investigate by setting up a labelling-and tracking system similar to Book Crossing or Where’s George?. People who had more than one child could also do mark-recapture studies, which gives me an excuse to mention my own pioneering work on the film direct Mike Leigh, something I am still rather pathetically proud of.

(Whenever I think about the ecology of everyday stuff, I think about this 1990 New Scientist article on the population biology of internal mail envelopes by Bill Sutherland.)

To desperately shoehorn in a proper science angle, this strikes me as being very slightly similar to the question of connectivity between coral reefs. One of the important topics in reef biology is understanding where the fish come from – are they born on the reef and stay there, or do they come from somewhere else? How much movement is there between reefs?

A dozen years ago, according to this paper, it was "generally assumed that larvae disperse away from their natal population so that local populations operate as 'open' systems, driven by recruitment of larvae from other sub-populations." But some studies (such as that one I just quoted, which looked at the fate of 10 million small fry on the Great Barrier Reef) find that many fish on a reef grew up there.

This varies, of course, depending on things such as how isolated a reef is, and understanding connectivity is a crucial question for reef conservation.

Mental obsolescence

The paper in this week's Science about how people outsourcie their memories to Google made me think of a piece I wrote for the FT weekend magazine some years back looking at the same idea - that mental skills fall out of use just as material technologies do.

That was occasioned by the 200th anniversary of the birth of the Scottish mathematician Edward Sang, who, working with his daughters, wasted devoted his life to producing the finest log tables ever seen. So I thought I'd use Science's finally catching up with me as a reason for reproducing the piece here (in unedited form). (This is the only story I've ever got from a paper in Historia Mathematica.)

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I must have been one of the last people in Britain taught to use logarithm tables. I'm not sure why our maths teacher bothered; at school in the mid 1980s, everyone already had an electronic calculator. The tatty book of numbers, sitting ignored on the desk while I punched buttons, held no appeal. But what I didn't know was that for hundreds of years this had been the most sophisticated computer available, and making it had consumed peoples' lives.

January 30th marks the 200th anniversary of the birth of one such individual: Edward Sang, a Scottish mathematician and engineer who, with his daughters' help, produced the finest log tables ever. Sang's monumental effort ended unhappily — one part Don Quixote to two parts King Lear — but he deserves to be remembered, both for his achievement and for what his story tells us about our relationship with technology.

Logarithms turn complex multiplication into simple addition. For example: the log of 10 is 1, and the log of 100 is 2; 1+2=3, which is the log of 1,000. But producing log tables was a lot harder than using them, and required human calculators to work through a vast number of repetitive and tricky calculations.

The first volumes of log tables were used mainly by mathematicians and astronomers. This changed in the 19th century, when the growth of engineering and finance created a vast crop of sums needing to be processed. It had also become clear that the original tables, compiled around 1620, were riddled with errors.

Sang was both a gifted mathematician and a practical man. While working in Constantinople in the 1840s, he came to despair of the inaccuracies in the available tables. He envisaged a complete set of tables that would allow just about any useful calculation to be performed easily, including trigonometric and astronomical calculations as well as logs — a Victorian personal computer.

On moving to Edinburgh in 1854, Sang began the task, aided by his daughters Flora and Jane, who he had taught his calculating skills. For the next 25 years, while Edward earned a living teaching and consulting on matters mathematical, the three of them worked on the tables in their spare time. They eventually produced more than 50 volumes of calculations of unmatched accuracy, each containing several million digits.

The problem was, nobody wanted them. Only one volume of log tables, covering the numbers between 1 and 200,000, was ever published, in 1871. Sang sought funding from learned societies the government to publish tables up to a million, but they all turned him down. He died, disappointed and in debt, in 1890.

In 1907, his two surviving daughters — Flora, then 69, and Anna, who had not worked on the tables —gave the work to the Royal Society of Edinburgh in return for a pension to ease their genteel poverty. The Society hailed the work as a "great national possession", but the First World War interrupted its publication plans. None of Sang's four daughters married, and his one son died in a lunatic asylum; it's easy to suspect, although impossible to tell, that the family's obsessive mathematical quest blighted their lives.

Machines, and the ability to use them, come and go. Young folk can't understand why their elders find programming a VCR so difficult. The next generation won't know what a VCR is. Sang's story is a reminder that intellectual obsolescence is just as prevalent, and powerful.

The Sang family devoted their lives to making their own mathematical expertise redundant. Their chosen medium, the logarithm, reigned for centuries, but electronic calculators made using log tables seem like a chore, and mental arithmetic came to seem as arcane a skill as conjugating Latin verbs.

No future computational technology will endure as long as log tables. The trend of getting machines to do our thinking is accelerating all the time. Satellite navigation lets us find our way without taking a compass bearing, or even reading a map. Translation software, although crude, will give you the gist of most foreign texts.

Now technology is replacing even more basic mental attributes — knowledge and memory. An electronic personal organizer will make sure you never forget to go to a meeting or send a birthday card. And now, when I rack my brains (When was the Origin of Species published? What was the Blue Peter tortoise called?), a search box pops into my mind's eye, and I imagine what I should type into Google. Phrase your search enquiries right, and you can retrieve something from the web almost as quickly as from your brain.

This is clearly a good thing. GPS navigation saves lives, and online information would be arduous or impossible to obtain by other routes. But the incapacitation I feel when my web connection goes down — and the flood of information that engulfs me when it doesn't — suggests that we may have swapped intellectual resourcefulness for convenience. Perhaps learning times tables, or tracts of poetry, or how to use logarithms, wasn't so useless after all. Perhaps it equipped us to think for ourselves in a way that Google can't.

It's like that philosopher said. What was his name? Greek bloke, or possibly German. Hang on a minute, I'll just look it up…

The biology and economics of home advantage

Every few years, the Fotherington-Thomases at the London Review of Books give David Runciman a break from writing about the sorry state of British political life, and let him indulge an apparent obsession with José Mourinho.

In the current issue, where he reviews Scorecasting by Tobias Moskowitz and Jon Wertheim, Runcimann uses the astonishing record of Mourinho’s teams – he went nine years at Porto, Chelsea, Inter and Real Madrid without losing a home league game – as a springboard to discuss the mysteries of home advantage.

Runcimann doesn’t like Moskowitz and Wertheim’s idea that teams win more at home because crowd pressure makes the officials biased in their favour. Or at least, he doubts that it’s the whole story. But I think he’s too quick to dismiss alternative ideas and declare the whole thing a mystery.

He’s no faith, for example, in the benefits of local knowledge:

What about local knowledge? Every ground is slightly different, so perhaps teams take advantage of their familiarity with their home environment. Even football pitches vary: some are wider, some are narrower, some are blowy, some are sheltered, some are rough, some are smooth. The differences are most noticeable in baseball, where some teams play at stadiums that suit hitters, and others at stadiums that suit pitchers (it’s a question of size, shape and atmospherics). Yet even in baseball, Moskowitz and Wertheim find it makes no difference. Teams that play in hitter-friendly stadiums do not outhit their opponents by any greater margin than teams that play in pitcher-friendly stadiums. This despite the fact that managers can pack the team with sluggers, sure that they will play at least half their games in advantageous conditions. Knowing what you need to do well in your own yard doesn’t help you do it any better. Home advantage seems to be entirely outside anyone’s power to control.

I’m no baseball expert, but I’d guess that in comparison with some other sports, environment doesn’t matter very much. What matters is the confrontation between pitcher and hitter, which is perhaps not very susceptible to outside influences. It’s interesting that home advantage is weak in baseball – the home side wins 54% of the time, compared with 60%+ for football.

Contrast that with cricket, where, because the ball bounces before it meets the batsman, local conditions make a huge difference. The slow, dusty wickets in India reward different skills to a hard and bouncy Australian track, or a Headingley greentop on a damp morning in May. Touring players often struggle to adjust their games to different conditions, which gives the natives a big advantage. (This despite the fact that official bias ought to be weaker, because cricket umpires are a long way from the fans, and the game’s manners are relatively good.)

Runcimann also suggests that home advantage might only apply to team games:

What if home advantage is a team phenomenon? There is plenty of evidence not considered by Moskowitz and Wertheim to suggest that it is. British tennis players have never seemed to gain much advantage playing at Wimbledon, despite the presence of thousands of people willing balls that are in to be called out (I’m talking pre-Hawk-Eye here). Are phlegmatic British line judges somehow impervious to these pressures in a way that football referees are not? It’s not just us Brits. No Frenchman has won the French Open since 1983; no Australian has won the Australian Open since 1976. Where’s the home advantage? One explanation might be that playing at home really makes a difference only when you’re part of a team. It’s a collective experience, in which case it dissipates for isolated individuals (including the individuals standing at the free-throw line in a basketball game or at the penalty spot in a football match). Somehow, playing at home breeds a sense of solidarity, or what used to be called team spirit, which means that players have more confidence in each other and work better as a unit. I’m not saying that’s definitely what happens. But Moskowitz and Wertheim haven’t proved that it doesn’t.

But again, it’s not the officials or some mysterious collective solidarity that are important here, but familiarity with the conditions. British players play Wimbledon once a year, just like anyone else. They might have the crowd behind them (although this might just make them nervous, and individual sports like tennis don’t lend themselves to the tribal devotions of team sports like football), but they don’t know the place any better.

Instead, like cricketers, specialize on the surface they grew up on or the one that best suits their game. Rafael Nadal is all but unbeatable on clay, the same went for Pete Sampras on grass. To a lesser extent, this is true of golf, where links courses demand a different type of game to those inland.

If you play a chase-ball game like football or basketball, your playing environment will be less variable. On the other hand, you’ll play fully half of your games at your home stadium, whereas your opponents will only visit it a handful of times a season. This will make you much more familiar with the surface, the dimensions of the pitch, the visual and acoustic environment, and so on. You become a specialist at playing at home, even if you can’t put your finger on what that specialism entails. You also become worse at playing away, where things are different.

It’s be interesting to know how home advantage varies between teams (although it’d be difficult to control for other factors – could you make other-things-being-equal pairs?). Mourinho has a superb eye for detail, an ability to make little things work in his favour, and a knack for nullifying the opposition, which might help him to maximize home advantage.

Besides specialism, there’s another biological/economic phenomenon that might be an even more important contributor to home advantage in sport. In territorial contests, the incumbent is most likely to win. This goes for male speckled wood butterflies fighting over sunny spots in a woodland, where (Mourinho-like) the resident always wins, and groups of feral horses contesting access for waterholes, where the incumbent wins 80% of the time.

Two psychological biases in humans also give incumbents an advantage in contests over territory or resources: the endowment affect – people value a thing more when they possess it than when they don’t – and, related to this, loss aversion.

So, in the words of a paper by the economist Herbert Gintis, incumbents are "willing to expend more resources to hold the resource than the intruder is to seize it."

Gintis goes on to model the conditions that lead to property rights, where challengers, be they animals or people, decline from fighting incumbents.

It seems plausible that the endowment effect and loss aversion are also at work in sport. The home team is the incumbent - it is defending its patch. It values winning more than the visitor, and so tries harder and wins more often.

Recommend a blog, win a book

When you write a book, the publisher sends you a questionnaire asking about promotional opportunities, on which you write down all your big-name author friends who will big-up your work, and all your TV-presenter buddies who will have you on their show.

I'm filling out the questionnaire for my forthcoming book, 'People Will Talk: The Science of Reputation' at present, and it's looking blank. So I'm hoping that someone reading this can recommend blogs to send a promotional copy.

The book is rooted in evolutionary biology, and branches out into all kinds of other stuff - online society, international relations, social networks, animal behaviour, social psychology, economics.

So what I'm looking for is tips on the top places on evo psych, (behavioural) economics, social networks (and capital), animal behaviour, business and brand-building, and so on - almost anywhere at the boundary of the social and natural sciences - who might be interested in the book and might want to review it.

I'd like to reward the person who sends the best recommendation(s) - based on how well they match the book, and how much I like the writing - with a copy of the book, which should be out in the autumn. I'll even sign it if you like, thus slightly lowering its resale value. A couple of rules for entrants:

1. I don't know you. If I do, please do send your recommendations, but either you can buy a copy, or I'll give you one anyway. You're not getting the prize.

2. I haven't heard of the site you mention. You'll have to take my word on this one. I'm not a big blog reader, but I think I'm aware of most of the big ones in evolution. I also know a few of the economics ones (crookedtimber.org and Marginal Revolution). Besides revealing promotional opportunities, I'm hoping that this exercise will broaden my mind.

Please leave suggestions as comments, or tweet me: @gentraso. (I'm not online every day, so don't be cross if I don't respond immediately.)