Pragma Synesi - interesting bits

Exercise and longevity

pragmasynesi — Sat, 28 Jan 2012 12:18:09 +0000

From the Jan. 21, 2012 print edition of the Economist:

Exercise and longevity: Worth all the sweat

Just why exercise is so good for people is, at last, being understood

ONE sure giveaway of quack medicine is the claim that a product can treat any ailment. There are, sadly, no panaceas. But some things come close, and exercise is one of them. As doctors never tire of reminding people, exercise protects against a host of illnesses, from heart attacks and dementia to diabetes and infection.

How it does so, however, remains surprisingly mysterious. But a paper just published in Nature by Beth Levine of the University of Texas Southwestern Medical Centre and her colleagues sheds some light on the matter.

Dr Levine and her team were testing a theory that exercise works its magic, at least in part, by promoting autophagy. This process, whose name is derived from the Greek for “self-eating”, is a mechanism by which surplus, worn-out or malformed proteins and other cellular components are broken up for scrap and recycled.

To carry out the test, Dr Levine turned to those stalwarts of medical research, genetically modified mice. Her first batch of rodents were tweaked so that their autophagosomes—structures that form around components which have been marked for recycling—glowed green. After these mice had spent half an hour on a treadmill, she found that the number of autophagosomes in their muscles had increased, and it went on increasing until they had been running for 80 minutes.

To find out what, if anything, this exercise-boosted autophagy was doing for mice, the team engineered a second strain that was unable to respond this way. Exercise, in other words, failed to stimulate their recycling mechanism. When this second group of modified mice were tested alongside ordinary ones, they showed less endurance and had less ability to take up sugar from their bloodstreams.

There were longer-term effects, too. In mice, as in people, regular exercise helps prevent diabetes. But when the team fed their second group of modified mice a diet designed to induce diabetes, they found that exercise gave no protection at all.

Dr Levine and her team reckon their results suggest that manipulating autophagy may offer a new approach to treating diabetes. And their research is also suggestive in other ways. Autophagy is a hot topic in medicine, as biologists have come to realise that it helps protect the body from all kinds of ailments.

The virtues of recycling

Autophagy is an ancient mechanism, shared by all eukaryotic organisms (those which, unlike bacteria, keep their DNA in a membrane-bound nucleus within their cells). It probably arose as an adaptation to scarcity of nutrients. Critters that can recycle parts of themselves for fuel are better able to cope with lean times than those that cannot. But over the past couple of decades, autophagy has also been shown to be involved in things as diverse as fighting bacterial infections and slowing the onset of neurological conditions like Alzheimer’s and Huntington’s diseases.

Most intriguingly of all, it seems that it can slow the process of ageing. Biologists have known for decades that feeding animals near-starvation diets can boost their lifespans dramatically. Dr Levine was a member of the team which showed that an increased level of autophagy, brought on by the stress of living in a constant state of near-starvation, was the mechanism responsible for this life extension.

The theory is that what are being disposed of in particular are worn-out mitochondria. These structures are a cell’s power-packs. They are where glucose and oxygen react together to release energy. Such reactions, though, often create damaging oxygen-rich molecules called free radicals, which are thought to be one of the driving forces of ageing. Getting rid of wonky mitochondria would reduce free-radical production and might thus slow down ageing.

A few anti-ageing zealots already subsist on near-starvation diets, but Dr Levine’s results suggest a similar effect might be gained in a much more agreeable way, via vigorous exercise. The team’s next step is to test whether boosted autophagy can indeed explain the life-extending effects of exercise. That will take a while. Even in animals as short-lived as mice, she points out, studying ageing is a long-winded process. But she is sufficiently confident about the outcome that she has, in the meantime, bought herself a treadmill.

Intestinal bacteria affects your mood

pragmasynesi — Thu, 05 Jan 2012 17:35:16 +0000

Eat your probiotic yogurt. From the September 3, 2011 edition of The Economist:

Bacteria and behaviour: Gut instinct

Tantalising evidence that intestinal bacteria can influence mood

Sep 3rd 2011 | from the print edition

A GOOD way to make yourself unpopular at dinner parties is to point out that a typical person is, from a microbiologist’s perspective, a walking, talking Petri dish. An extraordinary profusion of microscopic critters inhabit every crack and crevice of the typical human, so many that they probably outnumber the cells of the body upon and within which they dwell.

Happily, these microbes are mostly harmless. Some of them, particularly those that live in the gut, are positively beneficial, helping with digestion and keeping the intestines in good working order. That is no surprise—bacteria as much as people have an interest in keeping their homes in sound condition. What is surprising is the small but growing body of evidence which suggests that bacteria dwelling in the gut can affect the brain, too, and thereby influence an individual’s mood and behaviour. The most recent paper on the topic, published this week in the Proceedings of the National Academy of Sciences, reports (like much of the research in this field) on results in mice.

The researchers, led by Javier Bravo of University College, Cork, split their rodent subjects into two groups. One lot were fed a special broth containing Lactobacillus rhamnosus, a gut-dwelling bacterium often found in yogurt and other dairy products. The others were fed an ordinary diet, not fortified with microbes.

The team then subjected the mice to a battery of tests that are used routinely to measure the emotional states of rodents. Most (though not all) of these tests showed significant differences between the two groups of animals.

One test featured a maze that had both enclosed and open tunnels. The researchers found that the bacterially boosted mice ventured out into the open twice as often as the control mice, which they interpreted to mean that these rodents were more confident and less anxious than those not fed Lactobacillus.

In another test the animals were made to swim in a container from which they could not escape. Bacteria-fed mice attempted to swim for longer than the others before they gave up and had to be rescued. Such persistence is usually interpreted by students of rodent behaviour as evidence of a more positive mood.

Direct measurements of the animals’ brains supported the behavioural results. Levels of corticosterone, a stress hormone, were markedly lower in the bacteria-fed mice than they were in the control group when both groups were exposed to stressful situations. The number of receptors for gamma-aminobutyric acid, a natural chemical messenger that helps dampen the activity of certain nerve cells, varied in statistically significant ways between the brains of the two groups, with more in some parts of the treated animals’ brains and fewer in others. Most intriguing of all, when Dr Bravo cut the animals’ vagus nerves—which transmit signals between the gut and the brain—the differences between the groups vanished.

The idea that gut-dwelling microbes can affect an animal’s state of mind may strike some people as outlandish, and there are certainly loose ends still to be tied up. Beyond their evidence that the vagus nerve is crucial to the relationship, for example, Dr Bravo and his colleagues do not yet know the precise mechanisms at work. There is also an obvious follow-up question: whether a similar thing is going on in people. A few previous studies have hinted at the possibility. For example, bacterial treatments may help with the mental symptoms of illnesses such as irritable-bowel syndrome.

All this is forcing a reassessment of people’s relationship with the bacteria that live on and in them, which have long been regarded mainly as a potential source of infections. An editorial in this week’s Nature raises the possibility that the widespread prescription of antibiotics—which kill useful bacteria as effectively as hostile ones—might be one factor behind rising rates of asthma, diabetes and irritable-bowel syndrome. If Dr Bravo’s results apply to people, too, then mood disorders may end up being added to this list.

The unreliability of recalling events

pragmasynesi — Thu, 05 Jan 2012 16:54:11 +0000

The brain connects fragmented information with made-up bits, which is why it’s so hard for crime investigators to get reliable facts from witnesses. The current interrogational method of recalling events backwards has just been shown to be less effective than free recall. From the September 3, 2011 The Economist:

Forensic psychology:Backwards and forwards

A modern approach to interviewing witnesses of crimes may make things worse

Sep 3rd 2011 | from the print edition

Can you work back to the truth?PEOPLE love to tell tales. Indeed, even when someone’s memory is patchy, he will still do his best to spin the information he has into a credible yarn. This is not a matter of deceit. Rather, it is an established psychological phenomenon in which the brain tries to make sense of fragmentary information. Although such behaviour is natural and normal, it is a nuisance for the forces of law and order when they are trying to find out what happened during an incident by taking statements from witnesses. For this reason, psychologists working with the police often advocate asking witnesses of crimes to say what they saw in reverse order, to stop them making things up to help the story run smoothly. It sounds like sensible advice, and police forces in Australia, Britain, New Zealand, Norway, Spain and Sweden have all adopted it. But a new study suggests that far from improving recall, it makes things worse.

Coral Dando of Lancaster University, in Britain, showed 54 volunteers a short film of a staged mobile-phone robbery. The participants were then split into three groups and, two days later, interviewed about what they remembered from the film. All were asked to describe what they had seen twice, with no wait between the two descriptions. However, the way they were asked to make these descriptions differed from group to group. In one, participants were first told to recall the robbery freely, and then to recall it in reverse order. In another, they were told to recall the robbery in reverse order first and then to recall it freely. The third group was a control. Participants were told to recall the robbery freely on both occasions. All the interviews were recorded and passed to coders who were unaware of the purpose of the study, but who knew all the details of the film. These coders scored every apparent recollection in each interview by noting which items were correct, which were inaccurate (saying a dog was brown when it was really black, for example), and which were complete confabulations—things or events that bore no resemblance at all to anything in the film. A participant’s final score for each type of recollection was the number of such items recalled or invented in at least one of his two debriefings.

Dr Dando and her colleagues report in Cognition that reverse-order recall had a significant effect on the average number of correct items participants remembered—and not a good one. The control group, with no reverse recall, averaged 48.7 correct observations about the incident. The group that started with reverse recall and finished with free recall managed an average of only 42.2. The group that started with free recall but finished with reverse recall did worst, averaging 38.7 correct observations. And though the number of inaccurate recollections did not differ significantly between the groups, the tendency to make things up completely did.

Among the control group, an average of 0.2 such confabulations were created by each participant. Among those who freely recalled the robbery first and then recalled events in reverse order, this value climbed to 0.7. Among those asked to recall the robbery in reverse order first and then recall it freely, it was higher still, averaging 1.4 pure inventions per participant. Moreover, when the researchers analysed when these confabulations were mentioned, the majority (0.6 of the 0.7, and 1.2 of the 1.4) were told during the part of interview that involved reverse-order recall.

Why this is so is a mystery, for it is clearly not what psychology predicts. It does, however, point out the dangers of taking even logically plausible ideas on trust, rather than testing them. Psychologists are often accused by laymen of doing experiments to prove the obvious. In this case, a little more such testing of the obvious might have been sensible.

Game theory in practice

pragmasynesi — Thu, 05 Jan 2012 16:31:30 +0000

Advances in predicting human behaviour as applied to economics and politics. From the September 3, 2011 The Economist:

Game theory in practice

Computing: Software that models human behaviour can make forecasts, outfox rivals and transform negotiations

Sep 3rd 2011 | from the print edition
FOR a man who claims to lack expertise in the field, Bruce Bueno de Mesquita, an academic at New York University, has made some impressively accurate political forecasts. In May 2010 he predicted that Egypt’s president, Hosni Mubarak, would fall from power within a year. Nine months later Mr Mubarak fled Cairo amid massive street protests. In February 2008 Mr Bueno de Mesquita predicted that Pakistan’s president, Pervez Musharraf, would leave office by the end of summer. He was gone before September. Five years before the death of Iran’s Ayatollah Khomeini in 1989, Mr Bueno de Mesquita correctly named his successor, and, since then, has made hundreds of prescient forecasts as a consultant both to foreign governments and to America’s State Department, Pentagon and intelligence agencies. What is the secret of his success? “I don’t have insights—the game does,” he says.Mr Bueno de Mesquita’s “game” is a computer model he developed that uses a branch of mathematics called game theory, which is often used by economists, to work out how events will unfold as people and organisations act in what they perceive to be their best interests. Numerical values are placed on the goals, motivations and influence of “players”—negotiators, business leaders, political parties and organisations of all stripes, and, in some cases, their officials and supporters. The computer model then considers the options open to the various players, determines their likely course of action, evaluates their ability to influence others and hence predicts the course of events. Mr Mubarak’s influence, for example, waned as cuts in American aid threatened his ability to keep cronies in the army and security forces happy. Underemployed citizens then realised that disgruntled officials would be less willing to use violence to put down street protests against the ailing dictator.Mesquita & Roundell, Mr Bueno de Mesquita’s company, is just one of several consulting outfits that run such computer simulations for law firms, companies and governments. Most decision-making advice is political, in the broadest sense of the word—how best to outfox a trial prosecutor, sway a jury, win support from shareholders or woo alienated voters by shuffling a political coalition and making legislative concessions.

But feeding software with good data on all the players involved is especially tricky for political matters. Reinier van Oosten of Decide, a Dutch firm that models political negotiations and vote-trading in European Union institutions, notes that forecasts go astray when people unexpectedly give in to “non-rational emotions”, such as hatred, rather than pursuing what is apparently in their best interests. Sorting out people’s motivations is much easier, however, when making money is the main object. Accordingly, modelling behaviour using game theory is proving especially useful when applied to economics.

Follow the money

Modelling auctions has proved especially successful, says Robert Aumann, an academic at the Hebrew University of Jerusalem who received a Nobel prize in 2005 for his work in game-theory economics. Bids, being quantified, facilitate analysis, and predicting the right answer can be very lucrative. Consulting firms are popping up to help clients design profitable auctions or win them less expensively. In the run-up to an online auction in 2006 of radio-spectrum licences by America’s Federal Communications Commission, Paul Milgrom, a consultant and Stanford University professor, customised his game-theory software to assist a consortium of bidders. The result was a triumph.

When the auction began, Dr Milgrom’s software tracked competitors’ bids to estimate their budgets for the 1,132 licences on offer. Crucially, the software estimated the secret values bidders placed on specific licences and determined that certain big licences were being overvalued. It directed Dr Milgrom’s clients to obtain a patchwork of smaller, less expensive licences instead. Two of his clients, Time Warner and Comcast, paid about a third less than their competitors for equivalent spectrum, saving almost $1.2 billion.

Advances in game theory have “picked up dramatically” in recent years as it has become apparent that failing to do a proper analysis can be costly, says Sergiu Hart, a colleague of Dr Aumann’s at Hebrew University. For example, a few years ago Israel’s government added a novel twist to an auction of oil-refinery facilities. To encourage more and higher bids, the government offered a $12m prize to the second-highest bidder. It was an expensive mistake. Without the incentive, the highest bid would have been about $12m higher, an analysis showed—participants bid low because the loser would strike it rich. Combine that sum with the prize payout, and the government’s loss amounted to roughly $24m. The conclusion, then, is “don’t presume you know what the solution is” without help from modelling software, says Brad Miller, senior modeller at Charles River Associates, a consultancy in Boston. It designs game-theory software to model industrial auctions and the plotting of corporate mergers and acquisitions.

“The use of modelling makes business clients more inclined to adopt longer-term strategies.”

Software is not always needed. A student at Hebrew University, for example, demonstrated the Israeli government’s $24m loss using pen and paper. It took him about two days, however, according to a professor there. Software, naturally, is far faster. But gathering and handling the necessary data can require expensive expertise or training. Decide, the Dutch consultancy, usually charges €20,000-70,000 ($28,000-100,000) to solve a problem using its software, called DCSim, because it must first conduct lengthy interviews with experts. Its clients include government bodies in the Netherlands and abroad, and big companies including IBM, a computer giant, and ABN AMRO, a Dutch bank.

PA Consulting, a British firm, designs bespoke models to help its clients solve specific problems in areas as diverse as pharmaceuticals, fossil-fuel energy and the production of television shows. British government agencies have asked PA Consulting to build models to test regulatory schemes and zoning rules. To give a simple example: if two shrewd, competing ice-cream sellers share a long beach, they will set up stalls back-to-back in the middle and stay put, explains Stephen Black, a modeller in the firm’s London headquarters. Unfortunately for potential customers at the far ends of the beach, each seller prevents the other from relocating—no other spot would be closer to more people. Introduce a third seller, however, and the stifling equilibrium is broken as a series of market-energising relocations and pricing changes kick in. The use of modelling makes business clients more inclined to adopt longer-term strategies, Dr Black says.

But game-theory software can also work well outside the sphere of economics. In 2007 America’s military provided Mr Bueno de Mesquita with classified information to enable him to model the political impact of moving an aircraft carrier close to North Korea (he will not reveal the findings). Game-theory software can even help locate a terrorist’s hideout. To run simulations, Guillermo Owen of the Naval Postgraduate School in Monterey, California, uses intelligence data from the US Air Force to estimate on a 100-point scale the importance a wanted man attaches to his likes (fishing, say) and priorities (remaining hidden or, at greater risk of discovery, recruiting suicide-bombers). Such factors determine where and how terrorists decide to live. Game-theory software played an important role in finding Osama bin Laden’s hideout in Abbottabad, Pakistan, says Mr Owen.

Where is all this heading? Alongside the arms race of increasingly elaborate modelling software, there are also efforts to develop software that can assist in negotiation and mediation. Two decades ago Clara Ponsatí, a Spanish academic, came up with a clever idea while pondering the arduous Israeli-Palestinian peace process. As negotiators everywhere know, the first side to disclose all that it is willing to sacrifice (or pay) loses considerable bargaining power. Bereft of leverage, it can be pushed back to its bottom line by a clever opponent. But if neither side reveals the concessions it is prepared to make, negotiations can stall or collapse. In a paper published in 1992, Dr Ponsatí described how software could be designed to break the impasse.

Difficult negotiations can often be nudged along by neutral mediators, especially if they are entrusted with the secret bottom lines of all parties. Dr Ponsatí’s idea was that if a human mediator was not trusted, affordable or available, a computer could do the job instead. Negotiating parties would give the software confidential information on their bargaining positions after each round of talks. Once positions on both sides were no longer mutually exclusive, the software would split the difference and propose an agreement. Dr Ponsatí, now head of the Institute of Economic Analysis at the Autonomous University of Barcelona, says such “mediation machines” could lubricate negotiations by unlocking information that would otherwise be withheld from an opponent or human mediator.

Such software is now emerging. Barry O’Neill, a game theorist at the University of California, Los Angeles, describes how it can facilitate divorce settlements. A husband and wife are each given a number of points which they secretly allocate to household assets they desire. The wife may inform the software that her valuation of the family car is, say, 15 points. If the husband puts the car’s value at 10 points, he cannot later claim that he deserves more compensation for not getting the car than she would be entitled to.

Predicting an end to conflict

Participants need to be sure that such mediation technology is fully neutral. For large deals, audit firms closely monitor the development and use of such software to ensure that no party secretly obtains information about another’s bargaining positions, says Benny Moldovanu, a game theorist at the University of Bonn. He advises firms that design negotiation software for privatisation schemes and wholesale-electricity markets. This approach will spread to other utility markets, such as water, he believes.

Could software-based mediation spread from divorce settlements and utility pricing to resolving political and military disputes? Game theorists, who consider all these to be variations of the same kind of problem, have developed an intriguing conceptual model of war. The “principle of convergence”, as it is known, holds that armed conflict is, in essence, an information-gathering exercise. Belligerents fight to determine the military strength and political resolve of their opponents; when all sides have “converged” on accurate and identical assessments, a surrender or peace deal can be hammered out. Each belligerent has a strong motivation to hit the enemy hard to show that it values victory very highly. Such a model might be said to reflect poorly on human nature. But some game theorists believe that the model could be harnessed to make diplomatic negotiations a more viable substitute for armed conflict.

Today’s game-theory software is not yet sufficiently advanced to mediate between warring countries. But one day opponents on the brink of war might be tempted to use it to exchange information without having to kill and die for it. They could learn how a war would turn out, skip the fighting and strike a deal, Mr Bueno de Mesquita suggests. Over-optimistic, perhaps—but he does have rather an impressive track record when it comes to predicting the future.

How to Work With Others

pragmasynesi — Thu, 05 Jan 2012 15:48:04 +0000

Great tip from Wired magazine’s November 2011 edition:

Work With Others

Looking out for number one is not a great survival strategy. We know this intuitively or we wouldn’t tip waiters or stop at red lights. Game theorists discovered years ago that cooperative strategies usually produce the most success. Computer models show that the top dog isn’t the most ruthless; it’s the one who reciprocates. Math proves the golden rule.

There were conditions, of course. If you’re “nice”—that is, if you cooperate—but your competition responds with lying or cheating, you have to retaliate. (Forgiveness is part of the equation, too, though. Slap the wrist and move on.)

The theory got more support when evolutionary biologists started noticing how important cooperation is to evolution. “If I am willing to let others have a slightly bigger share of the pie, then people will want to share pies with me,” wrote Harvard researcher Martin Nowak. “Generosity bakes successful deals.” In other words, a social group that plays by these rules becomes a kind of superorganism. (Like an ant colony—or Twitter.) That’s especially true in a globally integrated world. So unless you’ve got a ship packed for Mars, best to play nice.—K. C. Cole

How to Gain Trust

pragmasynesi — Thu, 05 Jan 2012 15:46:36 +0000

Great tip from Wired magazine’s November 2011 edition:

Gain Trust

Trust is something you earn. And to earn it, you must slowly and painstakingly build a relationship based on mutual admiration and respect. Only kidding! Trust can totally be faked. The key, as researchers at Vrije University Amsterdam discovered, is in convincing others that you have a high level of self-control. The researchers conducted a series of experiments on married couples as well as complete strangers in an effort to determine how trust forms. In each instance, people who exhibited self-control—who decided against buying CDs when they were short on cash, for example, or who showed up at places on time—were deemed trustworthy. So if you want people to trust you, just tell someone you are on a diet, then pass on dessert. Or promise to do a favor for them, then do it. And be on time. It works. Trust us. —Erin Biba

How to Ace a Test

pragmasynesi — Thu, 05 Jan 2012 15:45:06 +0000

Great tip from Wired magazine’s November 2011 edition:

Ace a Test

You’ve studied. You’ve taken practice exams. You’ve gotten a good night’s sleep. there’s only one thing left to do before that big test: Get some exercise. According to experiments conducted at the University of Illinois at Urbana-Champaign, one of the best things you can do to prep your brain for an intellectual challenge is to get in a perfectly timed small workout. Here’s how to sweat your way to a better score.—Brendan I. Koerner

Consider a Treadmill
You need to get your heart racing to sharpen your cognition, but you don’t want to risk overtaxing your mind. So avoid athletic pursuits against opponents—even virtual ones. One study found that treadmill workouts improve mental performance but vigorous sessions of Wii games do not.

Hit the Sweet Spot
Avoid either under- or overexertion: Taking it too easy will leave you as dull as when you started, and overdoing it will make you too tired to focus. Aim for a heart rate of about 60 percent of max. Use a heart-rate monitor to make sure you keep that same exertion plateau for a full 20 minutes.

Timing Is Everything
The cognitive benefits don’t kick in the moment you hop off the treadmill. Ongoing research suggests it will be anywhere from five to 20 minutes before they take effect. So time your workout to end about 20 minutes before the proctor yells, “Go!”

Strategize
The cognitive boost can be short-lived. After about 50 minutes researchers saw a return to baseline. So tackle the hardest questions first—remember, they’re often placed at the end of each section.

How to Rekindle Your Relationship

pragmasynesi — Thu, 05 Jan 2012 15:34:27 +0000

Great tip from Wired magazine’s November 2011 edition:

Rekindle Your Relationship

Sooner or later, most relationships fall into a rut. Advice abounds on how to spice things up (cue the furry handcuffs). But the scientifically vetted solution for making sparks fly is much simpler, says Arthur Aron, a psychology professor at the State University of New York, Stony Brook. Aron set up an experiment in which couples roll a ball across a room toward each other, which they did with ease. He assigned other couples a similar task but with their hands and feet tied. Afterward, Aron asked everyone to complete questionnaires on how much they loved their partners. The bound couples reported being much more smitten than the unfettered ones, whose task was easier.

No, this doesn’t take us back to furry handcuffs. The moral of Aron’s experiment is actually this: Take on a new challenge and the excitement of tackling it will rub off on your relationship. “That exhilarating feeling may come from another source, but it’s still associated with your partner,” says Aron, who theorizes this happens because of brain chemistry. “When people fall in love, they get activation in the dopamine system,” he says. Novel or exciting pursuits also stimulate the brain to pump out more dopamine. Aron theorizes that even playing videogames together may draw a couple closer. (Who knew Grand Theft Auto could help your love life?)

One easy way to put this wisdom to work is to shake up date night, suggests Aron, who conducted another experiment in which he asked couples to spend 90 minutes a week doing unfamiliar activities like rock climbing or taking Italian lessons. Ten weeks later, when these couples filled out a questionnaire about how they felt about each other, they scored much higher than couples who had stuck to familiar date nights like dinner and a movie. Problema risolto!—Judy Dutton

How to Find a Soul Mate

pragmasynesi — Thu, 05 Jan 2012 15:31:25 +0000

Great tip from Wired magazine’s November 2011 edition:

Find a Soul Mate

There’s a probabilistic approach to finding the love of your life, and it even has a name: satisficing, a combination of satisfy and suffice. OK, technically, satisficing refers to getting a good enough outcome when you’re lacking complete information about your options. But isn’t dating like that? According to Peter Todd, professor of informatics and cognitive science at Indiana University, the question always comes down to this: “Do you keep searching and hope something better will come along, or do you stop searching when you find something that looks pretty good?”

In the face of this conundrum, the best strategy for picking a mate is to date enough people to establish some baseline standards, then settle down with the next person you meet who exceeds the bar. According to Todd, you should have a baseline after dating roughly 12 people. He’s dubbed this theory the Twelve-Bonk Rule, and it can also be applied to picking the right employee or choosing a home. So, if you’ve dated fewer than 12 people, you should feel free to keep looking. If you’ve had 30 relationships, odds are you’re being too picky. Quit obsessing over your new paramour’s dorky laugh.—Judy Dutton

How to navigate a crowd

pragmasynesi — Thu, 05 Jan 2012 15:28:55 +0000

Great tips from Wired magazine’s November 2011 edition:

Navigate a Crowd

Exiting a concert or ball game seems to take far longer than entering one. But because crowds can be highly predictable, it’s possible to outsmart the masses. Walk this way.—Katharine Gammon

Aim for the outside
The outer edges of crowds generally move faster than the sludgy middle of the pack. A researcher in London studied such so-called edge effects by making videos of groups of people squeezing through corridors of various sizes. Sure enough, people tended to move faster along the walls. Other studies suggest why: People start bumping into each other when crowd density reaches around 7 to 10 square feet per person—something that usually happens in the denser middle area—and that jams the flow.

Take the express lane
People naturally form lines when walking in crowds. It’s generally good to stay in one of these lines rather than race ahead, which might force others to put on the brakes. “There’s a lot of self-organization in crowds, but the problems come when people transition from a flow to stop-and-go—then things get turbulent” says Dirk Helbing, who studies social behavior at the Swiss Federal Institute of Technology in Zurich.

Look ahead
One of the best ways to navigate through a crowd is to lead with your eyes: Look directly ahead, which allows others to see clearly where you want to go. If you keep your gaze fixed, others will instinctively get out of the way. Finnish researchers found that people register cues from others’ eyes, not body position, to avoid head-on collisions.