ME and Ophelia

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HUMAN BEHAVIOUR AND THE ANIMAL KINGDOM
Community and the Blogosphere

The meaning of life, social interaction, quarrelsome, unfriendly, people and neighbourhoods, troublesome self serving neighbours, the natural laws of the animal kingdom, ants and sheep, lack of community in the blogosphere, the World drowning in oceans of data (the equivalent of a 30-foot pile of books of data is produced for everyone on Earth annually), and the comments left by readers in this report Web guru fights info pollution ("Ultimately, time is a non-renewable resource. Once that day is gone, it is never coming back"). What's it all for?

These are the things on my mind lately, whilst thinking about a post on community in the blogosphere - or more to the point, about the lack of it. I've looked forward to blogging about this issue but feel unable. This is not a "lazy" post, I just cannot manage any in-depth composition at the moment. Here are two reports on ants by John Whitfield, courtesy of Nature.

ANT GROUP DYNAMICS
Decision-making en masse ensures an ideal home

Lots of little brains can solve problems better than a big one has captured the imagination of computer scientists:

It's hard enough getting four people to agree on a rental video. Several hundred ants, however, pick the best among possible nest sites with ease. Each small act of an individual ant ensures that, together, the colony makes the right move.

Laboratory colonies of the European ant, Leptothorax albipennis, were made homeless by Stephen Pratt, of the University of Bath, UK. Pratt triggered migration by dismantling the ants' artificial nest, and giving them a choice of new homes.

When an ant scout finds a potential nest site she inspects it. The ants, who nest in rock crevices in the wild, prefer wide, dark crannies with small entrances. The scout returns to the old nest, and leads another ant there in a nose-to-tail procession. The new recruit forms a second opinion, returns home to lead a third, and so on.

But an ant thinks twice before she recruits the next advocate; the less she likes her potential new home, the longer she waits, found Pratt. "The ants are taking a sort of poll of their nest mates," he told the meeting of the Animal Behavior Society in Corvallis, Oregon. Desirable residences attract recruits quickly, while dumps' popularity withers.

If an ant arrives at a new site and finds many nest mates already there, her behaviour switches. Instead of leading new recruits, she starts to move belongings: carrying ants, larvae and eggs from old to new sites. A point seems to be reached when the colony's collective mind is made up, and migration accelerates.

Many individuals following a few simple rules result in complex and powerful behaviour. "You don't need a complex set of rules for patterns to emerge," says Jennifer Fewell, who studies ants at Arizona State University in Tempe. Brains, embryonic development and ecosystems show similar complex 'emergent' properties from simple interactions, says Fewell.

Such patterns may be an inevitable result of the interactions, rather than being favoured by natural selection, she says - studying them requires a different way of thinking. "We've looked at things from the perspective of evolution, rather than how the pattern gets there in the first place," says Fewell.

The idea that lots of little brains can solve problems better than a big one has captured the imagination of computer scientists. "There's an entire field developing based on ant algorithms," says Pratt. This tackles complex problems such as designing distribution networks.

Robotics engineers also foresee that groups of many simple machines could be adaptable and robust, as each individual is expendable.

© Nature News Service / Macmillan Magazines Ltd 2001 - Animal Behavior Society Meeting, Corvallis, Oregon, July 2001 - by John Whitfield
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ANTS SHAPE EUROPE'S BIGGEST CARNIVAL
Models of insect swarms teach scientists how to make street party safer

People in highly congested situations behave like a fluid - they move as one:

This weekend, almost a million people will pour into London's Notting Hill district for its annual carnival, Europe's largest street party. The authorities will treat them like ants in the hope of making their experience more pleasant.

Researchers have adapted computer models of insect swarms to work out the carnival parade route that is most likely to alleviate the crowding that can mar the event.

In the past, the parade has taken a circular route. This traps people in a small area and intensifies the crush. Two years ago, the Greater London Authority asked geographer Michael Batty of University College London and his colleagues to explore six alternative routes.

Last year, the team monitored the entry points into the carnival area. They combined this with information from transport authorities, first-aid providers and aerial police photos to work out how many people were going where.

The researchers then created a virtual Notting Hill. About 15,000 computerized pedestrians roamed simulated streets to find the quickest routes and prime attractions. People followed each other to entertainment hotspots, but were repelled by dense crowds.

This allowed the team to identify the potential crush spots and to predict the effects of different parade routes, blocked streets or closed underground stations.

The Notting Hill model predicted that an L-shaped parade route would reduce crowding most effectively. This foundered on the carnival organizers' desire to keep the route as circular as possible, and the wish of some local councils to keep the parade out of their area.

The compromise route is U-shaped - an interim solution, says Lee Jasper, a senior policy advisor to the Mayor of London. "We're taking an evolutionary approach," he says, to reconciling political and public safety concerns.

"The key thing is that we've now got several objective standards by which to make decisions, whereas in the past we've just had common sense and experience," says Jasper.

Mass movement

This type of simulation has been used to explain ants' behaviour, whereby many individuals following simple rules can produce complex and orderly transport networks without any outside control. "It's characteristic of how insects are attracted to food," says Batty.

Treating carnival-goers as individuals might work well for people heading into Notting Hill, comments computer scientist Jon Kerridge of Napier University in Edinburgh UK. But such simulations might not reflect the crush of the carnival, where freedom of movement is limited.

"People in highly congested situations behave like a fluid - they move as one," says Kerridge, who studies pedestrian movement. Often, for example, groups hold hands to stay in touch. Simulating individuals' movement might miss the effects of these behaviours on crowding, he says.

"Our model doesn't show the dynamics of crushing on a fine scale," admits Jake Desyllas of Intelligent Space, a London-based consultancy firm that collaborated in the project. "But it shows the key factors that influence crowds on an urban scale." The research team will be moving among the crowds at this year's carnival to collect information to refine their simulation.

© Nature News Service / Macmillan Magazines Ltd 2003, 22 August 2002 by John Whitfield