I am walking strangely. About a week ago, I pulled something to my left ankle, which now hurts during the part of each step just before the foot leaves the ground. As a result, my other muscles are compensating for this to minimise the pain and my gait has shifted to something subtly different from the norm. In similar ways, all animal brains can compensate for injuries by computing new ways of moving that are often very different. This isn’t a conscious process and as such, we often take it for granted.
But we can get a sense of how hard it actually is by trying to program a robot to do the same thing. It’s far from straightforward. Robots have been used for years to perform structured, repetitive tasks and as engineering has advanced, their movements have become more life-like and more stable. But they still have severe limitations, not the least of which is inflexibility in the face of injury or changes to their body shape. If a robot’s leg falls off, it becomes as useful as so much scrap metal.
So for robots, adaptiveness is a desirable virtue, especially if they are to be used in the field. Modern bots can independently develop complex behaviours without any previous programming but usually, this requires trial and error and lots of time. But not always. Josh Bongard and colleagues at Cornell University have developed an adaptable bot that’s programmed to continuously assesses its body structure and develop new ways of moving if anything changes.
It differs from other models in that it has no built-in redundancy plans, no strategies for dealing with anticipated problems. It’s simply programmed to examine itself and adapt accordingly. The concept of a robot that can adapt to new situations is often the precursor to nightmare scenarios in many a science-fiction film. So it is fortunate that Bongard’s robot isn’t armed or threatening, but instead looks more like a four-armed starfish.
Two strangers are having a normal conversation in the middle of a large crowd. No one else can see them. No one else can listen in. Thanks to advanced gadgetry, they are talking in coded messages that only they can decipher. These invisible conversationalists sound like they’ve walked out of a Bond film. But they are entirely real, and their skill at secrecy is biological, not technological. They are squid.
Squid and their relatives, the octopus and cuttlefish, are masters of concealment. They have the most sophisticated camouflage abilities in the animal kingdom and use them to avoid predators who would gladly feast on their soft shell-less bodies. Their remarkable abilities also allow individuals to communicate with each other through a rich vocabulary of colour-changes and body postures. But in doing so, they face a problem – how can they signal to each other without compromising their finely crafted camouflage?
Lydia Mathger and Roger Hanlon at the Marine Biological Laboratory, Massachusetts, have the answer and it lies in the squid’s dual-layered skin. The animals use these two layers to communicate with one another using polarised light, without ever compromising their perfect disguises.
You are on a date and by all accounts, it’s going well. Midway through dinner, you excuse yourself and head to the bathroom where, to your chagrin, the mirror reveals that you have a streak of sauce on the side of your face. Embarrassed, you wipe it away and rejoin your date.
It’s a fairly innocuous scene but it requires an ability that only the most intelligent of animals possess – self-awareness. It’s the understanding that you exist as an individual, separate from others. Having it is a vital step to understanding that others are similarly aware and have their own thoughts and desires. As such, it is intimately linked to mental qualities like empathy and selflessness. This may seem obvious to us but even human children only become self-aware in their second year of life.
In the animal kingdom, the skill is even rarer and has only been found in the most intelligent of species – humans, apes, dolphins and more recently, magpies. In 2006, Joshua Plotnik of Emory University added elephants to that list.
In medieval times, crusading Christian knights cut a swathe through the Middle East in an attempt to reclaim Jerusalem from the Muslims. The Muslims in turn cut through the invaders using a very special type of sword, which quickly gained a mythical reputation among the Europeans. These ‘Damascus blades‘ were extraordinarily strong, but still flexible enough to bend from hilt to tip. And they were reputedly so sharp that they could cleave a silk scarf floating to the ground, just as readily as a knight’s body.
They were superlative weapons that gave the Muslims a great advantage, and their blacksmiths carefully guarded the secret to their manufacture. The secret eventually died out in the eighteenth century and no European smith was able to fully reproduce their method.
Two years ago, Marianne Reibold and colleagues from the University of Dresden uncovered the extraordinary secret of Damascus steel – carbon nanotubes. The smiths of old were inadvertently using nanotechnology.
The art of auctioning is an ancient one. The concept of competitively bidding for goods has lasted from Roman times, when spoils of war were divvied up around a planted spear, to the 21st century, when the spoils of the loft are sold through eBay. But despite society’s familiarity with the concept, people who take part in auctions still behave in a strange way – they tend to overbid, offering more money than what they actually think an object is worth.
Some economists have suggested that people overbid because they are averse to risk. They would rather make spend more money to be sure of a win than to risk making a steal by gambling with a low bid. Others have suggested that it’s the element of competition that drives people to overbid – the joy of winning is what they’re after. Now, Mauricio Delgado and colleagues from Rutgers University have provided new evidence to show that neither theory is right.
With a combination of brain-scanning and psychological games, they have found that economists who suggested a social competition angle were moving along the right lines. But it’s not the joy of winning that’s important – it’s the fear of losing. People cough up too much because of simple social competition.
Delgado’s team (which included Elizabeth Phelps, whose work I have blogged about before) used a brain-scanning technique called functional resonance magnetic imaging (fMRI) to study the brains of 17 volunteers as they played two games – a two-player auction or a single-player lottery.
A caterpillar is an eating machine – a mobile set of mandibles, whose sole mission is to survive long enough to munch its way to adulthood. Standing in their way are spiders, birds and predatory insects that want to eat them, and parasitic wasps that want to convert them into living incubators for their own larvae.
With so many enemies, defence is paramount for caterpillars and the various species have evolved a dazzling array of countermeasures. Some camouflage themselves, others use bright colours to advertise their toxic chemical weapons, which in at least one species is powerful enough to kill a human. They are coated with irritating hairs, throw up their digestive juices, emit foul odours, hang from silken safety lines and recruit ants as bodyguards.
But one group of caterpillars – those of the metalmark moths (Brenthia) – lack any of these. They feed on the topsides of leaves, sheltering only under a flimsy sheet of silk that they themselves spin. Out in the open, they are among the most conspicuous of caterpillars and surely would make easy target for enterprising predators or parasites. But not so; Jadranka Rota and David Wagner from the University of Connecticut found that the metalmark caterpillars use a defensive measure all their own – a wormhole.
The metalmarks chew a small hole in the leaf they feed on, directly under their silken shelter. It’s an escape tunnel that allows them to flee to safety of the leaf’s underside if danger threatens. The caterpillar senses the arrival of danger with extremely long hairs that protrude from its sides. Those on its rear end are so unfeasibly long that they always touch the silk that surrounds the caterpillar and often form part of the silk web itself. These hairs convert the entire silken tent into a giant sensory organ.
Imagine that you have been given responsibility over a tract of land. Your goal is to maintain its precious biodiversity (increasing it if at all possible), prevent the local habitats from becoming degraded and among all that, find a way to eke out a way of life. Of the many possible ways of doing this, regularly and deliberately setting fire to the local plants might be low on the list. But that’s exactly what Aborigine populations in Australia have been doing for centuries and a new study shows that this counter-intuitive strategy does indeed work.
A team of American anthropologists led by Rebecca Bird at Stanford University studied the practice of “fire-stick farming” among the Martu people of Australia’s Western Desert. The Martu live mostly as hunter-gatherers and supplement their food with the odd supply bought from local outstations. Their homelands are mostly dominated by sandy plains and the ubiquitous spinifex grass (Triodia) and these are the areas that the Martu start fires in.
They have different words for land at various stages of post-fire recovery: nyurma is freshly scorched earth, waru-waru describes land where shoots have started to sprout; mukura turns up after a few years when grasses, flowering shrubs and edible plants have arrived; mangul occurs a few years later still when the growing spinifex starts to outcompete edible plants, leading to kunarka when the spinifex starts to die and leaves behind sterile hollows.
The “successional stages” follow one after another in predictable ways and the Martu only ever set fire to the last two, when spinifex is dominant. In doing so, they effectively press an ecological reset button, allowing plants to return to areas that had previously been won by the unbeatable spinifex.
Well this is exciting… A year ago, I was asked to contribute to a book that would detail 1000 awesome scientific thinkers, discoveries and events over the last century, to be called the Little Black Book of Science. And after a long silence, it’s finally out, albeit under the much less good title of “Defining Moments in Science”.
I wrote 20 of the 1000 articles (2%, for the percentage-inclined) and in total, the book represents the combined efforts of 60 or so of the UK’s finest science writers, including one of my co-bloggers at Cancer Research UK, Kat Arney. Many thanks to Hayley Birch and the good people at Null Hypothesis for editing the not-insubstantial undertaking. It was a great chance to delve into some historical aspects of scientific discovery that I don’t usually get to do.
The ones I did include:
Which marks the only time in my life that I have ever deliberately done a Google search for Viagra. Therein lies a world of horror and torment.
Unlike this book. Which you should get. Because it will be brill.
Soooo… I have good news, bad news and good news.
The good news (well for me anyway) is that as of Friday I will be away for month of blissful holiday. If you listen closely, you will probably hear the sound of me exhaling loudly and cheering even more loudly as my wife and I head off to Australia for four weeks of wildlife, snorkelling, vineyards, really big rocks, and even a wedding in the middle.
The bad news, therefore, is that as of Friday, I will be unable to blog about new science for a month, as I give my precious, weary metacarpals a chance to rest. I may get dragged into action if something really amazing turns up but I’m not counting on it. This also means that I won’t really be able to respond to comments as much as I’d like although I will periodically have email access.
The good news is that I may be on holiday but the site isn’t going into hibernation. I have set up posts from the Classic site to go up on a daily basis, so regular readers can still get your Not Exactly Rocket Science fix. Hopefully you’ll agree that a month of nano-swords, spear-wielding chimps, robot salamanders, biplane dinos, drug-resistant plague, virgin dragons, and culture-driving parasites are a suitable compensation for the lack of new stuff.