I’ve got a story out in Nature News about an “electronic skin” that can monitor a person’s heartbeat, brain activity, muscle contractions and more, without the need for bulky conventional electronics. It’s no thicker than a human hair and can be applied as easily as a temporary tattoo. It sticks without the need for any glue, and can flex and stretch without breaking.
It’s an amazing piece of technology. Go to Nature to read the full story. Meanwhile, I’m posting the full (lightly edited) transcript of my chat with John Rogers from the University of Illinois at Urbana-Champaign, who led the development of the electronic skin. He said a lot of interesting stuff that didn’t make it into the final piece and really gets across the many potential applications of the device.
In 1987, Charles Bonner discovered the fossilised bones of a large sea reptile on his family ranch. It was a flipper-limbed plesiosaur, probably Polycotylus, and one of many such fossils recovered from Logan County in Kansas. But this specimen was special – there was a smaller one inside it. This plesiosaur was pregnant.
Yesterday, I watched as hundreds of Londoners took to the streets in a heroic attempt to clean up the mess caused by rioters and looters the night before. Looking at pictures of large crowds getting off trains with cleaning equipment in hand and marching down streets with brooms held aloft, I’ve rarely felt so proud of my city.
The clean-up operation was a great move – a positive note in an otherwise depressing week and a chance for a beleagured capital to come together and reclaim its sense of community. But the act of cleaning away the preceding day’s damage was also important. To explain why, I’m reposting this piece from a few years back about a Dutch study which showed that signs of disorder only breed more disorder. To clarify, this is in no way an attempt to explain the psychology of the riots themselves; it simply suggests another reason why the clean-up operation was a smart move.
Imagine walking through a neighbourhood and seeing graffiti, litter, and shopping trolleys strewn about the place. Are these problems to be solved, or petty annoyances that can be ignored in the light of more serious offences? A new study suggests that the former is right – even the most trivial of transgressions can spread and spiral because their very presence stimulates more of the same behaviour. Through a series of stunning real-world experiments, Kees Keizer and colleagues from the University of Groningen have shown that disorder breeds more disorder. The mere presence of graffiti, for example, can double the number of people who litter and steal.
Their study provides strong support for the controversial Broken Windows Theory, which suggests that signs of petty crimes, like broken windows, serve as a trigger for yet more criminal behaviour. It follows that fixing small problems can prevent the build-up of bigger ones and the gradual decay of a neighbourhood. The idea was first proposed in a magazine article published in 1982, but soon became the basis of many a social policy.
It inspired Rudy Guiliani’s Quality of Life Campaign in New York, which focused attention on seemingly trivial fixes such as removing graffiti, clearing signs of vandalism and sweeping the streets. The campaign seemed to work, which motivated other cities to try the same tactics. But despite its popularity, the Broken Windows Theory still divides opinion, for it lacks the backing of hard evidence, it’s plagued by woolly definitions of “disorder” and critics have questioned its role in New York’s drop in crime. These are fairly hefty shortcomings for a concept that is so central to anti-crime measures and Keiser wanted to address them once and for all.
To do so, he took to the streets of Groningen and watched unknowing passers-by in real-life situations as they reacted to signs of disorder. The recurring question was this: would people exposed to inappropriate behaviour behave in a similar way themselves?
He began in an alleyway in a local shopping district, where bicycles are commonly parked and where a conspicuous red sign warned against graffiti. He attached a flyer from a fictional sportswear shop to the handlebars of parked bicycles and watched what people did as they returned to their rides. Under normal circumstances (picture on the left), most people took the flyer with them and just 33% littered by throwing it on the ground. But that all changed when Keiser covered the wall with graffiti (picture on the right). With this innocuous difference, the proportion of litterers doubled and 69% discarded their flyers on the street.
Keiser explains this behaviour in terms of “social norms” – the rules that separate appropriate behaviours from inappropriate ones. Problems arise when our view of what is common (in this case, graffiti) fails to mesh with our understanding of what society expects (as epitomised by the “No Graffiti” sign). Graffiti is frowned upon, but the covered walls send a message that it is common and therefore, more acceptable. Keizer calls this the Cialdini effect.
To see how far its influence would extend, he set up a temporary fence in front of a car park. He attached two signs to the fence, one banning people from locking their bicycles to it, and another saying that entry was forbidden and asking people to use a detour some distance away. When he placed four bicycles a metre away, just 27% of people disobeyed the detour sign and squeezed through the gap in the fence. But when the bikes were locked to the fence, in blatant disregard of the first sign, 82% of people ignored the detour sign too. With one rule broken, the other followed suit.
A third related study took place in a supermarket car park, where prominent stickers asked shoppers to return their carts to the main building. Keizer plastered various cars with the same flyer from the first study. If the garage was clear of carts, just 30% of shoppers littered with the flyer, but if four unreturned shopping carts were left lying about, 58% did so. Again, when people saw that one rule was broken, they felt less strongly about following another.
Together, these three experiments show that signs of disregarded rules can spread to affect commonly held behaviours (“don’t litter”) as well as specific requests from third parties (“don’t enter” or “return trolleys”).
Signs of disorder don’t even need to be seen to have such influences – they can be heard too. In the Netherlands, most people know that setting off fireworks in the weeks before New Year’s Eve is illegal and carries a small fine. Keiser found that he could trigger people to litter more frequently by giving them audible evidence that this law had been flouted. Again, he attached a flyer to bicycles parked near a train station. Under normal circumstances, 52% of cyclists littered but if they heard the sound of fireworks let off by Keiser at a nearby location, that figure grew to 80%.
For his final and most dramatic demonstration, Keiser showed that the mere presence of graffiti can even turn people into thieves. He wedged an envelope into the slot of a mailbox, with a 5 Euro note showing in the transparent window. If the mailbox and the ground around it were clean, just 13% of passers-by stole the envelope. If the mailbox was covered in graffiti, or if the ground around it was covered in litter, the proportion of thieves doubled to 27% and 25% respectively.
Keiser thinks that it’s unlikely that people inferred a reduced police presence by the presence of litter or graffiti – certainly, litter is generally tolerated by the police in Groningen. Instead, he thinks that one transgression was actually fostering another. This isn’t a simple case of imitation – littering doesn’t just beget littering. Keiser’s idea is that seeing the breakdown of one social norm makes it easier to ignore others, by weakening our general resolve to act appropriately and strengthening our temptations to act in our own self-interest.
All in all, the suite of experiments, all in a realistic setting, provide powerful evidence that the Broken Windows Theory is valid and all of Keiser’s results were statistically significant. Small, petty signs of disorder can indeed turn people away from the straight and narrow. His message to police and policy-makers is stark – it is worth spending time on small and seemingly trivial interventions, to prevent disorder from spreading and escalating.
Reference: Keizer, K., Lindenberg, S., & Steg, L. (2008). The Spreading of Disorder Science, 322 (5908), 1681-1685 DOI: 10.1126/science.1161405
In the Olympic Games of Ancient Greece, long-jumpers would leap while carrying weights called halteres in their hands. From either a standing start or a short run, they swung the weights and leapt as their arms came forward. The halteres each weighed up to nine kilograms, and would have added around 17 centimetres to a 3 metre jump. Olympians first used the hand weights in 708 BC, but other apes were jumping with a very similar technique millions of years earlier – gibbons.
Gibbons are undisputed masters of the treetops, best known for swinging around at unfeasible speeds from their long, powerful arms. Their wrists contain ball-and-socket joints, which allow their entire body to easily pivot about their hands. This style of movement, known as brachiation, is a gibbon speciality (see video below). But these apes are also accomplished jumpers. Field scientists have watched them clear gaps as large as 10 metres.
Most life on this planet goes about their business as single cells. Only rarely do these singletons unite in cooperative societies, creating bigger and more complex living things, from trees to humans. This transition from single-celled to ‘multicellular’ life is one of the most important transitions in the evolution of life on Earth and it has happened many times over.
There are two main routes to a multicellular life. Single cells can merge together, and some modern species recap how this might have happened. Individual slime moulds join to form mobile slugs, while myxobacteria can merge into predatory swarms. Alternatively, cells can multiply but remain attached, staying united in their division. The choanoflagellates, possibly the closest living relatives of animals, can do this, creating simple colonies from single cells.
So we have a reasonable, if basic, understanding of how multicellular creatures first evolved. But we’re still largely in the dark about why. What benefit did cells gain from sticking together, rather than swimming solo? John Koschwanez from Harvard University thinks he has one answer: by sticking together, clumps of cells became better at foraging for nutrients. The multicellular life was a well-fed one.
Compared to most other animals, humans are unusual in our tendency to help each other out. We donate to charity. We give blood. We show kindness to strangers, even when we stand to gain nothing in return. This behaviour is so odd that the natural question arises: are we alone in such selflessness? And if any animal could help to answer that question, it’s the chimpanzee, one of our closest relatives.
Dozens of scientists study the behaviour of chimps, looking at how these apes act towards their peers. But the results of these studies have been frustrating for many in the field. People who watch captive and wild chimps have documented hundreds of cases of seemingly altruistic behaviour. They have seen individuals helping each other to climb walls, consoling each other after fights, sharing food, risking death to save companions from drowning, and even adopting the babies of dead and unrelated peers. Anecdotes like these suggest that chimps, like humans, behave selflessly towards each other.
But experiments have often shown otherwise. In some studies, chimps choose to help their peers retrieve out-of-reach objects rather than doing nothing. But when chimps have a choice between two equal actions – say, cashing in a token that leads to personal gain versus another that also benefits a partner – they only looked out for themselves. One paper bore the title “Chimpanzees are indifferent to the welfare of unrelated group members”. Another concluded that “chimpanzees made their choices based solely on personal gain”.
Collectively, these studies championed a view of chimps as reluctant altruists, who only act selflessly in response to pressure, and who generally don’t help unfamiliar chimps, “even when they are able to do so at virtually no cost to themselves”. But Frans de Waal from the Living Links Centre at Emory University thinks that this portrait is wrong. He says, “The authors of these studies moved from not finding evidence for prosocial choice to thinking they had proven its absence.”
De Waal thinks that the previous tests handicapped the chimps by putting them in situations that masked their altruistic tendencies. They couldn’t communicate, they had to cope with complicated equipment involving levers, and they often sat so far apart that they had little understanding of how their choices affected their fellows. With his colleague Victoria Horner, de Waal designed a new experiment to account for these problems. And, lo and behold, chimps spontaneously helped their partners, even without any prompting.
Reference: :Simons, D., & Chabris, C. (2011). What People Believe about How Memory Works: A Representative Survey of the U.S. Population PLoS ONE, 6 (8) DOI: 10.1371/journal.pone.0022757
For large swathes of the brain, the neurons we’re born with are the ones we’re stuck with. But a few small areas, such as the hippocampus, create new neurons throughout our lives, through a process known as neurogenesis. This production line may be important for learning and memory. But it has particularly piqued the interest of scientists because of the seductive but controversial idea that it could protect against depression, anxiety and other mood disorders.
Now, by studying mice, Jason Snyder from the National Institute of Mental Health has found some of the strongest evidence yet for a connection between neurogenesis and depression (or, at least, mouse behaviours that resemble depression). He found that the new neurons help to buffer the brains of mice against stress. Without them, the rodents become more susceptible to stress hormones and they behave in unusual ways that are reminiscent of depressive symptoms in humans.
Mythology imbues the vampire bat with supernatural powers, but its real abilities are no less extraordinary. Aside from its surprising gallop and its anti-clotting saliva, the bat also has a heat-seeking face. From 20 centimetres away, it can sense the infrared radiation given off by its warm-blooded prey. It uses this ability to find hotspots where blood flows closest to the skin, and can be easily liberated by a bite. Now, Elena Gracheva and Julio Cordero-Morales from the University of California, San Francisco have discovered the gene behind this ability.
Among the back-boned vertebrates, there are only four groups that can sense infrared radiation. Vampire bats are one, and the other three are all snakes – boas, pythons, and pit vipers like rattlesnakes. Last year, Gracheva and Cordero-Morales showed that the serpents’ sixth-sense depends on a gene called TRPA1, the same one that tells us about the pungent smells of mustard or wasabi. Boas, pythons and vipers have independently repurposed this irritant detector into a thermometer.
Vampire bats evolved their ability in a similar way, but they have tweaked a different protein called TRPV1 that was already sensitive to heat. Like TRPA1, TRPV1 also alerts animals to harmful substances. It reacts to capsaicin, the chemical that makes chillies hot and allyl isothiocyanate, the pungent compound that gives mustard and wasabi their kick. In humans, it also responds to any temperature over 43 degrees Celsius. The vampire has simply tuned it to respond to lower temperatures, such as those of mammal blood.