To tie in with the launch of the Guardian’s new science blog network, Alok Jha – a veritable dervish of commissioning – has been asking various science bloggers and writers to contribute to a Science Blog Festival. It’s meant to be a “celebration of the best writing on the web” and Alok hopes that it will “give [readers] a glimpse of the gems out there.” It’s a great idea. The Guardian gets cool content, bloggers get more exposure to a vast audience, and readers get a miscellany of great stories.
Today, my first contribution is up and it’s a whirlwind tour through the incredible biology of Physarum, the decision-making, robot-inspiring, town-planning slime mould that manages to be surprisingly intelligent without a brain. Here’s the intro:
In 2009, scientists unleashed an amoeba-like blob on to Tokyo, and watched as it consumed everything in sight. In less than a day, the blob had spread throughout the entire city, concentrating itself along major transport routes.
Fortunately for the citizens of the great Japanese metropolis, the blob did its work on a model. Flakes of oats stood in for the major urban zones and the scientists involved were no B-movie villains. Rather, they were biologists studying the sophisticated behaviour of a slime mould, an oozing blob of goo that performs feats of apparent intelligence despite being completely brainless…
Without a brain, Physarum makes decisions by committee. The plasmodium is a single sac but it behaves like a colony. Every part rhythmically expands and contracts, pushing around the fluid inside. If one part of the plasmodium touches something attractive, like food, it pulses more quickly and widens. If another part meets something repulsive, like light, it pulses more slowly and shrinks. By adding up all of these effects, the plasmodium flows in the best possible direction without a single conscious thought. It is the ultimate in crowdsourcing.
Click across to read the whole thing. I wanted to push myself a bit for this so rather than covering a single paper (and there is a new one out today), I wanted to see if I could write a mini-feature about the entire field, in less than a weekend. I hope people enjoy the result.
And to any new readers who have come over from the Guardian: hello! Hang up your coats and have a look around.
Two party leaders have to cooperate in a coalition government, despite their political differences. A referee and a linesman have to make a decision that could spell success or failure in an international sporting tournament. Two heads have to direct the same groovy body towards saving the galaxy. From politics to sport to interstellar hitchhiking, there are many situations that require two people to work together.
Now, Bahador Bahrami from the Interacting Minds Project has found evidence that two proverbial heads can indeed be better than one… but only under certain circumstances. Through a simple experiment where volunteers cooperated to find a hidden image in a screen, Bahrami found that pairs trump individuals if they freely discuss their disagreements, not just about what they saw but how confident they were in their decision.
A couple arrive at a fancy restaurant and they’re offered the wine list. This establishment only has two bottles on offer, one costing £5 and the other costing £25. The second bottle seems too expensive and the diners select the cheaper one. The next week, they return. Now, there’s a third bottle on the list but it’s a vintage, priced at a staggering £1,000. Suddenly, the £25 bottle doesn’t seem all that expensive, and this time, the diners choose it instead.
Businesses use this tactic all the time – an extremely expensive option is used to make mid-range ones suddenly seem like attractive buys. The strategy only works because humans like to compare our options, rather than paying attention to their absolute values. In the wine example, the existence of the third bottle shouldn’t matter – the £25 option costs the same amount either way, but in one scenario it looks like a rip-off and in another, it looks like a steal. The simple fact is that to us, a thing’s value depends on the things around it. Economists often refer to this as “irrational”.
But if that’s the case, we’re not alone in our folly. Other animals, from birds to bees, make choices in the same way. Now, Tanya Latty and Madeleine Beekman from the University of Sydney, have found the same style of decision-making in a creature that’s completely unlike any of these animals – the slime mould, Physarum polycephalum. It’s a single-celled, amoeba-like creature that doesn’t have a brain.
In the digital age, many of us are compulsive multi-taskers. As I type this, I’m listening to some gentle music and my laptop has several programs open including Adobe Reader, Word, Firefox and Tweetdeck. I’ve always wondered what goes on in my brain as I flit between these multiple tasks, and I now have some answers thanks to a new study by Parisian scientists Sylvain Charron and Etienne Koechlin.
They have found that the part of our brain that controls out motivation to pursue our goals can divide its attention between two tasks. The left half devotes itself to one task and the right half to the other. This division of labour allows us to multi-task, but it also puts an upper limit on our abilities.
Koechlin has previously suggested that the frontopolar cortex, an area at the very front of our brains, drives our ability to do more than one thing at a time. It allows us to simultaneously pursue two different goals, holding one in the ready while we work on the other. Just behind the frontopolar cortex lies the medial frontal cortex (MFC), an area that’s involved in motivation. It drives our pursuit of multiple goals, according to the rewards we expect from them. Koechlin wanted to understand how these two areas cope with multi-tasking.
To do that, he used a brain-scanning technique called functional magnetic resonance imaging (fMRI) to study the brain activity of 32 volunteers, as they carried out a challenging task. They saw a steady stream of letters, all from the word “tablet”. For every block of three letters, they had to say if the first one was a “t” and if the other two appeared in the same order that they would in “tablet” (e.g. TAB rather than TEB). If the letters were red, they would get a sizeable cash reward but if they were green, the reward would be smaller.
Based on this same set-up, they had to cope with two slightly different tests. In the “branching” tests, they had to deal with two separate streams of triplets, a primary one indicated by normal letters and a secondary one indicated by italics. The primary stream was continuous and the volunteers had to revert back to it every time they finished a secondary triplet. They had to hold the primary stream in mind so that they could return to it after their interruption. In the simpler “switching” tests, they started afresh with every new triplet, so they only had to cope with a single stream of information.
Charron and Koechlin found that in the switching tests, when the volunteers were only faced with a single task, both halves of their MFC were active, particularly the dorsal anterior cingulated cortex (dACC) and the presupplementary motor area (PMA). The more money was at stake, the stronger the activity in these regions.
In the branching tests, both halves of the MFC were also active, but they were split between the two tasks. The right dACC took control of the secondary task; when the volunteers could earn more money from these triplets, only the right dACC became more active. The left half took control of the primary task; its activity matched the rewards associated with the primary triplets but not the secondary ones.
The frontopolar part of the brain also became active during the branching tests, which fits with its established role in multi-tasking. However, its attentions weren’t divided by the two tasks and it only became more active when both the primary and secondary rewards were higher. This suggests that the frontopolar cortex plays the role of coordinator. While each half of the MFC encodes the incentives of pursuing each separate goal, the frontopolar cortex encodes the incentives of pursuing both goals together.
It also suggests that we might not be able to cope with more than two tasks at the same time. Charron and Koechlin tested this with an even more fiendish “double branching” test, where the two streams of triplets in their original experiment were interrupted by a third stream. To succeed in this task, they had to retain three separate lanes of information at the same time. They couldn’t. When they tried to return to the first stream from the second, or the second from the third, their answers were no better than guesswork.
Despite what some psychologists have suggested, it seems that the human brain is capable of multi-tasking although to a far lesser extent than a computer can. While my laptop is running several different programs at once with nary a hint of discomfort, Charron and Koechkin’s work suggests that my brain can’t handle any more than two tasks at once.
Reference: Science http://dx.doi.org/10.1126/science.1183614
We like to be in control of our own lives, and some of us have an automatic rebellious streak when we’re told what to do. We’re less likely to do a task if we’re ordered to do it than if we make the choice of our own volition. It seems that this effect is so strong that it even happens when the people giving the orders are… us.
In a set of three experiments, Ibrahim Senay from the University of Illinois has shown that people do better at a simple task if ask themselves whether they’ll do it than if they simply tell themselves to do so. Even a simple reversal of words – “Will I” compared to “I will” – can boost motivation and performance.
Therapists and managers alike are taught to ask people open questions that prompt them to think about problems for themselves, rather than having solutions imposed upon them. Senay’s work suggests that this approach would work even if we’re counselling or managing ourselves. When we question ourselves about our deeds and choices, we’re more likely to consider our motivations for doing something and feel like we’re in control of our actions. The effect is small but significant.
We spend a lot of time wondering about what other people think of us. Do they find us attractive, intelligent, capable or trustworthy? Considering how often we mull over such questions and how confidently we arrive at conclusions, we are remarkably bad at answering them. We have a nasty tendency to use our own minds as a starting point when reasoning about other people’s and we rely too heavily on stereotypes and other expectations. In short, we are rubbish telepaths.
Mind-reading is still the stuff of science-fiction (or quackery) but Nicholas Epley is more interested in the everyday version of the skill, where we try and intuit what others think. Regular readers may remember him from last month’s post about how people rely on their own attitudes and beliefs when divining the mind of God. Now, together with Tal Eyal, Epley’s back with research that tries to teach us how to be better mind-readers.
It’s all about detail, or lack of it. We see ourselves in lots of detail, focusing on every single quality or imperfection. Others view us through a much broader and abstract lens. When it comes to ourselves, we’re experts, privy to a wealth of knowledge that others don’t have. We’re also psychologically close, always aware of our state in the here and now.
In practice, when thinking about our attractiveness, we tend to focus on how our hair sits, the small wrinkles on our faces or the specific hue of our clothes, while others tend to notice higher-level features like ethnicity, height or overall presentation. You know that your hair looks much better today or that you’ve got a new spot, while a potential date knows none of these things. The same applies to other areas – presenters might rate the quality of their talks by fretting over every word or slide, while audience members pay more attention to overall content and delivery style.
It’s this disparity between the way we see ourselves and the way others see us that makes us bad telepaths. The trick to more accurately working out how others see us is to view ourselves through a wide-angle lens rather than a microscope.
Some people go out of their way to help their peers, while others are more selfish. Some lend their trust easily, while others are more suspicious and distrustful. Some dive headlong into risky ventures; others shun risk like visiting in-laws. There’s every reason to believe that these differences in behaviour have biological roots, and some studies have suggested that they are influenced by sex hormones, like testosterone and oestrogen.
It’s an intriguing idea, not least because men and women have very different levels of these hormones. Could that explain differences in behaviour between the two sexes? Certainly, several studies have found links between people’s levels of sex hormones and their behaviour in psychological experiments. But to Niklas Zethraeus and colleagues from the Stockholm School of Economics, this evidence merely showed that the two things were connected in some way – they weren’t strong enough to show that sex hormones were directly influencing behaviour.
To get a clearer answer, Zethraeus set up a clinical trial. He recruited 200 women, between 50-65 years of age, and randomly split them into three groups – one took tablets of oestrogen, the second took testosterone tablets and the third took simply sugar pills.
After four weeks of tablets, the women took part in a suite of psychological games, where they had the chance to play for real money. The games were designed to test their selflessness, trust, trustworthiness, fairness and attitudes to risk. If sex hormones truly change these behaviours, the three groups of women would have played the games differently. They didn’t.
Their levels of hormones had changed appropriately. At the end of the four weeks, the group that dosed up on oestrogen had about 8 times more than they did at the start, but normal levels of testosterone. Likewise, the testosterone-takers had 4-6 time more testosterone and free testosterone (the “active” fraction that isn’t attached to any proteins) but normal levels of oestrogen. The sugar-takers weren’t any different. Despite these changes, the women didn’t play the four psychological games any differently.
Animals have distinct personalities and temperaments, but why would evolution favour these over more flexible and adaptible mindsets? New game theory models show that animal personalities are a natural progression from the choices they make over how to live and reproduce.
Any pet owner, wildlife photographer or zookeeper will tell you that animals have distinct personalities. Some are aggressive, others are docile; some are bold, others are timid.
In some circles, ascribing personalities to animals is still a cardinal sin of biology and warrants being branded with a scarlet A (for anthropomorphism). Nonetheless, scientists have consistently found evidence of personality traits in species as closely related to us as chimpanzees, and as distant as squid, ants and spiders.
These traits may exist, but they pose an evolutionary puzzle because consistent behaviour is not always a good thing. The consistently bold animal could well become a meal if it stands up to the wrong predator, or seriously injured if it confronts a stronger rival. The ideal animal is a flexible one that can continuously adjust its behaviour in the face of new situations.
And yet, not only do personality types exist but certain traits are related across the entire animal kingdom. Aggression and boldness toward predators are part of a general ‘risk-taking’ personality that scientists have found in fish, birds and mammals.
Max Wolf and colleagues from The University of Groningen, Netherlands, have found a way to explain this discrepancy. Using game theory models, they have shown that personalities arise because of the way animals live their lives and decide when to reproduce.