16 | NewScientist | 20 April 2013

WHEN it comes to making decisions, the conscious mind is the last to know.

We already had evidence that it is possible to detect brain activity associated with movement before someone is aware of making a decision to move. Now the same has been shown with abstract decisions. John-Dylan Haynes at the Bernstein Center for Computational Neuroscience in

Berlin, Germany, analysed brain scans of people deciding whether to add or subtract numbers. He found that, several seconds before that decision was consciously made, the same brain areas active prior to deciding to move were active (PNAS, doi.org/k6b).

Gabriel Kreiman of Harvard University, who has worked on movement decision-making, says he is now working on predicting

Magnetic death lets exoplanets dry up

SEEMINGLY habitable exoplanets may be missing their magnetic shielding, leaving them exposed to damaging radiation.

To support life as we know it, planets need thick, water-rich atmospheres and liquid surface water; conditions that so far have only been hinted at, based mostly on a planet’s distance from its star.

But water can get blasted away by stellar winds unless the planet has a strong magnetic field, point out Jorge Zuluaga at the University of Antioquia in Colombia and colleagues. A churning molten core helps to generate a magnetic field, so the team calculated how long it would take a rocky planet to cool so much that it stopped working (arxiv.org/abs/1304.2909).

They then checked three well-known rocky exoplanets thought to be potentially habitable. Two of them might have magnetic fields just barely strong enough, they found, but the third is doomed.

‘Blowhole’ method for killing dolphins is inhumane

NO BETTER than knives and spears – that’s the verdict on a new, supposedly more humane, method for killing dolphins that has been adopted in Japan.

Each year, hundreds of dolphins are herded into a cove near the fishing village of Taiji in south-east Japan, and killed with knives and spears. The culls drew global condemnation in 2009 after the Oscar-winning documentary The Cove publicised the practice. In 2010, Toshihide Iwasaki of Far Seas Fisheries and Yoshifumi Kai of the Taiji Fisheries Cooperative reported on another method. This involves using a thin rod to impale dolphins

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I know what you’re thinking... decisions in real time, and to see if it is possible to reverse a decision before it hits consciousness by flashing up the word “stop” on a screen as soon as telltale activity shows up in the brain.

Kreiman suspects there may be a “point of no return” in the brain, after which you cannot stop a decision. “We are trying to find out mechanisms of volition. It might help people with Parkinson’s disease, where people lose voluntary movement.”

behind their blowhole and sever the spinal cord. They said tests had shown that the animals died faster. As a consequence the method was adopted by Taiji fishermen. One striped dolphin (Stenella coeruleoalba) apparently took 5 seconds to die, less than the 300 seconds using conventional practices.

Andrew Butterworth of the University of Bristol Veterinary School, UK, and colleagues refute this claim. They assessed video footage of the 2011 Taiji cull and found dolphins took longer to die than the Japanese team claim (Journal of Applied Animal Welfare Science, doi.org/k67). “This method does not fulfil the internationally recognised requirement for immediacy,” says Butterworth. “It would not be permitted in any regulated slaughterhouse process in the developed world.”

LOST neutrinos help set off weak flashes of light that signal a black hole’s birth.

It’s thought that very massive stars explode when they die, and the stuff left behind collapses into a black hole. But models suggest that most stars forming black holes implode instead, making them hard to spot, says Elizabeth Lovegrove of the University of California, Santa Cruz. She and her colleagues realised the key to seeing an imploding star may lie in the large number of neutrinos released from a dying star’s core.

Without the neutrinos, the core suddenly becomes lighter. This sends a shock wave through the star’s outer layers (arxiv.org/abs/1303.5055), triggering a dim – but visible – flash.

Shock wave signals black hole birth

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