Posts Tagged ‘DAVID NIELD’

by David Nield

Since the 1980s scientists have spotted a link between naval sonar systems and beaked whales seemingly killing themselves – by deliberately getting stranded on beaches. Now, researchers might have revealed the horrifying reason why.

In short, the sound pulses appear to scare the whales to death, acting like a shot of adrenaline might in a human, and causing deadly changes in their otherwise perfectly calibrated diving techniques.

By studying mass stranding events (MSEs) from recent history, the team found that beaked whales bring a sort of decompression sickness (also known as ‘the bends’ or ‘divers’ disease’) on themselves when they sense sonar. When panicked, their veins fill up with nitrogen gas bubbles, their brains suffer severe haemorrhaging, and other organs get damaged.

“In the presence of sonar they are stressed and swim vigorously away from the sound source, changing their diving pattern,” one of the researchers, Yara Bernaldo de Quiros from the University of Las Palmas de Gran Canaria in Spain, told AFP.

“The stress response, in other words, overrides the diving response, which makes the animals accumulate nitrogen.”

The end result is these poor creatures die in agony after getting the whale version of the bends – not something you would normally expect from whales that are so adept at navigating deep underwater.

Typically, these animals naturally lower their heart rate to reduce oxygen use and prevent nitrogen build-up when they plunge far below the surface. Tragically, it appears that a burst of sonar actually overrides these precautions.

The researchers weighed up the evidence from some 121 MSEs between the years 1960 and 2004, and particularly focussed on the autopsies of 10 dead whales stranded in the Canary Islands in 2002 after a nearby naval exercise.

It’s here that the decompression sickness effects were noticed, as they have been in other stranding events that the researchers looked at.

While the team notes that the effects of sonar on whales seem to “vary among individuals or populations”, and “predisposing factors may contribute to individual outcomes”, there does seem to be a common thread in terms of what happens to these unsuspecting mammals.

That’s especially true for Cuvier’s beaked whale (Ziphius cavirostris) – of the 121 MSEs we’ve mentioned, 61 involved Cuvier’s beaked whales, and the researchers say they appear particularly vulnerable to sonar.

There’s also a particular kind of sonar to be worried about: mid-frequency active sonar (MFAS), in the range of about 5 kilohertz.

Now the researchers behind the new report want to see the use of such sonar technology banned in areas where whales are known to live – such a ban has been in place in the Canary Islands since the 2002 incident.

“Up until then, the Canaries were a hotspot for this kind of atypical stranding,” de Quiros told AFP. “Since the moratorium, none have occurred.”

The research has been published in the Royal Society Journal Proceedings B.

https://www.sciencealert.com/this-is-the-horrifying-reason-why-sonar-makes-beaked-whales-beach-themselves

Advertisements

ghosted-images-1_1024

by DAVID NIELD

New research suggests the human eye and brain are capable of seeing ghosted images, a new type of visual phenomenon that scientists previously thought could only be detected by a computer. It turns out our eyes are more powerful than we thought.

The discovery could teach us more about the inner workings of the eye and brain and how they process information, as well as changing our thinking on what we human beings can truly see of the world around us.

Having been developed as a way of low-cost image capture for light outside the visible spectrum, the patterns produced by these ghosted images are usually processed by software algorithms – but, surprisingly, our eyes have the same capabilities.

“Ghost-imaging with the eye opens up a number of completely novel applications such as extending human vision into invisible wavelength regimes in real-time, bypassing intermediary screens or computational steps,” write the researchers.

“Perhaps even more interesting are the opportunities that ghost imaging offers for exploring neurological processes.”

Ghost imaging works using a camera with a single pixel, rather than the millions of pixels used by the sensors inside today’s digital cameras and smartphones. When it comes to capturing light beyond the visible spectrum, it’s even a more cost-effective method.

These single pixel cameras capture light as it reflects from an object – by watching different random patterns of bouncing light, and crunching through some calculations, the camera can gradually build up a picture of something even with just one pixel.

In some setups, the single pixel camera is used in combination with a second light, modulated in response to the first, and beamed back on the original random patterns. The advantage is that fewer patterns are needed to produce an image.

In this case a second camera using some smart algorithms can pick up the image without having looked at the object at all – just by looking at the patterns being cast and the light being produced from them.

That’s the ghosted image that was previously thought to only be visible to computers running specialist software. However, the new study shows the human visual perception can make sense of these patterns, called Hadamard patterns.

This diagram from the research paper should give you an idea of what’s happening:

ghosted-images-2

It’s a little bit like when our eyes and brains look at a series of still images and treat them as a moving picture – the same sort of subconscious processing seems to be going on.

Of the four volunteers who took part in the study, all four could make out an image of Albert Einstein sticking out his tongue from the Hadamard patterns. Interestingly, though, the illusion only appeared when the patterns were projected quickly enough.

If the rate dropped below 200 patterns per 20 milliseconds, the image couldn’t be seen by the study participants.

As the researchers point out, this is potentially hugely exciting – it means we might be able to devise simple systems to see light outside the visible spectrum, with no computer processing required in the middle.

That’s all to come – and this is really preliminary stuff, so we can’t get too carried away. For now, the team of researchers is using the findings to explore more about how our visual systems work, and whether our eyes and brains have yet-undiscovered superpowers for looking at the world around us.

The research has yet to be peer-reviewed, but you can read it on the pre-print resource Arxiv.

https://www.sciencealert.com/human-eye-sees-ghosted-images-reflected-light

flatearthbeliefsconfidence_Web_1024

by DAVID NIELD

Why is it sometimes so hard to convince someone that the world is indeed a globe, or that climate change is actually caused by human activity, despite the overwhelming evidence?

Scientists think they might have the answer, and it’s less to do with lack of understanding, and more to do with the feedback they’re getting.

Getting positive or negative reactions to something you do or say is a greater influence on your thinking than logic and reasoning, the new research suggests – so if you’re in a group of like-minded people, that’s going to reinforce your thinking.

Receiving good feedback also encourages us to think we know more than we actually do.

In other words, the more sure we become that our current position is right, the less likely we are to take into account other opinions or even cold, hard scientific data.

“If you think you know a lot about something, even though you don’t, you’re less likely to be curious enough to explore the topic further, and will fail to learn how little you know,” says one of the team members behind the new study, Louis Marti from the University of California, Berkeley.

For the research, more than 500 participants were recruited and shown a series of colored shapes. As each shape appeared, the participants got asked if it was a “Daxxy” – a word made up for these experiments.

The test takers had no clues as to what a Daxxy was or wasn’t, but they did get feedback after guessing one way or the other – the system would tell them if the shape they were looking at qualified as a Daxxy or not. At the same time they were also asked how sure they were about what a Daxxy actually was.

In this way the researchers were able to measure certainty in relation to feedback. Results showed the confidence of the participants was largely based on the results of their last four or five guesses, not their performance overall.

You can see the researchers explain the experiment in the video below:

The team behind the tests says this plays into something we already know about learning – that for it to happen, learners need to recognise that there is a gap between what they currently know and what they could know. If they don’t think that gap is there, they won’t take on board new information.

“What we found interesting is that they could get the first 19 guesses in a row wrong, but if they got the last five right, they felt very confident,” says Marti. “It’s not that they weren’t paying attention, they were learning what a Daxxy was, but they weren’t using most of what they learned to inform their certainty.”

This recent feedback is having more of an effect than hard evidence, the experiments showed, and that might apply in a broader sense too. It could apply to learning something new or trying to differentiate between right and wrong.

And while in this case the study participants were trying to identify a made-up shape, the same cognitive processes could be at work when it comes to echo chambers on social media or on news channels – where views are constantly reinforced.

“If you use a crazy theory to make a correct prediction a couple of times, you can get stuck in that belief and may not be as interested in gathering more information,” says one of the team, psychologist Celeste Kidd from UC Berkeley.

So if you think vaccinations are harmful, for example, the new study suggests you might be basing that on the most recent feedback you’ve had on your views, rather than the overall evidence one way or the other.

Ideally, the researchers say, learning should be based on more considered observations over time – even if that’s not quite how the brain works sometimes.

“If your goal is to arrive at the truth, the strategy of using your most recent feedback, rather than all of the data you’ve accumulated, is not a great tactic,” says Marti.

The research has been published in Open Mind.

https://www.sciencealert.com/feedback-study-explains-why-false-beliefs-stick

\

by DAVID NIELD

A specific part of the brain called the caudate nucleus could control pessimistic responses, according to animal tests, a finding which might help us unlock better treatments for mental disorders like anxiety and depression.

These disorders often come with negative moods triggered by a pessimistic reaction, and if scientists can figure out how to control that reaction, we might stand a better chance of dealing with the neuropsychiatric problems that affect millions of people worldwide – and maybe discover the difference between glass half full and glass half empty people along the way.

The research team from MIT found that when the caudate nucleus was artificially stimulated in macaques, the animals were more likely to make negative decisions, and consider the potential drawback of a decision rather than the potential benefit.

This pessimistic decision-making continued right through the day after the original stimulation, the researchers found.

“We feel we were seeing a proxy for anxiety, or depression, or some mix of the two,” says lead researcher Ann Graybiel. “These psychiatric problems are still so very difficult to treat for many individuals suffering from them.”

The caudate nucleus has previously been linked to emotional decision-making, and the scientists stimulated it with a small electrical current while the monkeys were offered a reward (juice) and an unpleasant experience (a puff of air to the face) at the same time.

In each run through the amount of juice and the strength of the air blast varied, and the animals could choose whether or not to accept the reward – essentially measuring their ability to weigh up the costs of an action against the benefits.

When the caudate nucleus was stimulated, this decision-making got skewed, so the macaques started rejecting juice/air ratios they would have previously accepted. The negative aspects apparently began to seem greater, while the the rewards became devalued.

“This state we’ve mimicked has an overestimation of cost relative to benefit,” says Graybiel. After a day or so, the effects gradually disappeared.

The researchers also found brainwave activity in the caudate nucleus, part of the basal ganglia, changed when decision-making patterns changed. This might give doctors a marker to indicate whether someone would be responsive to treatment targeting this part of the brain or not.

The next stage is to see whether the same effect can be noticed in human beings – scientists have previously linked abnormal brain activity in people with mood disorders to regions connected to the caudate nucleus, but there’s a lot more work to be done to confirm these neural connections.

Making progress isn’t easy because of the incredibly complexity of the brain, but the researchers think their results show the caudate nucleus could be disrupting dopamine activity in the brain, controlling mood and our sense of reward and pleasure.

“There must be many circuits involved,” says Gabriel. “But apparently we are so delicately balanced that just throwing the system off a little bit can rapidly change behaviour.”

The research has been published in Neuron.

https://www.sciencealert.com/we-found-the-brain-region-for-pessimism