Neuroscientists Find Famous Optical Illusion Surprisingly Potent

The yellow jacket (Rocky, the mascot of the University of Rochester) appears to be expanding. But he is not. He is staying still. We simply think he is growing because our brains have adapted to the inward motion of the background and that has become our new status quo.

Similar situations arise constantly in our day-to-day lives — jump off a moving treadmill and everything around you seems to be in motion for a moment.

This age-old illusion, first documented by Aristotle, is called the Motion Aftereffect by today’s scientists. Why does it happen, though? Is it because we are consciously aware that the background is moving in one direction, causing our brains to shift their frame of reference so that we can ignore this motion? Or is it an automatic, subconscious response?

Davis Glasser, a doctoral student in the University of Rochester’s Department of Brain and Cognitive Sciences thinks he has found the answer. The results of a study done by Glasser, along with his advisor, Professor Duje Tadin, and colleagues James Tsui and Christopher Pack of the Montreal Neurological Institute, is published in the journal Proceedings of the National Academy of Sciences (PNAS).

In their paper, the scientists show that humans experience the Motion Aftereffect even if the motion that they see in the background is so brief that they can’t even tell whether it is heading to the right or the left.

Even when shown a video of a pattern that is moving for only 1/40 of a second (25 milliseconds) — so short that the direction it is moving cannot be consciously distinguished — a subject’s brain automatically adjusts. If the subject is then shown a stationary object, it will appear to him as though it is moving in the opposite direction of the background motion. In recordings from a motion center in the brain called cortical area MT, the researchers found neurons that, following a brief exposure to motion, respond to stationary objects as if they are actually moving. It is these neurons that the researchers think are responsible for the illusory motion of stationary objects that people see during the Motion Aftereffect.

This discovery reveals that the Motion Aftereffect illusion is not just a compelling visual oddity: It is caused by neural processes that happen essentially every time we see moving objects. The next phase of the group’s study will attempt to find out whether this rapid motion adaptation serves a beneficial purpose — in other words, does this rapid adaptation actually improve your ability to estimate the speed and direction of relevant moving objects, such as a baseball flying toward you.

http://www.sciencedaily.com/releases/2011/06/110628132603.htm

Quantum minds

When errors make sense (Image: Paul Wesley Griggs)

The fuzziness and weird logic of the way particles behave applies surprisingly well to how humans think

THE quantum world defies the rules of ordinary logic. Particles routinely occupy two or more places at the same time and don’t even have well-defined properties until they are measured. It’s all strange, yet true – quantum theory is the most accurate scientific theory ever tested and its mathematics is perfectly suited to the weirdness of the atomic world.

Yet that mathematics actually stands on its own, quite independent of the theory. Indeed, much of it was invented well before quantum theory even existed, notably by German mathematician David Hilbert. Now, it’s beginning to look as if it might apply to a lot more than just quantum physics, and quite possibly even to the way people think.

Human thinking, as many of us know, often fails to respect the principles of classical logic. We make systematic errors when reasoning with probabilities, for example. Physicist Diederik Aerts of the Free University of Brussels, Belgium, has shown that these errors actually make sense within a wider logic based on quantum mathematics. The same logic also seems to fit naturally with how people link concepts together, often on the basis of loose associations and blurred boundaries. That means search algorithms based on quantum logic could uncover meanings in masses of text more efficiently than classical algorithms.

It may sound preposterous to imagine that the mathematics of quantum theory has something to say about the nature of human thinking. This is not to say there is anything quantum going on in the brain, only that “quantum” mathematics really isn’t owned by physics at all, and turns out to be better than classical mathematics in capturing the fuzzy and flexible ways that humans use ideas. “People often follow a different way of thinking than the one dictated by classical logic,” says Aerts. “The mathematics of quantum theory turns out to describe this quite well.”

It’s a finding that has kicked off a burgeoning field known as “quantum interaction”, which explores how quantum theory can be useful in areas having nothing to do with physics, ranging from human language and cognition to biology and economics. And it’s already drawing researchers to major conferences One thing that distinguishes quantum from classical physics is how probabilities work. Suppose, for example, that you spray some particles towards a screen with two slits in it, and study the results on the wall behind (see diagram). Close slit B, and particles going through A will make a pattern behind it. Close A instead, and a similar pattern will form behind slit B. Keep both A and B open and the pattern you should get – ordinary physics and logic would suggest – should be the sum of these two component patterns.

But the quantum world doesn’t obey. When electrons or photons in a beam pass through the two slits, they act as waves and produce an interference pattern on the wall. The pattern with A and B open just isn’t the sum of the two patterns with either A or B open alone, but something entirely different – one that varies as light and dark stripes.

Such interference effects lie at the heart of many quantum phenomena, and find a natural description in Hilbert’s mathematics. But the phenomenon may go well beyond physics, and one example of this is the violation of what logicians call the “sure thing” principle. This is the idea that if you prefer one action over another in one situation – coffee over tea in situation A, say, when it’s before noon – and you prefer the same thing in the opposite situation – coffee over tea in situation B, when it’s after noon – then you should have the same preference when you don’t know the situation: that is, coffee over tea when you don’t know what time it is.

Remarkably, people don’t respect this rule. In the early 1990s, for example, psychologists Amos Tversky and Eldar Shafir of Princeton University tested the idea in a simple gambling experiment. Players were told they had an even chance of winning $200 or losing $100, and were then asked to choose whether or not to play the same gamble a second time. When told they had won the first gamble (situation A), 69 per cent of the participants chose to play again. If told they had lost (situation B), only 59 per cent wanted to play again. That’s not surprising. But when they were not told the outcome of the first gamble (situation A or B), only 36 per cent wanted to play again.

Classical logic would demand that the third probability equal the average of the first two, yet it doesn’t. As in the double slit experiment, the simultaneous presence of two parts, A and B, seems to lead to some kind of weird interference that spoils classical probabilities.

Flexible logic

Other experiments show similar oddities. Suppose you ask people to put various objects, such as an ashtray, a painting and a sink, into one of two categories: “home furnishings” and “furniture”. Next, you ask if these objects belong to the combined category “home furnishings or furniture”. Obviously, if “ashtray” or “painting” belongs in home furnishings, then it certainly belongs in the bigger, more inclusive combined category too. But many experiments over the past two decades document what psychologists call the disjunction effect – that people often place things in the first category, but not in the broader one. Again, two possibilities listed simultaneously lead to strange results.

These experiments demonstrate that people aren’t logical, at least by classical standards. But quantum theory, Aerts argues, offers richer logical possibilities. For example, two quantum events, A and B, are described by so-called probability amplitudes, alpha and beta. To calculate the probability of A happening, you must square this amplitude alpha and likewise to work out the probability of B happening. For A or B to happen, the probability amplitude is alpha plus beta. When you square this to work out the probability, you get the probability of A (alpha squared) plus that of B (beta squared) plus an additional amount – an “interference term” which might be positive or negative.

This interference term makes quantum logic more flexible. In fact, Aerts has shown that many results demonstrating the disjunction effect fit naturally within a model in which quantum interference can play a role. The way we violate the sure thing principle can be similarly explained with quantum interference, according to economist Jerome Busemeyer of Indiana University in Bloomington and psychologist Emmanuel Pothos of the University of Wales in Swansea. “Quantum probabilities have the potential to provide a better framework for modelling human decision making,” says Busemeyer….. Continue reading Quantum minds

Mapping the most complex object in the known universe


It’s paint-by-numbers for neuroscientists. At the Max-Planck Institute for Medical Research in Heidelberg, Germany, researchers have devised a faster way of computing the neural connections that make up the brain. Mapping out this intricate web previously depended on the human eye as no computer was powerful enough to handle the brain’s complex network of 70 billion neurons and thousands of kilometres of circuits. For this gargantuan task, even the smallest sliver of neural tissue was painstaking, demanding an experienced team to make modest progress.
Now with the help of two computer programs, Moritz Helmstaedter, Kevin Briggman and Winfried Denk have developed a faster and more accurate way of completing this neural cartography.
The first program, KNOSSOS – named after an ancient palace labyrinth in Crete – lets untrained users visualise and annotate 3D image data while the second, RESCOP summarises their work. In a test of this method, a team of 70 students created a detailed rendering of the connections between more than 100 retinal neurons in a mouse. Pictured above, the reconstruction outlines the dense bundles their projections form to receive input from photoreceptors.
The new programs could make the difficult but vital task of plotting out the brain’s neural circuitry possible.
http://www.newscientist.com/

Research finds how words are formed in the brain

Scientists have discovered a way to watch words form in the human brain in a breakthrough that could one day allow those with severe disabilities to ‘speak’.
The researchers have found a way to peer into the deepest recesses of the brain in order to watch words forming.

Mind-reader: Researchers have found the signals the brain gives off as speech is formed - and it is hope that this could lead to scientists being able to translate thoughts into words

Using electrodes they found the area of the brain that is involved in creating the 40 or so sounds that form the English language.
They then discovered that each of these sounds has its own signal which they believe could eventually allow a computer programme to read what people want to say by the power of their thoughts.
The mind-reading research was undertaken by a team from the Centre for Innovation in Neuroscience and Technology at the University of Washington.
Led by its director, Eric Leuthardt, they studied four people who suffered from severe epilepsy who each had 64 electrodes implanted into their heads.
The original reason for this was an attempt to try to find the cause of their epilepsy but Leuthardt also monitored the areas of the brain where speech is formed.
The subjects were asked to make four repeated sounds – ‘oo’, ‘ah’, ‘eh’, and ‘ee’.
The team then monitored the Wenicke’s and Broca’s areas of the brain for signals related to speech formation.
The scientists were then able to pick out the corresponding electrical signals, and while these four signals will not be enough to form sentences, further research could lead to this becoming possible.
Leuthardt told the Sunday Times: ‘What it shows is that the brain is not the black box that we have philosophically assumed it to be for generations past.
‘I’m not going to say that I can fully read someone’s mind. I can’t. But I have evidence now that it is possible.’
During his study, Leuthardt also found that the brain generates a signal when people just think about the sounds – but it was very different to when they speak it.
This has led to the implication that doctors could one day read people’s private thoughts as well as what they want to say.
And it is hoped the research will one day give people with locked-in syndrome the chance to speak – as currently electrode treatment on the brain can be carried out those that are severely ill.
It could, in principal, also lead to technology that could read the mind without surgery – and even lead forms of communication which work only by thought.
The research was published in the Journal of Neural Engineering.
http://www.dailymail.co.uk/sciencetech/article-1392139/Reading-mind-New-research-finds-words-formed-brain.html#ixzz1NqEdQTNV