Perception
edyong | March 29, 2009Anyone who has played video games for too long is probably familiar with the sore, tired and dry eyes that accompany extended bouts of shooting things with rocket launchers. So it might come as a surprise that playing games could actually improve a key aspect of our eyesight.
Renjie Li from the University of Rochester found that intensive practice at shoot-em-ups like Unreal Tournament 2004 and Call of Duty 2 improved a person's ability to spot the difference between subtly contrasting shades of grey. In the real world, this "contrast sensitivity function" is reflected in the crispness of…
dmunger | March 26, 2009The Rokeby Venus by Diego Velázquez is a good example of a very common illusion in many paintings:
Most viewers would say this picture depicts a woman viewing her own reflection in a mirror. But based on the orientation of the mirror, it's actually physically impossible for her to see her own reflection. Since we can see her face, then if she could see face in the mirror, her head would have to be positioned between us and the the mirror. At best all she would be able to see is us (or rather, the painter painting her picture).
Art critics have suggested that there's another problem with…
edyong | March 25, 2009We're used to thinking of neglect as a lack of appropriate care, but to a neuroscientist, it has a very different meaning. "Spatial neglect" is a neurological condition caused by damage to one half of the brain (usually the right), where patients find it difficult to pay attention to one half of their visual space (usually the left).
This bias can affect their mental images too. If neglect patients are asked to draw clocks, many only include the numbers from 12 to 6, while some shunt all the numbers to the right side. When two famous neglect patients were asked to describe a familiar square…
dmunger | March 18, 2009Take a look at these two pictures of the Mona Lisa:
They're derived from a series of images of the famous painting that had been obscured by random noise filters (like when your old analog TV wasn't getting a signal), like this:
Each picture appears to have a slightly different facial expression -- some happier, some sadder, depending on the random alteration of the image due to the visual noise. The two color pictures above are composites, made by picking the saddest (for picture B) and happiest (picture C) from over a hundred random images -- rated by 12 volunteers -- and combining them…
dmunger | March 16, 2009Attentional blink is a fascinating phenomenon that occurs when we see images, words, or numbers presented in a rapid sequence. As images flash by at about one every tenth of a second, you're asked to look for two in particular. If you were looking for numbers in a sequence of letters, the sequence might be SDLX3DJ9WVNBDR. The number 3 would be easy to spot, but 9, which follows 3/10 of a second later, is spotted much less frequently.
The effect works for images as well. You might be asked to look for flowers in a sequence of furniture pictures. Again, flowers that follow between 2/10 and 4/10…
edyong | March 7, 2009
Most of us could easily distinguish between spoken English and French. But could you tell the difference between an English and a French speaker just by looking at the movements of their lips? It seems like a difficult task. But surprising new evidence suggest that babies can meet this challenge at just a few months of age.
Young infants can certainly tell the difference between the sounds of different languages. Whitney Weikum and colleagues from the University of British Columbia decided to test their powers of visual discrimination.
They showed 36 English babies silent video clips of…
edyong | March 5, 2009The nice thing about writing features is that they're often solicited miles in advance so I can write something, totally forget about it and then be surprised when I open my weekly copy of New Scientist to find my name in a byline.
This week's issue has a feature by me entitled "Beyond east and west: How the brain unites us all" (I like the title; I didn't write it).
Following the piece I wrote on FOXP2, this is another of those "the media says this, but here's what's really going on" pieces. It's an exploration of the supposed cultural differences between East Asians and Westerners in the…
purepedantry | March 5, 2009Caught this bad description of an otherwise very interesting study at Science Daily:
Neuroscientists at Georgetown University Medical Center have, for the first time, shown what brain activity looks like when someone anticipates an action or sensory input which soon follows.
In the February 25 issue of the Journal of Neuroscience, they say this neural clairvoyance involves strong activity in areas of the brain responsible for preparing the body to move.
The findings were made by using functional magnetic resonance imaging (fMRI) in a group of student volunteers who brought with them favorite…
dmunger | February 26, 2009Last week, we presented research by Miranda Scolari's team about visual expertise and visual short-term memory. Their conclusion: "experts" don't have a larger visual memory capacity than non-experts, they just have the ability to process more details. Scolari's team was working under the assumption that all humans (or at least all the students in their experiment) are face-recognition experts.
It's true: we're amazingly good at recognizing faces we've seen before. Think how much easier it is to remember a face you've seen than it is to remember the name that goes with the face. But surely we…
dmunger | February 18, 2009Take a look at this quick video. You'll see a set of six small images, arranged in a circle, for 1 second. Then the screen will go blank for 1 second. Finally, one image will reappear in the place of one of the first six pictures. Your job: indicate whether the final image is the same or different as the image that originally appeared in that same spot.
Click here to view the movie (QuickTime required)
In principle, this should be an easy task, right? Your visual working memory can hold around six items at a time, so it shouldn't be hard at all to remember if the new picture is the same as…
dmunger | February 5, 2009Have you seen this "illusion" before?
The arrangement of the pacman shapes leads you to perceive rectangles, which are actually just empty spaces between the pacmen (that's a technical term -- it's in a journal article, so it must science!). Technically the rectangles are called "Kanizsa-type subjective contours," because while we perceive rectangles, there aren't actually rectangles there. It's a powerful effect, and once you see the shapes, it's difficult to look at the picture without perceiving them. Here's the identical figure with the pacmen rotated in random directions:
See? No…
dmunger | February 3, 2009You may have heard of the Stroop effect, and you may have even seen it demonstrated. But can the Stroop effect itself be manipulated? This short demo may show that it can.
In case you're not familiar with the effect, it occurs when you try to say the color a word is printed in, while the word itself names a color (so if you see "RED" you should say "green.") Try it with these short lists. Remember, say the color the word is PRINTED in, not the color named by the word.
Which column was most difficult? Let's make this a poll:
Which column was the most difficult? ( surveys)
The basic Stroop…
edyong | January 23, 2009It's been a big week. With a simple words, Barack Obama became the first black President of a country whose history has been so haunted by the spectre of racial prejudice. His election and inauguration are undoubtedly proud moments but they must not breed complacency. Things may be changing outwardly, but problems remain.
For a start, it goes without saying that many people, even the most liberal and left-wing among us, still harbour unconscious prejudices against members of other races. These "implicit biases" may be hidden, but their effects are often not. For example, a study published…
dmunger | January 22, 2009What are we looking at when we recognize faces? The shapes of of the individual components of the face -- eyes, nose, mouth? Or are we recognizing the larger patterns of how those parts relate to one another -- the distance between the eyes, the position of the mouth relative to the nose? We're actually probably doing some of each, with those configural patterns playing a slightly more important role.
But this raises an important question for perception researchers, because recognizing details and recognizing overall patterns utilize two different components of the visual system. Researchers…
dmunger | January 15, 2009In 2007 I received a really cool Christmas present that I still haven't used. It's a kit to help identify the various components of the aroma in a glass of wine. I haven't used it because I wanted to wait for the right occasion -- say, a party with some of my wine-loving friends. But I've also been secretly skeptical whether it would really help. The kit has tiny vials that are supposed to represent individual aromas: "oak," "hazelnut," "coffee," "cherry," and so on. What does identifying an aroma have to do with deciding whether you like a glass of wine?
As it turns out, more than you might…
purepedantry | January 9, 2009I caught this neuroscience question over at a new blog I like, Think Markets. Sandy Ikeda comments on a section of Daniel Gilbert's book Stumbling on Happiness:
I've been thinking about the following from Daniel Gilbert's Stumbling on Happiness:
Experiments have demonstrated that the moment we encounter an object, our brains instantly analyze just a few of its key features and then use the presence or absence of these features to make one very fast and very simple decision: "Is this object an important thing to which I ought to respond right now? [...] As such, our brains are designed to…
dmunger | January 8, 2009As a young child, my family was poor and we had to go to a public clinic for dental work. Since we were being seen by dental students, often the process was painful and took much longer than it should have. It was a tremendous relief when my uncle opened a swanky dental practice with a lake view, and soothing '70s rock wafted out over the audio system. I'm pretty sure my uncle was a better dentist than the students who had been seeing me before, but it also seemed like just the environment in his office contributed to me feeling better when he had to do an awful procedure like filling a…
dmunger | December 30, 2008[This entry was originally posted in April 2007]
The Beck effect is difficult to replicate online, because it involves testing reaction times. However, I think I've figured out a way to approximate the effect. This movie (Quicktime required) will show you how it works. Just follow the directions on the opening screen:
Now, which letter did you see first? Let's make this a poll:
If we manage to replicate the effect, there should be a bias in the results, which I'll explain below so everyone has a chance to try it out before learning the "answer."
In the 1960s, Jacob Beck found that when…
edyong | December 27, 2008
"Control - you must learn control!" These wise words were uttered by no less a sage than Yoda, and while he was talking about telekinetically hoisting spacecraft, having control has another important benefit. It protects a person from spotting false patterns that aren't there, from believing in conspiracies and from developing superstitions.
Control and security are vital parts of our psychological well-being and it goes without saying that losing them can feel depressing or scary. As such, people have strategies for trying to regain a sense control even if it's a tenuous one. Jennifer…
edyong | December 22, 2008
The video above seems completely unremarkable at first - man walks down a corridor, navigating his way around easily visible and conspicuous obstacles. But it's far from an easy task; in fact, it should be nigh-impossible. The man, known only as TN, is totally blind.
His inability to see stems from a failure in his brain rather than his eyes. Those work normally, but his visual cortex - the part of the brain that processes visual information - is inactive. As a result, TN is completely unaware of the ability to see and in his everyday life, he behaves like a blind person, using a stick to…