Perception

This article is reposted from the old Wordpress incarnation of Not Exactly Rocket Science.  The idea of an out-of-body experiences seems strange and hokey - certainly not one that would grace one of the world's top scientific journals. So it may seem surprising that two years ago, Science published not one, but two papers that considered the subject through the lens of scientific scrutiny. Out-of-body experiences are rare and can be caused by epileptic fits, neurological conditions such as strokes and heavy drug abuse. Clearly, they are triggered when something goes wrong in our brains. And…
tags: philosophy, thinking the improbable, middle world, atoms, atheism, physics, Richard Dawkins, streaming video In this video, Biologist Richard Dawkins makes a case for "thinking the improbable" by looking at how the human frame of reference limits our understanding of the universe [22:42] TEDTalks is a daily video podcast of the best talks and performances from the TED Conference, where the world's leading thinkers and doers are invited to give the talk of their lives in 18 minutes.
From the scientists who brought you the infamous 'Halle Berry neuron' and the 'Jennifer Aniston neuron' come the 'Oprah Winfrey neuron' and the 'Saddam Hussein neuron'. Four years ago, Rodrigo Quian Quiroga from Leicester University showed that single neurons in the brain react selectively to the faces of specific people, including celebrities like Halle Berry, Jennifer Aniston and Bill Clinton. Now, he's back, describing single neurons that respond selectively to the concept of Saddam Hussein or Oprah Winfrey. This time, Quiroga has found that these neurons work across different senses,…
[Originally posted in November 2006] The recent controversial shooting of an unarmed black man in New York has generated terrible grief and perhaps justifiable anger. But if officers honestly believed the man was armed and intended to harm them, weren't they justified in shooting? Perhaps, but an important additional question is this: were they predisposed to believe he was armed simply because he was black? Consider this quick movie: Click to play (QuickTime required) It will flash two pictures. One man is armed, the other unarmed. Who do you shoot? I've primed you to think about race, so it…
[Originally posted in January 2008] When we watch a movie, we're usually not conscious of the cuts made by the editor. The camera angle may change dozens of times during a scene, and we follow along as if the flashing from one viewpoint to another wasn't at all unusual. You might think this is just because we've been accustomed to watching TV and movies, but researchers have found that even people who've never seen a motion picture have no difficulty following along with the cuts and different camera angles in a video. But little research has actually been done on the impact of changing…
The hollow-face illusion is one of the most dramatic and robust illusions I've ever come across. It's been known for well over 200 years, but it never ceases to amaze me, as this video demonstrates: A three-dimensional hollow face mask held a few feet away will appear to be convex (turned "out" towards the viewer) no matter which side you look at (this image is from the Max-Planck-Institut für biologische Kybernetik in Tübingen). While the movie depicts a computer-generated model, the effect works just as well with a real physical mask. Scientists have attempted to explain the illusion for…
Take a look at this movie (you'll need a video player like QuickTime or Windows Media Player installed in your browser to see it). You'll see four different outdoor scenes flash by, one at a time. The scene itself will only be displayed for a fraction of a second, followed immediately by a distraction pattern designed to mask any image left over in your visual system. Your job is to spot any desert or mountain scene. Watch carefully! Did you spot them? What cued you in to the idea of a "desert" or a "mountain" scene? Was it a specific object in the picture (a mesa or a snowfield)? Was it a…
Take a look at the following pictures of U.S. dimes. As you can see, they are slightly different from one another -- the date is in the incorrect spot on one of them. Can you tell which one is "wrong"? Let's make this a poll: Which dime has the date in the correct spot?(polls) Is there anything else wrong with the dimes?(polling) Don't look at your pocket change before you answer! In case you don't have a dime handy, I'll reveal the correct answer later in the post. Even though most Americans will say they know what U.S. coins look like, a similar study in 1979 found that people can't…
I've always been amazed by people who are truly bilingual. While I've studied languages in school, I've never been able to seamlessly switch between languages, and even my best non-English language, French, is choppy at best. Compare this to the people I see in restaurants or on the subway, who can have conversations in two languages at once, speaking each language with equal fluency. They might tell a story in English, but save the punch line for Spanish. If a monolingual person talks to them, they instantly respond in the proper language, with hardly a second thought. There are enough…
In martial arts classes, students are often taught to treat weapons as extensions of their own body. But this is more than just a metaphor. It turns out that when we use tools - not just swords and spears, but toothbrushes and rakes as well - our brain treats them as temporary body parts. According to some psychologists, our brains rely on a mental representation of our bodies called the "body schema", which allows us to coordinate our various parts and to interact with the world around us. Now, Lucilla Cardinali from INSERM, France has found that we incorporate tools into this mental plan…
[Originally posted January, 2007] Nearly all video games that offer a first-person perspective -- where the view on-screen simulates what a real person would see as she navigates through the virtual environment -- also include a virtual map to help in navigation. Even my favorite golf game has one. Such maps can be indispensable, but they also invite a question -- should the map rotate to align with the player's viewing angle, or should they remain at a constant orientation? Aligning the map with the viewer's perspective makes it easier to find items, but constantly rotating the map might…
[Originally posted in April 2007] One "trick" dieters often use is to put their food on a smaller plate. The idea is to fool yourself into thinking you're eating more food than you really are. But doesn't our stomach tell us how full we are? Actually, it doesn't. Brian Wansink has devoted his career to studying how perception of food intake relates to actual eating behavior. Together with James Painter and Jill North, he's come up with a dramatic demonstration of how wrong our stomachs can be. Volunteers were recruited to participate in a soup-only lunch in a room adjoining the school…
[Originally posted in February, 2007] When you look out the window and then look away, how do you remember what you saw? Do you hold a picture of the window in your head, frame and all? What about a photo? Do you remember the physical photo, or do you imagine the real scene it represents? If you remember the scene, and not the photo, then how do you form the boundaries of the scene? Does your memory end precisely where the photo does? Here's a little test to see how accurate your short-term memory of a photo is. When you play the movie below, you'll have a second to get ready, then a photo…
It's pretty obvious to most people that the two shoes in this picture are the same size: But if you actually took a ruler to your computer display it would show that the image of my right shoe is nearly twice as wide as the image of my left shoe. Young children will mistakenly say that the real left shoe is smaller than the right shoe; it's only gradually that we learn to take the context of the photo into account and conclude that the shoes are the same size: the shoes appear to be a matched set; the left shoe is a bit out of focus, the railing to the left shows that the left shoe is…
Take a look at this video. Your job: decide which person speaks first: Click to view Video 1 (QuickTime required) Let's make this a poll: Which person in Video 1 speaks first?(web poll) Now, try another one. Once again, decide which person speaks first: Click to view Video 2 (QuickTime required) Make your response here: Which person in Video 2 speaks first?(opinion polls) David Rose and Tanya Clark showed videos like this to 17 student volunteers, and asked the same question: who spoke first in each video? The videos are point-light displays, which show movements of particular points on an…
Music can be thought of as a form of emotional communication, with which the performer conveys an emotional state to the listener. This "language" is remarkably powerful - it can evoke strong emotions, and make your heart race or send tingles down your spine. And it is universal - the emotional content of a piece of music can be understood by anyone, regardless of cultural background. Are the emotions evoked by  piece of music similar to, and can they influence, other emotional experiences? The answer to these questions is unclear. But a new study, which has just been published in…
Having your arm in a cast can be a real pain but immobilising your hand in plaster has consequences beyond itchiness, cramps and a growing collection of signatures. Silke Lissek from Bergmannsheil University found that just a few weeks in a cast can desensitise the trapped hand's sense of touch, and lower neural activity in the part of the brain that receives signals from it. The uninjured hand, however, rises to the occasion and picks up the sensory slack by becoming more sensitive than before. Lissek recruited 31 right-handed people, each of whom had one fractured arm encased in a cast,…
There is a fascinating case study in Current Biology. de Gelder et al. discuss a patient -- referred to as TN to protect his privacy -- who had two sequential strokes that damaged his brain. The parts of the brain that were damaged included the primary visual cortex in both hemispheres -- rendering the patient blind. However, the patient could still respond to some visual stimuli through a phenomenon called blindsight. Even more interesting, the patient could still navigate around visual objects, while reporting being unable to see them and having no memory for what they were. I have…
Take another look at this picture of the Rokeby Venus from last week's post on mirrors in art: Now, imagine you're actually in the room with Venus, as depicted in this painting. You suspend your astonishment long enough to conduct a quick test of the principle of how a flat mirror works. Consider what would happen to Venus' face in the mirror as you approach it. As you walk towards the mirror, would the proportion of the reflection taken up by Venus's face increase or decrease? In the painting, the face takes about 2/3 the width of the mirror. Would that proportion get bigger or smaller as…
For any animal, it pays to be able to spot other animals in order to find mates and companions and to avoid predators. Fortunately, many animals move in a distinct way, combining great flexibility with the constraints of a rigid skeleton - that sets them apart from inanimate objects like speeding trains or flying balls. The ability to detect this "biological motion" is incredibly important. Chicks have it. Cats have it. Even two-day-old babies have it. But autistic children do not. Ami Klim from Yale has found that two-year-old children with autism lack normal preferences for natural…