The Situationist

Posts Tagged ‘Illusion’

The Situation of Human Vision

Posted by The Situationist Staff on January 18, 2012

Experimental psychologist Professor Bruce Hood illustrating how human vision works (from the Royal Institution Christmas Lectures 2011).

Related Situationist posts:

Click here for a collection of posts on illusion.

Posted in Illusions, Video | Tagged: , | 1 Comment »

The Situation of Attention and the Gorilla in the Room

Posted by The Situationist Staff on August 2, 2010

Dan Simons has a new version of some well known illusions that he and Christopher Chabris helped to make famous.  Enjoy:

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To check out Simons and Chabris’s new book, “The Invisible Gorilla, and Other Ways Our Intuitions Deceive Us” click here.

For  a sample of related Situationist posts, see “Change Blindness,” “Neuroscience and Illusion,” Brain Magic,” Magic is in the Mind,”The Situation of Illusion,” ‘The Grand Illusion’ — Believing We See the Situation,”Neuroscience and Illusion,” The Heat is On,” and The Situation of Climate Change,”

Posted in Illusions, Video | Tagged: , , | 2 Comments »

The Spicy Situation of Food, Flavor, and Taste

Posted by The Situationist Staff on December 27, 2009

With holiday feasts now behind us, we thought this might be a good time to post some portions of Linda Bartoshuk’s article, “Spicing Up Psychological Science,” from the September issue of The Observer.  Here are some excerpts.

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The anatomy of spice perception involves illusion. We seem to perceive spices both with the senses of taste and smell, but in reality, smell does most of the work. Consider cinnamon . . . . Even with our eyes closed, the smell of freshly baked cinnamon rolls grabs our attention. Sniffing draws the cinnamon volatiles (chemicals that evaporate at low temperatures and make their way into our nostrils as vapors) up into our noses; the volatiles pass through a tiny opening at the top of the nasal cavity called the olfactory cleft. When odorants pass through the cleft, they gain access to the olfactory mucosa, the tissue that contains olfactory receptors. This process is technically called “orthonasal olfaction,” but we commonly call it “smell.”

But there is a second kind of olfaction. When we bite into a cinnamon roll and chew and swallow, the cinnamon volatiles are forced up behind the palate into the nose; because of the backward route by which the volatiles enter the nose, this process is called “retronasal olfaction.” The combination of taste (sweet, salty, sour, bitter) and retronasal olfaction is called “flavor.” Note that we do not use “flavor” as a verb to describe our perceptions of flavor in the same way we use “taste” as a verb to describe our perceptions of taste. To flavor food means to add flavor to food rather than to perceive the flavor of food. But this does not bother us because we use “taste” in everyday conversation to refer to our perceptions of flavor. One of the reasons that we do not notice this linguistic slip is because flavor is perceptually localized to the mouth. This trap caught even Aristotle. He listed olfactory sensations perceived from food in the mouth as tastes.

Why do we experience this illusion of localization? We are not sure, but we know that touch and taste both play roles. The brain knows the route by which an odorant gets to the olfactory receptors. Sniffing may provide the cue that says “orthonasal olfaction.” Oral touch and taste sensations may provide the cues that say “retronasal olfaction.”

In any case, olfactory information goes to different brain areas and is processed in different ways depending on which route was detected. For example, retronasal olfaction can be intensified by taste. Food companies make good use of this intensification. If you market a beverage like grape juice and you would like to intensify the grape flavor of the juice, just add sugar (another reason why we are bombarded with sweetened drinks). Incidentally, supertasters, those individuals with the most taste buds, perceive the most intense tastes, and because of the connection between taste and retronasal olfaction, supertasters also experience the most intense flavors . . . .

Current thinking is that the pleasure we experience from spices is learned. Cinnamon produces pleasure because it was previously paired with experiences our brains are programmed to view favorably (e.g., calories, sweetness of sugar). On the other hand, pair cinnamon with nausea and it will become unpleasant. One of the volatiles in cinnamon, eugenol, is also found in cloves. Cloves and cinnamon do not smell exactly the same, but their odors are similar. Oil of cloves is a natural analgesic and was used by dentists in an earlier era. I associate the odor of cloves with sickness associated with visits to my dentist; I do not share the enthusiasm of those lined up at Cinnabon for the overpowering scents of those calorie-rich rolls. Incidentally, the degree to which learning with one kind of olfaction generalizes to another is not yet clear. Love of cinnamon is learned through retronasal experience but clearly generalizes to cinnamon sniffed. On the other hand, some odors are pleasant with one kind of smell (e.g., cut grass is pleasant when sniffed) but not with the other (I can’t imagine a cut-grass flavor).

The person most responsible for explaining how we learn to love or hate flavors is Paul Rozin . . . .

. . . . Rozin described the “omnivore’s dilemma.” Somehow species like humans (and rats) that consume a large variety of different foods must take in important nutrients and avoid poisons. Rozin and his students have revealed how we do it (Rozin & Hormes, 2009). Our brains note the effects a given food has on us and make us like or dislike the sensory properties of those foods according to its notion of what is good or bad for us. For example, suppose we want to create a food item that will have great appeal. Begin with sources of calories (fat, carbohydrates), add sugar (for its hard-wired effect), and label the mixture with a salient odorant that will endow the item with a retronasal olfactory punch: I give you a brownie. On the other hand, let’s watch an undergraduate on his first alcohol binge get violently ill on screwdrivers. He will likely find screwdrivers distasteful the next day (and possibly for life). Further, the aversion may generalize to orange juice, orange candy, and a lot of other substances flavored with orange. The power of such conditioned aversions has even been used clinically to treat alcoholism . . . .

. . . [Consider one study designed] to explore the affective reactions to odorants in one and two-year olds . . . . The children, seated on their mother’s laps, were allowed to play with toys on a table in front of a picture with holes in it. While the child was engaged with a toy, an odorant was sprayed through one of the holes, and the child’s reaction was rated as pleasant, neutral, or unpleasant by observers in another room viewing the experiment through a one-way mirror. Two odorants were tested that are pleasant to most adults: amyl acetate (pears) and lavender. (To be honest, I don’t know how to describe lavender odor. It’s sold as a spice so there are samples in supermarkets. I suggest you try it.) Two odorants were tested that are unpleasant to most adults: dimethyl disulfide (garlic-like) and butyric acid (vomit-like). There were no significant differences in the reactions of the children to the four odorants. However, by age three, children begin to show preference reactions like those of adults (Engen, 1982; Schmidt & Beauchamp, 1988).  The lack of affect at two years along with the appearance of affect over time supports the learning of olfactory affect.

But another issue has yet to be considered: biological benefits of spices. Flavor volatiles in many of the plants we consume are derived from important nutrients; thus, those volatiles could serve as cues to the presence of those nutrients . . . . Further, the subset of plant volatiles that we call spices have been explicitly associated with health benefits. . . .

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The health benefits of spices suggest that we reconsider the possibility of hard-wired liking of at least some spices. For example, is it possible that during evolution some of our ancestors began using turmeric? If turmeric prolonged their lives could this have ultimately contributed to the proliferation of turmeric-likers?

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Harold McGee . . . is most famous for drawing back the curtain and revealing the chemistry behind what we do in our kitchens. . . . McGee [recently] reviewed efforts to find the origin of the burn of chili. He cited work suggesting that higher altitudes seems to produce chilis with greater burn, possibly because the climate at those altitudes may stress the plants, which might make the chilis more vulnerable to attack . . . . Since the burn appears to act as a deterrent to predators, the increase in burn may better repel those predators. This attention to the burn of chilis is a reminder that burn (produced by capsaicin) is a part of what we think of as spices, but it is not a retronasal olfactory sensation; rather, burn is mediated by the trigeminal nerve (which also mediates temperature and touch sensations).  Note that the oral burn that probably originated to repel predators can be transformed into a positive sensation in humans. Rozin recently commented that, “many innately negative stimuli . . . become highly desired and emerge as really important foods.”

How does this “hedonic reversal” occur? Some have argued that the biological benefits of chilis (e.g., antimicrobial properties, presence of vitamins A and C) somehow lead to our love of them. Whether or not this is so, children in cultures where chilis are an important part of the diet appear to learn the preference socially; that is, chili initially takes on positive value by association with intake by family and friends. Interestingly, it has proved difficult to induce animals to acquire a preference for chili. Rozin noted that some pets can acquire the preference through the social interaction of pet and owner, but attempts to condition preferences for chili in most animals have met with only modest success. However, one of Rozin’s students, Bennett Galef, was able to condition a mild preference for chili in naïve rats socially by exposing them to rats that had eaten the spice  . . . .

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To read the entire article or review its references, click here. To review a sample of related Situationist posts, see “The Situation of Snacking,”The Situation of Eating – Part II,” The Situation of Eating,” “McDonalds tastes better than McDonalds, if it’s packaged right,” “The Science of Addiction, The Myth of Choice,” The Situation of our Food – Part I,” “The Situation of Our Food – Part II,”The Situation of Our Food – Part III,” and “The Situation of our Food – Part IV.”

Posted in Food and Drug Law, Illusions, Life | Tagged: , , , | Leave a Comment »

Neuroscience and Illusion

Posted by The Situationist Staff on December 7, 2009

Laura Sanders wrote an interesting article, titled “SPECIALIS REVELIO!  It’s not magic, it’s neuroscience,” in ScienceNews. Here are some excerpts.

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Skill in manipulating people’s perceptions has earned magicians a new group of spellbound fans: Scientists seeking to learn how the eyes and brain perceive — or don’t perceive — reality.

“The interest for magic has been there for a long time,” says Gustav Kuhn, a neuroscientist at Durham University in England and former performing magician. “What is new is that we have all these techniques to get a better idea of the inner workings of these principles.”

A recent brain imaging study by Kuhn and his colleagues revealed which regions of the brain are active when people watch a magician do something impossible, such as make a coin disappear. Another research group’s work on monkeys suggests that two separate kinds of brain cells are critical to visual attention. One group of cells enhances focus on what a person is paying attention to, and the other actively represses interest in everything else. A magician’s real trick, then, may lie in coaxing the suppressing brain cells so that a spectator ignores the performer’s actions precisely when and where required.

Using magic to understand attention and consciousness could have applications in education and medicine, including work on attention impairments.

Imaging the impossible

Kuhn and his collaborators performed brain scans while subjects watched videos of real magicians performing tricks, including coins that disappear and cigarettes that are torn and miraculously put back together.  Volunteers in a control group watched videos in which no magic happened (the cigarette remained torn), or in which something surprising, but not magical, took place (the magician used the cigarette to comb his hair). Including the surprise condition allows researchers to separate the effects of witnessing a magic trick from those of the unexpected.

In terms of brain activity patterns, watching a magic trick was clearly different from watching a surprising event. Researchers saw a “striking” level of activity solely in the left hemisphere only when participants watched a magic trick, Kuhn says. Such a clear hemisphere separation is unusual, he adds, and may represent the brain’s attempt to reconcile the conflict between what is witnessed and what is thought possible. The two brain regions activated in the left hemisphere — the dorsolateral prefrontal cortex and the anterior cingulate cortex — are thought to be important for both detecting and resolving these types of conflicts.

Masters of suppression

Exactly how the brain attends to one thing and ignores another has been mysterious.  Jose-Manuel Alonso of the SUNY State College of Optometry in New York City thinks that the answer may lie in brain cells that actively suppress information deemed irrelevant by the brain. These cells are just as important, if not more so, than cells that enhance attention on a particular thing, says Alonso. “And that is a very new idea . . . . When you focus your attention very hard at a certain point to detect something, two things happen: Your attention to that thing increases, and your attention to everything else decreases.”

Alonso and his colleagues recently identified a select group of brain cells in monkeys that cause the brain to “freeze the world” by blocking out all irrelevant signals and allowing the brain to focus on one paramount task. Counter to what others had predicted, the team found that the brain cells that enhance attention are distinct from those that suppress attention. Published in the August 2008 Nature Neuroscience, the study showed that these brain cells can’t switch jobs depending on where the focus is — a finding Alonso calls “a total surprise.”

The work also shows that as a task gets more difficult, both the enhancement of essential information and suppression of nonessential information intensify. As a monkey tried to detect quicker, more subtle changes in the color of an object, both types of cells grew more active.

Alonso says magicians can “attract your attention with something very powerful, and create a huge suppression in regions to make you blind.” In the magic world, “the more interest [magicians] manage to draw, the stronger the suppression that they will get.”

Looking but not seeing

In the French Drop trick [see video below], a magician holds a coin in the left hand and pretends to pass the coin to the right hand, which remains empty. “What’s critical is that the magician looks at the empty hand. He pays riveted attention to the hand that is empty,” researcher Stephen Macknik says.

Several experiments have now shown that people can stare directly at something and not see it.  For a study published in Current Biology in 2006, Kuhn and his colleagues tracked where people gazed as they watched a magician throw a ball into the air several times. On the last throw, the magician only pretended to toss the ball. Still, spectators claimed to have seen the ball launch and then miraculously disappear in midair. But here’s the trick: In most cases, subjects kept their eyes on the magician’s face. Only when the ball was actually at the top part of the screen did participants look there. Yet the brain perceived the ball in the air, overriding the actual visual information.

Daniel Simons of the University of Illinois at Urbana-Champaign and his colleagues asked whether more perceptive people succumb less easily to inattentional blindness, which is when a person doesn’t perceive something because the mind, not the eyes, wanders. In a paper in the April Psychonomic Bulletin & Review, the researchers report that people who are very good at paying attention had no advantage in performing a visual task that required noticing something unexpected. Task difficulty was what mattered. Few participants could spot a more subtle change, while most could spot an easy one. The results suggest that magicians may be tapping in to some universal property of the human brain.

“We’re good at focusing attention,” says Simons. “It’s what the visual system was built to do.” Inattentional blindness, he says, is a by-product, a necessary consequence, of our visual system allowing us to focus intently on a scene.

Magical experiments

Martinez-Conde and Macknik plan to study the effects of laughter on attention. Magicians have the audience in stitches throughout a performance.  When the audience is laughing, the magician has the opportunity to act unnoticed.  Understanding how emotional states can affect perception and attention may lead to more effective ways to treat people who have attention problems.  “Scientifically, that can tell us a lot about the interaction between emotion and attention, of both the normally functioning brain and what happens in a diseased state,” says Martinez-Conde.

He expects that the study of consciousness and the mind will benefit enormously from teaming up with magicians. “We’re just at the beginning,” Macknik says. “It’s been very gratifying so far, but it’s only going to get better.”

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You can read the entire article here.  For some related Situationist posts, see “Brain Magic,” Magic is in the Mind,” and “The Situation of Illusion” or click here for a collection of posts on illusion.

Posted in Entertainment, Illusions, Neuroscience, Video | Tagged: , , | Leave a Comment »

Neuroscience and Illusion

Posted by The Situationist Staff on May 4, 2009

magicLaura Sanders recently wrote an interesting article, titled “SPECIALIS REVELIO!  It’s not magic, it’s neuroscience,” in ScienceNews. Here are some excerpts.

* * *

Skill in manipulating people’s perceptions has earned magicians a new group of spellbound fans: Scientists seeking to learn how the eyes and brain perceive — or don’t perceive — reality.

“The interest for magic has been there for a long time,” says Gustav Kuhn, a neuroscientist at Durham University in England and former performing magician. “What is new is that we have all these techniques to get a better idea of the inner workings of these principles.”

A recent brain imaging study by Kuhn and his colleagues revealed which regions of the brain are active when people watch a magician do something impossible, such as make a coin disappear. Another research group’s work on monkeys suggests that two separate kinds of brain cells are critical to visual attention. One group of cells enhances focus on what a person is paying attention to, and the other actively represses interest in everything else. A magician’s real trick, then, may lie in coaxing the suppressing brain cells so that a spectator ignores the performer’s actions precisely when and where required.

Using magic to understand attention and consciousness could have applications in education and medicine, including work on attention impairments.

Imaging the impossible

Kuhn and his collaborators performed brain scans while subjects watched videos of real magicians performing tricks, including coins that disappear and cigarettes that are torn and miraculously put back together.  Volunteers in a control group watched videos in which no magic happened (the cigarette remained torn), or in which something surprising, but not magical, took place (the magician used the cigarette to comb his hair). Including the surprise condition allows researchers to separate the effects of witnessing a magic trick from those of the unexpected.

In terms of brain activity patterns, watching a magic trick was clearly different from watching a surprising event. Researchers saw a “striking” level of activity solely in the left hemisphere only when participants watched a magic trick, Kuhn says. Such a clear hemisphere separation is unusual, he adds, and may represent the brain’s attempt to reconcile the conflict between what is witnessed and what is thought possible. The two brain regions activated in the left hemisphere — the dorsolateral prefrontal cortex and the anterior cingulate cortex — are thought to be important for both detecting and resolving these types of conflicts.

Masters of suppression

Exactly how the brain attends to one thing and ignores another has been mysterious.  Jose-Manuel Alonso of the SUNY State College of Optometry in New York City thinks that the answer may lie in brain cells that actively suppress information deemed irrelevant by the brain. These cells are just as important, if not more so, than cells that enhance attention on a particular thing, says Alonso. “And that is a very new idea . . . . When you focus your attention very hard at a certain point to detect something, two things happen: Your attention to that thing increases, and your attention to everything else decreases.”

Alonso and his colleagues recently identified a select group of brain cells in monkeys that cause the brain to “freeze the world” by blocking out all irrelevant signals and allowing the brain to focus on one paramount task. Counter to what others had predicted, the team found that the brain cells that enhance attention are distinct from those that suppress attention. Published in the August 2008 Nature Neuroscience, the study showed that these brain cells can’t switch jobs depending on where the focus is — a finding Alonso calls “a total surprise.”

The work also shows that as a task gets more difficult, both the enhancement of essential information and suppression of nonessential information intensify. As a monkey tried to detect quicker, more subtle changes in the color of an object, both types of cells grew more active.

Alonso says magicians can “attract your attention with something very powerful, and create a huge suppression in regions to make you blind.” In the magic world, “the more interest [magicians] manage to draw, the stronger the suppression that they will get.”

Looking but not seeing

In the French Drop trick [see video below], a magician holds a coin in the left hand and pretends to pass the coin to the right hand, which remains empty. “What’s critical is that the magician looks at the empty hand. He pays riveted attention to the hand that is empty,” researcher Stephen Macknik says.

Several experiments have now shown that people can stare directly at something and not see it.  For a study published in Current Biology in 2006, Kuhn and his colleagues tracked where people gazed as they watched a magician throw a ball into the air several times. On the last throw, the magician only pretended to toss the ball. Still, spectators claimed to have seen the ball launch and then miraculously disappear in midair. But here’s the trick: In most cases, subjects kept their eyes on the magician’s face. Only when the ball was actually at the top part of the screen did participants look there. Yet the brain perceived the ball in the air, overriding the actual visual information.

Daniel Simons of the University of Illinois at Urbana-Champaign and his colleagues asked whether more perceptive people succumb less easily to inattentional blindness, which is when a person doesn’t perceive something because the mind, not the eyes, wanders. In a paper in the April Psychonomic Bulletin & Review, the researchers report that people who are very good at paying attention had no advantage in performing a visual task that required noticing something unexpected. Task difficulty was what mattered. Few participants could spot a more subtle change, while most could spot an easy one. The results suggest that magicians may be tapping in to some universal property of the human brain.

“We’re good at focusing attention,” says Simons. “It’s what the visual system was built to do.” Inattentional blindness, he says, is a by-product, a necessary consequence, of our visual system allowing us to focus intently on a scene.

Magical experiments

Martinez-Conde and Macknik plan to study the effects of laughter on attention. Magicians have the audience in stitches throughout a performance.  When the audience is laughing, the magician has the opportunity to act unnoticed.  Understanding how emotional states can affect perception and attention may lead to more effective ways to treat people who have attention problems.  “Scientifically, that can tell us a lot about the interaction between emotion and attention, of both the normally functioning brain and what happens in a diseased state,” says Martinez-Conde.

He expects that the study of consciousness and the mind will benefit enormously from teaming up with magicians. “We’re just at the beginning,” Macknik says. “It’s been very gratifying so far, but it’s only going to get better.”

* * *

You can read the entire article here.  For some related Situationist posts, see “Brain Magic,” Magic is in the Mind,” and “The Situation of Illusion” or click here for a collection of posts on illusion.

Posted in Entertainment, Illusions, Neuroscience, Video | Tagged: , , | 5 Comments »

Magic is in the Mind

Posted by The Situationist Staff on March 28, 2009

Magician Thurston by libraryimages.netRobyn Kim and Ladan Shams have a nice article, titled “What Can Magicians Teach Us about the Brain?,” in Scientific American.  Here are some excerpts.

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. . . . Magicians . . . are masters of exploiting nuances of human perception, attention, and awareness. In light of this, a recent Nature Reviews Neuroscience paper, coauthored by a combination of neuroscientists (Stephen L. Macknik, Susana Martinez-Conde, both at the Barrows Neurological Institute) and magicians (Mac King, James Randi, Apollo Robbins, Teller, John Thompson), describes various ways magicians manipulate our perceptions, and proposes that these methods should inform and aid the neuroscientific study of attention and awareness.

Magicians Secrets Revealed

The underlying concept of using quirks in human perception to learn about how the mind works is an old one. Visual, auditory and multisensory illusions, in which people’s perceptions contradict the physical properties of the stimuli, have long been used by psychologists to study the mechanisms of sensory processing. Magicians use such sensory illusions in their tricks, but they also heavily use cognitive illusions, manipulating people’s attention, trains of logic and even memory. Although magicians probably haven’t studied these phenomena with the scientific method—they don’t do controlled experiments—their techniques have been tested over time, perfected by practice and performed under conditions of high scrutiny by skeptical audiences looking to spot the trick.

An example of a visual illusion used by magicians is spoon bending, in which a rigid horizontal spoon appears flexible when shaken up and down at a certain rate. This effect occurs because of how different parts of objects (in this case, the spoon) are represented in the brain. Certain neurons are responsive to the ends/corners of the object, whereas others respond to the bars/edges; the end-responsive neurons respond differently to motion than do the bar-responsive neurons, such that the ends and the center of the spoon seem misaligned when in motion.

Attention can greatly affect what we see—this fact has been demonstrated in psychological studies of inattentional blindness. To misdirect people’s attention and create this effect, magicians have an arsenal of methods ranging from grand gestures (such as releasing a dove in the theater to distract attention), to more subtle techniques (for instance, using social miscues). An example of the latter can be found in the Vanishing Ball Illusion . . . .

At the last toss, the magician does not actually release the ball from his or her hand. Crucially, however, the magician’s gaze follows the trajectory the ball would have made had it been tossed. The magician’s eye and head movement serves as a subtle social cue that (falsely) suggests a trajectory the audience then also expects. A recent study examining what factors produced this effect suggests that the miscuing of the attentional spotlight is the primary factor, and not the motion of the eyes. In fact, the eyes aren’t fooled by this trick—they don’t follow the illusory trajectory! Interestingly, comedy is also an important tool used by magicians to manipulate attention in time. In addition to adding to the entertainment value of the show, bouts of laughter can diffuse attention at critical time points.

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Magic’s Role in Neuroscience

Cognitive neuroscience can explain many magic techniques; this article proposes, however, that neuroscientists should use magicians’ knowledge to inform their research. . . .

More concretely, the use of cognitive illusions—for example, during brain imaging—could serve to identify neural circuits underlying specific cognitive processes. They could also be used to map neural correlates of consciousness (the areas of the brain that are active when we are processing a given aspect of consciousness) by dissociating activity corresponding to processing of actual physical events from the activity corresponding to the conscious processing.

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The entire aritcle is here.  To read some related Situationist posts, see “The Situation of Illusion” or click here for a collection of posts on illusion.

Posted in Illusions, Neuroscience, Video | Tagged: , | 1 Comment »

The Situation of Spinning

Posted by The Situationist Staff on August 25, 2008

In which direction does the dancer in the image appear to be spinning? The answer:  It depends on your situation.

From Neurologica Blog:

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These kinds of optical illusions . . . reveal . . . how our brain processes visual information in order to create a visual model of the world. The visual system evolved to make certain assumptions that are almost always right (like, if something is smaller is it likely farther away). But these assumptions can be exploited to created a false visual construction, or an optical illusion.

The spinning girl is a form of the more general spinning silhouette illusion. The image is not objectively “spinning” in one direction or the other. It is a two-dimensional image that is simply shifting back and forth. But our brains did not evolve to interpret two-dimensional representations of the world but the actual three-dimensional world. So our visual processing assumes we are looking at a 3-D image and is uses clues to interpret it as such. Or, without adequate clues it may just arbitrarily decide a best fit – spinning clockwise or counterclockwise. And once this fit is chosen, the illusion is complete – we see a 3-D spinning image.

By looking around the image, focusing on the shadow or some other part, you may force your visual system to reconstruct the image and it may choose the opposite direction, and suddenly the image will spin in the opposite direction.

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For a collection of other Situationist posts providing and discussing illusions, click here.

Posted in Illusions, Video | Tagged: , | 1 Comment »

The Situation of Illusion

Posted by JH on June 25, 2008

Magician - from NYPL GalleryIn a paper that Ronald Chen and I wrote a few years ago (part of our “Illusion of Law” series), we summarized a few of the ways that “magic” happens and the key role played by “the way people think.” Here’s an excerpt from that paper (note: we are quoting Nathaniel Schiffman’s book, Abracadabra! Secret Methods Magicians & Others Use To Deceive Their Audience (1997)).

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Explanations that are outside of our schemas – what we believe or what we want to believe about the things we see – will rarely be activated. It is often the case that we simply cannot fathom that the magician might be doing what he is doing:

. . . when Blackstone did his famous birdcage vanish (a cage with a live bird vanished from his bare hands) he would hold his arms outright in front of him, seemingly presenting the cage to the audience for their inspection. . . . The cage was specially designed to collapse on command. At the appropriate time, Blackstone would toss it forward, and the collapsed cage would be pulled up his sleeve – bird and all. Savvy adults watching the show might shake their heads and say, ‘Nah, it couldn’t go up his sleeve because he wouldn’t want to injure the bird.’. . .

* * *

Actually, in many cases the bird was injured or killed.

Convinced that the magician would never rely on a method that might harm the bird, audience members were unable to see the trick. Their “knowledge” that the magician was not the type to harm a bird simply for the purposes a magic trick blinded them to what was the most obvious explanation for the illusion.

Our inability to see the magician as a particular type of person –- capable of, and willing to do, the unexpected in order to achieve magic –- is, like magic, no coincidence. Relying on our schemas, we make assumptions about the magician and her willingness to follow what we might consider to be the “unwritten Fra Diavolo image from NYPL Galleryrules” of magic. Audiences at a magic show

expect the magician to perform his magic in front of them, in full view, while misdirecting away from those certain actions that constitute the trick-to-the-trick. The audience probably doesn’t realize they are making those assumptions, because they have no reason to believe their assumptions are being broken. But very often a magic trick works because the magician has broken the unwritten rules of theatrical performing.

For psychics or “mentalists,” the unwritten rules include the following: first, the assumption “that the man on stage alone is performing the magic”; second, “that all the magic is done in ‘real time’ as the performance is happening”; and, third, “that the magic is done on stage.” The mentalist’s trick is often in breaking those rules – for example, having assistants eavesdrop on conversations in the audience; collecting juicy morsels of information prior to the time the show begins (and sometimes days before); relaying surreptitiously gathered information from off-stage. Doing unglamorous, tedious detective work prior to the show is often exactly the way that the trick is done.

In the end, magic succeeds when the audience believes what the magician wants them to believe: the idea that “[their] act is so awe-inspiring and mystical and magical that how in the world could that amazing magic be due to such lowly subterfuges as microphones and assistants transmitting information?”

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The July issue of Harper‘s includes a remarkable article by Alex Stone, “The Magic Olympics.” Stone’s first-hand account of The World Championships of Magic is stunning, but I want to focus on just a few of his paragraphs that describe a particular illusion (similar to an illusion that we published in a post two weeks ago and re-publish in this post) and that further illustrates the message in the passage above.

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[W]e’re entertained . . . by a . . . hair-raisng sawed-in-half effect. I’v seen hundreds of bisections, but nothing like this. Dressed as a doctor, he chainsaws his patient in half, and then an attractive nurse wheels the torso around on an ersatz gurney, waving her arms hrough the void where his legs ought to be. No box. No curtains. No mirrors. Nothing. What the hell?

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Take a look at the brief Youtube video below.

Social psychology and related fields have demonstrated repeatedly that what we are prepared to see strongly constrains what we can and do see. Those constraints on our thinking leave us vulnerable to manipulation and victims of many illusions in including, as the following excerpt from Stone’s article suggests, the illusion of an illusion

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I board a small plane back to the States. Several of the artists and competitors are on the flight, all looking as haggard as I do, and feel. After a week of biblical astonishments, I feel hardened. Nothing can faze me. But as I file through business class, I see something for which I am wholly unprepared. In the first row sits the illustionist of last night’s sawed-in-half routine, a meaty, florid man with triangular eyebrows and thin red lips. His trick has been gnawing at me since I saw it. No boxes. No mirrors. How? Now suddenly, I understand. Sitting next to him, in th aisle seat, is a slender dark-skinned man who looks normal in all respects save one: his body terminates just below the waist. No legs. No hips. Nothing. I can’t help but stare, and for a moment I wonder if anyone can hear my mind snap.

Magicians will go to great lengths in pursuit of the ultimate illusion, concealing silk inside a thumb tip, or doves in a coat, or any number of small objects within the delicate folds of a well-hemmed topit. But concealing an entire man–or rather, half a man–and flying him across the glove in service of a five-minute routine is something else entirely, something far stranger, something brilliant, yes, but also sad. Did the half-man, kept hidden in a hotel room, see nothing of Stockholm? What sort of non-disclosure agreement had he signed? Can I, too, buy a half-man at my local magic store?

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Assuming that Stone’s revelation helps to explain the same trick that is captured in the video above (and it may not), how does your reaction compare to Stone’s? Please comment.

Posted in Entertainment, Illusions, Video | Tagged: , , , , , , | 2 Comments »

Arthur Shapiro’s Situationist Illusion

Posted by The Situationist Staff on June 18, 2008

Arthur Shapiro has posted another of his remarkable illusions this week on his outstanding blog, Illusion Sciences.

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This illusion has special significance to us because, it is a “situationist illusion.” As Professor Shapiro explains:

One of my favorite places on the web is The Situationist, a blog that explores how the “situation” (or context) affects interpretation. The site has numerous examples of how objects, people, and events in one context are interpreted differently from the same objects, people, and events placed in another context.

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The visual display above presents an example of the effects of the visual “situation.” In one situation (vertical orientation for the disks), the viewer interprets the disks with reference to the background context (i.e., the two curtains). One disk looks like a shadow on the curtain, and the other looks like a spotlight. The disks are therefore interpreted as a dark spot and a lighter spot on the curtains. In another situation (horizontal orientation), the viewer is able to separate the disks from the context of the curtains and therefore will identify the disks as having the same shading.

To learn why the disks look different or similar to one another depending on whether they are oriented vertically or horizontally, or to look at more of Professor Shapiro’s award-winning illusions, click here.

Posted in Blogroll, Illusions, Video | Tagged: , , , | Leave a Comment »

Slight of Head

Posted by The Situationist Staff on June 16, 2008

Posted in Illusions, Video | Tagged: , | Leave a Comment »

Kevin James Illusion

Posted by The Situationist Staff on June 13, 2008

Posted in Illusions, Video | Tagged: , , | Leave a Comment »

 
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