Braquio-abduction illusion explanation and references

Braquio-abduction illusion explanation and references

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Illusion: Lying down on a hard flat floor move arms up and down (as when doing a snow angel) while keeping them touching the floor. While repeating it a few times the floor begins to appear concave, with the deepest part where the arms as perpendicular to the rest of the body.

Questions: What is the origin of this illusion?

My guess: I think it might be related to the arms being harder to extend towards the back when they are perpendicular to the body than when they are at other angles.

Note: The name above is only the way I like to call it. I found this illusion when I was a kid, but I am sure others might have noticed it as well.

It may be because, when we move our shoulders towards our the body, also know as abduction (Fig 1.) gives the central part of the body an elevation. when we rotate our arms more upwards (Adduction), the elevation will be lost.

So in other words, when we are making snow angels,

  1. Start Normal position (hands near thighs) = Back and shoulders on ground
  2. Middle position (hands in middle) = Back elevated and shoulders on ground
  3. Final Position (hands upward) = Back and shoulders on ground again.

Due to this motion, it seems as if the ground become concave.


Anatomical Terms of Movement

Articulating the Importance of Joints in Anatomy

Chubb illusion

The Chubb illusion is an optical illusion or error in visual perception in which the apparent contrast of an object varies substantially to most viewers depending on its relative contrast to the field on which it is displayed. [1] These visual illusions are of particular interest to researchers because they may provide valuable insights in regard to the workings of human visual systems.

An object of low-contrast visual texture surrounded by a field of uniform visual texture appears to have higher contrast than when presented on a field of high-contrast texture. This illusion was observed by Charles Chubb and colleagues and published in 1989. [2] An empirical explanation of the Chubb illusion was published by Lotto and Purves in 2001. [1]

4 Comments Add yours

The subject of this blog post is very interesting as it describes how our senses shape the way we view the world, yet no one person views the world in the same perspective another person does. It is all based on our previous experiences with all of our senses and emotions, which are altered when we view an illusion. I also loved the examples that were provided because they are relatable and things that I have definitely talked about with my friends.

I really enjoyed reading this post as you gave a very comprehensive overview of illusions of different sensories. The examples you provided make me feel engaged with this article and they allowed me to gain a better conception of what illusions can be. I’m especially interested in the part in which you elaborated on how visual illusion is caused by our brains’ organization of “shortcuts” to see things.

Jorge, your post on sensory illusions is truly fascinating. I liked how detailed you are with illusions created by different senses and managed to explain the concept fairly well with pictures and illustrations. I thought the dress example and the Mueller-Lyer illusion are very inspiring. I read about the Mueller-Lyer illusion in psychology earlier, linking it back to the biology part of it and how that creates misperception is very refreshing! Great work!

It is really fascinating to just think about illusions, let alone finding the mechanism behind them. We often tend to generalize a lot unexplained as illusions when they may have simple mechanisms behind. Illusions are really about a lot of the details we choose to not pay attention in our lives. Like your example on the illusion of the length of two lines with different ends, we often find our sessional observations odd when we neglect the simple mechanism taking place. Whether they are auditory, visual, or tactile, illusions are all about how our senses perceive and select information for further interpretation.

The Institute for Creation Research

Everyone has some unhealthy habits and the best way to achieve long-term freedom from them is not to &ldquodrop&rdquo them but to &ldquoreplace&rdquo them with something better. The freedom-through-replacement reality is also useful during any conversation about evolution&rsquos failure to explain the origin of nature&rsquos design, since, at some point, an evolutionist is likely to ask, &ldquoWell, do you propose something better?&rdquo

Creationists, in fact, do have a scientifically better explanation to replace the notion that nature&rsquos design is all an illusion that stems from a purposeless process in which evolution&rsquos substitute god, the imaginary &ldquoNatural Selector,&rdquo 1 chooses the fittest mutations randomly arising in an organism&rsquos DNA. A concise answer could be, &ldquoOur claim that nature&rsquos design is produced by a real designer can be tested by observation and is mathematically quantifiable. Furthermore, compared to the legacy of evolutionary thinking, it liberates minds to pursue more rational approaches toward scientific research.&rdquo

That answer ought to catch attention and keep discussion on the main question: &ldquoWhat is the best explanation of nature&rsquos design?&rdquo The Bible says in Romans 1:18-23 that the Lord&rsquos witness to His reality is &ldquoclearly seen&rdquo from the &ldquocreation&rdquo by the things He has &ldquomade.&rdquo He used the language of design construction, not biology. Everyone can see nature&rsquos design and conclude it was designed&mdashby a cause bigger than nature. Thus, Romans details how everyone&rsquos accountability to acknowledge God has always been based on the very clear design-designer (i.e., created-creator) connection, demonstrated by all human cultures, and not on detailed biological insight.

So, the biological question &ldquohow do organisms adapt to environments?&rdquo is not the root issue, which is founded on a basic question corresponding to problem-solving activities of intelligent engineers:

Are features of design evident when the innate programming of organisms actively solves problems (or exploits opportunities) presented by environments?

Real Design: A Scientifically Superior Explanation

Begin by stating that you have carefully examined the two explanations head-to-head. You find the explanation for real design is more persuasive since the activities of real engineers&mdashwhich cannot be duplicated by natural processes&mdashare reflected in the living world. Then, enumerate four verifiable observations that reflect real design.

Possibly the clearest observation of organisms is that they have multiple intricately arranged parts that fit together for a purpose. Many of these parts show proper alignment, exact dimensions and shape, tight fit, proper balance, and moving parts with precisely synchronized timing. These complex patterns are features of design that have been observed to originate only in intelligently designed items&mdashnever by natural forces.

One fact about sections of DNA is that their four letters are precisely arranged as a set of plans and specification detailing the materials and controls to reproduce a new organism. Since DNA 1) selects 2) in advance 3) exact attributes 4) for a purpose, it has the same features of intelligence as any engineer&rsquos specification. Throughout recorded human experience, plans and specifications are always a product of intelligence. In addition, all known natural processes that randomly choose letters one-by-one outside the context of an intelligence to guide the selection&mdashas evolutionists assert&mdashalways yield nonsense that is totally inconsistent with information held in DNA.

Another certain feature of design is demonstrated when engineers foresee aspects of their project that cannot be built by increments. They respond by establishing conditions so all information and materials are 1) available, 2) localized together, 3) at the right time, 4) capable of functioning together 5) for the intended purpose. Only intelligent agents have been observed to set conditions where all of the parts must be collected and built together or none of a specific function is obtained. Creatures have many examples of this all-or-nothing unity, but the best example is reproduction. Evolution is a dead end without operative reproductive abilities. Intelligent foresight best explains why the minimum number of parts necessary for an organism to reproduce&mdashis the organism itself.

Mathematicians have quantified the probability of the information for the most basic functional proteins developing by natural processes as exceedingly small. 2 Therefore, it is not a stretch to assert that it is mathematically impossible to obtain by natural processes the information that is needed for the origin of a living, reproducing bacterium. Overcoming infinitesimally small probabilities in a single bound by engaging them&mdashas evolutionists do&mdashwith infinite numbers of resources generated by an infinite number of universes falls outside the realm of acceptable scientific explanations.

Intricately arranged parts, information for specifications, all-or-nothing unity, and the impossibly low probabilities of these things happening in living things by chance are real observations. Their association to the actions of real designers is visible. Science is based on observation and testing. Real design is the better scientific explanation.

A better scientific explanation supports a better approach to science. Since these features point so clearly toward real design, biological researchers should approach investigations of nature like engineers would study an unknown electronic device. They should expect to discover well-designed, coherent, and incredibly complex systems functioning for a purpose&mdashan expectation forbidden by the rules governing evolution&rsquos mental &ldquothought prison.&rdquo

Escaping the Thought Prison Called &ldquoApparent Design&rdquo

Being confined to a tiny cell is the depressing reality that makes prison awful. But even worse is when a mind is so straitjacketed by the atheistic philosophy of naturalism that it eagerly believes explanations that are resisted by scientific observations. Claiming that the purpose of an eagle&rsquos wing cannot be known and that the synchronized movement of all its precisely fitted parts is only an &ldquoillusion of design&rdquo is a perception contrary to real external stimuli. How much better could scientists&mdashset free to conclude design when they see design&mdashapproach research when released from misconceptions that flow from invalid, yet firmly held, reasoning constricted by naturalism?

First, researchers would be free to follow data wherever it leads, which allows them to never stop questioning and discovering. This mental state far exceeds the shackled thinking characterized by a candid statement from a Kansas State University professor:

Even if all of the data point to an intelligent designer, such a hypothesis is excluded from science because it is not naturalistic. Of course the scientist, as an individual, is free to embrace a reality that transcends naturalism. 3

Second, there is freedom from the sense-dulling obligatory conclusion that intricate designs are &ldquoonly an illusion&rdquo&mdasha peer-enforced mantra indistinguishable from forced indoctrination. Researchers would not be pressured by popular evolutionary authorities such as Cambridge&rsquos Richard Dawkins, who insists that &ldquobiology is the study of complicated things that have the appearance of having been designed for a purpose.&rdquo 4 Or by Francis Crick, a co-discoverer of DNA, who cautioned, &ldquoBiologists must constantly keep in mind that what they see was not designed, but rather evolved.&rdquo 5

Third, it would liberate researchers from a smothering presupposition that expects regular mistakes in nature due to millions of years of chaotic evolution. They will escape a blinding mindset inclined to label not-readily-defined findings as &ldquojunk,&rdquo &ldquovestigial,&rdquo or &ldquobad design.&rdquo Reacting to observations with ill-informed hasty conclusions such as labeling non-protein-coding DNA &ldquojunk DNA&rdquo or the human appendix a &ldquovestigial organ&rdquo is not only poor scientific practice, but this prejudice tends toward neglect in research. Stanford University reported on immunological research on &ldquonatural killer&rdquo cells that &ldquohave largely been ignored by immunologists&hellip[and] thought by some to be an archaic remnant of the primitive mammalian immune system.&rdquo 6

Pulling It All Together

In a conversation about the best explanation for the origin of nature&rsquos design, first expose the weakness of the assertion that design is &ldquoonly an illusion.&rdquo Recount how evolutionists rely on a mindless iterative process to accumulate genetic mistakes &ldquofavored&rdquo by totally imaginary forces from their stand-in god, natural selection. The impotence of this mechanism always forces them to make conclusions far exceeding what the data support. Consequently, they resort to &ldquocounter-intuitive&rdquo scenarios that are &ldquomystifying to the uninitiated,&rdquo full of infinite numbers of self-creating universes where microscopic biological machines &ldquoself assemble&rdquo by &ldquoco-opting&rdquo &ldquooff the shelf parts,&rdquo leading to creatures with &ldquoghost lineages&rdquo that magically &ldquoarise&rdquo or &ldquoburst onto the scene.&rdquo So even if the evolutionist doesn&rsquot ask &ldquocan you offer something better?&rdquo&hellipdo it anyway.

Creationists can show that nature&rsquos design has features associated with those known only to be derived from real designers. Support is based on actual observations of living things&rsquo intricately arranged parts, plans and specifications reflected in DNA&rsquos information, and many examples of all-or-nothing unity. This truth frees researchers to expect that nature is a product of a rational, coherent design, a path that will lead to research that is once again open to fresh insights into nature. In biology, discovering purposes is better than forcing the absurdity that purpose is unknowable. Real design is the better scientific explanation, and free minds are better than imprisoned minds.

  1. Hanke, D. 2004. Teleology: The explanation that bedevils biology. In Explanations: Styles of explanation in science. Cornwell, J., ed. New York: Oxford University Press, 143-155.
  2. Axe, D. 2004. Estimating the prevalence of protein sequences adopting functional enzyme folds. Journal of Molecular Biology. 341 (5): 1295-1315.
  3. Todd, S. C. 1999. A view from Kansas on that evolution debate. Nature. 401 (6752): 423.
  4. Dawkins, R. 1986. The Blind Watchmaker. London: WW Norton & Company, 1.
  5. Crick, F. 1988. What Mad Pursuit: A Personal View of Scientific Discovery. London: Sloan Foundation Science, 138.
  6. Weidenbach, K. Natural-born killers: An immunologic enigma solved. Stanford Report. Stanford University news release, January 14, 1998.

* Dr. Guliuzza is ICR&rsquos National Representative.

Cite this article: Guliuzza, R. 2011. Evaluating Real vs. Apparent Design. Acts & Facts. 40 (1): 10-11.

Free will is an illusion, biologist says

Three different models explain the causal mechanism of free will and the flow of information between unconscious neural activity and conscious thought (GES = genes, environment, stochasticism). In A, the intuitive model, there is no causal component for will. Will influences conscious thought, which in turn influences unconscious neural activity to direct behavior. In B, a causal component of will is introduced: unconscious neural activity and GES. But now will loses its “freedom.” In C, the model that Cashmore advocates, will is dispensed with. Conscious thought is simply a reflection of, rather than an influence on, unconscious neural activity, which directs behavior. The dotted arrow 2 in C indicates a subservient role of conscious thought in directing behavior. Credit: Anthony Cashmore.

(—When biologist Anthony Cashmore claims that the concept of free will is an illusion, he's not breaking any new ground. At least as far back as the ancient Greeks, people have wondered how humans seem to have the ability to make their own personal decisions in a manner lacking any causal component other than their desire to "will" something. But Cashmore, Professor of Biology at the University of Pennsylvania, says that many biologists today still cling to the idea of free will, and reject the idea that we are simply conscious machines, completely controlled by a combination of our chemistry and external environmental forces.

In a recent study, Cashmore has argued that a belief in free will is akin to religious beliefs, since neither complies with the laws of the physical world. One of the basic premises of biology and biochemistry is that biological systems are nothing more than a bag of chemicals that obey chemical and physical laws. Generally, we have no problem with the "bag of chemicals" notion when it comes to bacteria, plants, and similar entities. So why is it so difficult to say the same about humans or other "higher level" species, when we're all governed by the same laws?

As Cashmore explains, the human brain acts at both the conscious level as well as the unconscious. It's our consciousness that makes us aware of our actions, giving us the sense that we control them, as well. But even without this awareness, our brains can still induce our bodies to act, and studies have indicated that consciousness is something that follows unconscious neural activity. Just because we are often aware of multiple paths to take, that doesn't mean we actually get to choose one of them based on our own free will. As the ancient Greeks asked, by what mechanism would we be choosing? The physical world is made of causes and effects - "nothing comes from nothing" - but free will, by its very definition, has no physical cause. The Roman philosopher and poet Lucretius, in reference to this problem of free will, noted that the Greek philosophers concluded that atoms "randomly swerve" - the likely source of this movement being the numerous Greek gods.

Today, as researchers gain a better understanding of the molecular details underlying consciousness, some people think that we may discover a molecular mechanism responsible for free will - but Cashmore doesn't think so. Such a discovery, he says, would require a new physical law that breaks the causal laws of nature. As it is, the only "wild card" that allows any room for maneuvering outside of genetics and one's environment is the inherent uncertainty of the physical properties of matter, and even this stochastic element is beyond our conscious control. (However, it can help explain why identical twins growing up in the same environment are unique individuals.)

To put it simply, free will just doesn't fit with how the physical world works. Cashmore compares a belief in free will to an earlier belief in vitalism - the belief that there are forces governing the biological world that are distinct from those governing the physical world. Vitalism was discarded more than 100 years ago, being replaced with evidence that biological systems obey the laws of chemistry and physics, not special biological laws for living things.

"I would like to convince biologists that a belief in free will is nothing other than a continuing belief in vitalism (or, as I say, a belief in magic)," Cashmore told

It all seems quite rational, so why is our lack of free will so difficult to accept for many people? Cashmore explains that there are several compelling reasons that people have for believing in free will, not the least of which is that we have a constant awareness of making decisions that seem to be driven by our own volition. In addition, free will is a very useful concept when it comes to the justice system we take responsibility for our criminal actions and accordingly, are eligible for personal punishment, which is deemed to be necessary for protecting society.

However, Cashmore argues that there are deeper explanations for why we think we have free will. He thinks that there must be a genetic basis for consciousness and the associated belief in free will. Consciousness has an evolutionary selective advantage: it provides us with the illusion of responsibility, which is beneficial for society, if not for individuals as well. In this sense, consciousness is our "preview function" that comforts us into thinking that we are in control of what we will (or at least may) do ahead of time. As Cashmore notes, the irony is that the very existence of these "free will genes" is predicated on their ability to con us into believing in free will and responsibility. However, in reality, all behavioral decisions are nothing more than a reflection of our genetic and environmental history.

"Whereas the impressions are that we are making 'free' conscious decisions, the reality is that consciousness is simply a state of awareness that reflects the input signals, and these are an unavoidable consequence of GES [genes, environment, and stochasticism]," Cashmore explained.

"Few neurobiologists would argue with the notion that consciousness influences behavior by acting through unconscious neural activity," he said. "More controversial is the notion that consciousness plays a relatively minor role in governing our behavior. The conscious mind is conceivably more a mechanism of following unconscious neural activity than it is one of directing such activity. I find it interesting to compare this line of thinking with that of Freud, who created a controversy by suggesting that the unconscious mind played a role in our behavior. The way of thinking regarding these matters now has moved to the extent that some are questioning what role, if any, the conscious mind plays in directing behavior. Namely, Freud was right to an extent that was much greater than he realized."

To summarize, Cashmore's argument is that free will is an illusion derived from consciousness, but consciousness has an evolutionary advantage of conferring the illusion of responsibility. So what is the point of publicizing the fact that we have no free will, and letting everyone off the hook of individual responsibility? Cashmore says that, as researchers deepen their understanding of the molecular basis of human behavior, it will become increasingly difficult to entertain the fallacy of free will.

Can't Be Held Responsible

Perhaps the most obvious impact of this paradigm shift will be on our judicial system, in which the notions of free will and responsibility form an integral component. Currently, in order to be found guilty, a criminal must be considered responsible for his actions otherwise, he can be found not guilty by reason of insanity. Cashmore disagrees with these rules, noting that psychiatric research is finding its way more and more into the courts and causing time-wasting debates. (For example, is alcoholism a disease? Are sex crimes an addiction?)

"Where is the logic in debating an individual's level of responsibility, when the reality is that none of us are biologically responsible for our actions?" he said.

Cashmore proposes a change, based on "the elimination of the illogical concept that individuals are in control of their behavior in a manner that is something other than a reflection of their genetic makeup and their environmental history."

He says that psychiatrists and other experts on human behavior should not be involved in initial judicial proceedings. The jury should simply determine whether or not a defendant is guilty of committing a crime, and not be concerned with mental issues. Then, if the defendant is found guilty, a court-appointed panel of experts would advise on the most appropriate punishment and treatment. Cashmore argues that, even though individuals are not biologically responsible for their actions, in order to minimize criminal activity, people should still be held accountable, and be punished when necessary. Such punishment is rationalized on the grounds that it will serve as an incentive (an environmental influence) not to participate in criminal behavior.

"Here I introduce the practice of 'I am sorry about this but I am going to have to beat you,'" Cashmore said. "This punishment is rationalized in the sense that it serves as a lesson to individuals not to break the law. So people would be held accountable for their actions, even though they are not 'biologically responsible' for such actions. This punishment may involve fines or placing people in prison. Such punishment should not reflect any sense of retribution, and given this I do not personally see how one could continue to impose the death penalty - the alleged effectiveness of such a penalty presumably being far outweighed by its unfairness. The exact way in which one balances the presumptive requirement for punishment, and the lack of biological responsibility, would indeed be difficult, and would require much discussion within the legal system and society as a whole."

He said that tailoring punishment on an individual basis is presently done, at least to some extent.

"Why is it important to make a change? Because increasingly the legal system is being forced to confront the reality that people's behavior is governed by nothing other than their biological history: their genes, their environment and a degree of stochasticism (if you wish, a degree of chance). The legal system is increasingly seen to be a farce, with lawyers spending endless time and money debating this nonsensical question of how responsible or not their clients are. Why nonsensical? Because no one is biologically responsible for their actions. As Francis Crick said, 'Dream as we may, reality knocks relentlessly at the door.' And as a result of the rapid and ongoing progress in neuroscience, the reality that individual behavior is governed by one's genetic and environmental history is becoming increasingly apparent."

Your Brain Can’t Handle the Moon

W hat is this new theory?” the long-retired New York University cognitive psychologist, Lloyd Kaufman, asked me. We were sitting behind the wooden desk of his cozy home office. He had a stack of all his papers on the moon illusion, freshly printed, waiting for me on the adjacent futon. But I couldn’t think of a better way to start our discussion than to have him respond to the latest thesis claiming to explain what has gone, for thousands of years, unexplained: Why does the moon look bigger when it’s near the horizon?

He scooted closer to his iMac, tilted his head and began to read the MIT Technology Review article I had pulled up. 1 I thought I’d have a few moments to appreciate, as he read, the view of New York City outside the 28th floor window of his Floral Park apartment, but within a half-minute he told me, “Well, it’s clearly wrong.”

It wasn’t even my theory, yet I felt astonished. It described two researchers—Joseph Antonides (an undergraduate) and Toshiro Kubota (a computer scientist), of Susquehanna University in Pennsylvania—who had constructed a perceptual model in which the sky was contiguous with the horizon, so that the moon was placed, as it were, in front of the sky, occluding it. 2 Since our depth perception also places the moon farther away from us than the horizon, we are faced with a perceptual dilemma. The scientists reasoned that the horizon moon’s enlargement is a product of the brain trying to solve this dilemma.

It’s wrong, he told me, because “you can get the illusion if you have only one eye. Simple!”

To Be More Creative, Cheer Up

I pour a cup of coffee, sharpen my pencil, and get ready to create. I’ve dusted off a half-conceived novel outline I abandoned three years ago, but this time I’m not waiting for my muse to intervene. Instead I hit. READ MORE

T he moon illusion is a sort of Rip Van Winkle figure in the history of science. Unlike other astronomical puzzles, the moon illusion, wrote Rutgers University philosopher Frances Egan, “has persisted through massive changes both in our overall physical theory, and in our very conception of the scientific enterprise.” 3

The earliest mention of the moon illusion we know of was impressed almost 3,000 years ago, in cuneiform script upon a clay tablet, when it was housed in the royal library of Nineveh. 4 Later on, in the second century A.D., Ptolemy argued that it was the result of the magnifying properties of the atmosphere’s moisture and haze. “It is just like the apparent enlargement of objects in water, which increases with the depth of immersion,” he wrote. 5 On account of something like divine authority, this physical or “refraction” account of the problem went unchallenged for more or less 1,000 years, a real shame since he also had an alternative physiological account that went largely ignored until Newton’s time. 6

Can’t fool the camera: A time-lapse sequence of the moon setting * behind San Francisco’s Golden Gate Bridge. The camera is not fooled by the moon illusion, and accurately represents a constant moon size. Flickr / David Yu

Today, this physiological account is known as the “angle-of-regard” hypothesis, for the angle that our eyes (or head) make relative to the horizon. The more your eyes are angled upward, the thinking goes, the smaller something looks, due to the physiology of our visual system. Angle-of-regard sat dormant for hundreds of years after Ptolemy, until the Irish philosopher George Berkeley revived it, in 1709, as part of a debate with the then-new geometrical optics of philosophers like René Descartes and Nicolas Malebranche.

They took the moon illusion to support their contention that vision is inherently three-dimensional, and that we can compute size and distance using vision alone. In his “Essay Towards a New Theory of Vision,” Berkeley opposed this view, pointing out that the moon illusion could be explained away using the angle-of-regard hypothesis and claiming that there is nothing inherently three-dimensional about what we see—that instead we learn about how far and how big things are by moving around in the world, hands-on, as it were. Descartes, though, didn’t accept the angle-of-regard dismissal of the moon illusion. Instead he held to the “apparent distance” hypothesis, according to which the horizon moon seemed larger because we judged it to be farther away.

“It’s the challenge of solving a problem the likes of Galileo and Newton couldn’t handle.”

Neither hypothesis was generally accepted until the 1940s, when angle-of-regard was made briefly triumphant by the work of Harvard psychologist Edwin G. Boring. That was before Kaufman arrived on the scene in 1956, in search of a thesis topic for his masters in psychology. When I asked Kaufman why, out of all the unsolved mysteries in science, he chose to dedicate his attentions to this one, he offered his reason as if it ought to have been obvious. “It’s the challenge of solving a problem the likes of Galileo and Newton couldn’t handle.”

In their 1962 paper, Kaufman and his colleague Irvin Rock attacked angle-of-regard. They pointed out, in a section ominously titled “Grounds for Caution,” that if you looked at the horizon moon with your chin tucked in and your eyes elevated, the moon illusion persisted—regardless. They also criticized Boring’s experimental methodology and his evaluation of Descartes’ apparent distance hypothesis.

In pursuit of a new explanation, Kaufman and Rock performed a set of experiments using a device that could place a disk of light in the sky so that it was “exactly like looking through a window at the moon.” 7 They considered eye-elevation both outdoors and indoors, the moon’s color and brightness, and the presence of terrain. The first two had no effect, but the third was crucial: They concluded that if an observer’s view of the terrain is obstructed, the illusion vanishes.

This observation supported the apparent distance hypothesis: The presence of terrain increased the subjective sense of distance to the moon, so that while it was actually the same size, the perceptual system would “conclude” that it was a more distant object and thus inflate its size. Boring had rejected the apparent distance hypothesis because people reported that the horizon moon looks closer, not farther away. As the behavioral physiologist J.T. Enright points out, this size-distance paradox seemed to require some kind of disconnect between our conscious and subconscious perception of distance: We expand the moon to be larger given that it seems farther away, but then report that it seems closer. “The subconscious impression of distance, once it has determined apparent size, must remain irretrievably locked in the subconscious,” he wrote. “These seem to be unresolvable paradoxes.”

But Kaufman’s data clearly pointed to the importance of terrain, as did other experiments. 8 Kaufman even called the astronaut Ed Lu when he was overhead in the International Space Station to ask him if he saw the moon illusion up in space: He said no. “There’s nothing there but the curvature of the Earth,” Kaufman told me. “You got no distance.” Plus, he told me, he’s asked test pilots (“these guys have eyes like eagles”) if they see the moon illusion. They told him “sure, but only when we get down low.”

In a 2007 paper, Kaufman confronted the “size-distance paradox” head-on. 9 The traditional description of the paradox involves three consecutive acts of perception: First, we perceive the moon to be farther away because of terrain, then we perceive it to be larger because it is farther away, and then we perceive it to be closer because it is larger. But, Kaufman says, “perceptions do not cause perceptions.” One or more of the steps in this causal chain might involve a conscious judgment rather than a subconscious perception, or might result from a complex simultaneous network of connections and inferences of which we are unaware. We need to remember, says Kaufman, that “perceptions are outcomes of computational processes far more numerous and complicated than the perceptions themselves.” Judgment and perception might be correlated with each other, but they do not cause one another.

Clearly spelling out the error is hard, he told me, because “it’s not intuitive.” He said, “When I try to make it explicit, I run into a lot of difficulty, and that’s why I’m hung up on this last paper I’m doing.” Precisely explaining the mechanics of our vision is a problem Kaufman shares with some august company: It was Kepler who wrote four centuries earlier that, “perception does not belong to optics but to the study of the wonderful.” 10

Brian Gallagher is an editorial intern at Nautilus. He has written for Mic and the Santa Barbara Independent. @brianscottg

1. Moon illusion: New theory reignites debate over why moon appears larger near the horizon. MIT Technology Review (2013).

2. Antonides, J. & Kubota, T. Binocular disparity as an explanation for the moon illusion. Preprint arXiv 1301.2715 (2013).

3. Egan, F. The moon illusion. Philosophy of Science 65, 604-623 (1998).

4. Plug, C. & Ross, H.E. Historical review. In Hershenson, M. (ed.) The Moon Illusion Psychology Press, New York, NY (1989).

5. Ross, H.E. & Ross, G.M. Did Ptolemy understand the moon illusion? Perception 5, 377-385 (1976).

6. Enright, J.T. The moon illusion examined from a new point of view. Proceedings of the American Philosophical Society 119, 87-107 (1975).

7. Osmundsen, J.A. Modern psychology upholds Ptolemy on moon illusion Ptolemy upheld on explantion of why horizon moon is ‘larger.’ The New York Times (1960).

8. Hamilton, J.E. Effect of observer elevation on the moon illusion. American Journal of Optometry and Archives of American Academy of Optometry 42, 417-431 (1965).

9. Kaufman, L. et al. Perceptual distance and the moon illusion. Spatial Vision 20, 155-175 (2007).

10. Fishman, R.S. Kepler’s discovery of the retinal image. Archives of Ophthalmology 89, 59-61 (1973).

*As originally published, this caption stated that the moon was rising. It is, in fact, setting.

Turning the tables illusion

An astonishingly powerful though little-known perspective illusion in which a pair of identical parallelograms representing the tops of two tables appear radically different (see illustration). The illusion was first presented by the US psychologist Roger N(ewland) Shepard (born 1929) in his book Mind Sights: Original Visual Illusions, Ambiguities, and Other Anomalies (1990, p. 48). Shepard commented that ‘any knowledge or understanding of the illusion we may gain at the intellectual level remains virtually powerless to diminish the magnitude of the illusion’ (p. 128). The illusion arises from our inability to avoid making three-dimensional interpretations of the drawings, according to which the identical parallelograms would represent very different shapes because of perspective foreshortening, and it is based on his less powerful parallelogram illusion, published in an edited book entitled Perceptual Organization (1981, pp. 297–9). Also called the tabletop illusion. Compare Ames room, corridor illusion, Müller-Lyer illusion, Ponzo illusion.

Turning the tables illusion. Almost unbelievably, the tabletop on the left is identical in shape and size to the one on the right, as can be confirmed by tracing either of the white parallelograms and placing the tracing over the other.


Animation Topics

Four complex cell biology topics that many of my students struggle with are translation, replication, electron transport of cellular respiration, and the light reactions of photosynthesis. A group of freshman and sophomore students from The Citadel Military College participated in a study to learn these four topics by studying both traditional written lessons (with still figures) and animation lessons that I created. After studying the topics, they answered the short anonymous survey described below. The college's online Learning Management System (LMS), Blackboard Learn, was used to administer the lessons and to collect anonymous survey data. I should note that The Citadel's student body is predominantly male, with only 7% of students being female. Students were awarded extra credit points as an incentive to participate.

Development of Lessons

Animations: I created all the animations/movie lessons first as narrated Microsoft PowerPoint Shows (Howell & Howell, 2002) and then produced them as MP4 files with Camtasia Studio 4.0 software. Files were stored on a media server hosted at The Citadel, and the links below were provided to students through the LMS.

I first determined which aspects of each topic I wanted to illustrate with my animation, and then I created a simple hand-drawn storyboard to use as a template for my PowerPoint animation (Mou et al., 2013). Then, using PowerPoint, I created simple images to symbolize the various cellular components from the storyboard. PowerPoint drawing tools allow the user to create simple uniform images in various shapes, sizes, and colors that may be used to represent complex molecules for the animation. Simply select the shape you want from the “Drawing” palate on the Home tab of PowerPoint then click and drag the mouse on the slide to create an image of that shape. You can then change the image in various ways: its color can be changed by first selecting the image and then using the “Shape Fill” color option on the Drawing palate its size can be changed by selecting the image and then dragging the corner marker in or out to create the size you prefer its position on the slide can be changed by clicking in the center of the image and dragging it to the desired location. More complex images can be created by arranging separate small shapes around one another and then grouping them into a single figure the “Group Objects” option is available under the “Arrange” drop-down menu on the Drawing palate. Another PowerPoint Drawing tool that I find useful is the “Alignment” tool found under the “Arrange” drop-down menu simply select several images that you wish to align (selecting multiple images requires you to hold the Ctrl key while clicking on each one), then choose the type of alignment you need from the drop-down menu PowerPoint can line up your images in various ways, making your figure look more professional.

Once you have created the first slide with the basic images in place, creating animations in PowerPoint is easy. By copying and pasting the contents of one slide onto the next one, and then changing small details on each subsequent slide, you can create an illusion that the objects move and change. When you advance from one slide to the next in the “Slide Show” mode, your cartoon will operate much like the flip books used by Walt Disney and other early animators. Alternatively, you can use a more advanced feature of PowerPoint to animate an object on a single slide by first selecting the object and then using the options under the “Animation” tab to program the object to move in various ways. When you play the “Slide Show,” the objects will move as you have designated. PowerPoint is a powerful program, and to learn more of its many capabilities, simply review Microsoft's free online PowerPoint help resources (available by selecting the question-mark icon in the upper right corner of any PowerPoint window).

Once your slideshow runs properly, you can use a microphone to add narration, and you can set up the timing for each slide transition using the “Record Slide Show” option under the “Slide Show” tab. Another option is to simply narrate it yourself each time you show it in the classroom. You may prefer to keep your animation in the PowerPoint file format, but you can also take it a step further and produce it in various other formats using Camtasia Studio, which is more useful for online posting.

Camtasia Studio Software, like PowerPoint, is user-friendly and can be used to record the PowerPoint presentation while you play it as a “Slide Show.” Camtasia can be used to narrate your animation, and some prefer this over PowerPoint's narration tool. Many universities provide access to Camtasia Studio software in multimedia labs, but if that option is not available, you can purchase your own license for under $200 be sure to request the price for educators. The software can operate as an add-in to PowerPoint, and its toolbar will appear under the “Add-Ins” tab of PowerPoint after you install it on your computer. Simply choose the recording options you want and then click the Record button to record your PowerPoint animation with Camtasia Studio. The Camtasia toolbar is fairly self-explanatory, and online help is available by clicking the question-mark icon on the toolbar. The Camtasia-recorded show can then be edited and produced in various movie formats. I chose the format that is supported by my institution's media server, and then I requested assistance from the media manager, who helped me upload my animations to the server and provided me with the links for my students to use for access.

Readers of this manuscript should be able to view and use the animations described in this study by selecting the links below:

Written Lessons: I developed written lessons to teach each of the same four topics above so that students could study them online before taking the anonymous survey. All written lessons were created using text that was comparable to the narration in the animations and using illustrations that were individual frames captured from the animations. The four written lessons are provided in the supplement:

Anonymous Post-lesson Survey

All subjects were asked to respond to the following three survey questions after they completed the study:

Did you prefer learning from written lessons or from movies [animations]? Explain.

Did you feel you learned faster from written lessons or from movies [animations]? Explain.

Do you have any other comments about this study?


All participants were able to follow the instructions and maintain their attention during the whole experimental session. Touch-evoked potentials (all trials of one hand side combined, irrespective of condition) displayed a positive-going wave peaking at around 50 msec, with its maximum over the posterior contralateral part of the scalp, along with a negative-going wave with its maximum over the frontocentral part at the same time (scalp topography and average scalp maps are shown in Figure 2). Subsequent analysis was performed separately for each side and condition. For the CONGRUENT condition, only trials with the illusion reported as present were included. For INCONGRUENT, only trials where the illusion was absent were considered.

Scalp distribution of touch-evoked potentials. All trials of one hand were averaged, irrespective of the stimulation condition. Top: Scalp topography for right (A) and left (C) hand stimulation. A time window of −200 to +300 msec is shown. Bottom: Average scalp maps at 50 msec poststimulus for right (B) and left (D) hand stimulation. For all panels: left is left side of the head.

Scalp distribution of touch-evoked potentials. All trials of one hand were averaged, irrespective of the stimulation condition. Top: Scalp topography for right (A) and left (C) hand stimulation. A time window of −200 to +300 msec is shown. Bottom: Average scalp maps at 50 msec poststimulus for right (B) and left (D) hand stimulation. For all panels: left is left side of the head.

Sensor Level Analysis

For right-hand stimulation, sensor level analysis of differences among the stimulation conditions revealed significant clusters near electrode F3 at 56 msec (p = .006) and electrode P2 at 54 msec (p = .015 see Figure 3A). Inspection of the F3 sensor data pointed to a decreased amplitude at the frontal negative peak around 50 msec in the CONGRUENT condition as compared with REAL and INCONGRUENT. At sensor P2, a larger parietal positive peak emerged around 50 msec in the INCONGRUENT condition as compared with CONGRUENT and REAL (see Figure 3A).

Results of the sensor level analysis expressed as the statistical parametric maps of the F statistic testing for significant differences among the three conditions in sensor space. (A) Right-hand stimulation. Significant clusters (after FWE correction) indicating differences between the stimulation conditions were found near to electrodes F3 and P2 (top part of figure). Sensor data at F3 and P2 (bottom part of figure). (B) Left-hand stimulation. Clusters (p < .001 uncorrected) indicating differences between the stimulation conditions were found next to electrodes F6 and Pz (top part of figure). Sensor data at F6 and Pz (bottom part of figure). CONGRUENT: blue line REAL: green line INCONGRUENT: red line.

Results of the sensor level analysis expressed as the statistical parametric maps of the F statistic testing for significant differences among the three conditions in sensor space. (A) Right-hand stimulation. Significant clusters (after FWE correction) indicating differences between the stimulation conditions were found near to electrodes F3 and P2 (top part of figure). Sensor data at F3 and P2 (bottom part of figure). (B) Left-hand stimulation. Clusters (p < .001 uncorrected) indicating differences between the stimulation conditions were found next to electrodes F6 and Pz (top part of figure). Sensor data at F6 and Pz (bottom part of figure). CONGRUENT: blue line REAL: green line INCONGRUENT: red line.

For left-hand stimulation, no significant clusters survived FWE correction. However, we performed an exploratory analysis, setting the significance level at p = .001 (uncorrected). There was a very similar contralateral pattern, appearing slightly later than with right-hand stimulation, with clusters near electrode F6 at 66 msec and next to electrode Pz at 76 msec (see Figure 3B). Again, inspection of the F6 sensor data at the frontal negative peak around 50 msec pointed to decreased amplitude in the CONGRUENT condition as compared with the others. At sensor Pz, the parietal positive peak around 50 msec appeared to be larger in the INCONGRUENT condition as compared with CONGRUENT and REAL (see Figure 3B).

Source Analysis

For right-hand stimulation, post hoc contrasts on the source level response estimates showed significantly smaller amplitudes for CONGRUENT as compared with INCONGRUENT and REAL at the contralateral pre- and postcentral gyri, superior and inferior parietal lobule (p < .05). Moreover, for the INCONGRUENT condition, source amplitudes were larger at a scalp region overlying the contralateral postcentral gyrus and inferior parietal lobule as compared with the other conditions (see Figure 4A and Table 1).

Statistical parametric maps of the key statistics testing for (signed) significant differences between conditions in source space: Post hoc results on the source level for (A) right-hand stimulation and (B) left-hand stimulation. t Values for areas with significantly (p < .05, FWE-corrected) lower activation in the CONGRUENT condition (top part of figure) or higher activation in the INCONGRUENT condition (bottom part of figure) as compared with the respective other conditions are color-coded.

Statistical parametric maps of the key statistics testing for (signed) significant differences between conditions in source space: Post hoc results on the source level for (A) right-hand stimulation and (B) left-hand stimulation. t Values for areas with significantly (p < .05, FWE-corrected) lower activation in the CONGRUENT condition (top part of figure) or higher activation in the INCONGRUENT condition (bottom part of figure) as compared with the respective other conditions are color-coded.

Post hoc Results on the Source Level

Contrast . Anatomical Region . MNI Coordinates .
x . y . z .
Right Hand
CONGRUENT < REAL, INCONGRUENT L postcentral gyrus −32 −37 51
L precentral gyrus −22 −29 55
L inferior parietal lobule −37 −43 41
L superior parietal lobule −36 −64 55
L precentral gyrus −27 −17 55
INCONGRUENT > CONGRUENT, REAL L inferior parietal lobule −35 −39 41
L postcentral gyrus −30 −38 52
Left Hand
CONGRUENT < REAL, INCONGRUENT R postcentral gyrus 42 −35 58
R postcentral gyrus 39 −27 55
INCONGRUENT > CONGRUENT, REAL R postcentral gyrus 42 −35 58
R postcentral gyrus 39 −26 53
R postcentral gyrus 26 −30 59
R paracentral lobule 11 −33 73
Contrast . Anatomical Region . MNI Coordinates .
x . y . z .
Right Hand
CONGRUENT < REAL, INCONGRUENT L postcentral gyrus −32 −37 51
L precentral gyrus −22 −29 55
L inferior parietal lobule −37 −43 41
L superior parietal lobule −36 −64 55
L precentral gyrus −27 −17 55
INCONGRUENT > CONGRUENT, REAL L inferior parietal lobule −35 −39 41
L postcentral gyrus −30 −38 52
Left Hand
CONGRUENT < REAL, INCONGRUENT R postcentral gyrus 42 −35 58
R postcentral gyrus 39 −27 55
INCONGRUENT > CONGRUENT, REAL R postcentral gyrus 42 −35 58
R postcentral gyrus 39 −26 53
R postcentral gyrus 26 −30 59
R paracentral lobule 11 −33 73

For left-hand stimulation, post hoc analysis revealed significantly lower amplitudes for CONGRUENT as compared with INCONGRUENT and REAL at a region overlying the contralateral postcentral gyrus only and higher amplitudes for INCONGRUENT as compared with the other conditions at contralateral postcentral gyrus and paracentral lobule (see Figure 4B and Table 1).

Aesthetic Illusion as a Connection of Cognitive Neural Basis, Art Appreciation and Modern Ideology

Illusion is a significant concept in philosophy, art history, literary theory and aesthetics. It has a concrete scientific basis in the perspective of modern cognitive neuroscience. Historically, it has been critically discussed by many philosophers, including Plato, Bacon, Descartes, Kant, and Nietzsche, who considered it to be a distortion of reality. Yet illusion is connected with so many basic aesthetic issues -- such as ambiguity, imagination, and imagery -- that it remains an indispensable concept in modern aesthetics. In the different art media communication of creators with appreciators involves illusory imagery. Its importance is emphasized by Ernst Gombrich in his Art and Illusion, one of the most influential art history texts in the English-speaking world. The concept of illusion becomes the crossing point of classical philosophy and contemporary aesthetics. In this article, the philosophical, psychological and aesthetic bases of illusion will be introduced. In different fields, illusion has different content, but depends on the same psychological mechanisms. The neural mechanisms that underpin aesthetic illusion in contemporary artistic production also function in the modern ideology described by Adorno, Eagleton, and Williams. Not all aesthetic illusions have positive functions, which sometimes leads to distorted cognition and emotional complexity. When it deviates too far from reality, aesthetic illusion contains particular cognitive emotional qualities that conflict with artistic imagery in classical arts. As a bearer of modern aesthetic emotion, it is also shaped by special economic and political situations and always has a kind of ideological character. Thus aesthetic illusion often promotes new configurations of aesthetics and art history.

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Watch the video: 10 Mind Blowing Optical Illusions (February 2023).