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This new illusion tricks your mind and your eyes

<p dir="ltr">A new “expanding hole” illusion is strong enough that we’re both physically and mentally fooled, according to new research.</p> <p dir="ltr">The illusion depicts a black hole in the centre of a white background covered in smaller black circles and, if you’re one of the 86 percent of people tricked by it, the black hole will look like it’s expanding.</p> <p><span id="docs-internal-guid-35844208-7fff-7feb-1e6f-58b7e7c328f5"></span></p> <p dir="ltr">According to the researchers who studied this illusion, which is completely new to science, those who were fooled by the illusion had a physical reaction, with participants’ pupils dilating as if they were actually moving into a dark area.</p> <p dir="ltr"><img src="https://oversixtydev.blob.core.windows.net/media/2022/06/fnhum-16-877249-g001.jpg" alt="" width="1950" height="1221" /></p> <p dir="ltr"><em>Does it look like the black hole is growing? You’re not alone in thinking that, according to this new study. Image: Supplied</em></p> <p dir="ltr">Dr Bruno Laeng, a psychology professor at the University of Oslo and the study’s first author, said the illusion showed that our pupils react to light we perceive, “even if this ‘light’ is imaginary”.</p> <p dir="ltr">“The ‘expanding hole’ is a highly dynamic illusion: the circular smear or shadow gradient of the central black hole evokes a marked impression of optic flow, as if the observer were heading forward into a hole or tunnel,” he <a href="https://www.scimex.org/newsfeed/can-you-see-the-expanding-hole-most-peoples-brains-are-fooled-by-this-new-optical-illusion" target="_blank" rel="noopener">explained</a>.</p> <p dir="ltr">“Here we show based on the new ‘expanding hole’ illusion that the pupil reacts to how we perceive light - even if this ‘light’ is imaginary like in the illusion - and not just the amount of light energy that actually enters the eye.</p> <p dir="ltr">“The illusion of the expanding hole prompts a corresponding dilation of the pupil, as it would happen if darkness really increased.”</p> <p dir="ltr">After having tested the illusion using holes of varying colours - including blue, cyan, green, magenta, red, yellow and white - the team found the illusion was most effective when it was black.</p> <p dir="ltr">They also discovered that a black hole would cause the pupil to dilate, while coloured holes would result in the eye constricting.</p> <p dir="ltr">The study, published in the journal <em><a href="https://doi.org/10.3389/fnhum.2022.877249" target="_blank" rel="noopener">Frontiers in Human Neuroscience</a></em>, shows that these kinds of illusions are more than just gimmicks, with researchers in the field of psychosociology studying them to better understand how the complex system that allows us to see and make sense of the world around us works.</p> <p dir="ltr"><span id="docs-internal-guid-5dc1df7e-7fff-afc7-25e8-cbff597458d3"></span></p> <p dir="ltr"><em>Image: Supplied</em></p>

Mind

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Optical illusion baffles internet

<p dir="ltr">An optical illusion <a href="https://honey.nine.com.au/latest/optical-illusion-reveals-a-hidden-number-that-everyone-is-seeing-differently/e7610c56-b283-4e58-8487-55f389ab6174" target="_blank" rel="noopener">has sparked debate</a> on social media, after it caused each person to see a different number.</p> <p dir="ltr">The image, shared by Twitter user @benownie, features a black-and-white circle with a zig-zag pattern inside that contains a set of hidden numbers.</p> <p><span id="docs-internal-guid-04911ad0-7fff-6488-1bd5-dded8258746d"></span></p> <p dir="ltr">However, viewers can’t seem to agree on what those numbers are.</p> <blockquote class="twitter-tweet"> <p dir="ltr" lang="en">DO you see a number?</p> <p>If so, what number? <a href="https://t.co/wUK0HBXQZF">pic.twitter.com/wUK0HBXQZF</a></p> <p>— Benonwine (@benonwine) <a href="https://twitter.com/benonwine/status/1494084416494354432?ref_src=twsrc%5Etfw">February 16, 2022</a></p></blockquote> <p dir="ltr">“DO you see a number? If so, what number?”, the user captioned the post.</p> <p dir="ltr">Since the pattern aims to trick the eye into thinking the image is moving, it can be quite tricky to distinguish which numbers lie behind it, with most seeing a jumble of different numbers.</p> <p dir="ltr">“845283,” one person guessed.</p> <p dir="ltr">“45 283… and what’s the catch? Should I book an appointment with my GP?” another said.</p> <p dir="ltr">Another user and fan of Douglas Adams’ novel <em>The Hitchhiker’s Guide to Galaxy</em> pointed out the correct answer could be a sneaky Easter egg for fellow fans.</p> <p dir="ltr">“3452939. Strangely, this is also the telephone number of an Islington flat where Arthur Dent went to a fancy dress party, and met a very nice young woman whom he totally blew it with,” they wrote.</p> <p dir="ltr">“A few hitchhikers [sic] guide diehard fans peeking out of the closet here. I love you all x.”</p> <p dir="ltr">The image even prompted some to suggest others who struggled with the photo to get their eyes tested for astigmatism.</p> <p dir="ltr">“I can only see 528. Does that mean anything about my eyesight?” one concerned person wrote.</p> <p dir="ltr">“When was the last time you had a sight test?” a helpful commenter replied. “Sounds like you may have an astigmatism or difficulty with contrast.”</p> <p dir="ltr">Another user explained that the numbers a person can see could be proof of how good someone’s eyes were.</p> <p dir="ltr">“I’m guessing the numbers you see depends on your ‘contrast sensitivity’ (different from what a standard eye measures),” they explained. “It can be tested by opticians. Worth doing if you’re struggling, as it can affect your ability to see at night, or rain, fog, etc.”</p> <p dir="ltr"><span id="docs-internal-guid-1682cdf0-7fff-8b30-8c09-a8c9f0db6542"></span></p> <p dir="ltr">According to <em><a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/contrast-sensitivity#:~:text=Contrast%20sensitivity%20is%20a%20measure,enough%20contrast%20with%20its%20background." target="_blank" rel="noopener">ScienceDirect</a></em>, a repository for scientific research, contrast sensitivity describes “the ability to detect subtle differences in shading and patterns”, which is important for “detecting objects without clear outlines” such as “steps covered with a patterned carpet”.</p> <p dir="ltr"><img src="https://oversixtydev.blob.core.windows.net/media/2022/02/contrast-sensitivity-test.jpg" alt="" width="1280" height="720" /></p> <p dir="ltr"><em>An example contrast sensitivity test. Image: Vision Center</em></p> <p dir="ltr">It’s likely that your contrast sensitivity has been tested if you wear glasses, which <a href="https://www.visioncenter.org/refractive-errors/contrast-sensitivity/" target="_blank" rel="noopener">involves</a> reading out black letters from a white chart which become less distinct across each row and from the top to the bottom of the chart.</p> <p dir="ltr">This test is different from the one usually used during eye exams, such as those you take to receive or renew your driver’s licence.</p> <p dir="ltr"><span id="docs-internal-guid-1da2f46d-7fff-d6ad-4d43-1e48a7736a86"></span></p> <p dir="ltr"><em>Image: Twitter</em></p>

Mind

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Often fooled by optical illusions? Here’s why

<p><span style="font-weight: 400;">If you have ever seen an optical illusion and wondered why you may have been tricked by it, you’re not the only one.</span></p> <p><span style="font-weight: 400;">Researchers interested in cognitive science and visual perception have used optical illusions to see how our brain works - even when we’re not being amazed or tricked by a deceptive image.</span></p> <p><span style="font-weight: 400;">“Illusions help us understand the rules our brain uses to create reality, based on the input it receives from our senses,” says Mark Williams, an honorary professor of cognitive science at Macquarie University.</span></p> <p><span style="font-weight: 400;">“What we actually see or hear or feel or taste or smell isn’t actually what’s out there, but what we think is out there.</span></p> <p><span style="font-weight: 400;">“Because we don’t see the world as it actually is, illusions help explain to us how we are creating the world we actually perceive.”</span></p> <p><span style="font-weight: 400;">This means that our brains don’t see the world wholly, instead responding to everything it perceives and filtering out what it doesn’t think is important.</span></p> <p><span style="font-weight: 400;">“Our sensory systems respond to the sum of all contextual information in which the relative information is more important than the absolute,” says Dr Spehar, a psychologist from the University of New South Wales</span></p> <p><span style="font-weight: 400;">“So for example, you perceive colour relative to the background, or you see orientation relative to the frame of reference.</span></p> <p><span style="font-weight: 400;">Let’s put our perceptions of reality to the test with this multicoloured illusion.</span></p> <p><strong>Is it moving?</strong></p> <p><img style="width: 500px; height: 375.2900232018562px;" src="https://oversixtydev.blob.core.windows.net/media/7843585/109a9c3cc8949eb4a12d252545fb759c.jpg" alt="" data-udi="umb://media/9693caf172e54a1e8d66f94106e45659" /></p> <p><em><span style="font-weight: 400;">Image: Wikimedia Commons</span></em></p> <p><span style="font-weight: 400;">Though this image appears to move, staring at the centre of the image makes it stop.</span></p> <p><span style="font-weight: 400;">This illusion, known as rotating snakes, triggers receptors in your eyes that detect movement in your peripheral vision.</span></p> <p><span style="font-weight: 400;">Dr Spehar says that though we don’t fully know how the illusion works, it appears to involve the differences in contrast between the black, white, and coloured areas.</span></p> <p><span style="font-weight: 400;">“The illusion has a lot of light and dark elements, of both high and low contrast scattered everywhere,” Dr Spehar says.</span></p> <p><span style="font-weight: 400;">“[These] stimulate motion-sensitive neurons in the periphery of our visual field.”</span></p> <p><span style="font-weight: 400;">Even when you blink or move your eyes, parts of the illusion are projected onto different parts of your eye, meaning that it appears to move in a clockwise or counterclockwise movement.</span></p> <p><em><span style="font-weight: 400;">Image: Wikimedia Commons</span></em></p>

Mind

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Test your brain with this colourful illusion

<p><span style="font-weight: 400;">Optical illusions can be a fun way to test your vision, and this latest one is no different. </span></p> <p><span style="font-weight: 400;">In the below image, created by David Novick, the levitating spheres might seem like they are red, purple, or green at first, but if you look closely, you will spot their real colour.</span></p> <p><span style="font-weight: 400;"><img style="width: 500px; height:281.11111111111114px;" src="https://oversixtydev.blob.core.windows.net/media/7841416/colour-ball.jpg" alt="" data-udi="umb://media/957db14472df4edb87fccdec9ca1c173" /></span></p> <p><span style="font-weight: 400;">The spheres are actually all the same shade of beige, and are an example of the phenomenon known as the Munker-White illusion.</span></p> <p><span style="font-weight: 400;">How does the illusion actually work?</span></p> <p><span style="font-weight: 400;">David Novick, who is also a professor of engineering education and leadership at the University of Texas, said it is because “our acuity for shape is better than our acuity for colour, which means that we perceive the shapes with more detail and the colours with less detail.”</span></p> <p><span style="font-weight: 400;">He told </span><a href="https://www.sciencealert.com/these-balls-aren-t-really-all-different-colors-here-s-what-s-going-on"><span style="font-weight: 400;">Science Alert</span></a><span style="font-weight: 400;"> that, though the outlines of the spheres look identical, which they are, “the colour sort of bleeds over, or assimilates, to adjacent spaces”.</span></p> <p><span style="font-weight: 400;">The illusion relies on the hue of the stripes in the foreground rather than the colours behind the spheres.</span></p> <p><span style="font-weight: 400;">It works as the colour of the spheres gets “pulled” closer to the colour of the stripes that cross over them in the foreground, which warp our perception of the actual hue of the spheres.</span></p> <blockquote class="twitter-tweet"> <p dir="ltr">There's a great article by <a href="https://twitter.com/NicolettaML?ref_src=twsrc%5Etfw">@NicolettaML</a> about my research on illusions now posted at <a href="https://twitter.com/LiveScience?ref_src=twsrc%5Etfw">@LiveScience</a>: <a href="https://t.co/45T2TnLOHG">https://t.co/45T2TnLOHG</a>.</p> — David Novick (@NovickProf) <a href="https://twitter.com/NovickProf/status/1395081119490617347?ref_src=twsrc%5Etfw">May 19, 2021</a></blockquote> <p><span style="font-weight: 400;">So, removing the crisscrossing stripes will also remove the illusion, leaving only identical beige balls behind.</span></p> <p><span style="font-weight: 400;">Novick shares around two new illusions every week to </span><a href="https://twitter.com/NovickProf?s=20"><span style="font-weight: 400;">his Twitter account</span></a><span style="font-weight: 400;">, and has found that some of his older posts will get rediscovered, go viral, and sometimes make the news.</span></p>

Mind

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Is it a beach or a door? Infuriating new optical illusion baffles internet

<p>A new optical illusion asking people whether they see a beach or a door has left the internet baffled.</p> <p>The photo, shared on Twitter by social app <a href="https://twitter.com/9GAG/status/1033927593752449025"><strong>9GAG</strong></a>, asks its followers: “Is this a door, or a beach?”</p> <blockquote class="twitter-tweet"> <p dir="ltr">Is this a door, or a beach?<br />Don't let this become the next 'Black and Blue Dress' please<a href="https://t.co/4HN5KOrUgu">https://t.co/4HN5KOrUgu</a> <a href="https://t.co/lhqYgTAjd8">pic.twitter.com/lhqYgTAjd8</a></p> — 9GAG (@9GAG) <a href="https://twitter.com/9GAG/status/1033927593752449025?ref_src=twsrc%5Etfw">August 27, 2018</a></blockquote> <p>If you look at the photo vertically, the image looks like a section of a door: the blue being part of the door, the turquoise the frame, and the cream the concrete surround.</p> <p>But once you flip the image horizontally, it looks like a stretch of beach with a crystal blue sky, turquoise waters and cream coloured sand.</p> <p><img width="634" height="414" src="https://i.dailymail.co.uk/i/newpix/2018/08/30/10/4F85F61B00000578-6113599-image-a-9_1535621318449.jpg" class="blkBorder img-share b-loaded" id="i-5f88ec537d8c576"/></p> <p>The image quickly divided social media users, with both sides putting forward compelling evidence for their side.</p> <p>It is not yet known whether the image is a beach or a door – but what do you see?</p> <p> </p>

Art

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This baffling optical illusion tests your eyesight

<p>The latest brainteaser sweeping the internet is a red circle – but for some there's more to it.</p> <p>The optical illusion, posted on Playbuzz, tests your eyesight.</p> <p>It asks you to look for the hidden image inside the circle.</p> <p style="text-align: center;"><img width="498" height="420" src="https://oversixtydev.blob.core.windows.net/media/7817562/in-text-1_498x420.jpg" alt="In Text 1 (2)"/></p> <p>Some can see an outline of a figure, while others see a detailed image.</p> <p style="text-align: center;"><img width="499" height="428" src="https://oversixtydev.blob.core.windows.net/media/7817563/in-text-2_499x428.jpg" alt="In Text 2 (1)"/></p> <p>Last week, a test touted as a <span style="text-decoration: underline;"><strong><a href="http://www.stuff.co.nz/life-style/78413947/this-logic-puzzle-for-children-is-stumping-plenty-of-adults" target="_blank">straightforward logic puzzle for children</a></strong></span> had plenty of adults scratching their heads.</p> <p>The brainteaser challenges kids to answer nine questions based on a sketch of a campground, in order to test their powers of observation, logic and reasoning.</p> <p>Then there was the string of animals hiding among other animals tests, created by Hungarian cartoonist Gergely Dudas, also known as Dudolf.</p> <p>​Dudolf created a find the cat among the owls puzzle.</p> <p style="text-align: center;"><iframe src="https://www.facebook.com/plugins/post.php?href=https%3A%2F%2Fwww.facebook.com%2Fthedudolf%2Fposts%2F720342174734364%3A0&amp;width=500" width="500" height="614" style="border: none; overflow: hidden;" scrolling="no" frameborder="0" allowtransparency="true"></iframe></p> <p>The puzzles swept the internet, bamboozling Facebook users.</p> <p><em>Republished with permission of <a href="http://www.stuff.co.nz/" target="_blank"><strong><span style="text-decoration: underline;">Stuff.co.nz.</span></strong></a></em></p>

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The optical illusion that has stumped the internet – can you work it out?

<p><span>Optical illusions have the uncanny ability to manipulate our eyes to see things in a certain way.</span></p> <p><span>A new optical illusion is warping people’s minds with an image of a street.</span></p> <p><span>Internet users are struggling to comprehend two pictures posted on image sharing site Imgur, that claim to be the exact same photo.</span></p> <p style="text-align: center;"><span><img width="500" height="295" src="https://oversixtydev.blob.core.windows.net/media/7268009/1_500x295.jpg" alt="1 (87)"/><br /></span></p> <p><span>“This is the same photo, side by side,” the caption reads. “They are not taken at different angles.”</span></p> <p><span>“Both sides are the same, pixel for pixel.”</span></p> <p><span>However, the majority of people believe that the photos are taken from two different angles.</span></p> <p><span>“For me it looks like the roads are going in different directions, like one road forking off,” wrote one Reddit user.</span></p> <p><span>“For me my first reaction was the right side was on an angle and the left was more of a straight shot,” said another.</span></p> <p><span>One person has explained how this optical illusion is playing tricks on the viewer.</span></p> <p><span>“It's because the 2 streets come together at the bottom of the pictures,” wrote one user on Reddit.</span></p> <p><span>“Your brain tries to perceive this as one image with a fork in the road and therefore the street in the picture on the left must be at a different angle than the picture on the right.”</span></p> <p><span>For those who struggle to believe that they are the same photo, one user decided to place both images on top of each other to see what would happen.</span></p> <p style="text-align: center;"><span><img width="435" height="647" src="https://oversixtydev.blob.core.windows.net/media/7268011/2.png" alt="2 (61)"/></span></p> <p><span>Did you initially think that the photos looked different to each other? Let us know in the comments below.</span></p> <p><em><span>Image credit: Reddit</span></em></p>

Mind

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The incredible optical illusions of the 19th century

<p>Before the creation of movies, cartoons and photography, the art of optical illusions was captivating people around the world.</p> <p>Beginning in the 1830s, optical illusions were specifically created to entertain and were designed to be spun, twirled, reflected or illuminated for the illusion to work.</p> <p>In 1833, a French publisher started selling optical illusions to the public due to an idea by Joseph Plateau. The devices that would feature optical illusions were known as phénakisticopes, a French interpretation of the Greek word for cheating vision.</p> <p style="text-align: center;"><a href="https://giphy.com/gifs/iPAEzqIxtzyZq?utm_source=iframe&amp;utm_medium=embed&amp;utm_campaign=Embeds&amp;utm_term=http%3A%2F%2Fdustyoldthing.com%2Foptical-illusions-19th-century%2F" target="_blank" class="_2XBDTIVigBJDybhZvL-hU3"> <img src="https://media.giphy.com/media/iPAEzqIxtzyZq/200w.webp" class="nlSABoG9CSaJpsufv8WW9 _3vYn8QjoEvrXxHyqdn9ddZ _2XBDTIVigBJDybhZvL-hU3" id="gif"/></a></p> <p>Plateau was fascinated by movement and how the human eye discerned it. He created the device less than 10 years before he went completely blind himself, but the concept would be reproduced again and again. The name was altered throughout the years, until it was later known as zoetropes.</p> <p style="text-align: center;"><a href="https://giphy.com/gifs/animation-lsd-phenakistoscope-8Ag869uLpWjV6?utm_source=iframe&amp;utm_medium=embed&amp;utm_campaign=Embeds&amp;utm_term=http%3A%2F%2Fdustyoldthing.com%2Foptical-illusions-19th-century%2F" target="_blank" class="_2XBDTIVigBJDybhZvL-hU3"> <img src="https://media.giphy.com/media/8Ag869uLpWjV6/200w.webp" class="nlSABoG9CSaJpsufv8WW9 _3vYn8QjoEvrXxHyqdn9ddZ _2XBDTIVigBJDybhZvL-hU3" id="gif"/><br /></a></p> <p>The principles of zoetrope technology became the foundation for motion pictures and film animations.</p> <p style="text-align: center;"><a href="https://giphy.com/gifs/zoetrope-Hq7aL7e3mQ3iU?utm_source=iframe&amp;utm_medium=embed&amp;utm_campaign=Embeds&amp;utm_term=http%3A%2F%2Fdustyoldthing.com%2Foptical-illusions-19th-century%2F" target="_blank" class="_2XBDTIVigBJDybhZvL-hU3"> <img src="https://media.giphy.com/media/Hq7aL7e3mQ3iU/200w.webp" class="nlSABoG9CSaJpsufv8WW9 _3vYn8QjoEvrXxHyqdn9ddZ _2XBDTIVigBJDybhZvL-hU3" id="gif"/></a></p>

Art

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This McDonald's optical illusion is not for the faint of heart

<p>Most people only ever associate the golden arches with burgers and fries, but if this story is anything to go by soon McDonald’s is going to be synonymous with tests of the mind!</p> <p>McDonald’s shared the following optical illusion on its Facebook page in the UK, and it certainly isn’t for the faint of heart. Can you spot the hidden image in this picture?</p> <p><img width="500" height="500" src="https://oversixtydev.blob.core.windows.net/media/44539/mcdonalds-in-text_500x500.jpg" alt="Mc Donalds -in -text"/></p> <p><em>Image credit: Facebook / McDonald's UK</em></p> <p>Having trouble? You’re not the only one.</p> <p>“As if my eyes weren't bad enough... spent a good 10 mins looking at this now everything I look at looks like a zebra on steroids,” joked one.</p> <p>“That's just messed up my eyes, thanks McDonald's,” wrote another.</p> <p>So how do you solve this brain teaser? Well, a couple of McDonald’s have posted some handy hints for people who don’t want to succumb to eye-strain.</p> <p>“Just tilt your phone backwards so you see it at an angle, lol, no eye strain required,” suggested one.</p> <p>“Tip to anyone trying to strain to read this - just out stretch your arm and hold your phone far away from your face,” added another tipster.</p> <p>So, what’s the hidden image?</p> <p>Well, it’s a message that says, “Bring McNuggets”.</p> <p>Did you solve this optical illusion?</p>

Mind

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This is actually an optical illusion

<p>A tile company has created an optical illusion in their hallway to discourage visitors from running.</p> <p>British firm Casa Ceramica used a clever combination of black and white tiles to make the floor along its hallway floor look as though it is dangerously uneven, giving the impression that you could fall if you put one foot wrong.</p> <p><img src="https://pbs.twimg.com/media/DKRQKLQXUAAv4EC.jpg:large" class="media-image" style="width: 491px; height: 368px; margin: 0px auto; display: block;"/></p> <p>A photo of the hallway quickly went viral with many people commenting that it looks too dangerous to walk down.</p> <p>However, the floor along the hall is in fact a completely flat surface.</p> <p>Duncan Cook, the director of Casa Ceramica, shared a picture of the other side of the hallway on Twitter to reveal how they had created the illusion.</p> <p>The tiles were laid in a curved pattern which can be seen from a different angle.</p> <blockquote class="twitter-tweet"> <p dir="ltr">Correct, here is the view back the other way <a href="https://twitter.com/casaceramica?ref_src=twsrc%5Etfw">@casaceramica</a> <a href="https://t.co/c6LaVIw1sW">pic.twitter.com/c6LaVIw1sW</a></p> — Duncan Cook (@DuncanCook10) <a href="https://twitter.com/DuncanCook10/status/911127680241881088?ref_src=twsrc%5Etfw">September 22, 2017</a></blockquote> <p>Duncan said the illusion looked much more realistic on camera than it is in person, tweeting: “It doesn't look as bad to the human eye, only really come to life through the camera.”</p> <blockquote class="twitter-tweet"> <p dir="ltr">They are actual tiles <a href="https://t.co/7HvTqz9jHP">pic.twitter.com/7HvTqz9jHP</a></p> — Casa Ceramica (@casaceramica) <a href="https://twitter.com/casaceramica/status/911324299767767040?ref_src=twsrc%5Etfw">September 22, 2017</a></blockquote> <p>To prove his point further, he also shared a video of himself walking across the floor without stumbling, proving that is entirely even.</p> <blockquote class="twitter-video"> <p dir="ltr"><a href="https://twitter.com/DrGBuckingham?ref_src=twsrc%5Etfw">@DrGBuckingham</a> <a href="https://twitter.com/hashtag/tiles?src=hash&amp;ref_src=twsrc%5Etfw">#tiles</a> <a href="https://twitter.com/hashtag/illusion?src=hash&amp;ref_src=twsrc%5Etfw">#illusion</a> <a href="https://twitter.com/hashtag/Manchester?src=hash&amp;ref_src=twsrc%5Etfw">#Manchester</a> <a href="https://twitter.com/hashtag/lovetiles?src=hash&amp;ref_src=twsrc%5Etfw">#lovetiles</a> <a href="https://t.co/kvopveYXe3">pic.twitter.com/kvopveYXe3</a></p> — Casa Ceramica (@casaceramica) <a href="https://twitter.com/casaceramica/status/917748057432903681?ref_src=twsrc%5Etfw">October 10, 2017</a></blockquote> <p>Despite the company's explanation, many internet users admitted they would still be too scared to walk across the floor.</p>

Mind

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What optical illusions reveal about you

<p>Kim Ransley is a PhD student and Dr Alex Hocombe, an Associate Professor, from the School of Psychology at the University of Sydney.</p> <p>Visual illusions show us that we do not have direct access to reality. They can also provide an inkling of the mental processing that delivers our experience of the viewable world.</p> <p>Indeed, it is the processing happening inside our brains that is the basis for many illusions. Rather than delivering information from our eyes in nearly raw form as a camera would, the brain tries to determine what is actually out there – what are the shapes and the objects in the scene?</p> <p>When the information entering the eye is ambiguous, the brain must make educated guesses. The three displays below demonstrate this in rather delightful ways.</p> <p><strong>The illusion of sex</strong></p> <p><img width="458" height="232" src="https://cdn.theconversation.com/files/178966/width754/file-20170720-23985-1ulwpzf.png" style="display: block; margin-left: auto; margin-right: auto;"/></p> <p style="text-align: center;"><em> <span class="caption">The Illusion of Sex.</span> Imaege credit: <span class="attribution"><a href="http://www.richard-russell.net/" class="source">Richard Russell</a></span></em></p> <p>In this illusion by Richard Russell, the same face appears to be female when the skin tone is made lighter (left image) and male when the skin tone is made darker (right image).</p> <p>The illusion works because changing the skin tone affects the face’s contrast – the difference between the darkest parts of the face (lips and eyes) and lightest parts (the skin).</p> <p>Few would regard facial contrast as a defining feature of either sex, but in fact, contrast <a href="http://www.sciencedirect.com/science/article/pii/S0047248400904032">is on average higher</a> <a href="https://link.springer.com/article/10.1007/s40750-017-0068-x">in females than males</a>.</p> <p>Even without consciously knowing it, our brains are attuned to the difference in contrast between the sexes, and so contrast is one cue the brain uses to determine gender. When other cues are removed, contrast can be the deciding factor.</p> <p>Perhaps the most interesting thing about the illusion is that the contrast doesn’t simply help us work out the sex of the face - it provides an experience of “seeing” a face that is male or female. The use of the contrast cue is done by unconscious processes.</p> <p>The image in our mind’s eye has incorporated information that we already hold, and uses this to resolve ambiguity in the image.</p> <p><strong>The coffer illusion</strong></p> <p><img width="438" height="438" src="https://cdn.theconversation.com/files/178746/width754/file-20170719-25421-b18r67.jpg" style="display: block; margin-left: auto; margin-right: auto;"/></p> <p style="text-align: center;"><em><span class="caption">The Coffer Illusion. Image credit:</span> <span class="attribution"><a href="https://med.stanford.edu/profiles/anthony-norcia" class="source">Anthony Norcia</a></span></em></p> <p>The Coffer Illusion may initially appear as a series of sunken rectangular door panels, but after a few seconds, your brain’s representation of the image may “flip” to give you the experience of 16 circles.</p> <p>People have been fascinated by such ambiguous figures since at least <a href="http://www.psych.usyd.edu.au/staff/alexh/research/papers/NatureNewsAltschulerHolcombe.pdf">the time of the ancient Romans</a>.</p> <p>The Coffer Illusion plays on the fact that the visual brain is heavily geared towards <a href="https://dspace.mit.edu/bitstream/handle/1721.1/6241/AIM-340.pdf?sequence=2">identifying objects</a>. “Pixels” <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1363130/?page=1">are grouped</a> to form edges and contours, shapes, and <a href="https://theconversation.com/how-do-our-brains-reconstruct-the-visual-world-49276">finally objects</a>.</p> <p>Sometimes, as in the Coffer Illusion, there is no “right” grouping because the image is inherently ambiguous. Two different groupings make sense – a single set of horizontal lines can either form a circle, or be the intersection between two rectangles.</p> <p>For most people, the grouping into rectangles initially dominates. This may be because rectangles (including the ones we see in door panels) are often more common than circles in our daily environment, and so the brain favours the grouping that delivers rectangular shapes.</p> <p><strong>Mask of love</strong></p> <p><img width="419" height="468" src="https://cdn.theconversation.com/files/178748/width754/file-20170719-10341-1upggc0.png" style="display: block; margin-left: auto; margin-right: auto;"/></p> <p style="text-align: center;"><em><span class="caption">Mask of Love. Image credit:</span> <span class="attribution"><a href="http://www.archimedes-lab.org/presentation.html" class="source">Gianni A. Sarcon</a></span></em></p> <p>In Gianni Sarcone’s Mask of Love, a Venetian mask can be seen to contain either a single face or the faces of two people kissing.</p> <p>The illusion operates in a similar way to the Coffer illusion – the contours in the image can be grouped in two different ways, leaving the brain uncertain about which to choose.</p> <p>The difference with this illusion is that, at least for some people, neither grouping tends to dominate. The image appears to flip reasonably freely between the two plausible alternatives.</p> <p>Flipping is an interesting way for the visual brain to deal with ambiguity. Other parts of the brain <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.2044-8295.1931.tb00597.x/full">have mechanisms</a> that average ambiguous information, or simply choose the most likely representation and <a href="https://search.proquest.com/openview/fc37c99341aa735ad8b2bd0a103cf892/1?pq-origsite=gscholar&amp;cbl=40569">ignore all alternatives</a>.</p> <p>Flipping has the advantage of providing coherent information about what the image could be, which might be useful to know in working out how to interact with the world.</p> <p>Together, these three illusions demonstrate that visual processing is highly geared towards identifying what an object is.</p> <p>The representation in our mind’s eye is designed to be functional, so rather than delivering a mess of pixels, we have elaborate visual experiences of circles, rectangles, faces, and even the gender of faces.</p> <p>Kim, Alex and several other scientists will be showcasing illusions at <a href="http://whatson.sydney.edu.au/events/published/a-night-of-illusions">A Night of Illusions</a> on August 18-19 at 107 projects, Redfern, Sydney.</p> <p><em>Written by Kim Ransley and Alex Hocombe. First appeared on <strong><span style="text-decoration: underline;"><a href="https://theconversation.com/three-visual-illusions-that-reveal-the-hidden-workings-of-the-brain-80875">The Conversation.</a></span></strong></em> </p>

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