{"id":117,"date":"2018-04-27T05:54:18","date_gmt":"2018-04-27T05:54:18","guid":{"rendered":"https:\/\/live-optics-wp.pantheonsite.io\/oscoutreach\/?p=117"},"modified":"2025-03-17T13:03:03","modified_gmt":"2025-03-17T20:03:03","slug":"hollow-face-illusions","status":"publish","type":"post","link":"https:\/\/wp.optics.arizona.edu\/oscoutreach\/hollow-face-illusions\/","title":{"rendered":"Hollow Face Illusions"},"content":{"rendered":"\r\n<p><strong>Overview<\/strong>: Our eyes, and brain are used to seeing objects in a certain way, ie noses stick out. When our eyes see something not conforming to the norm our brain tells us &#8220;that can&#8217;t be right&#8221; and it &#8220;corrects&#8221; it to what it believes we should be seeing.<\/p>\r\n\r\n\r\n\r\n<p>\u200b\u200b<strong>Supplies<\/strong>: Einstein inverted mask, printed Gardner&#8217;s Dragon templates, scissors, tape<\/p>\r\n\r\n\r\n\r\n<p><strong>Objectives<\/strong>: How do our eyes perceive depth?<\/p>\r\n\r\n\r\n<hr class=\"wp-block-separator has-css-opacity\" \/>\r\n\r\n\r\n<p><strong>Setup:<\/strong><\/p>\r\n\r\n\r\n\r\n<ul class=\"wp-block-list\">\r\n<li>Place the mask of Einstein&#8217;s face on top of the light source with the inverted side facing the audience (his nose is furthest away from them).<\/li>\r\n\r\n\r\n\r\n<li>Try to match the height to as eye-level as possible.<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n<p><strong>How to run the demo:<\/strong><\/p>\r\n\r\n\r\n\r\n<ul class=\"wp-block-list\">\r\n<li>Turn on the light source, move from side-to-side, crouching and standing, and watch Einstein&#8217;s eyes follow you!<\/li>\r\n<\/ul>\r\n\r\n\r\n<div class=\"wp-block-image\">\r\n<figure class=\"aligncenter\"><img loading=\"lazy\" decoding=\"async\" width=\"450\" height=\"253\" class=\"wp-image-301\" src=\"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-content\/uploads\/sites\/75\/2018\/04\/Einstein.gif\" alt=\"\" \/><\/figure>\r\n<\/div>\r\n\r\n\r\n<ul class=\"wp-block-list\">\r\n<li>For the dragon (and other animals) templates, look at the eyes and move side to side like with the Einstein mask.<\/li>\r\n<\/ul>\r\n\r\n\r\n\r\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-9d6595d7 wp-block-columns-is-layout-flex\">\r\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis: 50%\"><div class=\"wp-block-image\">\r\n<figure class=\"aligncenter is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"300\" height=\"200\" class=\"wp-image-114\" style=\"aspect-ratio: 1.5;width: 372px;height: auto\" src=\"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-content\/uploads\/sites\/75\/2018\/04\/GardnersDragon-300x200.jpg\" alt=\"\" srcset=\"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-content\/uploads\/sites\/75\/2018\/04\/GardnersDragon-300x200.jpg 300w, https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-content\/uploads\/sites\/75\/2018\/04\/GardnersDragon.jpg 600w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/figure>\r\n<\/div><\/div>\r\n\r\n\r\n\r\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis: 50%\"><div class=\"wp-block-image\">\r\n<figure class=\"aligncenter\"><img loading=\"lazy\" decoding=\"async\" width=\"450\" height=\"253\" class=\"wp-image-303\" src=\"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-content\/uploads\/sites\/75\/2018\/04\/Dragon.gif\" alt=\"\" \/><\/figure>\r\n<ul>\r\n<li>Tip: If people are having trouble seeing the character eyes follow them have the person close one of their eyes and try again.<\/li>\r\n<\/ul>\r\n<\/div><\/div>\r\n<\/div>\r\n\r\n\r\n<hr class=\"wp-block-separator has-css-opacity\" \/>\r\n\r\n\r\n<p><strong>What&#8217;s Happening?<\/strong><\/p>\r\n\r\n\r\n\r\n<p>In order to perceive depth and distance, our brains use various cues to make a &#8220;best guess&#8221;.\u00a0 These cues can be features like shadows, distortion, relation to objects at a known distance, or elevation.<\/p>\r\n\r\n\r\n\r\n<p>When looking at an object like a face, our brains typically expect the contour to push outwards, as humans and animals that we see have faces with a convex shape.\u00a0 In addition, we generally expect lighting to come from above as with sunlight and room lighting.\u00a0 Our brains can gather information on the contour as the sharp transitions of lighting, and the gradual shift in shading gives us information about depth. So when an inverted object is illuminated from below, our brains perceive this as a 3D object illuminated from above.<\/p>\r\n\r\n\r\n\r\n<p><span style=\"text-decoration: underline\">Try this<\/span>:<\/p>\r\n\r\n\r\n\r\n<ul class=\"wp-block-list\">\r\n<li>Having trouble seeing the illusion? Look through a camera or try taking a video.<\/li>\r\n\r\n\r\n\r\n<li>It helps some people to close one eye at first, and be sure to view the object at eye level.<\/li>\r\n\r\n\r\n\r\n<li>To make your own Gardner&#8217;s Dragon, print out the following template and follow the instructions that are written around the outside.\u00a0 It takes a little bit of practice to get the correct mountain\/valley folds around the face, so remember that the eyes should be pointing inward. <strong><a href=\"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-content\/uploads\/sites\/75\/2018\/04\/dragon_template.pdf\">Gardner&#8217;s Dragon Template<\/a><\/strong><\/li>\r\n<\/ul>\r\n\r\n\r\n<hr class=\"wp-block-separator has-css-opacity\" \/>\r\n\r\n\r\n<p><strong>Learn more:<\/strong> (external links)<\/p>\r\n\r\n\r\n\r\n<p><a href=\"https:\/\/www.youtube.com\/watch?v=qQnBjeqw1uQ&amp;list=PL6DwVv2hudGZHkS34wAV-4NQ7Fw3zPTxf&amp;index=16\">Hollow Face demo<\/a><\/p>\r\n\r\n\r\n\r\n<p><a href=\"https:\/\/youtu.be\/ORoTCBrCKIQ\">BBC Einstein Mask Video<\/a><\/p>\r\n\r\n\r\n\r\n<p><a href=\"https:\/\/www.optics.arizona.edu\/sites\/default\/files\/2022-07\/Hollow%20Face%20Pamphlet.pdf\">Hollow Face take home pamphlet<\/a><\/p>\r\n","protected":false},"excerpt":{"rendered":"<p>People&#8217;s faces have features pointing outward. What happens when we look at a face with features pointing inward?<\/p>\n","protected":false},"author":43,"featured_media":114,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[],"class_list":["post-117","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-optical-illusion"],"_links":{"self":[{"href":"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-json\/wp\/v2\/posts\/117","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-json\/wp\/v2\/users\/43"}],"replies":[{"embeddable":true,"href":"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-json\/wp\/v2\/comments?post=117"}],"version-history":[{"count":20,"href":"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-json\/wp\/v2\/posts\/117\/revisions"}],"predecessor-version":[{"id":1896,"href":"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-json\/wp\/v2\/posts\/117\/revisions\/1896"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-json\/wp\/v2\/media\/114"}],"wp:attachment":[{"href":"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-json\/wp\/v2\/media?parent=117"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-json\/wp\/v2\/categories?post=117"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wp.optics.arizona.edu\/oscoutreach\/wp-json\/wp\/v2\/tags?post=117"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}