The Tricks of Perception – Optical Illusions Audrey Lee Eyes are called “the windows of the soul.” We rely on our eyes to see everything in the world. We believe what we see is true; the phrase “I see” has an equal meaning as “I understand,” which is a good example of how we trust our eyes. However, sometimes our eyes are not as smart as we think, which means we cannot trust them all the time. They are often deceived by visual tricks called “illusions,” including natural and artificial things. For example, you may have seen the well‐known duck‐
rabbit picture. (see fig.1) Then you may ask a couple of Fig. 1 Duck‐Rabbit (Ludwig Wittgenstein)
questions, “Why do I see illusions?” or “How can they trick me?” The answers of the questions are related not only to psychology, but also to geometry. There are many artists or designers that try to use illusions to mislead people. In fact, they often succeed. One of the marvelous graphic artists of optical illusions in the past is M.C. Escher. He used a lot of the techniques of illusions in his works, which combines geometry and graphics together. There are many different kinds of optical illusions. I will focus on two types, tessellation and the impossible figures, to analyze M.C. Escher’s works and answer the two questions above. Before we get into the magic world of illusions, we have to realize “how we see” first. There are some psychological theories are to explain the visual phenomena of illusion.
Don’t trust your eyes – The introduction of illusion According to the book that introduces Op Art, Lancaster writes that the world we see through our eyes “is a combination of vision and thought, for seeing and thinking are not independent.” We use our perception – our brain is able to deal with what we see and receive by our eyes and give a reasonable explanation from our previous experiences – to recognize the information that we see. We see things by our memory and knowledge about them; “…objects are not physically present they are represented…”(82‐83) Gestalt psychology is an interpretation of the way how we see. It “is a kind of psychological thinking that is primarily concerned with how the mind unifies and orders the perceptual environment,” claims Robert Wenger. (35) In the art and design field, artists often use gestalt principles to create visual tricks, especially Figure and Ground. Educator and web designer Tuck writes the definition of gestalt principles, which are the rules of visual perception in design, on Sixrevisions.com as below:
1. Figure and Ground – Andy Rutledge writes, “Our perception of the figure‐ground relationship allows us to organize what we see by how each object relates to others” There are a lot of visual pictures such as camouflage graphics and logos which use the principle. For instance, the negative space in Fedex logo between E and X shows an arrow, which means the service of Fedex express has high speed. (see Fig. 2) Fig. 2. Fedex logo (Fedex Company)
2. Similarity – People can group things when they look similar with each other. The “Dog Picture” shows the concept of the similarity. (see Fig. 3) The viewers may see a dog is drinking water near a river, and there is a tree at the upper left corner by combining the black and white blobs of the picture. The Fig. 3 Dog Picture (Tuck)
arrangement of the black and white blobs is related to our experience of the pattern of a dog, a tree, a river, and a road. Hence, our perception group these blobs together to become a picture.(Tuck) 3. Symmetry – People think that the symmetrical objects are balanced and united. Starbucks’ logo uses this principle. (see Fig.4) It seems stable, and it gives a feeling about a sense of safety of its product for people due to the symmetry of the logo.
Fig. 4 Starbucks Logo (Starbucks Company)
4. Closure – As literal meaning, it means ”we [the viewers] ‘close’ objects that are themselves not complete,” including the viewers’ perception of complete objects and the design. (Tuck) People can recognize each character as “A”, “V”, “V”, and “A”, but Fig. 5 AVVA Logo (“shahryaralex”)
in fact, there are simply different diagonal lines in this picture.(see Fig.5) People use their perception of closure to explain it as letters. 5. Proximity – which is “the concept underlying the concept of proximity is grouping.” For example, there are different kinds of grouping in the 2002 Europe Music Awards site. (see Fig. 6) The space is divided into two parts; there are two logos, MTV, and Europe Music Awards near the upper left corner, and several Fig. 6. 2002 Europe Music Awards site (Tuck)
small logos near the lower right corner. “The white space helps form the two groups, as do the two blue triangles in the corners.” The triangles show the relationship of the two groups, so they strengthen the meaning of them. (Tuck)
6. “Common Fate” ‐ Encyclopædia Britannica website indicates the definition of Common Fate “is a perceptual organization of movement. …[it] depends on movement and is quite striking when observed.” To illustrate, the cars in the picture show two “streams”. (see Fig.7) It is still a picture, which means it doesn’t Fig. 7 The cars picture (Tuck)
move, but people may feel the movement of the cars. People may feel the cars are going from the bottom to the top on the right “stream”. Moreover, the left “stream” is going from top to the bottom. (Tuck)
Sidney Cohen points out, “An illusion is an error in seeing based upon some sensory cue.” Lancaster claims that optical illusions make “distortions” to lead people to misunderstand the real thing. Distortions are divided into two groups. One is viewers’ perception. For example, you can see the Necker cube, “an ‘ambiguous’ figure,” from different angles, then you would get two interpretations from this cube. The viewers’ perception controls what the Fig. 8 The Necker cube. (Lancaster 86)
figure looks like. (see Fig. 8) The other one is the “impossible” figures, which means that they cannot exist in the world. The figures are rendered on a two‐
dimensional plane, but our perceptual system interprets them as three‐dimensional figures. The viewers have two solutions by seeing them from different sides, but the two different solutions Fig. 9 Impossible Figure(Lancaster 87)
blend together as one figure so that they confuse people. (see. Fig. 9) (86‐87) The magic world of illusion – M.C. Escher’s artworks M.C. Escher (1898‐1972) was a Dutch graphic artist who was proficient in using optical illusions in the twentieth century. I will analyze the two kinds of his optical illusions examples by using the criteria of gestalt psychology I’ve mentioned above. In his work “Sky and Water I”, the viewers can see two ambiguous images which are fishes and birds.(see Fig. 10) Escher’s works not only use figure and ground perception and similarity, but also focus on tessellations (or tiling), which is a geometric term. The definition of tessellation “ is covering of a surface by identical tiles without overlaps or gaps,” write Ahuja and Loeb.(41) The concept of tessellation is related to M.C. Escher’s explanation about his title of essay “The regular division of the plane:” A Plane, which should be considered limitless on all sides, can be filled with or Fig. 10 Escher: Sky and Water I, June 1938 (Escher) divided into similar geometric figures that border each other on all sides without leaving any ‘empty spaces’. This can be carried on to infinity according to a limited number of systems.(156‐157) He also used repetition and multiplication to create a sense of infinity. In the words of Ernst, he was interested in the regular division of the plane more than other works that he did. (141) Schattschneider thinks that there are some geometric rules to analyze the regular division of the plane. All the complex shapes come from the simple polygons in the geometric grid. Escher showed three geometric motions, including translation, reflection, rotation, and glide‐reflection to explain “how each of these motions can move a simple figure to a new position and create a replica of it.” (see Fig.11) (33) Fig. 11 Geometric motions, Translation, Reflection, Glide‐reflection, and Rotation from left to right. (Schattschneider 34)
Escher referred to his working process from the beginning to the end. (see Fig. 12) First, he begin with a gray plane, and then he devided it to many squares by parallel lines, so he can have a basic form of the work. Next, he chose translation to create tessellations in this example. Finally, it became more and more complicated in details until the last picture. (94‐98) Fig. 12 Working process of Escher’s work. (Escher 97)
How can we make it? We can see some rules of tessellations from this example. In fact, the black figures and the white figures are the same, but Escher uses different animals to present them so that they look different. Through patterns 5 and 6, it’s easy to figure out the process. First, the geometric shapes need to be decided on the plane such as rectangle, pentagon, or hexagon… Second, when the shapes are cut from one edge, they have to be moved to the opposite side as the same shapes. See one shape of the pattern 6, a triangle is cut from the left side, and it is moved to the right side. Third, we can repeat the same thing again and again to create the sense of infinity. Finally, we can think about what these shapes look like or what they can be, then add details on them to finish the tessellation. Fig. 13 Escher: Horseman (Escher 110)
We also can use different geometric motions to change directions and make more difference. (see Fig. 13) Therefore, in his tessellation works, although they seem complex, we are able to find geometric systems in them, and then crack the tricks. Another example I would like to talk about is impossible figures. The impossible figures confuse people between the two dimensional planes and three‐dimensional objects. In other words, they can be created on a picture plane, but they can’t exist in the real world. When they are made, people can only be deceived by one particular angle. “As soon as the observer moves, the Fig. 14 The Necker cube. (Lancaster 86) figure falls apart,” writes Teuber. (160) As I mention above, the Necker cube, the ambiguous figure, provides two kinds of solutions for people, it depends on the people’s perception. Fig. 15 Hyzer’s illusion (Pappas 13)
The impossible figures are the combinations of the two solutions. (see fig.14, 15) Escher showed his inspiration in his book, Escher on Escher, “The reality around us. The three dimensional world surrounding us, is too ordinary, too boring, too common. We [people] hanker after the unnatural or the supernatural, the impossible, the miraculous…” (135) Escher was obsessed with these perceptual experiments on the paradox of geometric configurations. His work “Waterfall”, the lithograph of 1961, is based on Penrose’s triangle, which seems to form a spatial object. (see. Fig.16, 17) There is nothing wrong at the corner of the three bars. However, something wrong happens between the connections. Escher infused this work with the impossible feature. (Ernst 148) The water Fig. 16 Escher: Waterfall, 1961 (Escher)
Fig. 17 Penrose’s Triangle (Lancaster 87)
flows between the foreground and the background, and back and forth. It flows forever. Another his lithograph work “Belvedere” of 1958 has relevance to the rib‐cube. (see Fig.15, 18) Fig. 18 Escher: Belvedere, 1958 (Escher)
However, according to Ernst, Escher hid part of the impossible cuboid in this work. The position of the cuboid in the center is not very clear, “the horizontal planes are depicted as being long and narrow, so that the center is free and the Fig. 19 (Ernst 133)
conflicting crossing of the two figures ‘Y’ [shape] are far apart near the border of the cuboid.” The original concept is on figure 19; through the process on figure 19 and 20, we can find some clues to analyze the work. “By building heavy and detailed blocks on top of the cuboid and under it [Fig. 20] the reality of the whole picture is reinforced while at the same time retaining its strangeness.” In Fig. 20 (Ernst 133)
addition, the woman on the top floor and the man on the middle floor are looking in vertical directions, which strengthen the sense of strangeness. (132‐133) After the amazing truth ­ Conclusion People often tend to believe their eyes. Our perception often turns impossible things to possible, so that’s why illusions can catch people’s eyes. M.C. Escher created a new vision of art in twentieth century. He didn’t create illusions, but he brought geometry, illusions, and art together. Not only do many researchers analyze his artworks, but his concepts of illusions are also spread all over the world and inspire many modern artists and designers. Nowadays, illusions are broadly applied in many different fields such as street art, advertisements, architecture, and graphics. You can easily be attracted into the magic would of illusions. The importance of Escher’s illusion works cannot be overemphasized. Though the brief information of Gestalt psychology and Escher’s examples, you may have some ideas about how I see illusions, how they can trick me, and how I can make them now. Illusions enrich people’s lives and make the world not become boring. Therefore, if you see illusions on the street next time, you can enjoy them and realize their tricks.