Visual Perception Front page

An Introduction to Visual Perception! What is visual perception? “visual perception is the end product of vision” It can be described as the way the brain interprets what the eyes see. George The brain

THE BRAIN The brain receives information from the retina, then using a hierarchical method processes this information using different parts of the brain e.g. lateral geniculate nucleus and the primary and secondary visual cortex of the brain. The main problem with visual perception is that it is not simply a translation of the image seen by the retina, making it difficult for scientists to explain what we actually see. Ryan The brain

This can be altered by previous experiences. The Chairs theory It can effect the way you see a situation. The Taxi theory It is used in media to make you have the opinion of someone that they want you to have. The Bad guys/good guys theory George

Human vision is not the only way the world is seen, Animals see the world in different ways. some animals don’t even see the world but rely on other senses e.g. bats and dolphins Flies have what’s known as composite eyes, a TV run at 25 frames per second but to a fly this is very slow. birds such as hawks can see up to 8 times further than a human. The range of distance is measured in dioptres, a child’s is 14, an old persons is 1, however a diving bird’s vision is 50 dioptres. field of vision also is limited on a human to between 160-240, where as a hare’s field of vision is 360. Different creatures vary the amount of brain is dedicated to vision, the octopus dedicates 50% to sight but we still don’t know how other creatures make sense of what there eyes see. No single creature can see all what others can. We forget that the human world of vision is only one such world. Ryan

Homo significans The world is seen in different ways by different creatures, as humans we put a large emphasis on visuals. We do not always believe our eyes, we know that a pencil in a glass jar will look bent and that a moon closer to the horizon will appear bigger and that there are such things as optical illusions. Humans as a species are driven by a desire to find meaning. This relates to the title, because as humans we are all “homo significans”- meaning makers. This is proved with a few simple shapes and lines, that the mind strives to find meaning in. What do you see here: Your more likely to see five pairs close together than 4 pairs more spaced with a line either side spare. We do this because the brain puts the closer objects together. Ryan

Hermann Von Helmholtz Hermann Von Helmholtz, seen as the founder of visual perception studies believed vision was a form of unconscious inference, (Inference is the act or process of deriving a conclusion based solely on what one already knows) Two well known assumptions are that light comes from above and that objects are viewed from above, not below. Visual illusions are where this process goes wrong e.g… Ryan herman

The Scintillating grid illusion Black spots will seem to appear very quickly at the intersections.

Optical illusion Focus on the black dot and move your head back and forth This creates the illusion that two circles are moving Ryan

Gestalt Theory The Gestalt Theory originally came about in the 1890’s. Gestalt is German for “Shape/Form/Likeness” There are 3 main Gestalt psychologists: Max Wertheimer (Is credited as the founder of the movement of Gestalt Psychology) Wolfgang Köhler Kurt Koffka The concept of Gestalts Psychology was originally foundered by an Austrian psychologist called Christian Freiherr von Ehrenfels The major problem with the Gestalt laws and principles are that they are mainly descriptive and not explanatory. Sarah

The Gestalt Principles can be split into 3 groups: Gestalt Theory The Gestalt Principles can be split into 3 groups: Figure and Ground Similarity, Proximity, Common Fate and Good Continuity Closure, Area and Symmetry Sarah

Gestalt Theory FIGURE AND GROUND Figure and Ground explains how we put different elements together to make one scene or a whole image. “Figure” is the more dominant shape. “Ground” can be referred to as the Background. What do you see this image as? A Goblet on a Black background A Black Silhouetted Profile on a White background. Once you have identified the figure, the rest of the image becomes the ground.   Camouflage is most likely a breakdown in the figure ground perception. When the dominant shape is so much like the ground it disappears from view. Can you spot the bird? The most famous “Figure and Ground” image is the one by the Danish psychologist Edgar Rubin. Sarah

Gestalt Theory SIMILARITY When we have similar objects of size, shape and colour again we form groups. This image is grouped together Squares and Circles by colours Sarah

Gestalt Theory PROXIMITY When objects which are closer to each other we tend to associate them together to form groups. You will see columns rather than You will see rows rather than rows columns Real life example. MTV Music awards. We group this image into 2 parts, the top left this shows us this is the MTV music awards, and the bottom right which groups together the sponsors of the awards. Sarah

Gestalt Theory COMMON FATE Objects which are facing the same direction or appear to be travelling in the same direction are usually grouped together. The arrows which are pointing in a Again the lines facing upwards tend common direction are usually grouped to be grouped together. together. Sarah

Gestalt Theory CONTINUITY Seeing things as a whole is important however seeing in a whole is not necessarily what we are meant to see. What do you see here? Sarah

Gestalt Theory CONTINUITY Seeing things as a whole is important however seeing in a whole is not necessarily what we are meant to see. What do you see here? Well there are two answers. Continuity makes us see 2 lines crossing BUT Is it actually 4 lines, A-O, O-D, C-O and O-B Sarah

Gestalt Theory CLOSURE If we have a large pattern with missing components we tend to fill in the missing parts to create the image we actually see. When joined you can see a triangle. This image can be seen as an “S” shape Looking at this object we tend to form a 3D sphere. If you look closely this image looks like the snake. These two images can be closed together to form a circle and a square. Real Life example. WWF Logo / IBM Logo This image can be closed This image creates the to make a panda illusion of 3 letters, I, B and M Sarah

Gestalt Theory AREA This principle shows us that when areas are overlapping, the smallest area is seen as the figure and the larger is the ground. When we look at this object, we see this as one object on top of the another instead of a hole in the larger area. We can reverse this perception by adding shading. On a black larger object we now see is hole. Sarah

Gestalt Theory SYMMETRY Objects which are symmetrical, we are more likely to group them together. This principle also describes looking at an image and perceiving it as a whole figure instead of it’s individual parts. What do you see here? 2 Overlapping diamonds 2 Large diamonds and 1 small diamond 2 L-Shapes and 1 diamonds If you are viewing this according to the principle you are Most likely viewing this as 2 overlapping diamonds. Sarah

Gestalt Views In Psychology Gestalt psychologist’s believe the problem of visual perception should be considered as a whole. Max Wertheimer believes that thinking happens in two ways: Productive thinking- is solving a problem with insight. Reproductive thinking-is solving a problem with previous experiences and what is already known. Other Gestalts psychologist such as Perkins believes insight deals with three processes: 1) Unconscious leap in thinking. 2) The increased amount of speed in mental processing. 3) The amount of short-circuiting which occurs in normal reasoning. George

Conclusion “Seeing is believing” Vision is not necessarily what we see but how our brain interprets the world around us, our own experiences can shape how we perceive this world. “Seeing is believing” George

Any Questions? George Watch the black cross To see the green circle