The Gestalt Principles and there role in the effectiveness of Optical Illusions. By Brendan Mc Kinney Abstract Illusion are created in human perception in relation to how the mind process information, in this regard on to speculate that the Gestalt Principles are a key process in the success of optical illusions. To understand this principle the research paper will examine several optical illusions in the hopes that they exhibit similar traits used in the Gestalt Principles. In this research report we will explore the Gestalt Principles and their implications and how human’s perception can be tricked. The Gestalt Principles are the guiding principles of perception developed from testing on perception and how human beings perceive their surroundings. Human perception can however be tricked by understanding the Gestalt principles and using them to fool the human perception. The goal of this paper is to ask how illusions can be created to fool human’s perception using the gestalt principles as a basis for human’s perception. To examine the supposed, effect the Gestalt Principles in illusions we will look at three, the first being Rubin’s Vase, followed by the Penrose Stairs and the Kanizsa Triangle to understand the Gestalt Principles in play. In this context we will be looking at Optical Illusion rather than illusions using sound to understand the Gestalt Principles influence on human’s perception of reality. Illusions are described as a perception of something that is inconsistent with the actual reality (dictionary.com, 2015). How the human mind examines the world around them can be different from the actuality before them, this is due to the Gestalt principles influencing people’s perception. The Gestalt principles were written in Germany by Kurt Koffka, Wolfgang Kohler and Max Wertheimer between 1912 and 1933. The focus of these principles examined the grouping of objects in the environment. The main paper effecting perception of objects was written in 1923 by Wertheimer in which he hypothesised several principles associated with perception (Brownie, 2006). The Principle of Similarity is defined by Wertheimer as an object or objects that share properties such as colour, shape, brightness, and the human mind together associates textures. Many military vehicles and animals use similarity to help disguise themselves by using discordant texturing to break up what is seen into different parts to confuse weather the vehicle for instance is one object or several (Mather,2009) see Figure 1 as an example. Similarity functions in conjuncture with the principles of proximity, Figure 1 common fate and pragnanz. Figure 2 shows an example of similarity, in the image there are two distinctive shapes, squares, and circles and due to their placement, it gives of the sense of similarity between the shapes. Due to their colour and shape the human mind immediately associates them with others of similar appearance to give a sense of grouping to the image. In Figure 1 similarity in terms of distance between the shapes also gives a sense of contrast between the circles and Figure 2 the squares. The Principle of Proximity is defined as objects located close to each other which will cause them to be perceived as being associates together, either belong to the same whole object or as part of a group of objects. Objects are normal grouped by human perception in conjuncture with other principles such as shape, colour and texture etc. Transparent objects violate this rule such as nets and windows. Edge detection is a key principle of the gestalt principles and has an impact on illusions for example the WWF Logo seen in figure 3 is a collection of shapes however they share similarity but are not connected, the image is of a panda however the lines connecting the black parts together, have been removed but human beings can still see this image and understand that it depicts a panda, human beings’ perception is fooled into believing that the lines are still there in some way, this is incorrect to the actuality where there are no lines. Human perception creates illusions to make connections. Edge detection runs in conjunction with similarity and proximity to create this illusion. Figure 3 Common Fate or Uniform Destiny relies on the theory that if two objects are connected when one moves the connected objects also follow the same movement, they share the object’s ‘fate’. The human mind tends to make the assumption that if two objects follow a similar movement or move in the same direction at a similar pace that they must be connected in some way. Flocks of birds follow a similar movement when moving and the human mind groups the birds together as a continuous group. Continuity follows the principle that Figure 4 when an object has similarities such as texture or colour but is separated by another object that limits the view of the person, their mind still has the capacity to link the two disjointed parts and understand that they are a whole separated by a different unconnected object. Past Experience in relation to the Gestalt principles is a principle that showcases how the past experience of a person can influence their mind and their perception of an object, this is mainly done through grouping objects together as in the past they were connected. A prime example of past experience influencing perception is colour interpretation such as traffic lights influencing how we see colour as well as a cultural perception of colour based upon past experience/integration into said culture (Bradley, 2014). A large part of the Gestalt Principles is ‘pragnanz’ which contains more principles that are slightly less defined than the aforementioned principles. Pragnanz can be understood as meaning good form and looks at closure, simplicity and symmetry. Closure is appealing to the human mind it works in closely with edge detection which in many ways creates closure through altering what the mind perceives slightly to give off the perception of closure. Simplicity is as it suggests objects with any similar traits such as colour, shape, size, and texture as an example. The principle of Symmetry follows the minds logic that objects have a central point Figure 5 and that objects are symmetrical. The human mind finds it visually pleasing for objects to be divided up into an even number of parts creating symmetry. Symmetry works in conjunction with similarity to help the mind group objects, if several objects have similarities and the symmetry lines up then they can be perceived to be in some way connected (Stevenson, 2013). The human mind prefers simple objects and shapes rather than complexity. Pragnanz is the human mind seeking simplicity usually by eliminating complexity through a focus on closure, simplicity, and symmetry. Illusions with regards to the gestalt principles examines optical illusions and if the principles outlined in gestalt’s theories. The image in figure 6 is an illusion known as an ambiguous image. The image is called the Rubin vase, the image is a good example of the gestalt principles particularly those that effect grouping. The Rubin vase developed by psychologist Edgar Rubin, and uses the fore-ground and background of the image to fool the perception into seeing two Figure 6 separate things, the white vase or the two black faces, logically it can only be one however both objects in this image are equally viable this is due to the simplicity of the image and the gestalt principles. The Penrose stairs also known as the impossible staircase is an optical illusion of a staircase comprised of four sides that ascend and descend in a continuous loop which is impossible to achieve in 3D, the reason human perception assists in seeing the Penrose staircase as viable is it is following the principles of continuity, symmetry, shape and similarity, the stair’s Figure 7 steps are similar in shape to real steps so the mind makes that connection as they have similarities, the Stairs also follow a continuity where they appear to be ascending/descending. A physical representation of these stairs would be somewhat impossible as this is something akin to a camera trick, however movies such as Figure 8 Inception have used trick photography to replicate the effect (Nolan, 2010). This is a prime example of an illusion highlighting the gestalt principles to alter human perception and logic by creating optical illusions. The next illusion is called Illusory Contours (also known as Subjective Contours) and uses the gestalt principle of edge detection to connect the black circles with lines that do not exist in that there is no colour change or texture change to create the lines however the mind sees the symmetry and identifies that there are edges there, Gestalt’s Principle of Closure seems to also play into the illusions effectiveness (Simmons, 1996). Illusory Figure 9 Contours have appeared in art dating back to the Middle Ages. Figure 9 shows the Kanizsa Triangle created in 1955 by Gaetano Kanizsa and is an example of Illusory Contours. This creates the sense that there are lines in those areas where there are none. This is another example of an illusion using the gestalt principle to alter perception (What Is Psychology, 2012). In conclusion after examining three optical illusions, the Rubin vase, the Penrose Stairs, and Illusory Contours we can make the hypothesis that the Gestalt principles influence the viability of illusions, from continuity, symmetry, shape, and similarity to good pragnanz. It can be presumed that optical illusions effect the majority of humans using the Gestalt Principles to fool human perception. The gestalt principles are a guiding force behind human perception but also unique to every human being thanks to past experience, this can help to explain why someone can be more easily fooled by illusion while others do not see the illusion or can easily see both outcomes of the Rubin’s Vase.