Gestalt psychology or gestaltism (German: Gestalt – "essence or shape of an entity's complete form") is a theory of mind and brain of the Berlin School; the operational principle of gestalt psychology is that the brain is holistic, parallel, and analog, with self-organizing tendencies. The principle maintains that the human eye sees objects in their entirety before perceiving their individual parts, suggesting the whole is greater than the sum of its parts. Gestalt psychology tries to understand the laws of our ability to acquire and maintain stable percepts in a noisy world. Gestalt psychologists stipulate that perception is the product of complex interactions among various stimuli. Contrary to the behaviorist approach to understanding the elements of cognitive processes, gestalt psychologists sought to understand their organization (Carlson and Heth, 2010). The gestalt effect is the form-generating capability of our senses, particularly with respect to the visual recognition of figures and whole forms instead of just a collection of simple lines and curves. In psychology, gestaltism is often opposed to structuralism. The phrase "The whole is greater than the sum of the parts" is often used when explaining gestalt theory, though this is a mistranslation of Kurt Koffka's original phrase, "The whole is other than the sum of the parts". Gestalt theory allows for the breakup of elements from the whole situation into what it really is.
Theoretical framework and methodology
The investigations developed at the beginning of the 20th century, based on traditional scientific methodology, divided the object of study into a set of elements that could be analyzed separately with the objective of reducing the complexity of this object. Contrary to this methodology, the school of gestalt practiced a series of theoretical and methodological principles that attempted to redefine the approach to psychological research.
The theoretical principles are the following:
Based on the principles above the following methodological principles are defined:
Emergence is the process of complex pattern formation from simpler rules. It is demonstrated by the perception of the dog picture, which depicts a Dalmatian dog sniffing the ground in the shade of overhanging trees. The dog is not recognized by first identifying its parts (feet, ears, nose, tail, etc.), and then inferring the dog from those component parts. Instead, the dog is perceived as a whole, all at once. However, this is a description of what occurs in vision and not an explanation. Gestalt theory does not explain how the percept of a dog emerges.
Reification is the constructive or generative aspect of perception, by which the experienced percept contains more explicit spatial information than the sensory stimulus on which it is based.
For instance, a triangle is perceived in picture A, though no triangle is there. In pictures B and D the eye recognizes disparate shapes as "belonging" to a single shape, in C a complete three-dimensional shape is seen, where in actuality no such thing is drawn.
Reification can be explained by progress in the study of illusory contours, which are treated by the visual system as "real" contours.
Multistability (or multistable perception) is the tendency of ambiguous perceptual experiences to pop back and forth unstably between two or more alternative interpretations. This is seen for example in the Necker cube, and in Rubin's Figure/Vase illusion shown here. Other examples include the Three-legged blivet and artist M. C. Escher's artwork and the appearance of flashing marquee lights moving first one direction and then suddenly the other. Again, gestalt does not explain how images appear multistable, only that they do.
Invariance is the property of perception whereby simple geometrical objects are recognized independent of rotation, translation, and scale; as well as several other variations such as elastic deformations, different lighting, and different component features. For example, the objects in A in the figure are all immediately recognized as the same basic shape, which are immediately distinguishable from the forms in B. They are even recognized despite perspective and elastic deformations as in C, and when depicted using different graphic elements as in D. Computational theories of vision, such as those by David Marr, have had more success in explaining how objects are classified.
Emergence, reification, multistability, and invariance are not necessarily separable modules to model individually, but they could be different aspects of a single unified dynamic mechanism.
The fundamental principle of gestalt perception is the law of prägnanz (in the German language, pithiness), which says that we tend to order our experience in a manner that is regular, orderly, symmetric, and simple. Gestalt psychologists attempt to discover refinements of the law of prägnanz, and this involves writing down laws that, hypothetically, allow us to predict the interpretation of sensation, what are often called "gestalt laws". These include:
Gestalt Laws of Grouping
A major aspect of Gestalt psychology is that it implies that the mind understands external stimuli as whole rather than the sum of their parts. The wholes are structured and organized using grouping laws. The various laws are called laws orprinciples, depending on the paper where they appear—but for simplicity sake, this article uses the term laws. These laws deal with the sensory modality vision however there are analogous laws for other sensory modalities including auditory, tactile, gustatory and olfactory (Bregman – GP). The visual Gestalt principles of grouping were introduced in Wertheimer (1923). Through the 1930s and '40s Wertheimer, Kohler and Koffka formulated many of the laws of grouping through the study of visual perception.
Law of Proximity—The law of proximity states that when an individual perceives an assortment of objects they perceive objects that are close to each other as forming a group. For example, in the figure that illustrates the Law of proximity, there are 72 circles, but we perceive the collection of circles in groups. Specifically, we perceive there is a group of 36 circles on the left side of the image, and three groups of 12 circles on the right side of the image. This law is often used in advertising logos to emphasize which aspects of events are associated.
Law of Similarity—The law of similarity states that elements within an assortment of objects are perceptually grouped together if they are similar to each other. This similarity can occur in the form of shape, colour, shading or other qualities. For example, the figure illustrating the law of similarity portrays 36 circles all equal distance apart from one another forming a square. In this depiction, 18 of the circles are shaded dark and 18 of the circles are shaded light. We perceive the dark circles as grouped together, and the light circles as grouped together forming six horizontal lines within the square of circles. This perception of lines is due to the law of similarity.
Law of Closure—The law of closure states that individuals perceive objects such as shapes, letters, pictures, etc., as being whole when they are not complete. Specifically, when parts of a whole picture are missing, our perception fills in the visual gap. Research shows that the reason the mind completes a regular figure that is not perceived through sensation is to increase the regularity of surrounding stimuli. For example, the figure that depicts the law of closure portrays what we perceive as a circle on the left side of the image and a rectangle on the right side of the image. However, gaps are missing from the shapes. If the law of closure did not exist, the image would depict an assortment of different lines with different lengths, rotations, and curvatures—but with the law of closure, we perceptually combine the lines into whole shapes.
Law of Symmetry—The law of symmetry states that the mind perceives objects as being symmetrical and forming around a center point. It is perceptually pleasing to divide objects into an even number of symmetrical parts. Therefore, when two symmetrical elements are unconnected the mind perceptually connects them to form a coherent shape. Similarities between symmetrical objects increase the likelihood that objects are grouped to form a combined symmetrical object. For example, the figure depicting the law of symmetry shows a configuration of square and curled brackets. When the image is perceived, we tend to observe three pairs of symmetrical brackets rather than six individual brackets.
Law of Common Fate—The law of common fate states that objects are perceived as lines that move along the smoothest path. Experiments using the visual sensory modality found that movement of elements of an object produce paths that individuals perceive that the objects are on. We perceive elements of objects to have trends of motion, which indicate the path that the object is on. The law of continuity implies the grouping together of objects that have the same trend of motion and are therefore on the same path. For example, if there are an array of dots and half the dots are moving upward while the other half are moving downward, we would perceive the upward moving dots and the downward moving dots as two distinct units.
Law of Continuity—The law of continuity states that elements of objects tend to be grouped together, and therefore integrated into perceptual wholes if they are aligned within an object. In cases where there is an intersection between objects, individuals tend to perceive the two objects as two single uninterrupted entities. Stimuli remain distinct even with overlap. We are less likely to group elements with sharp abrupt directional changes as being one object.
Law of Good Gestalt—The law of good gestalt explains that elements of objects tend to be perceptually grouped together if they form a pattern that is regular, simple, and orderly. This law implies that as individuals perceive the world, they eliminate complexity and unfamiliarity so they can observe a reality in its most simplistic form. Eliminating extraneous stimuli helps the mind create meaning. This meaning created by perception implies a global regularity, which is often mentally prioritized over spatial relations. The law of good gestalt focuses on the idea of conciseness, which is what all of gestalt theory is based on. This law has also been called the law of Prägnanz. Prägnanz is a German word that directly translates to mean "pithiness" and implies the ideas of salience, conciseness and orderliness.
Law of Past Experience—The law of past experience implies that under some circumstances visual stimuli are categorized according to past experience. If two objects tend to be observed within close proximity, or small temporal intervals, the objects are more likely to be perceived together. For example, the English language contains 26 letters that are grouped to form words using a set of rules. If an individual reads an English word they have never seen, they use the law of past experience to interpret the letters "L" and "I" as two letters beside each other, rather than using the law of closure to combine the letters and interpret the object as an uppercase U.
The gestalt laws of grouping have recently been subjected to modern methods of scientific evaluation by examining the visual cortex using cortical algorithms. Current Gestalt psychologists have described their findings, which showed correlations between physical visual representations of objects and self-report perception as the laws of seeing.