Creation of an image to communicate an idea presupposes the use of a visual language. Just as people can 'verbalize' their thinking, they can 'visualize' it.
The elements in an image represent concepts in a spatial context, rather than the linear form used for words. Speech and visual communication are parallel and usually interdependent means by which humans exchange information.
A diagram, a map, and a painting are all examples of uses of visual language. Its structural units include line, shape, color, motion, texture, pattern, direction, orientation, scale, angle, space and proportion.
What we have in our minds in a waking state and what we imagine in dreams is very much of the same nature. Dream images might be with or without spoken words, other sounds or colours. But in the waking state there is usually, in the foreground, the buzz of immediate perception, feeling, mood and fleeting memory. In a mental state between dreaming and being fully awake is a state known as 'day dreaming' or a meditative state, during which "the things we see in the sky when the clouds are drifting, the centaurs and stags, antelopes and wolves" are projected from the imagination.
Abstract art has shown that the qualities of line and shape, proportion and colour convey meaning directly without the use of words. Wassily Kandinsky in Point and Line to Plane showed how drawn lines and marks can be expressive without any association with a representational image. Throughout history and especially in ancient cultures visual language has been used to encode meaning " The Bronze Age Badger Stone on Ilkly Moor is covered in circles, lines, hollow cups, winged figures, a spread hand, an ancient swastika, an embryo, a shooting star? … It's a story-telling rock, a message from a world before (written) words."
Vision gives us inexhaustibly rich information about the objects and events of the outside world. The language we use to record these phenomena is, because of the simplicity of line, shape and colour, infinitely adaptable to the needs of communication.
The sense of sight operates selectively. Perception is not a passive recording of all that is in front of the eyes, but is a continuous judgement of scale and colour relationships, and includes making categories of forms to classify images and shapes in the world.
Thought processes are diffused and interconnected and are cognitive at a sensory level. The mind thinks at its deepest level in sense material, and the two hemispheres of the brain deal with different kinds of thought.
The brain is divided into two hemispheres and a thick bundle of nerve fibres enable these two halves to communicate with each other. In most people the ability to organize and produce speech is predominantly located in the left side. Appreciating spatial perceptions depends more on the right hemisphere, although there is a left hemisphere contribution. In an attempt to understand how designers solve problems, L. Bruce Archer proposed "that the way designers (and everybody else, for that matter) form images in their mind's eye, manipulating and evaluating ideas before, during and after externalising them, constitutes a cognitive system comparable with but different from, the verbal language system. Indeed we believe that human beings have an innate capacity for cognitive modelling, and its expression through sketching, drawing, construction, acting out and so on, that is fundamental to human thought."
The perception of a shape requires the grasping of the essential structural features, to produce a "whole" or gestalt. The theory of the gestalt was proposed by Christian von Ehrenfels in 1890. He pointed out that a melody is still recognisable when played in different keys and argued that the whole is not simply the sum of its parts but a total structure.
Max Wertheimer researched von Ehrenfels' idea, and in his "Theory of Form" (1923) – nicknamed "the dot essay" because it was illustrated with abstract patterns of dots and lines – he concluded that the perceiving eye tends to bring together elements that look alike (similarity groupings) and will complete an incomplete form (object hypothesis). An array of random dots tends to form configurations (constellations). All these demonstrate how the eye and the mind are looking for pattern and simple whole shapes. When we look at more complex visual images such as paintings we can see that art has been a continuous attempt to "notate" visual information.
Although it is believed that a form or object does not seem visual and may need much more accessories and details to be able to be understood and believed.
Richard Gregory suggests that, "Perhaps the ability to respond to absent imaginary situations," as our early ancestors did with paintings on rock, "represents an essential step towards the development of abstract thought."
Semiology of Graphics is a theory of information design, presented by Jacques Bertin in his 1967 book Sémiologie graphique. This theory is considered to be "a coherent and reasoned framework for the analysis and representation of data on paper. It is founded on Bertin's practical experience as a geographer and cartographer, rather than on empirical research". This work, accor[ding to [Edward Tufte]] (2003) "provides a close study of different graphic techniques (shape, orientation, color, texture, volume, size) for locating and signaling quantitative variation, often over geographic space (usually France) or over time. There is also the graphical analysis and sorting of data tables. The book contains several thousand illustrations, produced by Bertin and his colleagues. In addition, there are perhaps 20 graphics by others".