A sign is anything that communicates meaning. It is through 'signs' that everything we know is built from - (mediated). Both words and images are encoded and decoded into, and from, signs. These signs together create patterns. The brain then gives meaning to these signs and patterns and stores them for future use. It is that simple and basic.

The secret
The more we expose our brain to experiences, emotions, ideas in terms of range and diversity, the richer our brain 'library' is. The more capacity we have to create new ideas.
Myth buster
The brain does not run out of space (it is not a hard drive). However, it does delete ideas that are not used - the neural connection/wiring is 'disconnected .'
Meaning is generated in the process of encoding (production) and decoding (reception) through our visual thinking cognitive mechanism and other senses. Signs, both language and nonlanguage, are components of meaning.
Important to note - assuming all our senses are as nature intended them to be - the sense of sight has by far the most significant bandwidth. The implications of this a huge. Interestingly - our educational system has ignored this fact, and in some cases, actively downplayed it—a critical discussion for another post.
The brain interprets signs. We make sense of the intricate, complex dynamics of the signs we have in our brains.
In simple terms, the brain has pockets of meaning associated with a sign. These signs are always being combined and recombined to create explanations. We use 'story' as the tool to structure the characters into a sequence that makes sense - it provides meaning.
The beauty is that a single sign is used in different ways to tell a variety of stories. The sign then becomes rich and dense with meaning and acquires potential for further and more complex stories—the berth and possibility of innovation.
Pierce elaborated on this idea and explained it as a tripartite system – icon, indexes, and symbols.
Icons and indexes are motivated and open to interpretation. Symbols are less subject to variations – once the meaning is learned, it is fixed.
For instance – a question mark (?- symbol) is a question mark; however, a daisy is not always the flower (icon). It can mean summer (index) and innocence and purity (symbol).
The distinction between the three (icon, index, and symbol) is fluid - it is constantly changing (dynamic and emergent).
Visual thinking uses signs to create meaning. Signs stand for knowledge and ideas. It is a highly complex and sophisticated, but simply powerful way our brain has evolved.
The process is a dynamic (exchange) between the external world and the internal (brain) – our cognition processes are largely independent of language. Language comes next. Remember - language is a set of signs on its own.
Try this experiment for yourself (as described by Biederman) - while watching TV, close your eyes, and change channels with the remote control. Every time there is a click, open, and close your eyes immediately. Most people will have little trouble identifying and interpreting the image. In a 100-millisecond exposure of a new scene, people can usually interpret its meaning and recognize a pattern at a single glance. People do not think in words. Our mind processes information too fast to stop and put verbal labels on everything.
Interpretation of information happens independently from language.
When dealing with complex problems, visual reasoning is the best way to detect the subtleties and dynamics by using visual maps.
The meaning of signs is constructed through the complex interaction of perception and cognition, including individual and conventional (society) factors.
A thought is a sign requiring interpretation by a subsequent thought to result in meaning.
For example, the sign Man
There are interpretations of the basic concept of 'man.' Still, we can elaborate and make it richer for a specific man under question. This process is subjective based on our experience, observations, and knowledge. For example, the man is a family man with a boy and a girl for children. He is blonde, has pierced ears, has a mustache and goatee, dresses well, has money, we know his height. We could carry on and elaborate further. The more information we have, the richer the meaning.
The sign (the thing that stands something else) in the first instance gets translated into the basic concept, in our case 'man.'
However, the process has an infinite capacity to increase our understanding if we add layers of meaning. Suppose we introduce another sign, 'red man,' and see how that sign starts interacting with other signs. In that case, we begin to see things like behavior and personality. We would see the effects and relationships between the various signs and how new meaning starts to emerge. By adding more signs, we will then be able to observe a complex dynamic - an adaptive system emerges.
The process is the same with more abstract concepts like racism and sexism. The symbolism is woven into the structure of our pre-conscious mind. All thinking is the inferential interpretation of signs. The sign becomes a cue and infers the different types and levels of meaning captured in the cue and other cues' relationship.
For example, suppose someone arrives in an expensive car at a class reunion. In that case, the unspoken message is the 'accomplishment' of that individual. The meaning is not explicitly stated; it happens through inference.
When we look at an image, it becomes instantly and irreversibly integrated with our existing knowledge network - it happens without language.
Verbal communication is about manipulating a conventionally learned code, whereas visual thinking involves observations that lead to hypotheses about meaning. Visual thinking is abductive (see here – abductive post). It begins with observing cues, then moves on to a plausible theory or working assumption by putting forward a plausible answer/explanation about meanings and relationships about patterns.
This dynamic is a parallel process and evolves until there is some stability of meaning – temporary. It changes as new phenomena are observed that causes the system to adapt to a new, relatively stable state (will have a post on attractors). It is about the 'journey', not the 'destination.'
This post is one of a series of posts that explores how we use visual thinking to think.