Extensive research was conducted in the area of categorization in order to create the most accurate model, that would be able perform the process of categorizing similar items and predict a similar outcomes for each real world event the same way a human mind would do it. Here we will explore categorisation process and how it developed and grew over the years. Several researchers (fiske1989) reasoned that "The idea that categorization is a natural and adaptive, even dominant, way of understanding other people does not mean that it is the only option available." So, we will study the earliest and the latest concepts formed in the field along with the limitation in each one of them. By then end of the paper, the concept that presents less weakness will be obvious. Besides, we will present some of the studies conducted in the field of explaining how human categorisation process is actually done and the theories produced by pioneer researchers.
The way that the human mind categories daily events happens with out us noticing. In order to create an artificial model that can mimic this natural brain activity we need to understand the philosophy of categorization in human brain or even a more simple brain activity in animals, which is conditioning. In the literature of Categorisation, this process is defined as the process of grouping similar objects, which share similar traits all together. This assembly of similar objects will get the same response and result. There is two famous Primitive classical theories : Associationism and Hypothesis Testing .
Developed Concepts (Real- World):
One of the first pioneers Eleanor Rosch (1978) tried to form two generalized concepts for categorization. In order to form a category either by the function of category systems (for example: what does this category do or how) or by the structure of the information through mapping the category to a certain feature structure [Eleanor Rosch, 1978].
First Concept: Cognitive Economy.
Claimed to be the most common-sense concept, later we would argue otherwise and prove how it contradict with a basic common-sense point, that the main idea is to group items with the fewest basic information about their environment and the minimum usage of memory. Fundamentally, this concept looks at the situation from an economist point of view in saving memory and space. In order to have a better understanding we can look at it from a biological way, each organism has its own driven property; some properties are shared with other organisms while other properties are not. The first concept states that each category provides us with collective information based on the items that belongs to it. Accordingly, to perform many cognitive tasks all at once, spontaneously the mind would use the least energy to perfume another cognitive task with the least information that would indicate which category a specific item belong to. In other words, we are stereotyping the information we receive. In fact, many people perform cognitive tasks that way in their daily life. When some of us see a guy with "Half-moon" almond shaped eyes with fair skin, we would stereotype that person into “Asian” category even if he is actually not, exactly like “stereotype”. Indeed cognitive economy “stereotyping” can be really effective at times that would be described as “cognitively busy”, but still the major downside of it is it can give us a wrong or an unfair results just like the “Asian guy” example. Certainly we are saving time and memory space to perform a cognitive task this way, but the results we are having will not necessarily be as good as other cognitive concepts can give. Another shortcoming of this concept is you cannot depend on it all the time and definitely not in important matters when you need accurate results.
Second Concept: Perceived World Structure.
It works in another direction of similar stimuli but also by using organisms as well, a more “species – specific” [Eleanor Rosch, 1978] kind of categorization. Via perceiving the real world- not metaphorically but literally, one can say that it is structured of different, complex or simple characteristics. Some characteristics are more likely to accrue together then others. “The material objects of the world are perceived to possess ( Garner's, 1974, sense) high correlational structure”. The common example of three characteristics perceived in the world (fur, wings and feather). Two characteristics are more likely to occur together, which are (wings and feather) more likely to both are associated together then (wings and fur Or fur and feather). However, Groupings the characteristics of what we perceive in the real world objects dose not appear unvaryingly. Sometimes a number of characteristics happen together but half of them happen more often the other half. And some of them rarely or never logically happen together.
If we take dogs as a study case, we acknowledge that the “real world characteristic” their nose can sense- perceives - is not the same characteristics that a human nose can perceive. The reason behind that is dog’s physical body structure is different, the sense of smelling is extremely strong and can sense beyond what we as humans can sense. Their body react with objects in the real world different then ours. Accordingly, the objects perceived in a real world environment is different for every interactive – being and also different for each being based on its intention of the perceiving at a specific time based on what the task need to be done.
The combination of the two previously mentioned categorization concepts, cognitive economy and perceive the real world structure, directly impact the internal and external structure of a category in the process of being formed and after they are formed. We can visualize the category system as a dimensional system, with both a vertical and a horizontal axis. As for the vertical axis, it will cover the level generality of the category. For example, the category here will cover the general level of all birds, cats, insects and all living things that differ from one another. On the other hand, the horizontal one will cover the depth of each general segment. For example, which segment or type of birds cats, insects and so on. The two concepts previously mentioned affect the vertical axis in a way that the importance and usefulness of each categorization level are not equivalent. Nevertheless, the category level that is very general is the very level, which is abstract and broad in a way that it can reflect in parallel way the structure of the general category characteristics observed in the real world. On the other hand, the concepts of categorization affect the horizontal axis in a way that the category uniqueness, individuality and elasticity expand and grow, with more defined and explicit terms and properties. Additionally, the category will cover the characteristics that are most illustrative of objects inside it and at the same time least illustrative of objects outside it.