basic level categories

Categories have internal structure. Categories are like boxes; some are like toy boxes; merely the sum of their contents, others are like tackle boxes, with descending pyramid-like hierarchy. Category structure is relatively complex. Not all members are equal- there are degrees of membership. To learn vocabulary, one must also learn those categories in which they belong. The structuring of a domain in terms of contrast and inclusiveness is termed taxonomy.

Being that the acquisition of language involves learning taxonomy, a question that has intrigued linguists and psychologists is, "what's the lesson plan?" In what order do we learn and how? Psychologist Eleanor Rosch did important research into the cognitive development of children to answer these questions. She learned some interesting things about certain types of categories she called "basic categories" and how they shape taxonomy acquisition.

At first glance, there would appear to be three basic ways that one would learn a taxonomy:

1. Bottom-up approach- building generalizations between things, and from there inferring higher-level categories.
2. Top-down approach- recognizing categories first, then classifying individual things while learning finer and finer divisions
3. Random approach- there is no real order, one simply learn things in an arbitrary manner.

Rosch noted that children learned classes first in terms of concrete cases, or prototypes, rather than in terms of defining features. For example, a robin may serve as the prototype for "bird."

When Rosch did her research, she found that none of these three hypotheses worked. We actually start in the middle and work outwards. This middle part of the taxonomy is called the "basic level." Rosch defined a hierarchy of categories; superordinate, basic and subordinate:

• A basic category is the largest class of which we can form a fairly concrete image, like bird or fork. These are the first classifications that children make.
• Superordinate categories are collections of basic categories: i.e. furniture includes chairs, lamps, desks, beds, etc. Toys include balls, dolls, furry animals and blocks. No one object clearly represents them.
• Subordinate categories represent divisions of basic classes, e.g., pheasants or salad forks.

Rosch stated that the functional purpose of classes was "to provide maximum information with the least cognitive effort."

One of the most important features of basic level categories is that they have prototypes. They are the most inclusive categories that can be defined by prototypes. These common prototypes have many features in common, although other members of the same class might share only a few of those features.

Basic level categories are:

• the level at which subjects are fastest at identifying category membership
• the level with the most commonly used labels for category members

• the first level named and understood by children

• the first level to enter the lexicon, or vocabulary of language
• the level with the shortest primary lexemes, or word stems
• the level at which terms are used in neutral contexts, i.e.:

there's a dog on the porch

there's a mammal on the porch

there's a wire-haired terrier on the porch

• the level at which most of our knowledge is organized

Most basic level categories of physical objects can be recognized by their profiles. They also usually have characteristic motor program- a standard way of physically interacting with them, i.e., swinging a hammer, playing a guitar.

Basic level categories are truly basic in their operation; their unique properties make them ideal for their function as the building blocks of mental taxonomies.

When asked to categorize things, we almost always give a basic level categorization.

Basic level things are also more accessible to the memory- we can remember them much more quickly.

Essentially, the entire mental structure of taxonomy is constructed around prototypical representations of objects, and because basic level categories are the highest level taxonomic categories that possess such easily identifiable prototypes, they are nearly always acquired first.