Towards twelve months babies start to make use of “categories” or “object classes”. They are able to group them by their colors, shapes, or sizes and surprisingly by non-perceptual characteristics such as their functions. This new ‘know-how’ is observed when they group toys, chips, balls, things from their house, their clothing, etc. The incipient use of categories renews his way of apprehending the world, expands his knowledge and opens new possibilities in the consolidation of his thought.
This competition shows that children have discovered the ‘use of objects’. They understand that things around them have specific uses that others do not and that these operating characteristics belong to a group of various objects and not just one. At the same time, they know that the same object can fulfill various functions. Making ‘meow meow’ like the cat or ‘wow wow’ like the dog, are traditional games that apparently start with imitation and knowledge of the functions and characteristics of animals. But towards thirteen months, little by little, these functions are extended to other objects, the carts have wheels to roll them, the glasses and the bottles are containers for drinking, the combs are used to comb one’s own hair and, in addition, to his mother or his friends.
The conquest that this expansion of knowledge allows is called “inductive generalization” 16, it explains that children are capable of generalizing an action such as “displacement”, initially applied to a truck to another vehicle, such as a cart, then to the view is different, but which in turn meets the characteristic of having tires and being able to roll. This new competence involves using the categories or classes that children have previously created based on perceptual characteristics, such as the physical appearance of objects and also conceptual ones, such as functions and uses and has a wide impact on the way they appropriate the world. It could be said that categorization and inductive generalization are the sample of a step-by-step construction and from practice, of a true ‘knowledge’.
By the year and a half, they no longer only walk and coordinate their two hands, but they use instruments and know-how to build them. To reach a toy that they cannot reach, they begin to use intermediaries, a stick, a hook, a rope, or another object that is nearby, making use of more complex coordinations.
Activities in which children show that they understand objects as instruments to achieve goals and beyond when they manage to create them, constitute another of the great revolutions. They show us the way in which the child is relating all his activities, they show us that he is weaving relationships through the use that things have. The creation of intermediaries in the daily life of children also has another priceless value. The spoon, the glass, the stick, and other objects begin to play the role of extensions of his own hand, of his arm, of himself. From those extensions of his body, they quickly go to see objects in various ways. In addition to their meaning or value, they have another, the one that their own actions and needs can give them.
In the course of these ‘knowledge’ and ‘doings’ that are transformed into ‘power to do’, they carry out generalizations of the functions of the objects and generalizations of the categorizations. They constitute initial, very revolutionary, and important forms in the process of constructing children’s thinking.