Lev Semyonovich Vygotsky has figured prominently in American Psychology since the publication in 1962 of his monograph Thought and Language. Five years ago, at the urging of Vygosty’s student Alexander Luria, we agreed to edit a collection of Vygotsky’s essays which would reflect the general theoretical enterprise of which the study of the relation between though and language was one important aspect. Luria made available to us rough translations of two of Vygotsky´s works. The first, “Tool and Symbol in Children´s Development” (1930), had never been published. The second was a translation of a monograph entitled The History of the Development of Higher Psychological Functions, which appeared in the second volume of Vygotsky´s writings published in Moscow in 1960. A cursory study of these essays quickly convinced us that de scope of Vygotsky`s work reached considerably beyond Thought and Language. Furthermore we came to believe that the image of Vygotsky as a sort of early neobehaviorist of cognitive development―an impression held by many of our colleagues―was strongly believed by these two works.

The primary purpose of this book is to characterize the uniquely human aspects of behavior, and to offer hypotheses about the way these traits have been formed in the course of human history and the way they develop over an individual’s lifetime.

This analysis will be concerned with three fundamental issues: (1) What is the relation between human beings and their environment, both physical and social? (2) What new forms of activity were responsible for establishing labor as the fundamental means of relating humans to nature and what are the psychological consequences of these forms of activity. (3) What is the nature of relationship between the use of tools and the development of speech? None of these questions has been fully treated by scholars concerned with understanding animal and human psychology.

A special feature of human perception―which arises at a very young age―is the perception of real objects. This is something for which there is no analogy in animal perception. By this term I mean that I do not see the world simply in color and shape but also as a world with sense and meaning.  I do not merely see something round and black with two hands; I see a clock and I can distinguish one hand from the other. Some brain-injured patients say, when they see a clock, that they are seeing something round and white with two thin steel strips, but they do not know it is a clock; such people have lost their real relationship with objects.

The child mastering his speech has the ability to direct his attention in a dynamic way. He can view changes in his immediate situation from the point of view of past activities, and he can act in the present from the view point of the future.

The very essence of human memory consists in the fact that human beings actively remember with the help of signs. It may be said that the basic characteristic of human behavior in general is that humans personally influence their relations with the environment and through that environment personally change their behavior, subjugating it to their control.

Based on the data we obtained from several series of experiments carried out by my colleagues and myself about the function of speech in reorganizing perception and creating new relations among psychological functions, we are able to describe in schematic form the basic laws that characterize the structure and development of the child‘s sign operations. These will be presented through a discussion of memory, which is exceptionally appropriate for study of the changes that signs introduce into basic psychological functions because it clearly reveals the social origin of signs as well as their crucial role in the individual’s development.

What creates the zone of proximal development is an essential learning trait; that is, learning awakens a variety of internal developmental processes that are able to operate only when the child is interacting with people in his environment and in cooperation with his peers. Once these processes are internalized, they become part of the child’s independent developmental achievement. Our hypothesis establishes the unity but not the identity of learning processes and internal developmental processes. It presupposes that the one is converted into the other. From this point of view, learning is not development; however, properly organized learning results in mental development and sets in motion a variety of developmental processes that would be impossible apart from learning. Thus, learning is a necessary and universal aspect of the process of developing culturally organized, specifically human, psychological functions. Therefore, it becomes an important concern of psychological research to show how external knowledge and abilities in children become internalized.

We called the internal reconstruction of an external operation internalization. This process of internalization consists of a series of transformations:

a)   An operation that initially represents an external activity is reconstructed and begins to occur internally. Of particular importance to the development of higher mental processes is the transformation of sign-using activity, the history and characteristic of which are illustrated by the development of practical intelligence, voluntary attention, and memory.

b) An interpersonal process is transformed into an intrapersonal one. Every function in the child’s cultural development appears twice: first, on the social level, and later, on the individual level; first, between people (interpsychological), and then inside the child (intrapsychological). This applies equally to voluntary attention, to logical memory, and to the formation of concepts. All the higher functions originate as actual relations between human individuals.

c) The transformation of an interpersonal process into an intrapersonal one is the result of a long series of developmental events.  The process being transformed continues to exist and to change as an external form of activity for a long time before definitively turning inward. For many functions, the stage of external sign lasts for ever, that is, it is their final stage of development. Other functions develop further and gradually become inner functions. However, they take on the character of inner processes only as a result of a prolonged development. Their transfer inward is linked with changes in the laws governing their activity; they are incorporated into a new system with its own laws.

The internalization of socially rooted and historically developed activities is the distinguishing feature of human psychology, the basis of the qualitative leap from animal to human psychology

In zone of proximal development, teaching represents the means through which development progresses. If there are no internalization processes in teaching, there is no learning; and if there is no learning, there is no development. School education is qualitatively different from education in the broadest sense of the word. At School, the child is faced with certain task: to grasp the foundations of scientific study, that is, a system of scientific conceptions. If there are no internalization processes in the child, he will be not able to grasp the system of scientific conceptions that is needed as a basis for the study of a certain topic. So it is crucial that the internalization process takes place in school teaching.   

In general, any fundamentally new approach to a scientific problem inevitably leads to new methods of investigation and analysis. The invention of new methods that are adequate to the new ways in which problems are posed requires far more than a simple modification of previously accepted methods.

The search for method becomes one of the most important problems of the entire enterprise of understanding the uniquely human forms of psychological activity. In this case, the method is simultaneously prerequisite and product, the tool and the result of the study.

The influence of play on a child’s development is enormous. Play is a leading factor in development, it brings about important internal transformations in the child’s development.  In play the child learns to act in a cognitive, rather than an externally visual, realm by relying on internal tendencies and motives and not on incentives supplied by external things. In play thought is separated from objects and action arises from ideas rather than from things. A child’s greatest achievements are possible in play, achievements that tomorrow will become her basic level of real action and morality. In play a child always behaves beyond his average age, above his daily behavior; in play it is as though he were a head taller than himself. As in the focus of a magnifying glass, play contains all developmental tendencies in a condensed form and is itself a major source of development.