Vygotsky's Zone of Proximal Development

Background Information

Lev Vygotsky worked under Alexander Luria at the Moscow Institute of Psychology from 1924 to 1934. He also worked closely with Leont'ef, in the field of what was then called peadology and defectology, although the terms child psychology and special education would be preferred today.  Vygotsky was writing the at the same time as Jean Piaget but his life was cut short by consumption in 1934 and his work fell into relative obscurity until interest was revived in the 1960's (Guthke 1993a). A detailed discussion of his ideas on the cognitive development of children is beyond the scope of this project. All that needs to be said here is that, whereas some of his contemporaries seemed to imply that cognitive development took place in stages which were a simple function of the age of the child, Vygotsky believed that interaction with the outside world also played a very important part in the process.

Of most importance to this study is a theoretical construct described by Vygotsky as the Zone of Proximal Development. This concept is perhaps best described, in the following quote from Vygotsky's classic work, Myshlenie i rech (published in English in 1986 as Thought and Language, although the phrase literally means Thought and speech):

Most of the psychological investigations concerned with school learning measured the level of mental development of the child by making him solve certain standardised problems. The problems he was able to solve by himself were supposed to indicate the level of his mental development at the particular time ... We tried a different approach. Having found that the mental age of two children was, let us say eight, we gave each of them harder problems than he could manage on his own and provided slight assistance ... We discovered that one child could, in cooperation, solve problems designed for twelve year olds, while the other could not go beyond problems intended for nine year olds. The discrepancy between a child's mental age [indicated by the static test] and the level he reaches in solving problems with assistance is the zone of his proximal development. (Vygotsky 1986 p.186-7)

This concept represents the basis for much of the work which has been done in the dynamic assessment of learning potential (Hamers and Resing 1993).

Difficulties with Vygotsky's Procedure

The Zone of Proximal Development (ZPD) as described above, could be redefined as a response to a treatment; the treatment of interaction with an adult. The response was quantified by Vygotsky, but the treatment was not. Vygotsky seems to have assumed that interaction with an adult is a Boolean quantity; something which is either given or is not given, and which if it is given, is always the same. Everyday experience would suggest that this is not the case.

In the second place Vygotsky seems to have overlooked the statistical problems associated with the measurement of change. How did he find that each child in the passage above had a mental age of eight? What were the measurement errors in the technique he used to reach this finding? What did Vygotsky mean when he describes a problem as designed for a twelve year old? What statistical procedure was used to establish the age level of each test item? What were the measurement errors?

The procedure Vygotsky describes is essentially a measurement of change. Practical research into the measurement of change indicates that the errors often outweigh the change (Sijtsma 1993).

A further problem is the cost of administration. A common theme running through the literature on interactive assessment is that the cost of the technique is too high in relation to any improvement in efficacy over that of the static alternative. This reflects the human involvement in the interaction.

The technique is difficult to standardise for the same reason, and as a result is often not regarded as very reliable (Buchel & Scharnhorst 1993).

Measuring Interaction

The project described on these pages sets out to overcome these problems by replacing human interaction with interaction with a computer.

The project uses software which sets questions of gradually increasing difficulty in order to determine the existing knowledge of the child. As long as the questions are within the current capabilities of the child, he or she can answer them in quick succession and progress to the next level of difficulty.

As soon as the child encounters a question a little beyond his or her current ability level, he or she can switch the computer from test mode to teach mode, by activating a Help button. This will initiate a lesson which specifically addresses the question on which difficulty was encountered.

This is where the computer begins to mimic Vygotsky's conceptual tutor. A computer can never be a perfect mimic of a human tutor (please refer to the scribbling headed Interactive Assessment) but it has one major advantage. It can record meticulously exactly how much and what kind of help is given.

The computer offers three kinds of lesson. There is a long slow lesson which uses animation and sound to illustrate how to address the question. There is a quicker lesson which just uses animation which leads the student to the answer in an arithmetic progression. And there is a very quick lesson which uses animation to illustrate the answer. The interesting thing about this lesson is that although it reveals the answer, some children who use it, when faced with the same question a second or two later, have not retained the answer, and have to use Help again.

Every time help is used the computer records what kind of help was used and at what stage in the test it was used. In this way the computer measures the amount of interaction needed by a child to arrive at however many correct answers were submitted.

Measuring Ability and Item Difficulty

The project will use Item Response Theory (IRT, Sijtsma 1993) to estimate the ability of the children participating in the project and the difficulty of the items in the interactive tests. A detailed discussion of IRT is beyond the scope of this section, but it is worth noting that IRT has been developed in the last thirty years and was not available to Vygotsky.

However, in the context of the passage quoted above, it is reasonable to suggest that had it been available Vygotsky would have used it to make a systematic estimate of the difficulty level of the questions in his test and the ability level of his candidates sitting the test alone and sitting it with tutorial assistance.

Cost of Administration

With careful management the cost of administrating the interactive test used in this project can be close to zero. The computer sets the questions and records all the pertinent information. The software is very easy to use. A single click on a button initiates a test. The child types in his or her age, and the test begins. The computer sets fifty questions and logs the child out.

The researcher visits the school when as many children as required have completed as many tests as required with a floppy disk. The floppy disk is inserted into the computer and the session record file is copied on to the floppy. The researcher takes the disk back to base, exports the data into a spreadsheet or database application, and then processes it in the same way as the data from a manual test.

Call for external participants

This project is currently being conducted in the metropolitan area of Perth, Western Australia. I have about a hundred children in Grades 1 through 5 participating so far. This is enough to satisfy the strictly statistical needs of the project. However, I should like to include some children from outside the Perth metropolitan area.

If you represent a school or research institution and you would like to participate in the project, I should be very happy to send you a copy of the software to try out. If you think your children would benefit from using the software, and that they would not mind participating in my research project, we could make an arrangement for you to send me the data I need.

Please write to me, using the email address given at the base of this page (or simply click on the word email in this sentence).

Try out an interactive test

To download some unique software which applies Vygotsky's ideas on interactive assessment and the Zone of Proximal Development, follow this link.

References

Buchel FP, Scharnhorst U (1993) The Learning Potential Assessment Device (LPAD): Discussion of theoretical and methodological problems
Learning Potential Assessment: Theoretical methodological and practical issues (Hamers JHM, Sijtsma K, Ruijssenaars JM Eds) Swets & Zeitlinger, Amsterdam, N.L. Ch3pp 43-68

Guthke J (1993) Current trends in theories and assessment of intelligence
Learning Potential Assessment: Theoretiacal methodological and practical issues (Hamers JHM, Sijtsma K, Ruijssenaars JM Eds) Swets & Zeitlinger, Amsterdam, N.L. Ch3pp 43-68

Hamers JHM, Resing WCM (1993) Learning Potential Assessment: Introduction
Learning Potential Assessment: Theoretiacal methodological and practical issues (Hamers JHM, Sijtsma K, Ruijssenaars JM Eds) Swets & Zeitlinger, Amsterdam, N.L. Ch2pp 23-42

Sijtsma (1993) Classical and modern test theory with an eye toward Learning Potential Assessment
Learning Potential Assessment: Theoretiacal methodological and practical issues (Hamers JHM, Sijtsma K, Ruijssenaars JM Eds) Swets & Zeitlinger, Amsterdam, N.L. Ch2pp 23-42