It’s hard to have a discussion about learning without someone sooner or later chipping in with the Russian developmental psychologist, Lev Vygotsky’s zone of proximal development (ZPD) to support their position. This might, in part, be because Vygotsky is one of the very few theorists covered in many teachers’ training, but it’s also because it feels intuitively right.

Briefly, most people use ZPD to suggest that there is a ‘Goldilocks Effect’ where the level of challenge for a child is ‘just right. If work is too easy, it’s argued, then no learning will take place, and if it’s too hard, then it will be inaccessible and students will become frustrated. Vygotsky himself describes ZPD as, “the distance between the actual developmental level as determined by independent problem solving and the level of potential development as determined through problem solving under adult guidance or in collaboration with more capable peers” (Vygotsky, 1978, p. 86).

But, as Seth Chaiklin says in this paper, “popularity has its price”:

Wertsch (1984) suggested that if this theoretical construct was not elaborated further, then there was a risk that “it will be used loosely and indiscriminately, thereby becoming so amorphous that it loses all explanatory power” (p. 7). Mercer and Fisher (1992) believe that “there is a danger that the term is used as little more than a fashionable alternative to Piagetian terminology or the concept of IQ for describing individual differences in attainment or potential” (p. 342). Palinscar (1998) suggests that in the context of research about the negotiated nature of teaching and learning it is “probably one of the most used and least understood constructs to appear in contemporary educational literature” (p. 370). (Chaiklin p. 2)

Clearly, there’s a common sense aspect appeal. It stands to reason that a novice will be able to achieve more if helped by an expert, and it also follows that the experience of working in collaboration with an expert might result in the novice being able to replicate a process independently. But, Chaiklin identifies three rarely articulated assumptions which underlie this assumption:

  1. The generality assumption: that there is a ZPD for learning every different kind of subject matter
  2. The assistance assumption: that learning is dependent on support from an expert
  3. The potential assumption: that teaching in the ZPD will result in easy or effortless learning.

This understanding of ZPD, “supports or inspires a vision of educational perfection, in which the insightful (or lucky) teacher is able to help a child master, effortlessly and joyfully, whatever subject matter is on the day’s program.” This might lead teachers to believe that it is possible to identify a child’s zone of proximal development for each learning task, discover how to teach in a way that will be sure to engage the zone of proximal development so that learning will significantly accelerate in a smooth and joyful way. This is a tempting proposition but one that is unsupported by Evidence of even by Vygotsky’s own writings.

In order to understand the problems with the way ZPD is applied in educational contexts we need to critique each of the three assumptions in turn.

The generality assumption

If Vygotsky had intended ZPD to apply to all learning situations, why didn’t he call his theory the ‘zone of proximal learning’? Let’s not forget that Vygotsky was primarily concerned with child development and he developed the concept to help consider the development of children in general rather than to any or all particular skills or domains of knowledge. Vygotsky believed, like Piaget, that learning occurred in clearly defined developmental stages. When a child moved from stage to another she would acquire new “psychological processes” which make more advanced learning possible. We can think of his theory like this: learning within one stage of development which leads to children access a new stage and thus more advanced learning. And so on until maturity. In this worldview, there are blurred edges between different developmental zones and that if learning situations are focussed correctly, children can be assisted in moving from one developmental stage to the next. As I explained in this post, this sort of model of child development is now considered to be wrong. 

The assistance assumption

Vygotsky was interested in exploring the well-known ‘fact’ that “with collaboration, direction, or some kind of help the child is always able to do more and solve more difficult tasks than he can independently” (Vygotsky, 1934/1987, p. 209). This may be true, but he saw the more important question as being why. Why is it that collaboration and direction help move children to independent performance. More recent research into practice and expertise indicates that this has something to do with children establishing mental representations or models of what independent performance looks like. If you just watch someone else perform a task then often you are left with very little idea about the processes they went through to achieve success. But, if you collaborate with, or receive direction from an expert then they share their own mental representation with you and explain their thought processes with you. Once we know that establishing effective mental representations is they key, then we can start to see how this might be achieved without requiring one-to-one assistance.

The potential assumption

It’s quite clear from Vygotsky’s own writings that learning within a ZPD must be enjoyable – he even discusses how losing a race might be an important developmental event. More importantly though, he did not think that potential was a property of the child, instead he thought of it as a property of the learning situation which might – or might not – contain the potential to move a children from one developmental stage to the next. What we can infer from this is that it would be a mistake to believe that there is a ‘sweet spot’ in every child which teachers need to discover and then target instruction. Instead, Vygotsky saw learning within the ZPD as instruction in a domain which was likely to advance a child’s psychological development.

With all this in mind we can perhaps conclude that bandying about the term ZPD is unhelpfully vague and imprecise. Learning and development are obviously closely linked but they’re not synonymous. At one level we can make claims such as ‘all learning is development’ or ‘all development requires learning’ but then we’re in danger of using circular logic. These statements are meaninglessly tautological.

I have to thank Dylan Wiliam put putting me on to the Chaiklin article, and  helping me formulate my objections to the way ZPD is used in education debate. In our email exchange he sums up the situation in typically pithy and uncompromising style:

The trouble is that most people who use the term ZPD apply it to learning, not development. In other words, they think that if a child cannot add fractions on their own, but can do with the help of a higher-achieving peer, they are somehow working in the ZPD. They are not. If anything, they are working in their zone of proximal learning, which when you think about it, is a fairly vacuous notion, since the purpose of all education is to help children do things they couldn’t do. And this is why I claim that almost everyone who uses the term ZPD is (a) using it in a different sense from Vygotsky, and (b) talking bollocks because they are making something simple sound complicated and academic.