Endnote for Lecture 7: The Laws of Development of the Nervous System
With this lecture, Vygotsky ends his course in the foundations of pedology, Accordingly, Vygotsky
looks back to previous chapters and notes their similarities. Although there is no general “law” of
development which covers every aspect of development even within the psychological line of
development or the physiological line of development, there are still patterns that occur in both forms
of development and even in the development of systems. For example, Vygotsky notes that both
kinds of development are uneven, that both are characterized by changing and even reversible
dominances and dependencies, and that in the course of development damage to a lower
psychological function and to a lower physiological system are both more damaging to a child than to
an adult, because the child cannot use higher functions or higher systems to compensate. A child who
loses hearing before she or he acquires the ability to speak is in a very different situation from a
speaking adult who grows hard of hearing in old age.
Vygotsky is also looking forward to the next course he will build on these foundations, namely the
course on age periods. So on the one hand, development means that new higher centres arise and
control other systems and their functions as a whole. For example, the nervous system arises and
controls the other systems of the body, and within the nervous system, the higher nervous system,
and within the higher nervous system, the brain and the higher centres associated with speech. But
on the other, the child’s functions and systems must be able to function as a whole without this higher
centre for the higher centre to arise in the first place. Development provide a natural experiment,
showing us what the whole system was like without the centre, and how it is raised to a qualitatively
different level by the emergence of the higher centre. Of course, this means that development cannot
be reduced to growth, nor is it reducible to one higher centre replacing another; it must involve the
revolutionary reorganization of the whole. That is precisely what the lectures on the age periods must
describe (to be published by 살림터 in 2016).
Vygotsky begins with three basic laws of development: the transfer of functions from lower centres to
higher ones, the conservation of functions in a subordinated, controlled form by lower centres, and the
‘emancipation’ of lower nervous centres in the case of the failure of the higher centres (7-1~7-18). But
once again, Vygotsky demands that we revise and amend the last law to take account of
development: it appears that under some conditions, adults can use higher functions to overcome the
loss of lower functions by sheer will power, an option that appears to be unavailable to children; this
yields a fourth law, which explains why the same neurological lesion looks so different in adults and in
children: in children, centres which are developmentally above the lesion will suffer more disruption,
while in adults it is centres which are developmentally low which will be more impaired (7-19~7-38).
Vygotsky promises some general conclusions linking the development of the brain to psychological
development, and in the end he generalizes further still: noting that all forms of development—
psychological and physiological, endocrine and neurological—have in common patterns of growth and
differentiation, and by speculating that it is not growth which pushes forward development or even
development that somehow drags growth behind it; instead, growth realizes and is the outcome of
development. (7-39~7-45)
I Introduction: Three Laws of Development. With scarcely any introduction at all, Vygotsky lays out
the three “customary” laws of neurological development (7-1~7-18).
A) The first law is that functions which are initially carried out in lower “centres” of the nervous system
are subsequently taken over by higher centres when these emerge (7-3). The law is first of all a
phylogenetic observation. Vygotsky points out that the brain develops in layers during evolution: the
basis of lower elementary functions such as breathing and heartbeat is the same in almost all animals
(that is, it is located in the midbrain and the medulla). In fish and frogs, we see the emergence of a
cerebellum, in reptiles the cerebrum appears, but it is only in mammals and especially in man that the
the cerebrum begins to make up the bulk of the brain. Vygotsky then turns his attention to
ontogenesis and to brain functions. He notes that in little babies there are movements which resemble
the movements of lower animals (squirming and writhing and reflexes such as Babinsky’s reflex) but
that these disappear as higher brain “centres” mature. They only reappear in cases of brain lesions,
for reasons explained by the second law (7-4~7-9).
B) The second law is that lower centres that transfer their functions to higher centres retain the ability
to perform the function, but they do so only under the control of higher brain centres. Vygotsky argues
that this higher control of a function makes the function more flexible, more responsive, and above all
more voluntary. One example of this is locomotion: if we wish to see what walking is like without the
direction of higher centres, we have only to examine patients where the areas of the cerebral cortex
which are involved in the control of walking have been affected by a brain lesion, and we see that the
person’s walking begins to resemble that of lower animals, and can even be completely paralyzed. (710~7-14).
C) The third law is a generalization of this example. Vygotsky says that in any case where a higher
centre has already emerged (e.g. in an adult) and taken over control of functions from lower centres, if
the higher centre is disabled, the function can be resumed by the lower centres. Vygotsky points out
two corollaries of the law. The first is that in cases of brain lesions, we see a reversion to
developmentally primitive forms of behavior. The second is simply the converse of this: in early
moments of development, we see primitive forms of behavior that are analogous to pathological
symptoms. So for example in the case of a brain lesion, adults will sometimes develop a Babinsky
reflex, and the Babinsky reflex in infants reminds Vygotsky of adult pathology. Similarly, in the case of
a brain lesion, perception becomes unreliable and it is difficult to resolve objects (agnosia), which
reminds Vygotsky of perception in infants, and perception in infants appears to Vygotsky to be similar
to what is reported in pathological brain conditions. Vygotsky explains this by the “emancipation” of
the lower centres, and their resumption of the functions previously transferred upwards (7-15~7-18).
D) However, Vygotsky warns that this analogy is misleading. First of all, it is an analogy between two
functions considered statically. When we consider ontogenetic and pathogenetic development
dynamically, we see iimmediately that they are headed in opposite directions, and their momentary
coincidence is a little like a train going from Moscow to Leningrad which passes the train going from
Leningrad to Moscow (7-19~7-21). Earlier,Vygotsky introduced these laws of development of the
nervous system as conventional (7-2) and remarked that the third law, in particular, would require
revision and amendment (7-15). This revision is what Vygotsky undertakes in the next section.
II Revision of the Third Law. In this section, Vygotsky argues that while “emancipation of the lower
centres” can result in introvolution, as when in a commander is wounded in battle and the enlisted
men are left leaderless or the commander’s place is taken by a lower officer (7-22). There is,
Vygotsky argues, another possibility: a still higher centre may take control. This is the basis for the
argument that Vygotsky makes for circuitous and indirect forms of compensation that Vygotsky makes
in his “defectological” works, and also in Chapter One of History and Development. He offers a
number of examples from clinical practice. (7-22~7-38).
A) Vygotsky’s first example of compensation by still higher centres is precisely the example of
agnosia given in laying out the Third Law. Unlike the infant, who does not yet have higher centres, an
adult suffering from agnosia can mobilize reason, hypothesizing, and interpreting, as normal people
do when they find themselves suddenly in an unexpected situation (7-23). This explains why, for
example, a man might mistake a pair of scissors for a pair of eyeglasses, or even mistake his wife for
a hat. Vygotsky reminds us that in the presentation of the Third Law, there were two corollaries—one
comparing early stages of ontogenesis to pathogenesis, and one comparing pathogenesis to early
development. While the second corollary seemed irrelevant to development, Vygotsky now shows
that it is in fact relevant to developmental pathology: the same pathological condition can have very
different significance at different points in development (7-25). For example, a person who is born
deaf will not develop speech in the same way as a person who goes deaf after speech acquisition has
taken place (7-25~7-26).
B) Vygotsky says that just as the same pathological condition can have different significances,
different pathological conditions can have the same significance (7-27). Vygotsky then generalizes
this. If a child suffers a lesion in a given centre B, the child’s higher centre C, as yet undeveloped, will
be hard hit, while the lower centre A will be relatively unaffected, but with an adult, the reverse
situation obtains: the higher centre A will be developed and intact, and in a position to compensate for
the loss of B, but the lower centre C will be affected. (7-27~-7-28).
C) Vygotsky offers clinical examples in support of this generalization from epidemic encephalitis, a
brain inflammation that was epidemic in Vygotsky’s time, appears to lead to uncontrollable activity in
children, but a state of near immobility in adults (7-29~7-30).
1. A patient who cannot perform a lower function may be induced to do so by invoking a
higher function. So for example a patient may not be able to put one foot in front of another and walk
on a level floor, but if a chair is placed in the patient’s path, or if the patient is asked to walk upstairs,
the patient finds it possible to step up and over (7-31). Similarly, a patient who cannot close his eyes
at will finds it possible to do so if he is asked to role play sleep (7-32).
2. A patient who cannot click a telegraph key or who does so slowly may be asked to use the
key to indicate his age in years, and then finds it possible to click thirty seven times (7-33).
D) Vygotsky argues that the situation is somewhat similar to the situation we observed in the last
lecture, with endocrine development. That is, if the pituitary gland does not develop in a child, then the
sex glands do not develop normally either (pituitary dwarfism). But if the sex glands do not develop
normally in an adolescent, then the pituitary does not undergo its normal involution (eunuchoid
growth). In development, then, the higher centre C depends on the development of the lower centre B,
but in a developed organism, the lower centres B depends on the higher centre C (where “dependent”
is understood as the relationship between an independent and a dependent variable). (7-35~7-38).
III Conclusion: Growth Emerging from Development. Vygotsky now presents a set of general
conclusions, which are clearly aimed towards the next course on the syllabus (7-39~7-45).
A) Vygotsky notes that all of the processes explored in this course—psychological and physiological
development in general, as well as endocrine and nervous development—are part of a complex but
unitary process of development. Without the brain, the mind does not develop. But without the
endocrine glands, the brain does not develop either. This complex interdependency explains why
there are general patterns, and also why there are no domain-specific laws that explain any one
process exhaustively (7-40).
B) Vygotsky says that this complex but unitary process may be understood as a set of age periods,
and that it is the change of internal relations within a stage which permits ascent to the a new stage.
At the beginning, everything depends on the relationship between lower centres. But as higher
centres emerge, these lower centres become dependent on them in turn. This appears to be as true
of the brain centres as it was of the endocrine glands, and from this Vygotsky concludes that the
central fact of development is the organization of relations between organs in a system, and between
systems in a complex whole. (7-41~7-43)
C) Vygotsky concludes with the idea, which he attributes to a researcher in the field of child anatomy,
that if we think of development chiefly in terms of bulk, we have to say that it is only at the beginning
that development is intensive (e.g. it is only in infancy that the child doubles his or her weight in a
single year). But if we think of development in terms of inter-systemic relations, we have to say that on
the contrary, there is very little development in the early months of life, and that instead development
increases with age. Vygotsky takes this even further, and suggests that viewed qualitatively, even
growth changes, and that growth is not the cause but the realization of development (7-44~7-45).