2.1 The historical materialist foundations for explaining mental functions

The socio-cultural school of psychology accepts that mental functions depend on the biological evolution of the human organism and its brain, but asserts that they are not direct products of biological evolution. Rather the human brain and its functions develop and form during the history of human social life as a consequence of social (material and theoretical) practice. Since this practice changes historically, it is, in principle, impossible to base the explanation of specific mental functions on the structure and activity of the brain alone.³

This psychology is informed by the Marxian notion of man as a tool-making, tool-using animal. The modes of production and application of these tools are historically transmitted.⁴

3.1 Socio-cultural research¹¹

For Luria's detailed description of this research, see Luria [1974] 1976b; 1979.

Luria and some colleagues carried out socio-cultural research in 1931 and 1932 to confirm the assertion that the development and structure of mental functions depended on appropriation of cultural means within social practice. Research was conducted in villages and rural regions of Uzbekistan and Kirghiszia in Central Asia where people had lived for generations in conditions of backward economy and illiteracy until drastic socioeconomic and cultural changes were introduced in the mid-1920s (Luria [1974] 1976b, 13–14). Schools were established to overcome illiteracy. Agriculture was collectivized and technological innovations were introduced. Short courses were offered for professional training of pre-school teachers and for teaching techniques of elementary agriculture.¹²

The subjects belonged to an ethnically homogeneous population who differed in practical and social activities. Two groups included illiterate women or illiterate peasants who maintained traditional economic and cultural life in isolated mountain areas. Other groups included young people who after minimal professional training were actively involved in the socioeconomic and cultural change: a group of collective-farm activists trained to manage the collective farms, a group of women students in short preschool courses (barely literate), and a group of women students at teachers' schools who had previously received two to three years of schooling.¹³

To study visual perception, classification, and abstraction, an investigator joined a group of subjects, showed them drawings of geometric figures and asked them to name the figures. The non-literate village women named geometric figures as familiar objects. For example, when looking at a square, they named it a window frame; a trapezoid was also named a window frame. A dotted circle and a dotted square were called watches. A complete circle was called a plate, and an incomplete circle was called a bracelet or earring. When asked to say which figures were alike, they classified the geometric forms according to familiar concrete conditions where the object-form usually appeared.

Only the most advanced subjects, the students at teachers' schools, classified geometric figures according to their general configuration (abstracted from concrete conditions) such as a circle, a square, a triangle, etc., even when the figures were incomplete. Most of the other subjects used mainly object-oriented names rather than categorical names. When the subjects were shown pictures of a hammer, a saw, a log, and an ax and were asked to say which ones belonged together, illiterate traditional subjects said that all four things belonged together. When the investigator argued that according to some people only the hammer, saw, and ax belong together, these subjects agreed that a hammer, saw, and ax were tools but insisted that the log had to be there too since these tools are useless without it. Subjects who actively participated in the new socio-cultural and economic way of life immediately classified the working tools as belonging to one category (ibid., 31–47).

The research data showed that perception and classification of objects and of geometric forms by illiterate, traditional subjects was concrete and object-oriented, relying on practical experience. In other words, their forms of cognition and mental activity reflected their concrete and practical experience. For them, the function of words was to establish the practical interrelations among things. When subjects actively participated in new forms of social and economic relations, the structure of their mental functions and processes changed. Since they were now mediated by means of representation (language), their mental functions did not differ from those of educated people who use words for abstracting and generalizing (Luria 1979, 72–84; [1974] 1976b, 13, 17–18, 98–99). Similar results were obtained in tests for categorizing color, perception of visual illusions, logical thought processes (mainly syllogistic reasoning), imagination, and self-awareness.¹⁴

According to the data, cultural-economic changes, changes in social practice, and appropriation of cultural means resulted in the emergence of new mental functions and changes in the structure of each mental function. Mental functions that had depended directly on the individual's experience or on the functional-concrete conditions became abstract verbal (symbolic) and logical functions that depend on the representational system. For example, although the illiterate peasants were familiar with general concepts such as “tools,” or “working tools,” they categorized objects according to familiar concrete situations from their practical experience. The fact that the illiterate peasants knew the general concepts but refused to use them as criteria for classification confirms Luria's claim that acquiring the means and its application depends on social practice and social interrelations within practice. Accordingly, subjects who had acquired some education and were involved in the activities of the collective, categorized objects according to general concepts, abstracting from direct individual experience or concrete conditions, and relying on the categorization of sophisticated language.

3.2 The role of speech in cognitive development

Luria's psychology contends that language is the most important cultural means that affects the development and structure of mental functions. Language does not depend on a particular individual; it is an objective tool, a historically transmitted and accumulated socio-cultural product. Appropriating spoken language is the main factor that affects the child's intellectual and cognitive development from the very first months of life. From the moment of birth, the child's relationship to the surrounding (natural and cultural) objects develops through the mediating help of adults. The child appropriates the language of his environment from adults by shared practice and speech. When adults name objects, they also define the relations between these objects according to the relations established earlier in human history within that language, thus creating in the child new forms for representing reality, for analyzing, generalizing and encoding his own experience (Luria [1974] 1976b, 9). Consequently, all the fundamental cognitive processes of the child are reorganized. In other words, language conditions the development of mental functions by changing the way reality is represented and creating new and complex forms of perception, attention, memory, imagination, thought and action (Luria and Yudovich [1956] 1959, 22–26).

Language is first applied as an external regulating factor when the child performs the verbal instructions of the adult. The child gradually acquires the system of instructions and uses them to regulate his own behavior. Speech, which is primarily a means for communication, becomes the main means for internal analysis and synthesis of reality. Speech also plays a central role in forming complex human behavior such as organized goal-directed activity: Speech is used for verbally formulating goals, for planning their realization and for objectively and critically comparing the outcome with the initial goals.

Luria further claims that the acquisition of speech effects changes in the nervous system by forming new neural connections. He shows that in cases of brain lesions or of abnormal development, the process of forming new connections in the nervous system may be impaired. Therefore, when brain lesions cause speech disturbances, the development of complex mediated mental functions is inhibited (ibid., 30–32).

For instance, when deaf children do not appropriate language and refer to objects by gesture, they are incapable of abstracting the action from the object or of creating abstract concepts, and are limited to categories of objects and conditions that rely on their direct visual and practical experience. Thus deaf children who do not appropriate language do not develop complex perceptual processes. This disturbance can be overcome by acquiring verbal speech. Environmental conditions may also cause retardation in the development of speech, when there is no objective need for active verbal communication within the social environment. Luria's research on twins illustrates such a case (ibid., 34).

4.1. Central concepts in neuropsychology

Luria explicitly stated that his approach to neuropsychology stemmed from his psychological theory. He claimed that psychology and neuropsychology were closely interconnected, since neuropsychology was the science studying the brain systems underlying human mental processes (Luria 1973, 16, 42).¹⁶

4.2. Luria's theory of “the working brain”

Luria's theory of “the working brain” relies on his main psychological assertions; on the definitions of functional system, localization, and symptom; and on data from mainly his own research on brain lesions.¹⁹

According to Luria, the human brain consists of three principal functional units that are necessary for any type of normal mental activity:

• a. A unit for regulating cortical tone or waking;
• b. A unit for obtaining, processing and storing information;
• c. A unit for programming, regulating and verifying mental activity.

The functional units are not homogeneous. Each unit consists of a group of brain areas that carry out different specific elementary functions, and accordingly differ in their anatomy and cytoarchitecture. Luria claims that human “conscious activity… always takes place with the participation of all three units, each of which has its role to play in mental processes and makes its contribution to their performance” (ibid., 43).

His analysis of the brain structures underlying mental functions into functional units, and his discussion of the central role of each functional unit are consistent with his psychological theory. However, most of the theory presents general and rather superficial outlines for normal brain activity and does not explain his objection to fixed localization of mental functions in the human brain, nor the variability in the structure of the functional brain systems underlying mental processes. The flexible and dynamic structure of the functional brain systems is illustrated only in Luria's discussion of ontogenesis.

4.3. “The working brain” in ontogenesis

Luria maintains that in the early stages of mental development, mental activity is based

Changes in the structure of mental functions and in the relationship between the fundamental psychological processes during ontogenesis lead to changes in the structure and organization of their underlying brain systems. The circumscribed brain areas that participate in the activity of a particular functional system change, especially in the hierarchical relations of activity between primary, secondary, and tertiary cortical zones and also in the participation of one and the same circumscribed brain area as a component in a wide variety of diverse functional systems.

Therefore, when brain lesions occur at an early age in brain areas that participate in establishing complex mental processes, retardation and anomaly in all the more complex aspects of intellectual functioning occur, and normal mental development is impaired. Generally development of the proper functioning of the secondary cortical zones in the young child depends on the intact structure and functioning of the primary zones. There is a similar dependence of the tertiary cortical zones on the primary and secondary zones. So a lesion in a cortical area responsible for relatively elementary forms of mental activity in the young child impairs the development of higher structures that are based on this activity, for example, a lesion in the secondary areas of the visual cortex impairs visual thought.

In the adult, however, this dependence is reversed. Because the higher cortical zones have already acquired a dominant role, the functioning of the tertiary zones can sometimes compensate for pathological damage to the secondary or primary zones. For example, a lesion to the secondary areas of the occipital (visual) cortex in the adult causes optic agnosia, but does not affect the more complex forms of thought that had already been formed. Adults suffering from such a lesion are not blind: they can still see the individual features of objects, though they cannot visually recognize the whole object or its pictorial representation. Such a lesion in the adult does not affect speech or intellectual functions, and in fact language can be used in order to compensate, to a certain degree, for the visual disturbances. Adult patients who suffer from optic agnosia may compensate for the visual disturbance by analysis and hypothesis based on the perception of individual features, and by comparing details and deducing the meaning of the perceived image. However, a lesion of “higher” areas in the adult leads to disintegration of the more elementary functions that have already developed a complex structure, and therefore now depend on the activity of a higher order of organization in the brain (Luria 1961; 1963b; 1966; 1973, 32–33, 74–75, 116–119, 232–233; 1979, 126–127; [1962] 1980).

Similar differences between children and adults are found in cases of hearing disability. Deafness in an adult does not cause drastic changes in mental functions that have already developed. However, even a relatively minor hearing disturbance at a young age hinders the child's intact acquisition of speech, and therefore delays further mental development and sometimes leads to slight retardation (Luria 1966, 58–59).

These and other examples clearly illustrate the importance Luria ascribes to the role of sensory and motor mechanisms, and to the role of speaking, reading, and writing for mental development. Sensory and motor mechanisms are essential, since Luria asserts that mental development depends on active interrelations with the socio-cultural environment, and that spoken and written language are the main cultural means that condition the development of all higher mental functions.

5.1 Rehabilitation

Most of Luria's research concerns cases of lesions in circumscribed brain areas. In such cases, rehabilitation of higher mental or behavioral functions cannot be achieved by restoring the activity of the lesioned brain zones since there is no regeneration of destroyed nerve cells in the human brain (Luria [1948] 1963a, 32). Cases of partial spontaneous restoration (or restoration after long rehabilitation training) of mental functions after brain injury are often explained by transfer of the higher mental function to the corresponding area in the opposite hemisphere. Luria rejects this explanation, claiming that restoration of a mental function by such transfer is rare (Luria [1947] 1970, 457). He argues that in most cases, the rehabilitation of a disordered mental function due to local brain damage is possible by reconstructing or reorganizing a new structure for the damaged brain system (Luria [1948] 1963a, 55; [1947] 1970, 382–383).²²

Sometimes partial or full spontaneous rehabilitation occurs in brain-damaged patients at an unconscious level. For example, lesions to part of the visual field (as an outcome of partial damage to the retina, to the optic nerve, or to the primary visual areas of the cortex) are sometimes spontaneously rehabilitated when quick eye movements are used to reorganize the visual system. Even in cases of brain lesions in parts of the motor cortex that cause paralysis of a certain organ, the damage can sometimes be compensated for in a relatively simple way by performing the movement using other intact parts of the motor system (Luria [1948] 1963a, 52, 55–58).

Rehabilitation of complex functions by compensation is also well known in cases of physical injuries where intact limbs take over the role of the injured or missing limb, and the motor function is unconsciously reorganized. Moreover, it is possible to partly restore the function of a physically injured limb within its own motor system by reorganizing the motor function on a conscious level (ibid., 44–47). The same approach can also be used for rehabilitation in cases of brain damage, when, as in most cases, the rehabilitation does not occur spontaneously. When rehabilitation is not spontaneous, Luria's methods focus on appropriating external cultural means as auxiliary aids for developing new functional brain systems. The damaged functional brain systems will reorganize by including the external auxiliary means in the newly formed functional systems.²³

Luria describes the use of auxiliary means to rebuild a disrupted functional system after brain injury by analogy to the use of prostheses to compensate for the amputation of a limb. Suitable auxiliary external aids to compensate for damaged links in the functional system are selected and offered to the patient after diagnosing the complex of symptoms and identifying which brain centers were not damaged. Therefore, each case of rehabilitation requires not only an accurate and detailed diagnosis of the disturbance in the disordered function, but also an accurate diagnosis of the disturbance in the language system and in any other components related to the appropriation and application of cultural means.

The rehabilitation treatment is ultimately aimed at enabling patients to appropriate and internalize the auxiliary means so that they no longer need these aids and can automatically perform the activity that was impaired. However, a prolonged period of retraining may be needed in order to build and stabilize the new functional system. In fact, only in few cases are the external means fully internalized and newly structured internal functional systems formed. In most cases, reorganization of the complex functional system does not become fully automatic or unconscious, but requires constant conscious regulation of the mental function (Luria [1947] 1970, 382, 457–458; 1979, 143–144).²⁴

5.2 Methods for reorganizing (rehabilitating) mental functions

Rehabilitation after brain injury can be achieved by two different methods. One method can be used only when the brain areas of the more elementary function were not damaged. Repetitious training of some intact residual automatisms can then be used to reorganize the disturbed function on a more primitive and automatic level of activity. However, Luria maintains that this method limits the possibilities for maximum restoration of the mental function.

A better method is transferring the performance of the disturbed function to a higher, conscious level (Luria [1947] 1970, 385) by applying external auxiliary means, especially the language system – speech, writing, reading, and other sign systems – to compensate for the damaged parts of the functional system and reorganize it. Thus speech (or more generally language) is often included in the new structure of the functional system. This method depends on an accurate diagnosis and may require more effort, but according to Luria usually leads to better results, and is the method applied in most of the cases he describes. This is the method he chose in cases of damage to cortical centers that resulted in disturbance of a higher functional system as well as in cases of damage to sub-cortical brain structures. In fact this method is similar to the way mental functions develop in ontogenesis, by applying and internalizing language and other cultural means. During treatment, the patient first acquires the external application of the auxiliary means. At first, the restored activity requires much effort and is performed very slowly. However, after internalization of the auxiliary means, the disordered function reorganizes, and gradually becomes more automatic. In some cases, the patient internalizes this application after long practice; however, the signs of the reorganization rarely disappear completely. Nevertheless, Luria argues that this is the most effective method for the rehabilitation of mental functions after circumscribed brain damage (Luria [1948] 1963a, 62–65, 69, 72–77; [1947] 1970, 387–388). He gives examples of brain-injured patients who could say only a few spontaneous words, but not simple sentences even after several years of attempts to strengthen residual speech automatisms. Two or three months after changing the rehabilitation methods and directing them to conscious reorganization of the defective components, considerable improvement in speech was observed (Luria [1948] 1963a, 73–76).

Another case was a patient who suffered a parasagittal shrapnel wound in the pre-motor area of the cortex (Luria [1947] 1970, 386–387) and lost his ability to perform complex voluntary movement smoothly and skillfully. For instance, he could not voluntarily tap various rhythms with his finger. Attempts to train the patient to perform the action by repeated practice did not help. However, by learning to use external auxiliary means for reorganizing the function on a conscious level, the patient's ability to perform these coordinated movements was restored. When the patient was told to count out loud as he tapped, he immediately managed to master the rhythm. Visual representation of the rhythm as external signs achieved similar results, enabling the patient to tap the rhythm, thus again constructing the new functional system on a conscious level. At first the patient's activity had to be fully conscious, and relied entirely on the mediation of the external auxiliary means. However, after a short period of training he could count internally to himself or create an internal image of the representation, and thus rely on this image to tap the rhythm. On the surface, his activity was identical to the normal activity before brain injury; however, the newly organized function had to be totally conscious, and the patient was aware that the underlying mechanism was different. During treatment, the patient showed great skill in devising auxiliary means to tap the rhythm. Yet if forced to give up verbal mediators, his ability to tap rhythmically was immediately destroyed. Even after a prolonged period of practice, the patient did not develop automatism for this process (for more examples, see Luria, [1948] 1963a, 59–69).

Luria used similar methods of applying external auxiliary means consciously for rehabilitating active thinking. One of the patients, aged 34 years, suffered from a non-penetrating wound of the pre-motor region close to the upper part of the pre-motor area with a parasagittal depressed fracture of the skull. The patient lost automaticity of all the higher mental processes, and although he did not suffer from any motor or articulation problems, he could not perform a continuous series of movements smoothly, and could not produce fluent spontaneous speech. Though the patient had no difficulty in giving short replies to questions, he was incapable of fluent narrative speech. He complained of the loss of fluency of speech and thought. When asked to relate a short story after it was read to him, to write a composition, or to describe a picture, he used separate disjointed phrases, though he could relate the story and describe the picture perfectly in the form of answers to separate questions. During rehabilitation treatment, the patient was given a card with a series of words that could be used as “transition formulas” such as “once upon a time,” “once,” “then,” “however,” “whereas,” “after,” “since.” Using this card, the patient learned fluency in relating a story, describing a picture, or organizing his fragmented thoughts. Initially these formulas were applied as external supports between the separate parts of his description or thoughts. With practice they began to develop spontaneously and the patient started to actively seek the adequate formulas for orienting his thoughts and for developing fluency of thought and of narrative speech (Luria [1948] 1963a, 17–21, 215–220; [1947] 1970, 452–457).

Complete or even partial success of Luria's rehabilitation program demonstrates that by applying external auxiliary means, it is possible to reconstruct a functional brain system from brain components that differ from the original components in the intact brain. Such successful cases of rehabilitation emphasize the cultural-historical nature of higher human mental functions, and refute the assumption that higher mental functions are localized in fixed or innately determined circumscribed brain areas. The fact that it was possible to rehabilitate cases of circumscribed brain damage by applying (and in most successful cases internalizing) external auxiliary means shows that cultural means and their appropriation are crucial for the development and structure of mental functions. Successful rehabilitation by Luria's methods confirms the assumption that the development of mental functions and their structure are culturally dependent. In addition it confirms Luria's assertion that the development of mental functions during ontogenesis depends on the appropriation of cultural means. In fact, Luria's clinical work, i.e. his methods of diagnosis and rehabilitation confirm his main psychological and neuropsychological assertions.