LEFT – HANDED CHILDREN AND THE LEARNING PROCESS

ДЕТИ – ЛЕВШИ И ПРОЦЕСС ОБУЧЕНИЯ

Дюсембеева Руфина Маратқызы

студент Западно-Казахстанский университет имени Махамбета Утемисова, Казахстан, г. Уральск

Abstract. The article provides a brief overview of theories on the causes of left-handedness. It discusses the functioning of the left and right hemispheres of the brain, as well as the mechanisms of their interaction. Special attention is given to speech, as the most complex function of the brain. It is emphasized that in the educational process, teachers and parents should take into account the specific characteristics of left-handedness, as this affects the success of their learning and the quality of social functioning.

Аннотация. В статье представлен краткий обзор теорий о причинах леворукости. В ней обсуждается функционирование левого и правого полушарий головного мозга, а также механизмы их взаимодействия. Особое внимание уделяется речи, как наиболее сложной функции мозга. Подчеркивается, что в образовательном процессе учителя и родители должны учитывать особенности леворукости, так как это влияет на успешность их обучения и качество социального функционирования.

Keywords: Left-handedness, interhemispheric interaction, asymmetry, speech process, education.

Ключевые слова: леворукость, межполушарное взаимодействие, асимметрия, речевой процесс, образование.

Introduction.

Left-handers, like those who differed from the majority with some individual characteristics, have always aroused curiosity and attracted heightened interest. Typically, the attitude towards left-handers was wary, and sometimes even sharply negative. Such an attitude has been manifested in many cultures and languages. For example, in the Russian language, there are still numerous examples of this kind: "левый товар" (left goods) refers to goods sold illicitly (in an illegal manner) or counterfeit, fake goods. Similarly, there are terms like "левый доход" (left income) and "левые деньги" (left money). In English, the word "left-handed" also has other meanings – "sinister," "hypocritical," "awkward," and "illegal." Similar examples can be found in other languages as well.

Regarding the origins of right-handedness and left-handedness, there are many interesting hypotheses, the listing of which would require writing a separate book. It is now proven that not labour and articulate speech were the causes of asymmetry. It arose in the process of evolution as an important adaptive feature even among our animal ancestors, which, ultimately, allowed the human species to occupy a leading position in the existing world of animals on Earth.

Throughout different epochs, the number of left-handers appears constant, making up about 7–8% of the population. Ambidextrous individuals, i.e., those equally proficient with both their left and right hands, are roughly twice as numerous. Left-handedness occurs 1.5–2 times more often in men than in women, which is attributed to the lesser specialization of hemispheres in women and their greater ease of retraining at an early age. In cases of various brain injuries in one hemisphere, left-handers exhibit disorders never seen in right-handers. Such disorders include mirror writing, i.e., writing all letters in reverse, as in a mirror image, mirror reading, mirror perception, the phenomenon of expanded visual space, and the phenomenon of anticipation, i.e., the accurate description of events that have not yet occurred and that happen later. Many of them show increased tactile sensitivity. For example, they can identify the colour of objects with their eyes closed and sometimes perceive their images on paper. Their psyche is more vulnerable, mood fluctuations more pronounced, and they often experience unaccountable anxiety and stress. Left-handers typically possess a more vivid imagination, artistic inclinations, transformation abilities, and a unique view of the world around them. Notably, left-handers have included sculptor Michelangelo, Leonardo da Vinci, artist Picasso, actor Charlie Chaplin, and many other art representatives.

Today, there is a prevailing notion that left-handers are unfortunate people because "the whole world" is against them. Indeed, upon closer observation, it's easy to notice that everything in our daily lives is adapted for right-handed individuals. And this is not surprising: left-handers still make up only 6–11% of the world's population, according to various sources.

In recent times, the phenomenon of left-handedness has been actively studied. The results obtained allow for a change in the stereotypical perception of left-handers, which makes it possible to develop teaching methodologies for them. In the past, left-handers in schools were often forced to retrain, to be "fitted" into a right-handed class (and for the teacher as well), but today, educators are aware that this is extremely harmful. They understand the need for an individual approach to left-handed children, using different teaching methods that are more natural for them and therefore more effective.

Main Part.

To this day, there is no consensus on the cause of left-handedness. The most developed and scientifically substantiated theory is that of the functional asymmetry of the brain's hemispheres. We will examine these theoretical foundations in more detail, as we consider them to be leading in this phenomenon.

Let's start with human speech, as the most delicate, fragile, and complex function of the brain. Well-developed speech is precisely the feature that sharply distinguishes humans from the animal world. The mechanisms of speech and their representation in the brain's structures have always been the subject of keen interest among researchers. However, it should be noted that systematic observations on this subject have not been conducted as long as one might imagine: only since the 1830s. It was during this time, more precisely in 1836, that the French doctor M. Dax presented at a medical society a report in which he summarized the observations of 40 patients suffering from loss of speech due to brain haemorrhages. All the patients had damage to the left hemisphere, which, in addition to speech disorders, caused partial paralysis of the right limbs. Here it's important to recall the anatomical structure of the nervous system. The left half of the brain controls the right half of the body, and the right half controls the left half. This feature is due to the crossing of nerve paths exiting the brain at the level of its stem structures. Therefore, paralysis of the right limbs indicates damage to the left hemisphere and vice versa. From his observations, Dax made a valid conclusion that speech is controlled by the left hemisphere.

The most comprehensive evidence of hemispheric asymmetry was provided by the French physician P. Broca. Like Dax, he observed patients with loss of speech and always found accompanying paralysis of the right limbs. The brain area whose damage causes loss of speech—aphasia—in medical terminology, has firmly entered science under the name "Broca's area." It is located in the left hemisphere in the lower third of the frontal lobe near the anterior central gyrus. Further research noted that aphasia could exist in several forms. What Broca observed is now called expressive aphasia and is characterised by impairment of the patient's speech. Understanding of others' speech remains intact. Such a patient either does not speak at all or speaks with great difficulty, stuttering, and long pauses, without intonation and with disrupted grammatical construction of sentences. An accompanying disorder of writing is observed, but the understanding of written speech is preserved.

Another type of speech disorder, mainly associated with the understanding of speech, was first described in 1874 by the German researcher K. Wernicke, who, like Broca, linked this disorder to a specific area of the brain. This area is now called "Wernicke's area." It is also located in the left hemisphere, in the posterior part of the first temporal gyrus between the primary auditory cortex—the area of the brain's cortex where signals from the auditory organs arrive—and the angular gyrus, where visual signals are transformed into auditory ones. Damage to Wernicke's area leads to receptive aphasia: the patient has significant difficulties in understanding speech but loses the ability to speak to a much lesser extent. The fluency and rhythmic emphasis of speech may be preserved. Moreover, unlike patients with expressive aphasia, patients with receptive aphasia do not notice defects in their speech and become angry when others do not understand them.

Even today, after so many years and the acquisition of numerous new data, Wernicke's model is still considered accurate. According to his concept, the understanding of speech and the construction of phrases occur in the area named after him. From there, information is transmitted to Broca's area, which details the program and issues commands to the corresponding muscles to form voice sounds. The realization of the motor response, i.e., movements of the lips and tongue, occurs through the motor fields of the anterior central gyrus. A heard word reaches the primary auditory cortex, located near Wernicke's area, where the auditory signal is directly recognized at the speech level. In the case of visual perception of a word (reading), it first arrives at the visual cortex, located in the occipital regions of the brain. From there, the information goes to the angular gyrus, where it is translated into a form accessible for Wernicke's area, i.e., into the code of auditory receptors.

All the processes described above occur exclusively in the left hemisphere of the brain. But what about the right hemisphere? What are its functions? If the left hemisphere operates with words, meaning it processes thoughts and logically is considered leading or dominant in the overall brain function. For a long time, this view of the hemispheres' operation prevailed among scientists. However, the last 40-60 years have brought significant revisions to these views.

It was established that contrary to popular belief, only 15% of left-handers have their speech centres located in the right hemisphere. For 70% of left-handers, like right-handers, the left hemisphere performs speech functions, and in 15% of cases, speech centres are present in both the left and right hemispheres of the brain.

There is a significant difference in the speech specialization of the hemispheres between men and women. In males, hemisphere specialization is formed by the ages of 5–7, while in females, it does not form until at least age 13, and sometimes not at all. In women, even during prenatal development, an auxiliary speech centre located near Wernicke's area and later involved in the formation of syllabic speech is duplicated, moving from the left hemisphere to the right. Thanks to this feature, girls begin to speak earlier and are more capable of learning languages than boys. The same characteristic is observed in left-handed men. Naturally, the presence of an additional speech centre in the right hemisphere somewhat reduces its capacity for imaginative thinking and the thought processes based on it. Specifically, abilities for foresight, intuition, etc. A broader representation of speech functions leads to a preference for using verbal-analytical strategies in solving non-verbal tasks. This can significantly slow down the speed of thought processes, as the volume of information processed using an imagery strategy, characteristic of the right hemisphere, is 10^6 times greater per unit of time than with a verbal strategy.

What conclusions can be drawn based on all the data obtained using various methods in healthy and sick individuals over the past decades? Has the theory of the left hemisphere's dominance in right-handers been confirmed? No, interhemispheric relations appear much more flexible than previously thought. Indeed, speech functions are governed by the left hemisphere, but not as completely as assumed. The fact is that the right hemisphere is involved in processing all signals received by the brain, including speech signals. Primary parametric processing includes the distribution of signals by pitch, volume, and some other physical characteristics, without which further circulation of the signal in the brain is impossible. In case of damage to the right hemisphere, the left hemisphere can take over these functions, but it will perform them much slower and less efficiently, and in complex cases, it may not cope at all. This is akin to a novice starting to work instead of a master professional. There are no skills, no dexterity, and the tools are not the same. Therefore, injuries to the right hemisphere also affect speech functions in right-handers, albeit less noticeably than injuries to the left hemisphere.

In Fesenko.Y. A, & Lokhov.M. I research, for example, it was found that in 80% of cases of stuttering in children, there are visible EEG disturbances in the function of the parietal-temporal zone of the right hemisphere of the brain [1]. In addition to inefficiently performing functions that are not inherent to it, the left hemisphere becomes overloaded due to additional work and starts to perform its direct activities worse, which causes stuttering.

In addition to complex interactions, there are several functional features inherent to each hemisphere. One of the most important features is undoubtedly the method of information processing and the associated thought processes. The left hemisphere is characterized by logical processing, expressed in symbolic form, and the method of processing itself is quite similar, apparently, to the principles embedded in modern electronic computers. Symbolic information is fixed in spatial and temporal coordinates, making it easily comprehensible. However, this feature is completely alien to the right hemisphere, which operates with images and more resembles an analogue computer, albeit with even greater stretches in comparison to computers for the left hemisphere. The mental processes of image formation turn out to be fundamentally non-conscious, as their most important feature is the inability to organize information in spatiotemporal coordinates. Likely, a processing method based on holographic principles is used here.

The unconscious has always seemed strange and frightening to people. In this context, the observations of psychologist L. V. Zankov are very interesting, he noted that the right half-space, associated with the left hemisphere of the brain, is associated with truth, a bright world, kindness, and clarity [2]. The left half-space is endowed with opposite properties. Analysis of the oldest and later works of art shows a reliable predominance of left-to-right direction in the movement of depicted objects. Even the examination of Neolithic art (cave paintings) shows that the depicted animals move from left to right and are presented with their right profile. Psychologically, this coincides with the process of turning the flow of images from the unconscious right hemisphere into a real symbol. "By depicting animals, the artist thereby summoned them from non-existence, from the otherworldly realm; the act of creation was simultaneously an act of creation."

Summarizing all the data available to date on the functioning of the brain hemispheres, it can be noted that the most characteristic feature is not dominance but interaction, based not only on some duplication of functions, and their complementarity but also on some opposition.

Now let's turn to the question of some other causes of left-handedness. The most common is so-called genetic left-handedness. To date, the mechanisms of transmission of this trait are not precisely known, but it has been reliably established that left-handedness occurs approximately 10 times more frequently in families where at least one parent is left-handed. Genetic left-handers may not have any developmental disorders, in which case this is considered simply an individual peculiarity, a variant of normal development.

There is also what is called "compensatory left-handedness," associated with brain damage of any genesis, more often, as mentioned above, its left hemisphere. Since the activity of the right hand is regulated by the left hemisphere, its damage at an early stage of a child's development causes the corresponding functions to be taken over by the right hemisphere: the left hand becomes the leading, more active one in performing daily actions, including writing.

"Hidden left-handedness" is also encountered in children. This refers to a change in the dominant hemisphere. We have discussed the critical period when the main functions of the brain are evenly distributed between the two hemispheres, after which specialization occurs (in boys, hemisphere specialization is formed by the ages of 5–7, in girls not before 13). At such a critical moment in "hidden left-handers," the right hemisphere begins to dominate, and they are often called "hidden" or "psychic" left-handers, implying that their left-handedness traits are not associated with the dominance of the left hand in a "pure" form.

"Enforced left-handedness" should also be mentioned, where the choice of the leading hand is associated with an injury to the right hand. This form of left-handedness can also be the result of imitating someone significant (family, friends, etc.).

Pseudoleft-handedness. This refers to atypical mental development, where, during the critical period, children do not develop a dominant hemisphere concerning the hand. In this case, there is roughly equal use of both hands. It can also happen that a child eats with the right hand but writes with the left.

Conclusions.

To ensure the success of a left-handed child in their education, both educators and parents need to understand the reasons behind their left-handedness. These reasons can vary, and they may affect the development of certain individual qualities in the child.

Left-handedness offers some advantages in sports that require quick reactions, such as boxing, wrestling, tennis, etc. In right-handed individuals, the image is perceived by the right hemisphere, and motor commands are sent from the left hemisphere to the right hand. In left-handers, everything happens within one hemisphere, so the speed of movement execution is greater. From all this, it follows that a left-hander cannot be considered simply as a "right-hander in reverse." It represents a unique and original arrangement of the central nervous system.

If there is reason to believe that a child's left-handedness (or "ambidexterity") is caused by disruptions in the specialization of the brain hemispheres, it is necessary to consult specialists (psychologist, neuropsychologist, neurophysiologist) who can conduct special sessions to correct interhemispheric connections. Often, even after a small number of sessions, a child may begin to write and draw with the right hand without any coercion. To more accurately determine the individual characteristics of left-handed children, it is necessary to consider the entire set of human asymmetries. Therefore, modern psychology uses the term "individual profile of the lateral organization of functions" (IPLF), which reveals a certain combination of sensory and motor asymmetry.

To determine the IPLF, and with its help, to identify possible left-handedness, a methodology has been developed that includes three groups of tests: to determine the leading hand, leading ear, and leading eye (sometimes the leading foot is also determined, although this information is not included in the analysis of the obtained profile).