What is the difference between left-handed and right-handed thinking? How is a left-hander different from a right-hander: features, interesting facts, recommendations Which leg dominates in left-handers

Why are there many left-handers among artists, musicians - representatives of the so-called creative professions, and, say, pilots, as a rule, right-handers? Why do left-handers recover faster after traumatic brain injuries? What are the similarities and differences between people with different individual asymmetry profiles? What are the mechanisms of formation of such features? The answers to these questions are of interest not only to neurophysiologists, but also to specialists in many other fields of knowledge.

The French anatomist and anthropologist Paul Broca in 1861 showed for the first time that damage to the left hemisphere of the brain leads to aphasia (loss of speech), while injury to the right hemisphere is not accompanied by such a pathology. Based on these data, a concept that has long existed in science arose: the left hemisphere in right-handed people is the leading one, while the functional role of the right one is secondary. However, as the facts accumulated, it became clear that it also performs a number of important functions. But in left-handers, the right hemisphere was considered dominant in speech, but, as it turned out, this opinion is erroneous: in fact, speech representation in individuals with this type of asymmetry can be left hemisphere and even bilateral (mixed).

The number of right-handers in the human population, according to various sources, ranges from 80 - 95%, while the rest are left-handers and ambidexters (people with equal capabilities of both hands). Judging by the statistics, the number of left-handers, for example, in Europe has grown 3-4 times over the past half century, which is rightly attributed to the widespread cessation of their retraining, the creation of technical devices and tools adapted to them. "Left-handedness" is becoming an object of increasing attention of researchers in the field of neurophysiology, psychology, and sociology. In general, this knowledge is necessary in Everyday life- when raising and educating a child, choosing a profession. Lefties have been found manifestations of special artistic and musical talent, artistic abilities, as well as high general awareness, often combined with achievements in mathematics, architecture, and other sciences.

EEG coherence spectra in symmetrical regions of the brain of a right-hander at rest.

The growing interest in studying the organization of the brain of left-handers or left-handers (the latter term includes the definition of not only the dominant hand, but also other organs of movement and senses) is also associated with the needs of medical practice. So, with the same nature of brain damage as right-handers, psychoneurological disorders are accompanied by dissimilar manifestations of syndromes. There is evidence of a higher risk of left-handed people suffering from diseases such as epilepsy, schizophrenia, etc., and their increased vulnerability to external and internal factors has been revealed.

Numerous evidence has now been accumulated that in each of us, regardless of the asymmetry profile, one hemisphere of the brain differs from the other in a number of morphological, functional and biochemical parameters, which are reflected in the features mental activity. common to all representatives Homo sapiens It is also that the asymmetry of the brain progressively increases in children over the years, thereby determining their normal mental development, reaches a maximum by adulthood, when the brain is most efficient, and levels out in the elderly - with aging, its productivity decreases. Note: thanks to the rapid development of modern research methods - positron emission tomography, etc. - we now better understand the mechanisms of these complex processes.

The anatomical differences between the two hemispheres of the brain have been most thoroughly studied in right-handers. It turned out that a number of structures of the left hemisphere (hemisphere) are characterized by a large size compared to the symmetrical sections of the right. And a particularly pronounced (sevenfold!) neuroanatomical asymmetry is found in the auditory cortex. Similar differences are also characteristic of the posterior part of the postcentral gyri. There is evidence that the left occipital pole is longer and often extends beyond the midline compared to the right, while the right hemisphere is wider than the left in the central and frontal regions. The difference in the blood supply to the hemispheres can be judged at least by the size of the left internal carotid artery and the arterial pressure in it - they are larger. According to available information, the same can be said about the volume of the left lateral ventricle and the amount of gray matter in proportion to the white matter in the left hemisphere, although the right is heavier. At the same time, the cortical (cortical) areas involved in the implementation of speech signals are more widely represented in the left hemisphere.

Neuroanatomical differences in the brain of right-handers are characteristic not only for the "speech" zones, but also apply to other structures - visual, posterior associative (parietal), the size of which in the right hemisphere is greater than in the left. At the same time, these comparisons allow us to say that this asymmetry is not modal-specific - the "verbal" hemisphere versus the "visual" hemisphere. Most likely, the primary projection zones of both systems are concentrated mainly in the left hemisphere of the brain. But the cortical areas of the intermodal associative zones are localized more in the right hemisphere.

EEG coherence spectra in symmetrical regions of the brain of a left-hander at rest.

These features create the prerequisites for unequal functional capabilities of the hemispheres: in the left, short-axon connections predominate, especially in the primary projection areas of the cortex, while in the right, connections between areas are interregional. Consequently, in right-handed people, the left hemisphere has structural bases for providing "local" processing of the stimulus, while in the right-handed person, the possibilities for processing complex information are wider. Thus, in the picture of neuroanatomical asymmetry of the brain of right-handers, two basic features are distinguished: sensory and motor areas are more representative in the left hemisphere, while associative zones are characteristic of the right one; in the left there is a predominance of intracortical connections, in the right - intercortical connections.

The described differences are the basis for the differentiated role of the hemispheres in the use of cognitive (cognitive) strategies. The leftist plays a leading role in solving linguistic, verbal problems, he is provided with conscious psychomotor activity, speech and thinking and memory based on it. The right one dominates in solving spatial and constructive problems, is responsible for the psychosensory sphere: the perception of the world and oneself in it, emotional experiences, remembering events in the form of sensory images with an accurate reflection of the space and time in which events occurred and their image was formed in the human mind.

Information about the neuroanatomical organization of the brain of left-handed people is scarce, but it can also be used to judge its lesser asymmetry compared to right-handed people. In 71% of left-handed people, the Sylvian sulcus* is located symmetrically in both hemispheres. Although there is information about the large size of the auditory cortex in the right hemisphere compared to the left. The internal carotid artery and blood pressure are in many cases greater in the right hemisphere (remember: the situation is different for right-handed people). However, the neuroanatomical asymmetry of the brain of left-handers is not a "mirror" reflection of that described in right-handers, and their variants are much more numerous.

When analyzing the ability of each of the hemispheres to perform the functions of the other, it was established that in right-handed people, the defeat of the left in the early stages of ontogenesis does not lead to the occurrence of aphasia, and speech develops due to the preservation of the right hemisphere. At the same time, the violation of non-verbal forms of behavior that occurs when the right hemisphere is damaged is not compensated for by the functioning of the intact left hemisphere. Left-handers, on the other hand, are characterized by the absence of a clear correlation between the side of the brain lesion and the onset of localized disorders, which indicates a more diffuse representation of verbal and constructive functions than in right-handers.

Evidence is currently accumulating that the interhemispheric differences observed in the performance of cognitive tasks in both right-handed and left-handed people are associated not only with the difference between the cortical systems of the right and left hemispheres, but also with subcortical structures. On the basis of the results of clinical studies, it was suggested that in the course of evolution in the left hemisphere of right-handers, the implementation of mental processes passed into the cortex, and subcortical formations began to play the role of pacemakers**. This did not happen in the right, and the same processes take place with significant activity of deep formations, in particular, diencephalic ones ***, which have closer functional ties with it. The data concerning left-handed people testify to a lower degree of formation of functional differences in subcortical structures compared to right-handed people.

There are different theories regarding the mechanisms of interhemispheric interaction, but they, as a rule, concern right-handers. According to the American neurophysiologist Victor Denenberg, expressed in the early 90s of the XX century, it is possible with the simultaneous implementation of three processes - activation, inhibition and correlation (by the latter, the author means that both hemispheres are components of a control system operating on the principle of negative feedback).

Formulated in the 80s of the XX century. Doctor of Biological Sciences Vitaly Bianchi (Leningradsky State University) the model of interhemispheric interaction is also based on three basic principles of brain activity - asymmetry, dominant and complementarity. The model provides for the participation of both horizontal and vertical flows of excitation and inhibition, which form the asymmetry of the cerebral hemispheres - they are probably dissimilar in right-handers and left-handers. Numerous observations show that in right-handers, as the brain matures, the systems and processes necessary for the implementation of such functions as speech, visuospatial and motor functions are formed and stored in one hemisphere while simultaneously suppressing them in the other. In left-handers, an atypical development of the mechanisms of interhemispheric interaction occurs with a fairly independent and stable formation of motor, speech engrams **** in the right and left hemispheres during ontogenesis.

"Communication" of the hemispheres is carried out through numerous commissures (adhesions), in particular the corpus callosum*****, the dissection of which disrupts the exchange of sensorimotor, tactile and other forms of information. By the way, the corpus callosum in left-handed people is larger than in right-handed people, and this undoubtedly decisively affects the interhemispheric organization of mental processes in the former, as well as the nature of the manifestation of pathological symptoms in them.

Over the past decades, a lot of facts have been accumulated about another side of brain asymmetry - neurochemical. So, in right-handers, various biochemical substances, including mediators, are asymmetrically distributed in various structures of the right and left hemispheres. In particular, the content of dopamine ****** is greater in the basal ganglia ****** of the left hemisphere compared to the right. The asymmetry of the level of this hormone in various structures of the brain increases as it matures. When analyzing data on the enzymatic activity of the cortical substance of right-handed people in the precentral and frontal areas of the cerebral cortex, large values ​​of the content of acetylcholine******** were found in the left hemisphere compared to the right. Neurochemical studies of the distribution of serotonin metabolites *********, on the contrary, showed that they more often predominate in the right hemisphere, especially in the mediofrontal regions of the brain. In the future, these facts should be taken into account in clinical practice when using various pharmacological drugs that affect the mediator systems of the brain to effectively restore the functions of the right or left hemisphere.

Let us add that in left-handers the same pharmacological agents, in particular anesthetics, can cause a dissimilar therapeutic effect compared to right-handed people, which is probably due to a neurochemical asymmetry of the brain that is different from the latter and requires the attention of practicing physicians.

An analysis of the distribution of neurohormones and neuropeptides and their receptors revealed differences associated with this factor in the cerebral hemispheres in right-handers and left-handers, as well as a more frequent occurrence of diseases of an immunological nature in the latter (2.5 times) compared to the former. This made it possible to put forward an immune theory of the origin of "left-handedness" (along with genetic, cultural and pathological).

Electrophysiological studies significantly complement the picture described above, since one of the approaches to the study of interhemispheric asymmetry is the analysis of the main rhythms of the electroencephalogram (EEG) recorded in the cortex, which, like the tip of an iceberg, reflects deep, basic neuroanatomical and biochemical processes in the brain. When comparing the amplitude-frequency characteristics of the main EEG rhythm of a healthy person - the alpha-rhythm ********** - it was revealed that in right-handed people in a state of calm wakefulness in the occipital regions, it has a lower amplitude in the left, dominant hemisphere. At different types mental activity decreases its amplitude and increases the frequency, and these parameters depend on the nature of the task. The specific asymmetry of the alpha rhythm depends on the preferred strategy, the nature of the task being performed - verbal or spatial-constructive, emotional factor, the degree of anxiety of the subject, etc.

Dynamics of average levels of EEG coherence and motor responses to a sound stimulus in right-handed and left-handed people during falling asleep and waking up.

An increase in the number of recorded potentials and analyzed ranges of EEG rhythms (slow - delta and theta and frequent - beta and gamma) should contribute to obtaining more complete information about the inclusion of the corresponding brain structures in specific cognitive processes. Our many years of work have shown that for the analysis of the features of the functioning of the hemispheres, the most interesting is the coherent *********** analysis of the rhythmic components of the EEG, which reflects the effectiveness of connections between different areas of the brain and is widely used both in our country and abroad. abroad.

Our analysis has shown that hemispheric differences between right-handers and left-handers are most clearly revealed when assessing intracortical interaction in the cortical areas associated with the localization of speech zones. In the fronto-central regions, coherence had higher values ​​in the right hemisphere in both right-handers and left-handers. This can be explained by the greater intensity of cerebral blood flow and metabolic processes in the fronto-central cortex of the right hemisphere and the right hippocampus, which reflects not so much intracortical as cortical-subcortical interaction. Violation of the above interhemispheric relationships may be accompanied by emotional imbalance - as a result of dysfunction of the median structures and the right hemisphere, associated with the formation of negative, phylogenetically older basic human emotions.

The nature of the change in the selected ranges of EEG rhythms in the symmetrical frontal and central parts of the brain in right-handers and left-handers.

Distinct differences in EEG organization between right-handers and left-handers were revealed during functional loads, in particular, when performing movements, especially with the dominant hand. At the same time, in right-handers, a local increase in EEG coherence was observed in the symmetrical central areas of the cortex for the alpha and beta ranges of rhythms (the zone of the cortical projection of the motor analyzer) in combination with its decrease in other sections, including in the symmetrical areas of the right hemisphere. Left-handed people are characterized by a unidirectional change in coherence for most areas of the cortex and rhythm ranges. The features shown probably reflect the formation of local systems involved in the regulation of movements in right-handers and diffuse systems in left-handers.

Of particular interest are the multidirectional changes in the coherence of the alpha and theta ranges recorded in right-handers, and unidirectional (in-phase) changes in left-handers. These facts, in comparison with data on the genesis of different ranges of EEG rhythms, indicate the different participation of cortical and subcortical structures of the brain and the specific nature of their interaction in the regulation and execution of voluntary movements.

The differences in the spatiotemporal organization of the EEG found between right-handed and left-handed people under conditions of active activity were also confirmed in the experimental situation of the opposite nature - during falling asleep. Both right-handers and left-handers showed a decrease in the interhemispheric asymmetry of the brain, characteristic of wakefulness, due to a more pronounced decrease in the average levels of coherence in the dominant hemisphere. During the experiment, the subjects were asked to simultaneously press the buttons in both hands in response to randomly presented sound signals. It turned out that as the EEG coherence in the dominant hemisphere decreased, right-handers first stopped motor responses with the right hand, while the responses of the left hand remained, which faded only when falling asleep completely; upon awakening, the opposite picture was observed. In left-handers, the same regularity had the opposite character or manifested itself less distinctly.

However, more important is the fact that in the situation under consideration, right-handers showed a multidirectional change in the coherence of oscillations of the alpha-beta and theta-delta rhythm ranges when changing functional states(wake-sleep); in left-handers, in all areas of the cortex, a unidirectional, in-phase change in the coherence of all the distinguished ranges of the same rhythms was observed.

In short, we can assume that the different behavior of EEG rhythms in right-handed and left-handed people reflects the different specialization of the brain regulatory systems in the formation of interhemispheric asymmetry. Thus, in right-handers, the maintenance of left hemispheric asymmetry at rest, due mainly to the alpha range, can be ensured by intracortical interaction. In contrast to the left hemisphere, the right hemisphere asymmetry observed during falling asleep, when the coherence of theta-delta bands increased, indicates the existence of functionally significant connections of the right hemisphere with diencephalic and, probably, limbic************ structures (including hippocampus). The maintenance of left hemispheric asymmetry in them also occurs with the participation of the beta range, which indicates the functional connections of the left hemisphere with stem structures.

Scheme of interaction of the cerebral cortex and subcortical regulatory systems of the brain in right-handers and left-handers.

Left-handers, on the one hand, as well as right-handers, show signs of functional connection of the right hemisphere with diencephalic and, probably, limbic structures, on the other hand, less specificity of the hemispheres and the formation of these connections in relation to stem structures are manifested. The multidirectional behavior of fast and slow EEG rhythms that we revealed in right-handed people reflects the presence of elements of competition both between the hemispheres and between cortical and subcortical structures, acting on the principle of negative feedback. In left-handers, the in-phase character of the behavior of EEG rhythms may indicate the formation of a predominant interaction between the hemispheres, as well as cortical and subcortical structures, according to the principle of positive feedback.

The proposed concept of the features of the organization of the brain of right-handers and left-handers contributes to a better understanding of various clinical manifestations detected in cerebral pathology. In particular, we have collected information that left-handers who participated in the aftermath of the accident on Chernobyl nuclear power plant, after 5 - 7 years, more severe psychoneurological disorders developed compared to right-handers, up to epileptic seizures. This is consistent with clinical evidence that left-handers are at higher risk of developing epilepsy than right-handers and suggests hypersensitivity the first to radiation exposure.

At the same time, we, together with the staff of the Institute of Neurosurgery. Academician N. N. Burdenko of the Russian Academy of Medical Sciences compared the features of the restoration of impaired functions in right-handed and left-handed people with same character, severity and side of traumatic brain injury. It was found that in left-handers, compared with right-handers, this process was faster and more complete, which is explained not only by the lesser functional specialization of the cortical centers, but also by the principles of organization of their brain.

In conclusion, I would like to emphasize that the features of the left-handed brain described above most likely constitute physiological basis repeatedly noticed in the literature and their characteristic extraordinary features, making non-standard decisions, including in creative activity (by the type of insight). They are probably the basis for the fact that geniuses are more common among left-handed people than in a right-handed population. We would like to recall these facts in contrast to the frequently encountered point of view about the pathological nature of the formation of asymmetry in the brain of left-handed people. We believe that the principle of organization of the brain, which is different from right-handers, which have advantages in certain types of activity, say, camera work, is also successful for others, including creative types of activity.

* Sylvius furrow - lateral (lateral) furrow of the cerebral hemispheres.

** Pacemakers are neurons that spontaneously generate impulses.

*** Diencephalic - related to the diencephalon.

**** An engram is a hypothetical structure that stores memory traces.

***** The corpus callosum is a strand of nerve fibers that connects the left and right hemispheres of the brain.

****** Dopamine is a neurotransmitter of the nervous system, a neurohormone: a biochemical precursor of norepinephrine and adrenaline.

******* Basal nuclei - an anatomically isolated group of paired subcortical structures; facilitate the movements triggered by the cortex and suppress unnecessary accompanying ones.

******** Acetylcholine is a mediator (carrier) of nervous excitation. When it enters the blood, it lowers its pressure, slows down the heartbeat, etc.

********* Serotonin is a mediator of nerve impulses passing through the synapse. Brain neurons that use it are involved in the regulation of many forms of behavior, sleep processes, and thermoregulation.

********** When studying brain potentials, their spectral analysis is often carried out, and different components of the spectrum have different names: delta (0.5 - 4 Hz), theta 1 (4 - 6), theta 2 (6 - 8), alpha (8 - 13), beta 1 (13 - 20), beta 2 (20 - 40 Hz), gamma waves (include the frequency of beta 2 rhythms and above).

*********** Coherence is the coordinated flow of several oscillatory or wave processes in time.

************ The limbic system is a collection of a number of brain structures. Participates in the regulation of the functions of internal organs, smell, instinctive behavior, emotions, memory, sleep, wakefulness, etc.

ZHAVORONKOVA L.

18.04.2019 Flatulence

Ten to fifteen percent of the world's population are left-handed - people who write and perform most tasks with their left hand.

Which of the hands will take on the dominant role depends on the upbringing, heredity and characteristics of the intrauterine development of the unborn child. Men are left-handed much more often than women. It has also been noted that among epileptics, children with developmental delay, Down syndrome, autism, dyslexia, there is a fairly large percentage of left-handers. Often there are left-handers and among those with deviations in the sexual sphere.

However, all these statistics absolutely do not mean that only people with certain disabilities can be left-handed, it’s just that the brain of left-handers really works a little differently. The hemisphere of the brain opposite to the hand is usually responsible for the dominance of one or another hand. In lefties, the right hemisphere dominates. This feature is innate and must be taken for granted.

Left-handers, due to the dominance of the right hemisphere, tend to very quickly perceive and process information that is presented to them in the form of a holistic image. They are well oriented in space, have good coordination of movements and greater, in comparison with right-handers, mobility. It is quite difficult for left-handed people to cope with tasks for logic, sequential thinking, step-by-step analysis, so they may have problems with reading, arithmetic, grammar in oral form and in writing. This is due to the fact that at the expense of logic, speech is answered by the left hemisphere, which is not so actively developed in left-handed people.

But a well-developed right hemisphere provides left-handers with a well-developed imagination, spatial and temporal orientation, musicality and artistic taste. They can succeed in geometry, architecture, music, painting, sports. In general, there are no restrictions for left-handed people in choosing the type of activity, since their mental abilities are in no way inferior to right-handers, simply, choosing this or that occupation, preference should be given to activities for which the right hemisphere is responsible. Lefties love activities where you can take your own initiative, use intuition. Working in a team with strict subordination, subordination, a strict schedule for performing work and entering the service is practically unacceptable for them.

Left-handed people are more emotional and vulnerable than right-handed people, they often give in to anxiety, but they are more resistant to climate change and have a good ability to adapt.

Previously, it was believed that the dominance of the left hand is a kind of deviation, which must be eliminated by retraining the child to use the right instead of the left hand. Long-term studies and observations of specialists have shown that retraining left-handed children can cause real psychological trauma to such children, delay their development for a long time, cause speech defects, stuttering, neuroses, sleep and appetite disturbances, enuresis, headaches and many other problems. Loving and caring parents generally should not focus the child's attention on his difference from most children. Left-handedness is not a deviation from the norm, it's just idiosyncrasy person. Do not force the child to use the right hand more, giving up the left. Don't let the teachers do it. school teachers which largely affect the development and emotional state of the baby. Nature created such people as left-handers, and, as you know, she does not tolerate any violence against herself.

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Finally, society can also influence the phenomenon of right- or left-handedness. In Soviet times, for example, it was believed that left-handed children should be retrained. Therefore, if the parents saw that the child was holding a spoon or a pencil with his left hand, they forbade him to do so and insisted that he use his right hand. Kindergarten teachers and school teachers did the same. Therefore, in principle, there may be more congenital left-handers than we think.
What is the difference between lefties and righties?
It is known that many prominent personalities - politicians, scientists, actors, artists, composers - were left-handed. Among them - Isaac Newton, Albert Einstein, Julius Caesar, Alexander the Great, Napoleon Bonaparte, Winston Churchill, Bill Clinton, Leonardo da Vinci, Pablo Picasso, Andersen, Mozart, Aristotle, Nietzsche, Charlie Chaplin ... But does this mean that all left-handers – potential geniuses?
Ohio psychologists Stephen Christman and Ruth Propper conducted a curious experiment to test memory. They selected 62 people and asked them to memorize 55 words that flashed on the screen. Left-handers coped with the task two (!) times better than the rest. According to scientists, this is due to a closer interaction between the hemispheres of the brain. However, the memory of lefties is selective. So, it is easier for them to remember where they put some thing than to reproduce by heart a culinary recipe or a historical date.
Over the past three decades, the number of left-handed people in the world has increased markedly. According to Swedish researchers, this is due to the fact that the ultrasound procedure, which expectant mothers undergo during pregnancy, affects the brain and central nervous system unborn children. According to some reports, there are now more than 800 million left-handers in the world, and by 2020 their number will exceed one billion ...
Finally - a test for hidden "left-handedness", recommended by psychologists. Cross the fingers of both hands together. If the thumb of your left hand is on top, you are left-handed from birth.

I remember a magazine with a photo of "The Beatles" in the classroom when I was a distant school child. “Why is he holding the guitar backwards? someone asked about Paul McCartney. So for the first time we learned that one of the Beatles is left-handed.

And then, years later, I read that the drummer of the famous band Ringo Starr is also left-handed. Having become a journalist, I saw with my own eyes how the magnificent singer Mireille Mathieu signs an autograph for the readers of my newspaper with her left hand.

Lefty- a phenomenon rare and common at the same time. Wherever more than thirty people gathered, there is always a left-hander.

Linguists have found that in different languages ​​the word "right" is consonant with the words "right" and "right", while "left" is similar to words such as "sinister" and "broken". Left-handed people have always been viewed as a deviation from the generally accepted norms: the English left-handed is translated not only as “left-handed”, but also as “clumsy”, “hypocritical”, and as “defective” and “deceitful”. But is it fair?

Video: Features of left-handed people (children) or who are left-handers

So far, it has not been possible to absolutely accurately establish the reason why a person becomes left-handed. According to scientists, about half of the cases are to blame for violations in genetic code. In the other half - the wrong course of interchangeable processes during the development of the fetus (this leads to a number of problems characteristic of left-handed people: early puberty, dyslexia, insomnia ...), or birth trauma.

In nature, leftism and rightism- a little studied phenomenon, although asymmetry is one of the fundamental properties of nature. How does it manifest itself at the level of organic substances and living organisms? It is known, for example, that a living cell is asymmetric in structure, while a dead cell is symmetrical. Louis Pasteur's observations in the 19th century were that many organic molecules can form two distinct shapes that are mirror images in the same way that a right hand glove is a mirror image of a left hand glove. Being chemically identical, such molecules differ morphologically, they are called stereoisomers.

Stranger still, living beings are capable of producing either one or the other stereoisomer, while laboratory chemistry always yields an equal mixture of the two. Take for example a lemon and an orange - two fruits with a characteristic flavor for each, which, although similar, are somewhat different. So, these two distinct smells are given by the same chemical substance - limonin. However, the atoms in its two molecules are arranged differently: the limonin produced in a lemon is a mirror image of the same chemical born in an orange.

“From the observations of naturalists it is known that in nature the movement goes from right to left. All luminaries and their satellites describe circular paths from east to west. In humans, the right hand is better developed than the left ... The curls of the shell, with rare exceptions, are wrapped from right to left. And if a shell comes across - lefty, connoisseurs value it worth its weight in gold, ”wrote Jules Verne.

Most people consider leftism to be anomalous, but life itself is predominantly morphologically leftist.

Are left-handers a genetic anomaly?

The helix of the DNA molecule is invariably twisted in left side. And although all people outwardly look symmetrical, they all have a hidden one-sidedness that has nothing to do with being right-handed, this person or lefty. So, in almost all of us, the heart is located on the left side, and the liver is on the right. Beneath our skin, we are highly asymmetrical.

For biological forms, however, there are exceptions. In ten thousand people there is one in which the location of the internal organs is upside down. This phenomenon is called "situs inversus" in Latin. Dr. Nigel Brown of St. George's Hospital School of Medicine, who wrote a paper on situs inversus, is convinced that body asymmetry is ultimately determined by the left or right morphology of the chemical "building blocks" of life, although he admits that it is directly related to the molecule and the mammal not yet possible. But does this mean that if the DNA helix were oriented to the right, then all people would have a heart located on the right? Dr. Brown thinks no, although he is equally sure that there is some kind of chemical trigger that somehow tells the human fetus at the age of fifteen days what is left and what is right.

8% of the world's population use their left hand

So, if a mirror arrangement of internal organs is observed in one person out of ten thousand, then people who write with their left hand, play tennis with it, are quite common - 8 percent of the total number of Homo sapiens. Dr. Christopher McIenas of University College London suggested that a two-stage process occurs in the human body. In our body there is a gene that allows us to distinguish between left and right, a kind of label. This label is then read by another gene, not yet discovered by scientists. It is he who determines whether a person will be left-handed or right-handed.

If we are born with one variant of the last gene, then we become right-handed. But a significant part of people have a different version of it, it reads the label so that they become lefties.

The division into right-handers and left-handers is a unique feature of man. Curiously, only half of left-handers are genetically left-handed, and 50 percent are compensatory, that is they became left-handed as a result of damage to the left lobe of the brain.

Many little things annoy a lefty in a "right" world. He enters the subway - the slot of the coin acceptor is located on the right. All training manuals for any manual labor are designed for right-handed people. And so in everything. Therefore, the slogan "Saving the drowning is the work of the drowning themselves" was adopted by left-handers in the Western world. They have created all sorts of unions, associations and societies designed to protect their rights. There is a well-known case when, in 1980, International Association The left-hander achieved the reinstatement of the American left-hander Franklin Winboard, who was fired from the police for refusing to wear a holster on the right.

And it's right. In some cases, left-handed people need no less help than disabled people. The most striking example: all doors are hung so that their opening is designed for right-handers. If a young weak girl - lefty, and the door has a strong spring, then it is simply not possible for her to open the door.

Left-handed problems begin in childhood. In Russia, for example, there are practically no prescriptions for left-handed children. By the way, until the mid-80s in Soviet schools they were forcibly retrained to be right-handed. The production of scissors for left-handed people has long ceased (in Soviet times they were made in Gorky). At all left-handers need a lot of "left" items- from trifles to serious things: hockey sticks, watches, cameras (all models have shutter buttons on the right), phone books and so on and so forth.

If you want to imagine how a left-hander lives in our “right-handed” society, tie your right hand to your body for at least an hour or two. Or reread Alice Through the Looking Glass, where ingenious left-hander Lewis Carroll skillfully described the feeling of a left-handed person from life in a right-handed world. By the way, Nikolai Leskov, who wrote "Lefty", was left-handed.

famous people who are left handed

There are not as many famous left-handers as there are right-handers, and yet there are a lot of fighters in their regiment. The word "fighters" is quite appropriate, since many prominent generals were left-handed. And among them are such geniuses as Alexander the Great, Julius Caesar, Charlemagne, Napoleon ... Joan of Arc, who became famous in the military field, was also left-handed. But her left-handedness became one of the arguments of the prosecution, which led the Maiden of Orleans to the stake.

Fidel Castro - left handed

Left-handedness is not an obstacle for those who make a political career, nor does it determine the moral character of a person-politician. Queen Victoria and Adolf Hitler were left-handed. All US presidents of the last two decades of the 20th century - George W. Bush, Ronald Reagan and Bill Clinton - are left-handed, the tradition could continue if Al Gore (also left-handed) won the last presidential election. By the way, their common worst and geographically closest opponent is Fidel Castro, also left-handed.

Left-handers are traditionally strong in art. This is probably due to the fact that they have better developed imaginative (intuitive) thinking, for which the right hemisphere, which controls the left hand, is responsible than logical thinking. Lefties were Leonardo da Vinci and Michelangelo, Raphael and Rubens, Pablo Picasso Pizarro, Franz Kafka and Paul Verlaine, Mozart and Beethoven, Paul Simon and Jimi Hendrix...

Left-handers simply occupied Hollywood. Among them are such stars as Greta Garbo, Marilyn Monroe, Deanna Durbin, Jean Harlow, Demi Moore, Whoopi Goldberg, Julia Roberts, Charlie Chaplin, Robert De Niro, Tom Cruise, Robert Redford, Bruce Willis, Sylvester Stallone ...

Left-handed athletes effectively use their anatomical feature in those types of competitions where tactical martial arts are present - tennis, boxing, fencing. Left-handed tennis players include ten-time Wimbledon winner Martina Navratilova with her signature backhand, Monica Seles, Rod Laver, named the best tennis player of all time; Jimmy Conors and John McEnroe. In boxing, left-handers win up to 40 percent of gold medals, although they are three times less in this sport than right-handers.

Albert Einstein is left handed

There are not so many left-handed scientists among scientists, but a few are quite significant: physicists Albert Einstein and James Maxwell, physiologist Ivan Pavlov, theologian and physician Albert Schweitzer.

Among the famous left-handed entrepreneurs, there are also a few. Exceptions - John Rockefeller, Henry Ford, Bill Gates. If among ordinary people left-handers - 8 percent, then among geniuses - 20 percent. That is, left-handers in general are more than twice as gifted as right-handers. So if your child is lefty, dont be upset. Just try to see the genius in him. By the way, left-handedness is often inherited. It is possible that you yourself are a genius. Only as yet undiscovered and unrecognized. Do not miss your chance.

Ecology of life. Science and Discovery: For a long time, the ability of some people to use their left hand in situations where the majority use their right hand has attracted ...

Debunking the Myths

For a long time, the ability of some people to use their left hand in situations where the majority uses their right has attracted attention and caused much controversy.

In the dark Middle Ages, left-handers were considered minions of evil spirits and were burned at the stake. In the 20th century, until the 80s, they tried to retrain left-handed children and turn them into right-handers.

In many languages, the word "right" means "correct", and "left" - "false", "false".

Some experts who were interested in the problem of left-handedness, including the Italian psychiatrist Cesare Lombroso, tried to prove that left-handedness is a deviation, which, in particular, is characteristic of mentally handicapped criminals. Such a negative attitude could not but cause protest in society and attempts to prove that being left-handed is not at all bad, but, on the contrary, very good.

Recently, it has been customary to “prove” the special giftedness of left-handers, finding them among famous people. For the sake of truth, it should be noted that for some reason no one is looking for famous right-handed people. Probably no one is interested.

Who are lefties?

Throughout the world, a left-handed person is called a person who has left hand more dexterous than the right (no more). There are about 10% of such people in the population. Among people you can find pure left-handers, pure right-handers and mixed variants. Mixed left-handed / right-handed people are either ambidexters, who can perform any actions with both the right and left hands with the same effect, and “two-handed”, which perform some actions (for example, writing, using a spoon and scissors) with the right hand, while others (for example , hammering nails, threading the eye of a needle) - left.

In the 70-80s of the last century, a whole scientific "boom" broke out, pursuing the goal of finding out how left-handers differ from right-handers. Some researchers found lefties more creative, creative, musically and mathematically gifted. The other part claimed that among left-handers a high percentage of people with disabilities mental development(delay mental development and learning difficulties) and neuropsychiatric diseases such as schizophrenia and epilepsy.

There have also been attempts to argue that the brain of left-handers differs from the brain of right-handers in that in left-handers, the right hemisphere is dominant, more active (in some versions, both hemispheres and they are more closely related to each other). Differences in the activity of the brain and tried to explain the greater giftedness, intelligence and creativity of left-handers.

Modern research, having a significantly greater material equipment and the ability to study huge masses of people (including with the help of social networks), unfortunately, do not confirm earlier conclusions. Neither in behavior, nor in mental abilities, nor in the frequency of occurrence of various diseases and deviations, left-handers do not differ from right-handers. The only advantage left-handers have is in some sports, such as boxing, tennis, and even then for a completely banal reason - athletes are trained to fight a right-handed opponent, simply because there are so many more right-handers.

Interestingly, scientists were able to find some differences when comparing pure left-handers and right-handers with mixed options. It turns out that pure left-handers and right-handers are more authoritarian and egocentric, while “mixed” ones are more prone to magical thinking (they believe in myths, omens, horoscopes, sorcerers, etc.) and are more creative.

The brain of left-handers differs little from the brain of right-handers both in its structure and function. This is revealed thanks to modern methods research, such as functional magnetic resonance imaging, which allows you to study the work of the brain in the process of solving various problems.

The control of the dominant hand in most lefties is really carried out by the right hemisphere (and in righties - by the left), but this truth is not absolute. So, for example, in some pathological conditions (in particular, after a stroke in the motor cortex), control over hand movements can be transferred to the opposite hemisphere.

The "speech" of the majority (60%) of left-handers, as well as of right-handers, is the left hemisphere, and only 10% - the right.

It is even more difficult to talk about the brain organization in left-handers of other functions, such as perception, memory, etc. Therefore, by the dominant hand (as well as by the dominant eye and ear) one cannot judge how the human brain is functionally organized.

The myth of the so-called "hidden left-handedness" that some psychologists find in a number of children is just a myth. With its help, they try to explain the features of the development of the child and often, as a result, ignore real problems and real ways to solve them.

Where does left-handedness come from?

Many researchers are looking for an explanation in heredity. It is shown that if the parents of the child are left-handed, then the probability that he will also be left-handed is higher (21.4-27%) than in cases where both parents are right-handed (8.5-10.4%). However, there is no 100% probability either there or there. Left-handed mothers have left-handed children more often than left-handed fathers, and there are slightly more left-handed boys than girls.

One of the most significant arguments in favor of the genetic origin of left-handedness is the very early manifestation of the dominant hand. Already 10-week-old fetuses suck mainly on the right or left finger, and after birth, the chosen hand is often the leading one. However, there are also counterarguments. One of them (and a very strong one) is the frequent occurrence (18%) among identical twins of differences in the dominant hand (one is right-handed and the other is left-handed).

The cultural aspect also plays a certain role. Retraining leads to the fact that the proportion of pure left-handers in society is declining.

They also continue to talk about the pathological aspect of left-handedness. It turns out that it can develop due to the influence of unfavorable factors on the child's body. These factors, in particular, include the unfavorable condition of the child immediately after birth (low Apgar score) and maternal smoking during pregnancy. Both are associated with an increased incidence of brain damage in the newborn.

How to determine if a child is left-handed or right-handed?

There are many methods by which a child's tendency to be right-handed or left-handed is determined.

The so-called "activity" questionnaires are especially popular. The child is invited to perform a series of actions: draw, cut the paper with scissors, put the string through the hole, throw the ball, show how he eats soup with a spoon, how he combs his hair, brushes his teeth. The result is judged by the predominant use of the right or left hand in everyday activities.

Another method is to assess hand dexterity. For this purpose, you can take, for example, a narrow pencil case in the form of an open box and a dozen pencils. First, the pencil case is placed to the right of the center, and the pencils are placed on the left on the table in front of the child and the child is asked to put the pencils into the pencil case one at a time as quickly as possible. Then the pencil case is placed on the left, and the pencils on the right, and they are asked to do the same with the left hand. Compare the speed and accuracy of the movements of the child's hands.

With the help of these simple tricks, you can guess which hand is better for teaching a child to write if he can’t decide on his own.

If parents have doubts about the origin of a child's left-handedness, whether it is associated with changes in the functioning of the brain, especially if he has learning problems or deviations in behavior, it is best to seek the advice of a neuropsychologist.

Titova Natalia, mother of three children, two of whom are left-handers

About 15% of people are left-handed, that is, approximately every seventh inhabitant of the planet. Parents, seeing that their child is not like the rest, begin to fear difficulties both in learning and in later life.

A little theory: where do left-handers come from

Who are they left-handed? These are people whose dominant hand is the left. lefties in addition to the left hand, the left leg is used more often, they hear better with the left ear and see more clearly with the left eye. Also in the world is ambidextrous- those who use both the left and right side of the body equally well.

How is it that some people are left-handed and others are right-handed? As a rule, women carried babies on their left hand, closer to their hearts, and male warriors protected the area of ​​​​the heart with a shield, therefore, the right hand of both was freer for vigorous activity. Thus, its dominance was determined. Left-handedness is the exception to the rule.

Left-handedness is also inherited: according to statistics, about 50% of left-handers are born to parents whose dominant hand is the left.

If one of the parents is left-handed, then the child is destined to mainly use the left hand in more than 16% of cases. And if both parents are right-handed, the child will be left-handed only in 6% of cases.

Left-handedness is also a consequence of developmental pathology, ranging from brain developmental disorders to injuries to the right hand in early childhood. But that is another story.

My personal experience: what is the difference between left-handers and right-handers

I am a mother of three children, one of which is right-handed and the other two are pure left-handers. I'll tell you about the difference between them from personal observation.

Right-handed. My right-handed child is not prone to spontaneous actions, unexpected actions, but is always reliable and firm in his beliefs and preferences. He consistently does things, is more structured, he has an analytical mindset, a penchant for design activities. Stability and sustainability are important to him, so that everything is in its place - now, tomorrow, in a few years. In all this, the rationalism of the left hemisphere is visible.

Lefty. In contrast, left-handers - both the girl and the boy - are more artistic, have a fine mental organization. These are creative people who love non-standard solutions. They express themselves through feelings, are ready for adventure, change, are more open to the world. Left-handers do not calculate options (“what will happen if ...”), they live here and now, they are ready to do several things at once, they always have a desire to improve what they have. Rearranging the room, going for three weeks, combining football and theatrical activities - what are they not addicted to! By the way, theater, writing poetry, drawing, choir, playing the guitar, painting paired sneakers in different colors - this is all a consequence of the work of a more creative right hemisphere, which is responsible for the left half of the body.

How did it happen that in one family there are such different children, you ask. My children were partly left-handed through me (I am ambidexter), my grandmother and my uncle, who were partly left-handed. But left-handedness manifested itself in full in children. But the son inherited the genes of right-handedness from his father.

If your child does not show himself left-handed from birth, draw final conclusions about his left-handedness no earlier than 4-4.5 years. To do this, use special tests to determine the leading hand.

Remember: in no case should left-handers be retrained, because of this, serious malfunctions in the work of interhemispheric connections can occur, and this can also be fraught with health problems.

To help your child learn new skills faster, buy special items that are designed for the left hand: pens, scissors, copybooks.

Left-Handed Benefits

Yes, it is a bit difficult for left-handed people to live because of the unsuitability of the world to their characteristics. However, they have many advantages that you need to know and use.

Fast adaptation. The one who was born left-handed has to adapt all his life to life in the right-handed world. And they are good at it.

Creative skills. Left-handed people are more emotional, perceive the world more as visual images. Therefore, they are capable of original artistic creativity.

The ability to turn a non-working hand into a working one. Left-handers use their right hand much more often than right-handers use their left.

There are a lot of left-handed people among brilliant people: the great silent film actor Charlie Chaplin, the inventor and painter Leonardo da Vinci, the Roman emperor Tiberius, the artist Pablo Picasso, the scientist Albert Einstein, the author of Alice in Wonderland, Lewis Carroll, a member of The Beatles, Paul McCartney, Emperor Napoleon, commander Alexander the Great, composer Ludwig van Beethoven, football player Diego Maradona, Microsoft founder Bill Gates and others.

So, if you or your child turned out to be left-handed, be grateful for such a wonderful gift and use these wonderful advantages in life!

How often do we face labeling? Unfortunately, in modern world this happens quite often. Literally from birth, children are subject to a clear division depending on the social status of their parents, nationality and race. And over time, the number of labels only increases, but still there is one feature that divides all people the globe only two categories - right-handers and left-handers. We are such by birthright, and it is impossible to change this fact. Yes, and it is not necessary. Long gone are the days when left-handers were burned at the stake as children of the devil and retrained to use their right hand. Today, a child can be the way nature created him. But to understand how left-handers differ from right-handers, absolutely all parents should know.

Left-handedness and right-handedness: a brief description

Who will be your child - right-handed or left-handed - is laid already at the moment of conception. Scientists have long attributed this factor to hereditary, because the chances of having a left-handed baby in the same parents increase to forty-five percent. Although, when both parents are right-handed, this figure does not exceed two percent. However, scientists say that no more than twenty percent of the population are true left-handers in the world. Moreover, this number almost always remains stable.

In the scientific world, there is a clear definition of right-handedness and left-handedness. For example, a right-handed person is considered to have the dominant activity of the right hand, ear, eye and leg. At the same time, the primary processing of information and most of the thought processes take place in the left hemisphere of the brain. In left-handers, all processes proceed differently, their brain activity is associated with the right hemisphere.

Historical reference

At all times, lefties were treated with caution. They were often considered children of the devil, and parents sought to get rid of such babies. The fate of red-haired left-handed girls was especially sad. They were usually expected by the fire of the Inquisition, because they were recognized as witches without trial or investigation.

In Rus', left-handed people were wary and believed that they could easily contact the dark forces. Therefore, such people could not hold important positions in the community or testify in court. All words spoken by a left-handed person were questioned and could not be used as evidence.

Fortunately, today's world is very favorable to any manifestations of individuality. And left-handers are considered completely normal children who are naturally a little more talented than most of their peers.

Left-handed and right-handed: differences

It seems that everyone knows the difference between a left-handed child and a right-handed child. First of all, with the leading left hand, because he takes all the objects with it and writes, unlike the right-hander. But few people imagine that lefties fall into two main categories:

• hidden;
• true.

Hidden left-handedness can be expressed in the dominant left hand and, for example, the leading right eye. Of the total number of left-handers, there are about half of such people. Moreover, they often do not even realize that their body functions half as well as in right-handed people.

True left-handed people are completely guided by the sense organs located on the left side of the body. On the same side is the leading arm and leg. There are no more than twenty percent of such people.

Naturally, the differences don't end there. The main differences between left-handers and right-handers are in brain activity. Scientists say that left-handers are for the most part creative and creative people, ready to approach any problem with enthusiasm. Left-handers process all the information they receive with the right hemisphere of the brain, so they tend to draw parallels, think figuratively and with the help of an associative series. It is easy for them to memorize various texts, and they quickly grasp the essence of any issue. It is believed that left-handers are able to "absorb" information and see any problem in its entirety, as if from above. This allows them to make quick decisions in a critical situation. A left-hander can be identified by emotionality, vulnerability and rapid speech, which sometimes seems completely incoherent to other people. Left-handers are often shy, conscientious, impressionable, unrestrained, sensual, and more pessimistic than right-handers or ambidexters (people who use both right and left hands equally).

The brain of a right-handed person functions quite differently. All information enters the left hemisphere, which allows right-handed people to successfully build cause-and-effect relationships, think over a strategy of behavior and decompose any problem into its component parts. In addition, such people tend to exact sciences, and the approach to solving complex issues allows them to choose the most effective and only correct one from the mass of options.

Parents often do not pay attention to such characteristics as left-handedness and right-handedness. This fact interests them only in connection with everyday nuances, but in fact, the peculiarities of thought processes should be taken into account by parents when raising children. After all, knowing whether your child is left-handed or right-handed, it is much easier to convey the necessary information to him. But how do you know?

Is my child left-handed or right-handed: how to determine

Child psychologists say that as early as three months you can determine whether your baby is left-handed. But the difficulty lies in the fact that before the age of five, most children are ambidexters. This category of people equally well owns the right and left hand, this ability persists during the first four or five years of life and then disappears. It is at this age that the dominant hemisphere is finally determined in the child, which will guide his activity for the rest of his life.

If your baby is already five years old, then you can conduct a series of tests and game form find out if your child is left-handed or right-handed. For example, a child can be asked to brush their hair, cross their arms over their chest, or look through a telescope. In this way, the dominant hand and eye can be identified. You can also blindfold the baby and give a pencil in each hand. Then ask him to draw two circles or squares at the same time. Usually a more even figure is obtained with a dominant hand.

Observe which side your child likes to sleep on. The body always extinguishes excessive activity in a dream, so the right-hander will fit on the right side, unlike the left-hander, who seeks to fall asleep on the left side.

For older children, different levels of tests can be done. For example, different text should go to each ear with the help of headphones. The leading ear is determined by the amount of stored information. Keep in mind that ambidexters give completely different results. They may have a leading right hand and left foot, which is quite common among such people.

In order not to make mistakes with the tests, be sure to run them several times. Only in this case can the results be considered as reliable as possible.

Features of the education of left-handers

If you find that your baby is left-handed, then try to educate him in such a way as to reveal all the hidden talents and abilities. After all, it has been proven that left-handed children have a penchant for art. Watch your child - he will tell you what activity he is interested in. And here parents need to show patience and perseverance so that their child fully reveals his talents.

Keep in mind that left-handed people are very emotional and often moody, so try to teach your child to pull himself together and deal with surging emotions. Do not forget about the vulnerability of left-handed children, they are very difficult to tolerate criticism and any negative opinion about them. This also needs to be taken into account when raising a child. Indeed, in order to achieve from him the fulfillment of his requests, it is necessary to convey information calmly and kindly.

Is it worth it to retrain the left-hander?

IN Soviet times The left-hander was always retrained, which aroused in the unfortunate children a persistent hatred of school and completely spoiled the handwriting. Therefore, this technique is not currently practiced. Scientists say that retraining a lefty is extremely dangerous. This affects the emotional state of the child, and also causes a number of difficulties:

• mirror letter;
• distortion of proportions;
• poor concentration and slowness;
• loss in space and the like.

Therefore, you should not create for your baby additional difficulties just let him be himself. After all, it does not matter who he is - right-handed or left-handed - in any case, the main thing is that he grows up a happy and successful person.

Celebrities among lefties

Are there many left-handed people among celebrities? Which of the famous and famous possessed or possesses the leading left hand? As it turned out, there are many talented scientists and people of creative professions among the left-handers. There are many examples of "left-handedness" and among them there are philosophers, scientists, military men, politicians, pioneer travelers, writers, poets and artists, actors. Here are just a few of them: Aristotle and Friedrich Nietzsche, Leonardo da Vinci and Michelangelo, Napoleon and Adolf Hitler, Leo Tolstoy and Alexander Pushkin, Isaac Newton and Albert Einstein, Marilyn Monroe and Charlie Chaplin, Paul McCartney and David Bowie, Angelina Jolie and Scarlett Johansson, etc.

Left-Handed Presidents

Among the left-handers were the heads of state:

Benjamin Franklin
Winston Churchill

President Ford
Ronald Reagan
George Bush Senior
George W. Bush (our shame!)
Bill Clinton
Fidel Castro
Mahatma Gandhi
Benjamin Netanyahu
Colleen Powell
Al Gore
Queen Victoria
Barack Obama

Well, as for the President of our country, Vladimir Putin, many argue that he is also more left-handed than right-handed, and some signs are evidence of this - for example, the fact that Vladimir Vladimirovich gesticulates mainly with his left hand, in addition, our president wears a watch not on the left, as is customary among right-handed people, but on the right hand. Although on this occasion, he somehow answered live at a meeting with compatriots - "I wear a watch on my right hand, because this way the crown does not rub my brush, that's the whole secret." But it is also possible that Russian President is an ambidexter, that is, a person who is equally good at using both hands.

Every year more and more left-handed children are born in the world, and now the left-handed army numbers millions of people, somewhere around 10% of the entire population of the planet. And psychologists are convinced that the future belongs to left-handers. And who knows what awaits us in the future, if according to statistics - every fifth genius is left-handed ...