There are only 10% left-handed people worldwide, and this proportion remains a big mystery. Explaining why someone who is left-handed or right-handed is really not easy.
Most people are right-handed
Hand movement is controlled by the motor cortex – the part of the brain’s surface that controls all movement. The left side of the body is controlled by the right hemisphere of the brain and vice versa. In the hemisphere, where the dominant side control has more connections between the neurons of the motor cortex – this can always be shown in magnetic resonance imaging by cell activity. nerve. In the past, it was thought that left-handed people simply redirected activity of the hemisphere compared to right-handed people, but that was not the case. For example, in 96% of right-handed people, the speech center and the hand motion control center are in the same left-hemisphere. In left-handed people, the speech center can be located anywhere: 70% of people are in the left hemisphere, 15% are in the right hemisphere, and the rest of the speech center is symmetrically distributed. worthy in both hemispheres. According to one theory, the left-brain hemisphere’s speech centers could evolve based on our ancestors’ right-handed gesture centers. Men are more left-handed than women Among men, 13% are left-handed, and among women -11%. In couples where a mother is left-handed, the child is usually left-handed. The explanation for this is that the mother’s behavior is imitated by her child during childhood development. By repeating the movements of the mother, the child can become left-handed. Researchers have tried to determine whether signs of right-handed or left-handed people are related to gender. It is impossible to determine this with certainty, but there is reason to believe that the development of right-handed and left-handedness can be influenced by sex hormones: testosterone androgen testosterone and dihydrotestosterone. Left-handed and right-handed people can feel the world differently There is a basis to believe that left-handed and right-handed people perceive the world around them differently. In a classic experiment: two boxes were placed in front of two testers, they were given pictures of different animals and asked to place the animals in one of the boxes. Agree on a list of animals they like. As a result, right-handed people put their favorite animals in the box on the left, and left-handed people put them on the right. This means that left-handed and right-handed people perceive space differently: for left-handed people, the space on the left is associated with something good, for right-handed people. right hand – is the right side. 
Lefties tend to have a better artistic penchant – American rocker Kurt Cobain pictured here. Trying to be right-handed is not necessary In the past, left-handed people were often rehearsed for right-handedness: they tied their left hand behind their back, hit it with a ruler or took objects from their left hand and transferred them to their right hand. With practice, the lowercase script gets worse: in children, it often involves fine-tuning of precise movements in kindergarten and elementary school. But change often has a negative effect. Fortunately, coercion is no longer common now. Attempts to practice left-handed people can have consequences. In the past, it was believed that in this case, development of speech disturbances could arise, such as stuttering. However, researchers currently have not found evidence of this. But forcing a left-handed person to be a right-handed person can cause serious trauma, especially for children. A right-handed person can become a left-handed (and vice versa) in the event of an injured arm. Adults need more time than children to adjust to this. In children, the transformations last up to 6 years and they typically use both hands for everyday activities, but just as easy activities (like moving the pencil from hand to hand while drawing) . Are left-handed people smarter? In academic studies studies, left-handed people appear to be more gifted than right-handed people. To assess aptitude, different thinking tests are often used, which suggest an alternative or creative way of using something, for example, a pen. It is also believed that in creative industries related to art such as music and architecture, left-handed people have about 10% more. This can be explained by the fact that left-handed brains are more symmetrical so they can access the resources of the two hemispheres at the same time. However, it is not possible to officially confirm this hypothesis in systematic studies. Is right or left handedness related to genetics? Genetic factors are still inconsistent: the probability of having a left-handed child is 37% for both left-handed parents, when there is only one left-handed person – 22%. If both parents are right-handed, the probability of having a left-handed child is only 11%. But in most cases the vast majority of children are right-handed, regardless of which parent is right-handed. In 80% of the cases the twins are either left-handed or right-handed, but in 20% of cases one is left-handed and the other is right-handed. This shows that hand-handedness must be determined by a combination of both genetic and environmental factors. There is no specific gene for right-handed or left-handedness. It is generally accepted that the dominant hand is determined by a very large number of genes, each of which holds only a very small fraction and that their coordinated interactions are not entirely clear-cut. It is now accepted that left-handed and right-handed are genetically determined to be 25%, while 75% are by environmental conditions.
You must log in to post a comment.