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Lateralization is a natural feature of the human body that it is not completely symmetrical. Usually, at an early stage in a child’s development, one side of the body becomes dominant over the other. This shaping of lateral domination is precisely called lateralization.
Physiological foundations of lateralization
The brain is responsible for the development of dominance of a specific part of the organism, the opposite hemispheres of which differ in terms of their competences and functions. The dominance of one hemisphere results in the dominance of the opposite side of the organism.
The basic manifestation of lateralization is the domination of one hand in various activities. At the same time, a properly educated human body can effectively coordinate the movements of both hands, performing complex manual activities. Experts believe that the fact that one side is dominant is beneficial from an evolutionary and practical point of view. One-handedness is preferable to ambidextrous, as it allows you to perform more and more advanced activities.
Before the advancement of physiological and medical knowledge, it was widely believed that it was normal for the right side of the body to dominate the left side. This belief was incorrect and resulted from insufficient knowledge about the functioning and development of the human body. It is true that in most people we observe the dominance of the right side, which is manifested in right-handedness, it should be noted, however, that the less frequent statistical occurrence of the dominance of the left side is a completely natural and normal phenomenon.
Lateralization is not limited to the dominance of one hand, but also applies to the leg, eye and ear. Unilateral laterality is referred to when the dominant organs / limbs are only on the left or right side.
When does laterality develop?
It is impossible to establish the exact moment at which one side of the organism begins to dominate. It is estimated that the earliest signs of developing laterality can be noticed even at 6 months of age, when the child develops a one-handed grip reflex. However, it should be noted that the laterality of the organism decreases around the age of 2, when the child is already physically fit and can move independently. Learning to walk involves the work of both hemispheres, which results in the inhibition of laterality. When the child is skilled in moving independently, the laterality of the organism becomes visible again. For this reason, the first clear and unequivocal symptoms of the predominance of the right or left side can be observed in the child’s behavior in the period between 3 and 5 years of age.
In properly developing children, the laterality of a specific side of the organism is fully developed already in the fourth year of life.
The course of lateralization
In the development of the lateralization of the organism, the following stages are distinguished:
- at the age of 3 months: assembly asymmetry,
- at the age of 3-6 months: symmetry of movements,
- at the age of 6-12 months: first symptoms of preference for one hand,
- at the age of 1-2 years: gradual weakening of the symptoms of lateralization,
- at the age of 2-4: development of the domination of one hand,
- at 4-6 years: definitively establishing the dominance of a specific side of the organism.
Different types of laterality
Cross-laterality is also distinguished, which is a natural phenomenon consisting in a varied distribution of dominance between the sides of the organism in terms of different parts of the body. Such a situation usually does not constitute a source of problems in the further development of the child. An example would be a child who has right-handed, right-footed, right-ear, and left-ear dominance.
Lateralization can also take the form of ambidextrous. In this case, we observe in children a coordination disorder in the performance of manual work with hands. In the developing ambidextrous children, other disorders are also often observed: slower speech development, decreased concentration, and memory.
When the occurrence of laterality moves away in time, disturbances in the functioning of the organism are often noticeable. Most often, delayed lateralization is associated with a disturbance of spatial orientation and a reduced awareness of one’s own organism. In such a situation, it is worth supporting the development of lateralization by performing appropriate development exercises with the child. Accelerating the development of sided dominance will help the child’s overall motor and manual development