Question

Is lateralization related to handedness?

Answer 1

Yes, the brain lateralization is related to handedness.

Explanation:

The term brain lateralization refers to the fact that the two halves of the human brain (right hemisphere and left hemisphere) are not exactly alike each other. Each hemisphere has separate functional specializations. The brain is “cross-wired”, with the left hemisphere controlling the movements on the right side of the body, and the right hemisphere controlling the movements of left side of the body.

There are several definitions for handedness: the hand that performs faster or more precisely on manual tests/ other definition is the hand that one prefers to use, regardless of performance. Some researchers define it as the hand used by individuals in writing.

Each human's brain develops differently leading to unique lateralization in individuals. The organization of brain for different mental processes may be different among people; one of such individual differences that have been focused is the notion of handedness.

Most of the people are right handed. Left handedness is less common than right handedness. Handedness reflects the structure of our brain, more specifically its asymmetry. The functional differences in the right and left brain hemispheres are believed to underline the phenomenon of hand dominance. Handedness is probably the most obvious manifestation of the fact that our brain functions in an asymmetric manner. While the left hemisphere controls right-handedness, i.e., the dominant right hand, the right hemisphere controls dominant left-handedness. Asymmetry of the brain and handedness become detectable very early, even during fetal development. Ultrasound examinations have revealed that even at the 10th week of gestation, most fetuses move their right arm more often than the left one, while from the 15th week the majority of fetuses suck the right thumb. This is believed to be predictive of future handedness.

A person’s handedness tends to indicate a specialized hemisphere on the brain's opposite side, so that a right-handed person probably has a left-hemisphere language specialization, and vice versa.

The brain lateralization for language functions is greatly related to handedness of people. Actually, in most of the studies, the hand preference of the subjects is considered as a predictor of brain lateralization. The left-hemisphere involvement is more in right hand individuals and the right-hemisphere involvement is more in left hand individuals. Therefore the organization of the brain in left hand individuals is different from that of right-handers, with left-handers having a right hemisphere or bilateral dominance with regard to language functions.