Brain Lateralization & Handedness

General
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  1. The human brain is divided into two hemispheres: left and right.
  2. Motor control is contralateral → the left hemisphere controls the right side of the body, and the right hemisphere controls the left side.
  3. So, in left-handers, motor functions of the left hand are primarily coordinated by the right hemisphere.

Is the “right brain more active” in left-handers?

  • This is partly true, but oversimplified.

  • While the right hemisphere does play a bigger role in left-handers, it doesn’t mean the left hemisphere is inactive.

  • In fact, language functions, usually dominant in the left hemisphere for right-handers, are more variable in left-handers:

    • ~70% of left-handers still have left-hemisphere dominance for language.

    • ~15% have right-hemisphere dominance.

    • ~15% have more bilateral distribution.

    Key Findings from Neuroscience

    1. Greater interhemispheric connectivity → Left-handers often show stronger connections via the corpus callosum, which may allow more flexible thinking.
    2. Cognitive and creative tendencies → Right hemisphere is linked to visuospatial skills, pattern recognition, and music/art appreciation, which sometimes show higher activity in left-handers.
    3. Genetics and environment → Handedness is influenced by genetic factors, but also prenatal environment.

MBH/PS

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