Venstrehendthet

Venstrehendthet, or left-handedness, is the preference for using the left hand for tasks such as writing, throwing, and other fine motor activities. It is estimated that about 10 to 12 percent of people are left-handed, a proportion that is relatively stable across populations though precise numbers vary by study.

Causes are complex, involving genetic, prenatal, and environmental factors. No single gene explains handedness; several genetic variants appear to contribute small effects, and non-genetic factors such as fetal development and early-life experiences may influence lateralization.

Brain and development: In most left-handed individuals, language is in the left hemisphere, but a minority may have bilateral or right-hemisphere language dominance. Left-handedness is associated with greater variability in brain lateralization.

Social and cultural aspects: Historically, left-handedness faced stigma in some cultures; today adaptations like left-handed scissors or desks are common, and the stigma has diminished.

Health, cognition, and behavior: Research has explored possible links between handedness and cognitive styles, creativity, or risk for certain conditions. Most associations are weak and not diagnostic. Some studies have reported associations with certain neurodevelopmental conditions, but results are inconsistent.

In sports and everyday life: left-handed individuals may have advantages in certain sports due to opponents' relative unfamiliarity, while there can be disadvantages in right-handed-dominated contexts.