righthandedness

Righthandedness, or right-handedness, is the tendency to prefer the right hand for performing skilled tasks such as writing, throwing, and manipulating objects. The majority of people show a clear right-hand preference, with estimates typically around 85 to 90 percent. Some individuals are left-handed, and others are ambidextrous or exhibit mixed preferences depending on the task.

Handedness is usually assessed with self-report inventories or simple tasks, and researchers sometimes use a laterality index to summarize multiple measures. The Edinburgh Handedness Inventory is a common tool, but classifications can vary across assessments. Handedness exists along a spectrum, and many people are stronger in some tasks than others.

Neurobiologically, right-handedness is often associated with left-hemisphere dominance for language and motor control. This lateralization is not universal, and there is substantial variation among individuals. Genetic factors, prenatal development, and environmental influences all contribute, though no single gene determines handedness.

Developmentally, hand preference begins in infancy and becomes more consistent with age, typically stabilizing in early childhood. Cultural and practice-related factors can influence observed preference, and parental handedness correlates with that of children but does not determine it.

From an evolutionary and functional perspective, the high prevalence of right-handedness remains the subject of study and debate. Some theories emphasize coordination and social interaction within populations; others stress developmental and neural factors.

Left-handedness and mixed handedness have been studied in relation to brain structure and language development, though findings are not conclusive. Today, society generally accommodates diverse handedness, with many tools and arrangements designed for either hand.