  the term laterality refers to the preference most humans show for one side of their body over the other. examples include left-handedness/right-handedness and left/right-footedness, it may also refer to the primary use of the left or right hemisphere in the brain. it may also apply to animals or plants. the majority of tests have been conducted on humans, specifically to determine the effects on language. == human laterality == the majority of humans are right-handed. many are also right-sided in general (that is, they prefer to use their right eye, right foot and right ear if forced to make a choice between the two). the reasons for this are not fully understood, but it is thought that because the left cerebral hemisphere of the brain controls the right side of the body, the right side is generally stronger; it is suggested that the left cerebral hemisphere is dominant over the right in most humans because in 90-92% of all humans, the left hemisphere is the language hemisphere. human cultures are predominantly right-handed, and so the right-sided trend may be socially as well as biologically enforced. this is quite apparent from a quick survey of languages. the english word "left" comes from the anglo-saxon word lyft which means "weak" or "useless". similarly, the french word for left, gauche, is also used to mean "awkward" or "tactless", and sinistra, the latin word from which the english word "sinister" was derived, means "left". similarly, in many cultures the word for "right" also means "correct". the english word "right" comes from the anglo-saxon word riht which also means "straight" or "correct." this linguistic and social bias is not restricted to european cultures: for example, chinese characters are designed for right-handers to write, and no significant left-handed culture has ever been found in the world. when a person is forced to use the hand opposite of the hand that they would naturally use, this is known as forced laterality, or more specifically forced dextrality. a study done by the department of neurology at keele university, north staffordshire royal infirmary suggests that forced dextrality may be part of the reason that the percentage of left-handed people decreases with the higher age groups, both because the effects of pressures toward right-handedness are cumulative over time (hence increasing with age for any given person subjected to them) and because the prevalence of such pressure is decreasing, such that fewer members of younger generations face any such pressure to begin with.ellis, s. j., ellis, p. j., marshall, e., &
Chirality Mental_processes Motor_skills