According to the Merriam-Webster dictionary, ambidextrous means to use “both hands with equal ease or dexterity.” In 1646, Sir Thomas Browne combined the Latin word, dexter, (situated on the right side) with the Latin prefix, ambi, (both). He described those who are “right-handed on both sides” as ambidextrous. Over the years, the root, dexter, became associated with general skillfulness, giving rise to words like dexterous. The meaning of ambidextrous has evolved into skillfulness with both hands.
The late 19th and early 20th centuries saw the development of two competing movements in regard to left-handedness. The first view, that right-handedness is the preferred state and left-handedness is potentially dangerous, was promoted by the Italian criminologist, Cesare Lombroso (1835-1909). His writings (1876 to 1897) associated left-handedness with criminality and mental instability. He argued that left-handers were not as civilized and culturally advanced as their right-handed peers leading to the proposal that “left-handedness…may contribute to form one of the worst characters among the human species.”
The second perspective is exemplified by the British Ambidexterity Culture Society whose roots stem from the late 1880’s. Sir Robert Baden-Powell, founder of the Boy Scouts, supported this movement. He wrote that the use of both hands stimulates both hemispheres of the brain resulting in a more symmetrical, intelligent and gifted child. John Jackson’s 1905 book, Ambidexterity: or, Two-handedness and two-brainedness, argued that ambidexterity gave both hands a chance to dominate. Jackson rejected the preeminence of the right hand claiming that handedness could be trained and changed by life experiences. The ambidexterity movement embraced rather than stigmatized the use of the left hand.¹
What scientists have learned about being ambidextrous over the intervening 100+ years favors the position of the Ambidexterity Culture Society. A right-handed person, with enough practice, can learn to use the left hand. The most difficult behavior to master is the highly lateralized (sided) action of cursive handwriting but even this skill can be acquired with systematic and continued practice. Left-handers have an advantage in gaining expertise with the right hand. They have repeated opportunities to practice right-handedness while navigating the many environmental arrangements favoring right-hand use.
Research results define ambidexterity in two ways. Most people are ambidextrous across one-handed activities. They do some things with the left hand (write) while doing other things with the right hand (throw a ball, use a tennis racket). They show equal dexterity with the left and right hand but for different behaviors.
A smaller subset of individuals are ambidextrous within a one-handed activity. The most common examples are found in sports. There are baseball players and cricketers who bat equally well from a right- and left-handed stance and golfers who play with equivalent skill from a right- and left-handed position. It is difficult to achieve true ambidexterity for highly lateralized behaviors such as cursive handwriting. Only a few people can write or draw equally well with the right and left hand. It is easier to achieve ambidexterity for less lateralized behaviors such as opening a jar lid. One can acquire equal skill with the right and left hand when performing this action.
People engage in many one-handed activities. It is difficult but not impossible to imagine an individual who is equally proficient with the right and left hand for all possible one-handed behaviors. I have not encountered such a person in all my years of handedness research activities but, if such a person exists, he or she would show true overall ambidexterity.
¹Kushner, H.I. (2017). On the other hand: Left hand, right brain, mental disorder, and history. Baltimore, MD: Johns Hopkins University Press, pgs. 18-26.