Handwriting and the non-dominant hand
by Katherine J. Collmer, M.Ed., OTR/L
Frank R. Wilson, in his renowned discussion of the evolution of the hand, poses the suggestion that bimanual tasks result in the development of a visual vocabulary. He defines a “visual vocabulary” as one that is established as a result of a mysterious, nonverbal language. This language can be witnessed in the arts, from jewelry making to writing, as each creator uses “internalized rules for combining materials and structural elements” to produce unique patterns of work. These works of art take on a meaning for both the designer and viewer and become the personal stamp of the creator. (1) In this sense, handwriting can be defined as a nonverbal language that results from the production of lines and shapes that are placed within spatial constraints according to predetermined directional and alignment rules. They become words and sentences that take on a meaning that the writer conjures up in our minds to share thoughts, feelings, information, and knowledge. Although Wilson describes handwriting as a task commonly considered to be a unilateral hand skill, (1) one that is considered by researchers to require only the “specific coordination between the finger and wrist movements” of one hand, (2) it appears that handwriting under the label of a visual vocabulary would then be considered a bimanual task.
The production of a visual vocabulary, in the arts and handwriting, depends on the ability of the hands to form a complementary partnership in their role as a vehicle for expression. This partnership consists of a dominant and non-dominant hand that become one unit in the completion of bimanual tasks. Brain lateralization and the intercommunication between the two sides of the brain have been considered the foundational requisites that facilitate the establishment of a dominant hand and determine handedness in humans. However, the establishment of hand dominance remains a confusing and baffling human trait that scientists admit there is little known about its history or neurologic foundations. The study of the evolution of handedness has taken anthropologists back to an examination of how the hands were used by our Stone Age predecessors to wield stones as hammers to create tools for building or cooking or to design weapons intended to kill game or to act as protection against predators. Their studies revealed that the tool users would have divided the tasks of hammering or throwing into two distinct parts, utilizing one hand to steady the object to be hammered or to balance the body against gravity in throwing and the other hand to perform the precise movements necessary to direct the stone toward a target with accuracy. This division of labor has been labeled as the dominant and non-dominant hand movements.
Hand dominance** has been suggested to have been a “critical survival advantage” to hunters and gatherers as they engaged precision tasks within their competitive environments. (1) Given that precision tasks demand practice for mastery, their consistent use of one hand to perform and perfect an accurate aim-and-throw movement may have organized the brain-hand pathways and established a hand dominance. Again, the baffling question remains: Why did these early humans select the right versus the left hand for precision tasks? While scientists have yet to uncover the answer to this conundrum, they have turned with equal wonder at the mystery of the perceived underdevelopment of the non-dominant hand. Some ask the question, “Did it stagnate? Was it ‘dumbed down’ somehow, in order to guarantee the emergence of a manual performance asymmetry?” Or was the non-dominant upper limb intended to become specialized in a different way? (1) This latter view of the non-dominant hand suggests that the two hands are complementary, forming a whole that is dependent on the accurate production of the specified movements of both sides. This is an enlightening perspective on the role of the non-dominant hand, for sure.
Dominant and non-dominant hands were once referred to as the “good” and “bad” hands, with the non-dominant hand being labeled as the “somewhat disabled one.” (1) The right hand was viewed as the “good” hand despite the occurrence of left-handedness in some children. Left-handedness, in fact, was considered to be a deficit and children were strongly encouraged, sometimes forced, to ignore their tendency to use their left hand and to switch instead to their right hand for writing and drawing. The argument and prejudice against left-handedness was promoted by the confusing fact that an overwhelming number of people were right-hand dominant. In the end, regardless which hand became dominant, the non-dominant hand was believed to be an unequal force in the production of bimanual tasks. It was considered to be inferior to the more precise hand. As researchers began to investigate more closely the interaction of the hands in bimanual skills, they questioned this idea and considered instead the likelihood that they were interdependent. Bimanual tasks, by definition, involve the use of both hands. While some bimanual tasks can be accomplished with the use of one hand (as evidenced by the rehabilitation efforts of persons who have suffered from a stroke), most often the speed, fluidity, and accuracy of their production are compromised by the lack of a supporting hand. In general, then, bimanual tasks demand the use of both hands for efficiency, as is seen in activities such as playing a musical instrument, golfing, tying our shoes, cutting our food, and handwriting.
Wilson describes handwriting as a task commonly considered to be unilateral hand skill, (1) one that is considered by researchers to require only the “specific coordination between the finger and wrist movements.” (2) However, in light of the research that considers the two hands as partners in a task, an analysis of the the non-dominant hand in handwriting has revealed it to play “a complementary, though largely covert, role by continuously repositioning the paper in anticipation of pen movements.” (3, qtd in 1) In 1987, French psychologist Yves Guiard studied the complementary hand movements in handwriting relative to the idea that the physical characteristics of the movements of each hand, as well as the sensory control mechanisms that supported those movements, were significantly different. He proposed that their scaled movements were spatially and temporally divided into two categories. In Guiard’s theory, the scale of the dominant hand’s movements is considered to be “micrometric,” or produced within a smaller space with slower speeds relative to the supporting hand. Its performance is rehearsed and mostly internally driven or pre-programmed, directed by the development of motor patterns and the automatic reproduction of those patterns. (1) In contrast the movements of the non-
dominant hand in its role as the paper positioner are “macrometric.” They are conducted to facilitate improvised adjustments using faster speeds within a larger context. They are externally driven, being directed by the writing hand to set the spatial boundaries within which it can perform its skilled movements. In effect, the non-dominant hand is supporting the precise movements of the dominant one by providing a stabilizing environment that allows for frequent alterations that are responsive to the movements of the skilled hand. This perspective of the non-dominant hand elevates its significance in the production of handwritten work. The actions of the supporting hand require controlled motor movements that can transition within a diverse range of “improvised hold and move sequences” that do not follow strict rules for patterns or rhythm. These movements require sensory control mechanisms that can detect, analyze, and integrate visual perceptual information, such as spatial boundaries or paper angles, relative to the movements of the dominant hand. The supporting role of the non-dominant hand demands flexibility to “conform its movements both to the behavior of an external object and to the actions of the other hand, to ensure that the object and the handheld tool will intercept at the intended time and place.” (1) Guiard discovered that these alterations are anticipated and initiated before the movements of the skilled hand take place, leading to his proposition that “there is a logical division of labor between the two hands that appears to govern the entire range of human bimanual activities.” (1)
The precise, rehearsed, and preprogrammed facets of handwriting rely on the supportive role of the less-precise hand to guide the dominant one in producing the “collection of identical hash marks” (1) that create an individual penmanship style and comprise the visual vocabulary that delivers each writer’s personal message. The supporting role of the non-dominant hand places handwriting among our most creative bimanual tasks. In this light, an assessment of handwriting development skills would warrant an evaluation of the behaviors demonstrated by the supporting hand and rehabilitative efforts designed to develop it to its highest skill level.
**For more information about the developmental stages of hand dominance and the it plays in handwriting mastery, please read my article, “Hand Dominance – a key factor in handwriting success,” and my book, Handwriting Development Assessment and Remediation: A Practice Model for Occupational Therapists,” which can be purchased on my website.