Left-handed Writers Research Articles

The Direction of Slant and Horizontal Stroke as Potential Suggestive Markers for the Determination of Handedness

Abstract Background: The task of document examiners is very challenging, as they need to gather all the relevant facts to make an informed decision regarding the questioned document. In the present study, a total of 300 handwriting samples from 100 different writers (involving 50 right-handed and 50 left-handed) were collected at Bundelkhand University, Jhansi. Slant and stroke, as characteristic features of handwriting, were visually examined under a stereomicroscope to ascertain the handedness. Methods: Slants and Strokes as characteristic features were analyzed in a total of 300 handwriting samples collected from 50 left-handed and 50 right-handed writers of age 17–22 years. A reference text comprising three pangram sentences printed on A4 paper and a blue ball point pen was used for sampling. Results: The data collected during the study were analyzed using a statistical method (Chi-square test) and revealed that the left-handed writers (LHWs) had a significantly (P < 0.05) different writing style than the right-handed ones. Results indicated that LHWs are more likely to make strokes in the right-to-left direction and slant of letters in the backward direction, while right-handed writers make strokes in the left-to-right direction and slant of letters in the forward direction. Conclusions: The findings of the study showed valuable insight and highlighted the significance of the direction of slant and horizontal stroke as potential indicators for the determination of handedness.

Discrimination between right- and left-handed writers based on sister lines.

Forensic document examiners are often confronted with questioned documents written with ballpoint pens. Depending on the force applied (or pressure) as well as the angle between the pen and the surface, sister lines running parallel to the inked strokes can be left by the lip of the housing ball. In a real case, sister lines were observed on the left side of inked strokes of a questioned signature. To assess whether the writer of that signature was a left-handed or a right-handed writer based on this result, an experimental study was carried out. Handwritten samples and signatures from 182 right-handed and 18 left-handed writers were collected with different ballpoint pens. For every writer, the presence or absence of sister lines was recorded. Sister lines were observed in 49% of the writers of the studied population (in 50% of the right-handed and ca. 39% of the left-handed writers). Most individuals who left sister lines showed a writing angle of 50°-55°. The location of sister lines was tabulated to inform probabilities of observing sister lines at a given location, if the writer is a right-handed or left-handed writer. In the case at hand, a likelihood ratio of 48 was obtained in support of the proposition of a left-handed writer, rather than a right-handed writer. Applying Bayes' theorem, such value moves the prior probability of 15% that the writer of the questioned signature is left-handed to a posterior probability of 89%.

Handwriting status among Iranian primary school students: a cross-sectional study

Background/Aims Handwriting difficulties among school students are the primary reason for referral to school-based occupational therapy. Appropriate criteria and a complete view of the students' handwriting status are lacking in Iran. The purpose of this study was to gather comprehensive information about handwriting issues for therapists and related disciplines in Iran. Methods In this cross-sectional study, the handwriting status of 1262 Persian-language elementary school students (grades 2 and 3) from governmental schools was surveyed using the Persian handwriting assessment tool. Results There were statistically significant differences in handwriting components between second and third grade students except for word size and text slant. Handwriting components were different between boys and girls, and between right- and left-handed writers. Regression analysis revealed a positive relationships between age and grade and most of the handwriting components. Conclusions The results of this study have implications for teachers, therapists and other specialists who work and research on handwriting status of typically healthy students and students who are disabled in Iran. Handwriting skills improve over time and it seems that girls and right-handed writers are better writers regarding legibility.

Differentiation and Comparison of Left handed and Right handed writers on the basis of Strokes and Slope of letter

Handwriting is a written speech of an individual with characteristics peculiar to himself. The handwriting of a person is a product of his mental, emotional, intellectual and physical personality. Once the handwriting is set it is unique expression of his graphic personality. The differentiation for the identification of handedness of author plays an important role to identify an individual in document cases and to study this differentiation and comparison of left handed and right handed writers on the basis of strokes and slope of letter, the present study was conducted at Bilaspur district, Chhattisgarh in which 100 samples of handwriting, 50 left-handed and 50 right-handed writer were collected. The handwriting samples were examined by hand lens, flexible arm illuminated magnifier, grid scale and the characteristics features like stroke and slope were observed in various letters. A significant difference was observed in left handed and right handed writing and was concluded that left-handed writer make strokes in right-to-left direction and the slope of letters has an inclination in backward direction where as right-handed writer make strokes in left-to-right direction and the inclination of slope was in forward direction. Thus, this differentiation and comparison helps to solve many document cases.

The handwriting experiences of left-handed primary school students in a digital age: Australian data and critique

Left-handers comprise about 10% of the Australian population. In Australia and elsewhere, there has been a history of discrimination against left-handedness, expressed in a variety of ways. Although negative attitudes to left-handedness have become less common in recent times, researchers have not investigated the extent to which left-handedness is now acknowledged or encouraged in Australian schools, or whether left-handed students have to overcome difficulties due to their handedness. This study investigated the handwriting experiences of 10 primary school students and the opinions of 11 primary school teachers on handwriting and on left-handed writers. The left-handed students identified a range of issues including the need for specialized writing equipment, writing speed and neatness. The teachers also mentioned these issues along with legibility and writing instruction. The results are discussed in terms of guidance on writing instruction and the place of writing in an increasingly digitized world.

Assessing the suitability of individual whiteboards for left-handed writers within the Early Years Foundation Stage

This study examines the provision for left-handed children learning to write in the foundation stage of the primary phase of education. Through a case study, it explores the recognition of the needs of left-handed children and the resources available for the effective and confident teaching of writing skills. Finding revealed that the current approach, incorporating the use of individual dry-wipe white boards, inhibited writing skill development in left-handed children and adversely affected self-esteem. The approach advocated by South Australian Curriculum Standards and Accountability (2006) and the use of magnetic writing boards were found to significantly improve the quality of early stage left-handed writing.

The influence of right or left handedness on the ability to simulate handwritten signatures and some elements of signatures: A study of Arabic writers

It has been widely assumed since the 1970s that right-handed writers, on average, do not write or simulate handwriting any better than left-handed writers. This study has dug deeper into that question, to find narrow language environments which left-handed and right-handed writers simulate with different degrees of success or making different types of errors. These might provide useful markers of handedness in writers or forgers. The sample of 823 native Arabic-writing adults, 763 right handed and 60 left handed, first attempted to simulate two Arabic signatures. As expected, the accuracy of the simulations of the two groups was not significantly different. Simulation accuracy of a variety of narrower elements was then measured to search for small environments in which the two groups performed differently. Two elements - slant and alignment - were significantly more poorly simulated by left-handed subjects than right-handed subjects, although the differences were not great enough to be useful in suggesting the handedness of a forger. These differences in simulation accuracy were not totally explored or explained. Instead, the differences in types of errors to slant and to alignment were investigated. Left-handed simulators, but not right-handed simulators, showed a strong tendency that had been predicted for both groups: to slant strokes and letters toward the side of the writing hand, when the target strokes and letters slanted in the opposite direction. The difference between the handedness groups was great enough that a strong preference for leftward slant in an Arabic writer or forger might suggest left handedness, but not, of course, rule out right handedness. Right-handed simulators, but not left-handed simulators, showed a strong tendency that had also been predicted for both groups: for the line of writing to be higher on the side where the writing hand was located. Again, the difference between handedness groups was great enough that a strong tendency for the writing line to fall to the left in Arabic writing and simulation might suggest right handedness, but would certainly not rule out left handedness. Thus, suggestive, but not absolute, markers of handedness have been found. In an effort to explain these almost mirror-image patterns, it was noticed that the operation of two more tendencies, in addition to the operation in both groups of the two predicted tendencies, might explain the patterns of the data. If we assume that both handedness groups tended to slant toward the writing hand and tended to make the writing line higher on the side of the writing hand, the two other tendencies operating in both groups would have been a tendency to slant strokes and letters toward the end of the writing line, and a tendency for writing to fall toward the end of the writing line. The operation of these four tendencies would account quite well for the right-handed and left-handed patterns in the two groups.

Handedness and socioeconomic status in an urban population in Uzbekistan

The persistence of left-handers in every human population studied to date is an evolutionary puzzle in light of evidence of survival costs associated with left-handedness. Associations between left-handedness and socioeconomic advantages have been observed in Western countries and could provide left-handers fitness benefits through higher survival chances and greater reproductive success. We aimed to explore the generality of this result in another culture. For this purpose, we investigated several socioeconomic status indicators and the number of children alive for 917 men and women in Uzbekistan and compared results for two different measures of handedness: hand preferences for writing and for knife use. Among both men and women, left-handed writers were significantly more likely to own a car, own a washing machine and have a bank account. Left-handed women (using both measures) had a higher income than right-handed women. Among men, left-handers for knife use had a higher income than right-handers. The results of our study suggest that the previously observed socioeconomic advantage of left-handers in Western populations also applies to non-Western populations, at least in the urban environment studied. However, we did not detect any difference in the number of children. We discussed how the frequency-dependent socioeconomic status advantage could be responsible for the persistence of left-handers throughout human evolution.

Digit ratio (2D:4D) and hand preference for writing in the BBC Internet Study

The ratio of the length of the second to the fourth digit (2D:4D) may be negatively correlated with prenatal testosterone. Hand preference has been linked with prenatal testosterone and 2D:4D. Here we show that 2D:4D is associated with hand preference for writing in a large internet sample (n>170,000) in which participants self-reported their finger lengths. We replicated a significant association between right 2D:4D and writing hand preference (low right 2D:4D associated with left hand preference) as well as a significant correlation between writing hand preference and the difference between left and right 2D:4D or Dr-l (low Dr-l associated with left hand preference). A new significant correlation between left 2D:4D and writing hand preference was also shown (high left 2D:4D associated with left hand preference). There was a clear interaction between writing hand preference and 2D:4D: The left 2D:4D was significantly larger than the right 2D:4D in male and female left-handed writers, and the right hand 2D:4D was significantly larger than the left hand 2D:4D in male and female right-handed writers.

Phonology and handedness in primary school: predictions of the right shift theory

The right shift (RS) theory of handedness suggests that poor phonology may occur in the general population as a risk associated with absence of an agent of left cerebral speech, the hypothesised RS + gene. The theory predicts that poor phonology is associated with reduced bias to right-handedness. A representative cohort of primary school children was assessed on tests of phonology, nonverbal ability, literacy, and handedness. There were three types of analysis; for discrete variables, poor phonology and left hand preference; for continuous variables, phonology factor scores and hand skill; for "cases" of specifically poor phonology. Reduced bias to dextrality was found in those with poor phonology for all types of analysis. Trends were similar for both sexes but stronger in males than females. Poor phonology was associated with a raised proportion of left-handed brothers. There was a strong association between poor phonology and poor literacy, but not all those with specifically poor phonology were poor readers or spellers. Among children with poor phonology but not poor for other variables, some 23-31% were left-handed writers. Poor phonological processing is associated with reduced bias to the right hand, consistent with absence of an agent of left hemisphere advantage.

Adaptations of writing posture in response to task demands for left- and right-handers

Handedness and writing posture are visible manifestations of differences between left- and right-handers. Although an inverted posture is witnessed in both groups, there is a much higher proportion of left-handers who invert. This study is framed within the adaptation hypothesis of writing posture, which states that invertedness in left-handers develops in response to the demands of cursive writing. Participants (N = 57) comprising left-handed inverters, left-handed standard writers, and right-handed standard writers engaged in tasks that required them to form letters and pen strokes at extreme angles. In addition participants were questioned about attempts to change writing posture. We hypothesised that letter angle controls posture in both left- and right-handers and that inverted posture would be a target of intervention. The results of the study showed some support for these hypotheses in that left- and right-handers adapted their posture in response to the constraints placed upon them and inverters reported more intervention.

Parallels between asymmetries of planum temporale and of hand skill

Relationships between the skill of each hand and differences between the hands are described for a sample of 14–15-year-olds representative of the general population. The description is modelled on the account of Galaburda et al. ( Neuropsychologia 25, 853–868, 1987) of relationships between asymmetries of the Planum Temporale (PT) and measures of PT area on each side, in order to show parallels between findings for the two types of asymmetry. For both PT and hand skill, the extent of asymmetry appears to depend on the greater variability of the weaker side rather than of the larger or “better” side. The findings are also described as a replication of the study of hand skill in children by Annett and Manning ( Br. J. Psychol. 80, 213–226, 1989). As no score transformations were needed in the present sample, the grounds for doubt raised by Bishop ( Handedness and Developmental Disorder, Blackwell, Oxford, 1990) about the earlier sample are removed. Repetition of the analyses for right-handed and left-handed writers separately demonstrates very close similarities for findings in the two hand preference groups. Theories about the mechanisms responsible for asymmetries appear to require the presence of factors which reduce brain area and hand skill on one side. For most people the reduction is to the right PT and to the left hand.

Cognitive performance among left-handers differing in strength of handedness and familial sinistrality

Male ( n = 48) and female ( n = 54) left-handed writers were subdivided according to familial sinistrality (FS+ vs. FS−) and strength of handedness (Consistent (C) vs. Non-Consistent (NC) left-handedness). Performance in computerized reaction time (RT) and maze tests was assessed by skill, solving-strategy and laterality indices. Verbal ability was assessed by a vocabulary test. The main findings demonstrated that sex, but not FS or C/NC affected RT. Females were slower, particularly for left-sided stimuli, and made fewer errors in choice RT tasks. C subjects, of which a majority were females, were inferior in maze performance, in spite of using a speed-preferring solving strategy, which is assumed to reflect right-hemisphere processing. When controlling for factors of FS and C/NC, expected sex differences in maze performance were markedly attenuated. The findings underscore the importance of analyzing not only skill, but also strategy and laterality indices in studies of left-handers, and of considering factors of FS and C/NC particularly when studying cognitive sex differences.

Mixed-handedness and achievement test scores of grade school children.

Normal Curve Equivalent Scores on subtests of the California Achievement Test for mixed-handed children, 52 boys and 58 girls from Grades 3 and 4, who are right- and left-handed writers, indicate no differences by handedness in girls, but among the mixed-handed fourth grade boys, those who wrote right-handed scored lower on Study Skills than the boys who wrote left-handed.

Maps on Center Stage

Several excellent resources will help middle level and secondary teachers understand the legibility problem and assist them in providing appropriate instruction for students with handwriting problems. Clark, Margaret M. 1974. Teaching left-handed children. London: University of London Press, 48 pages. This small volume focuses attention on left-handed writers and appropriate instructional techniques for them. Specific suggestions and clear diagrams provide assistance with handwriting problems, positioning of paper, grip, and types of writing instruments. Harrison, Stephanie. Spring, 1981. Open letter from a left-handed teacher: Some sinistral ideas on the teaching of handwriting. Teaching Exceptional Children, 13: 116-120. This excellent article describes the needs and problems of left-handed writers and provides specific and detailed suggestions for teaching these unique learners. Barbe, Walter B., & Lucas, Virginia H. February, 1974. Instruction in handwriting: A new look. Childhood Education, 50: 207-209. This article explains the rediscovery of handwriting, the extent of its neglect, and the increased demand for legibility. An examination of critical handwriting issues and the most appropriate methods for instruction will assist middle and secondary school teachers.

Incidence of left-handed writers and the inverted writing position in a sample of 2194 German elementary school children

In a sample of 2194 German elementary school children, 6.9% of the females and 9.5% of the males wrote with the left hand. The proportion of left-handers writing with the inverted writing position was much higher than in comparable Canadian samples, particularly in the early grades. The higher incidence in early grades was related to the earlier introduction of cursive style writing in the German sample. There was a significant effect of writing position on the directional consistency of the letter shafts in the writing samples: noninverted writers were more inconxistent in their letter shaft orientation within and between words than inverted writers. The results stress adaptation to the technical demands of left-handed writing in the genesis of the inverted writing position, in support of recent studies ( Guiard and Millerat, Neuropsychologia 22, 535–538, 1984) that come to similar conclusions.

Inverted and noninverted lefthanders compared on the basis of motor performance and measures related to the act of writing

Pen angles, tilt of writing page, head tilt, slant of writing, mirror writing, laterality quotients and familial sinistrality of inverted and noninverted lefthanded writers were measured. Subjects also performed two motor tests. Reliable differences were found only in terms of the pen angles and the tilt of the writing page, measures that define the groups in the first place. It was concluded that technical aspects of writing from the left to the right with the left hand and environmental pressures are important factors in the genesis of the inverted writing position in the lefthander.

Dichotic ear asymmetry and writing posture

A right ear advantage for right-handed writers with normal posture was found, but not among left-handed writers with a normal or inverted posture, nor among right-handers with an inverted posture. Writing posture cannot be related to cerebral lateralization for verbal stimuli presented in the auditory modality.

Secular variation in handedness over ninety years

Left-handed writers of high socio-economic status born in Australia or New Zealand were found to increase from about 2 to 13% over the period 1880–1969. The change was well represented by a symmetrical sigmoid curve which allowed the upper asymptote to be evaluated as 13.63 ± 0.16%. The observed secular variation differed in shape and began earlier than in the United States perhaps because of differences in social status between the samples. It is suggested that differential perinatal death may operate together with cultural relaxation in promoting an increasing proportion of sinistrals with time.

Handedness in psychiatric patients.

Eight hundred psychiatric patients and eight hundred controls completed a handedness preference questionnaire. There was no significant difference in handedness between the two samples, but, contrary to some previous reports, excess of sinistrality was not associated with male sex. The distribution of handedness was similar in neurotics and controls, but among psychotics in general there was a higher proportion of fully right-handed subjects. Among schizophrenics there was a significantly higher proportion of left-handed writers among males than females. There were relatively few left-handed writers of either sex among patients with affective psychosis. Female patients with personality disorders had a significantly higher proportion of mixed handedness than controls. The findings are considered in relation to suggestions that functional psychoses may be associated with asymmetrical cerebral dysfunction, and that poorly lateralized function may be related to anomalous psychological development.