Correlates of Early Handwriting: Differential Patterns for Girls and Boys

ABSTRACT Research Findings: Fluent and legible handwriting is associated with longer texts and higher text quality and is therefore an important goal in the primary school curriculum. While girls’ handwriting tends to be more proficient than boys’, potential differences in the correlates of girls’ and boys’ early handwriting are poorly understood. In this exploratory study, we investigated early handwriting (legibility, fluency, and time) and potential motor (fine motor skills, visuomotor integration) and cognitive (executive functions: inhibition, shifting, working memory) correlates in a sample of 118 first-grade children (46% girls, Mage: 7 years, 5 months). We tested gender differences and explored correlates of early handwriting skills of girls and boys. Extending previous findings, fine motor skills and visuomotor integration were related to early handwriting legibility, fluency, and time. Furthermore, shifting and working memory, but not inhibition, were related to specific handwriting skills. Moreover, girls outperformed boys regarding fine motor skills, visuomotor integration, and handwriting legibility. Interestingly, while the correlates of handwriting were diverse and strong for girls, only a few weak correlates were identified for boys. Practice or Policy: These results lay the ground for tailoring adequate interventions to support girls and boys (differently) in acquiring fluent and legible handwriting.

easily at speed, without inappropriate effort and hesitation (Caravolas et al., 2020;Feder & Majnemer, 2007).While measures of handwriting legibility usually consider specific static handwriting features (e.g., letter formation, size, spacing between letters and words, and degree of line slant; e.g., Rosenblum et al., 2003;Santangelo & Graham, 2016), handwriting fluency is typically measured either by the number of produced letters in a specific time (e.g., Kent et al., 2014) or by means of technologies that allow detailed real-time recordings and analyses of handwriting processes (e.g., Fitjar et al., 2022, for elaborate insights).To develop fluent, legible, and efficient handwriting, fine motor and visuomotor integration skills are essential.Fine motor skills comprise the coordination and control of the small muscles of the fingers and hands (Bruininks & Bruininks, 2005), whereas visuomotor integration describes the integration of visual input (e.g., seeing the letter shape) with a motor response (e.g., drawing the letter shape), which requires remembering and maintaining the letter shape (Beery et al., 2010).
There is empirical evidence pointing to the importance of fluent and legible handwriting.An accumulating body of evidence shows that handwriting fluency uniquely predicts the quantity and quality of text composition across the primary school years and beyond (Berninger et al., 1997;Connelly et al., 2005;Kim et al., 2011;Limpo et al., 2017).The fluency of handwriting affects not only the productivity of composing text (Graham et al., 2000) but it seems also to affect the quality of the produced text (Alves et al., 2016).Low fluency negatively influences a child's ability to focus on the writing content (Graham et al., 2001) and consequently impacts text quality (Skar et al., 2022).Low fluency, as operationalized in this study, is indicated by a high number of segments per letter, that is, multiple velocity changes (i.e., increase and decrease of speed) within a letter.Low fluency is often associated with fatigue and less legible writing (Rosenblum et al., 2006).Besides the number of speed changes within a movement unit (i.e., a letter), handwriting time is a further indication of handwriting fluency.More efficient handwriters can produce more text in a certain time and tend to cope more easily with classroom demands than less efficient writers (Rosenblum & Livneh-Zirinski, 2008;Rosenblum et al., 2006).
Handwriting legibility, besides other non-context factors such as spelling correctness, affects the reader's (e.g., teacher's) judgment about the ideas and content of the text (the Presentation Effect; reviewed by Graham et al., 2011).As pointed out by Fitjar et al. (2022), in most educational settings, untidy handwriting typically leads to teacher criticism and a vicious cycle, in which criticism reduces self-esteem which often results in avoiding handwriting activities and ultimately in reduced handwriting practice (Danna et al., 2016).Furthermore, the handwriting process of children struggling with neat and fluent handwriting consumes an undue amount of cognitive resources that limit the cognitive capacities left for other writing processes, such as composing (Santangelo & Graham, 2016).

Theoretical Framework
Handwriting is a complex multi-component task.In fact, the handwriting product is the overt manifestation of various cognitive and motor processes (Van Galen, 1991).According to the Simple View of Writing (Berninger et al., 2002;adapted by Ahmed et al., 2021), transcription skills (e.g., handwriting or keyboarding, and spelling) together with specific cognitive functions (i.e., executive functions: e.g., working memory, including conscious attention, and planning) build the foundation for writing.This model represents the shape of a triangle, in which transcription skills building the lower left corner of the triangle, interact with executive functions, building the lower right corner.Ultimately, transcription skills together with executive functions build the prerequisites for "higherlevel" writing (top corner) comprising composing and revising text.
The transcription skills we explore in this study comprise the graphomotor skills (i.e., fine motor skills, visuomotor integration) needed to copy letters and words accurately (Sägesser & Eckhart, 2016), especially in early grades when handwriting is not yet automatized and demands attention.Executive functions are typically defined as a set of three cognitive functions: (1) inhibition of distracting or competing stimuli, for instance by focusing attention on writing, (2) shifting attention flexibly (i.e., cognitive flexibility), for instance by switching visual attention between the original (reflecting the uptake of information) and the copy (reflecting monitoring of writing) in a copying task (Brown & Donnenwirth, 1990), and (3) working memory, which refers to actively holding verbal or visuospatial (e.g., written) information in mind while writing (i.e., manipulating) it (Diamond, 2013;Miyake et al., 2000).These core attentional processes are assumed to underlie more complex executive functions such as planning or revising text (Ahmed et al., 2021;Vanderberg & Swanson, 2007).

Correlates of Early Handwriting
The crucial role of fluent and legible handwriting for academic achievement (e.g., Graham et al., 2011;Limpo et al., 2017) raises the question of the correlates of handwriting, which might help us understand individual differences in handwriting.From a motor viewpoint, a single stroke, such as the letter "I," represents the smallest meaningful unit of the writing movement (Thomassen & Van Galen, 1992).In automated (i.e., proficient) handwriting, single stroke movements are characterized by a velocity profile with only one peak (inversion of direction) and a bell shaped course (Tucha et al., 2006(Tucha et al., , 2008)).The strokes of automated movements lead to a smooth and repetitive velocity course (Mai & Marquardt, 2007).To acquire such smooth strokes, which build the basis of legible and fluent handwriting, fine motor skills and visuomotor integration play a meaningful role (Sägesser & Eckhart, 2016).
Prior studies reported associations between visuomotor integration and handwriting legibility (Feder & Majnemer, 2007;Van Hartingsveldt et al., 2015).Children in early primary grades who copy shapes more accurately tend to write more legibly, their texts are of better quality, and they typically write more fluently (Duiser et al., 2014;Kaiser et al., 2009;Truxius et al., 2023).In contrast to these findings, some studies did not reveal any association between visuomotor integration and handwriting legibility (Marr & Cermak, 2002; association found only in girls) or handwriting fluency (e.g., Wicki & Hurschler Lichtsteiner, 2018).With regard to fine motor skills as correlates of handwriting, previous studies' results provide evidence for associations between fine motor skills and handwriting legibility (Parush et al., 2010) and fluency (Wicki & Hurschler Lichtsteiner, 2018).These findings are in line with studies showing that primary school children with poor fine motor skills typically show poor handwriting legibility and vice versa (Hamstra-Bletz & Blöte, 1993;Seo, 2018).
Concerning the cognitive correlates of handwriting, executive functions were found to be associated with handwriting across the primary and secondary school years (Drijbooms et al., 2015, in Grade 4;Salas & Silvente, 2020, in Grades 2-8;Volman et al., 2006, in Grades 2-3) both in children with and without handwriting difficulties (Rosenblum & Manalo, 2018).Children with poor executive functions tend to show lower handwriting fluency and writing quality (Costa et al., 2018).Even at the very beginning of handwriting acquisition, 5-to 6-year-old children's executive functions correlated weakly with fluency, and moderately with legibility in a copying task (Maurer & Roebers, 2021).

Gender Differences in Early Handwriting
Studies considering the child's gender typically find differences favoring girls in literacy, fine motor skills, and writing (Cordeiro et al., 2018;Flatters et al., 2014;Morley et al., 2015).Although girls and boys (and all genders) are alike in most, but not all psychological variables (see Hyde, 2005, for a meta-analysis), boys are -concerning handwriting skills -typically overrepresented among the poor writers (Vlachos & Bonoti, 2006, in Grades 2-6).With a specific focus on handwriting legibility and fluency, several studies report more legible and fluent handwriting of girls compared to boys (Blöte & Hamstra-Bletz, 1991, handwriting legibility and fluency in Grades 2-6; Cordeiro et al., 2018, handwriting fluency in Grades 4-9;Skar et al., 2022, handwriting fluency in Grades 1-3).However, studies that did not find any gender differences in handwriting (e.g., Adams et al., 2015, in Grades 1-3;Weintraub & Graham, 2000, in Grade 5) point to our still fragmentary understanding of potential gender differences in early handwriting and the correlates of these differences.If handwriting acquisition and their correlates differ for girls and boys, these findings will not only lead to a more nuanced understanding of early handwriting that informs theoretical conceptualizations of handwriting development but allow more tailored support for children with handwriting difficulties.

Research Gap
Reviewing the evidence, specific gaps of knowledge emerge.On the one hand, it becomes apparent that studies in beginning (compared to more proficient) writers are relatively scarce (but see Fitjar et al., 2021;Skar et al., 2022) and typically do not consider executive functions as potential cognitive correlates.On the other hand, previous studies typically either focus on handwriting legibility or fluency, but rarely on both simultaneously.As the varying conditions in a classroom require a child to constantly choose a trade-off between legibility and speed to cope with writing in different settings, it is important to consider both (Parush et al., 2010).In their experiment, Bara and Bonneton Botté (2021) implemented a handwriting condition with reduced visual feedback of the emerging trace using a non-inking pen.Without seeing the trace of their writing, kindergarten children copied the letters faster and more fluently, lifted the pen less often from the paper, but also copied the letters less neatly (i.e., legibly) compared to the condition with visual feedback.The authors conclude that the more children pay attention to the letter shape and rely on visual information of the trace, the more likely it interrupts handwriting fluency.These findings clearly show that legibility and fluency of handwriting interact in early handwriting and should both be considered when investigating handwriting.

The Present Study
In the present study, we investigate handwriting legibility, fluency, and time in a sample of first-grade children.We aim to explore the potential motor and cognitive correlates of early handwriting in girls and boys.Beyond gender differences in early handwriting, we explore whether and how the pattern of associations between early handwriting skills and potential motor and cognitive correlates differs between girls and boys.
Based on prior evidence on handwriting development we assume fine motor skills and visuomotor integration, the two central predictors of graphomotor skills (Sägesser & Eckhart, 2016), to be correlates of early handwriting legibility, fluency, and time.As investigations so far did not look at potential differences between girls and boys in various handwriting skills, and motor and cognitive correlates simultaneously in first-grade children, we did not formulate any hypotheses.The present exploratory study pursued the following three research questions: (1) Are fine motor skills, visuomotor integration, and executive functions correlates of early handwriting legibility, fluency, and time in first-grade children?(2) Do girls and boys differ in their early handwriting?
(3) Do girls and boys differ in their motor and/or cognitive correlates of early handwriting?

Method
An a priori power analysis was conducted using G*Power version 3.1.9.7 (Faul et al., 2007) to determine the minimum sample size required to test the research questions.Results indicated a required sample size of n = 42 per group (i.e., girls and boys; n = 84 in total) to achieve 80% power for detecting a medium effect, at a significance level of α = .05.

Participants
A sample of 118 first-grade children (46% girls) with a mean age of 7 years and 5 months (SD = 5.26 months; range = 6 years 8 months to 8 years 7 months) participated in this cross-sectional study.Part of the data presented is from a single time point in a larger project.
According to parent-reported questionnaires (return rate 80.5%), the first language of one third of the children (31.4%) was not Swiss-German/German.However, as most of those children (91.2%) had been living in Switzerland for more than three years, their language level was proficient enough to follow task instructions.In terms of parental educational level, parents' reports showed that 25.4% of the children's parents obtained a university degree, while 12.6% indicated obligatory school as their highest education, which is somewhat below the country's mean educational level (Federal Statistical Office, 2021).
This study was approved by the Ethics Committee of the University of Bern (Approval No. 2020-10 -00,005).Parents gave written informed consent, and children verbally agreed to participate in the study.Children and parents could withdraw from the study at any time.

Procedure
Trained instructors conducted the tasks with the children in three sessions.In session one, children's fine motor skills and visuomotor integration were measured.In sessions two and three, children's handwriting and executive functions were assessed.While early handwriting was assessed in small groups of three to four children, all remaining tasks were conducted with the whole class in groups of up to 20 children.

Fine Motor Skills
We measured children's fine motor skills with the subtest Fine Motor Precision of the Bruininks-Oseretsky Test of Motor Proficiency, Second Edition (BOT-2; Bruininks & Bruininks, 2005).This subtest contains five tasks: coloring a circle and a star, connecting four dots with ideally straight lines, tracing a curvy and an angled trail with a pen, folding paper, and cutting a circle with scissors.This subtest measures children's fine motor skills reliably (Hands et al., 2015;Wuang & Su, 2009) and ecologically validly (Vinçon et al., 2017).We used the sum score (raw score) of this subscale as the measure of children's fine motor skills.

Visuomotor Integration
We used the graphomotor Screening GRAFOS (Maurer et al., 2023;Sägesser & Eckhart, 2016) to measure children's ability to copy different geometric shapes (e.g., circle, square, rhomboid, cross).These shapes require fundamental elements of letter writing.Accurately copying shapes requires visuomotor integration and fine motor skills.The GRAFOS Screening is embedded in a cover story, in which children are asked to copy as accurately as possible 13 different geometric shapes, each shape six times, in predefined fields of 1 cm 2 on the screening sheet.The accuracy of each shape (78 in total) was then scored based on specific criteria (1 = accurate, 0 = not accurate).The internal consistency (Cronbach's Alpha) of the 13 items of the screening was high (α = .79).The sum score across all shapes was used as the measure of visuomotor integration.

Early Handwriting
In Switzerland, children learn a partly-connected handwriting (the so called "Deutschschweizer Basisschrift") which is taught without connections between letters in first grade.The written language of the region where the study was conducted was German.To assess early handwriting, children copied four German sentences of the Lese-und Rechtschreibtest SLRT-II [reading and writing test SLRT-II] (Moll & Landerl, 2014), each one on a plain, non-lineated sheet of paper (A5 size).There was no time restriction for this task.The four template sentences of four words each (e.g., "Heute scheint die Sonne" [Today, the sun shines]) remained visible throughout the task.We assessed and evaluated handwriting fluency and legibility based on these four sentences.
Fluency.To capture the fluency of handwriting, a graphical tablet (Wacom Intuos PRO medium®) and a magnetic induction pen (Intuos5 Inking Pen®) with regular ink were used.Children copied each sentence on a sheet of paper lying on a tablet that was connected to a computer.We used the software package CSWin Pro 2016® (Mai & Marquardt, 2007) which measures and calculates acceleration and position data with a frequency of 200 Hz and accuracies of 0.1 mm in both the x-and y-axis (Marquardt & Mai, 1994).This software has been used previously to measure handwriting kinematics (e.g., Hurschler Lichtsteiner et al., 2018;Tucha et al., 2006;Wicki & Hurschler Lichtsteiner, 2018).
As an estimation of handwriting fluency, we used the mean number of inversions in velocity (NIV).An NIV of 1 indicates one acceleration maximum within a movement unit (e.g., letter).The higher the NIV, the more often a child changed velocity (increased and decreased speed), and consequently, the lower the handwriting fluency.We measured three further indications of handwriting (dys)fluency, referred to as handwriting time, namely the time in seconds the tip of the pen is in contact with the paper (time on-paper), the time the tip remains within 1 cm above the paper (time off-paper), and the number of pauses with the tip on the paper (number of pauses).
Handwriting Legibility.We evaluated five different handwriting legibility dimensions (11 criteria), which have been recognized by other researchers (e.g., Rosenblum et al., 2003): 1) Holistic legibility (sentence, letters, and corrections), 2) letter formation (size, regularity, under-and over lengths of letters), 3) spacing (letters and words), 4) line alignment, and 5) inclination.We evaluated and scored handwriting legibility for each criterion and sentence separately (1 = accurate, 0 = not accurate).We used the sum score across all 44 evaluations (four sentences, 11 criteria each) as the measure of handwriting legibility.The agreement of two independent evaluators (the author and a trained assistant) in 20 children was high.A two-way random effect Intraclass Correlation (ICC) of .86 absolute agreement and a 95% confidence interval of .80-.90 revealed good interrater reliability (Koo & Li, 2016).

Executive Functions
We measured children's executive functions with two tasks presented on a tablet computer (12.1' screen) connected to over-ear headphones.Audio task instructions allowed highly standardized instructions and testing of the entire class simultaneously.If a child did not pass the practice trials of the task, a signal appeared on the screen, and an instructor explained the task to the child again until the child understood the task and passed the practice trials.
Inhibition and Shifting.The Hearts and Flowers Task (Davidson et al., 2006;Diamond et al., 2007) was used to measure children's inhibition and shifting skills.In this task, children react to a heart, or a flower presented on the screen by pressing either the right or left external response button as quickly and accurately as possible.The task consisted of three blocks of trials: A congruent, an incongruent (inhibition), and a mixed block of trials (shifting).In the congruent block of trials (24 trials), a heart appeared either on the right or left side of the screen and children were instructed to press as quickly and as accurately as possible the response button on the same side as the heart.In the incongruent block of trials (36 trials), a flower appeared, and children should press the button opposite the flower.Finally, in the mixed block (60 trials; 48 hearts, 12 flowers, in fixed pseudo-randomized order), children should switch flexibly between the two previously learned rules.At the onset of each trial, a fixation cross was presented for 500 ms.The stimuli were presented for 1200 ms in the congruent and incongruent block, and 600 ms in the mixed block.The response latency was 500 ms.The accuracies (percentage of correct responses) for the incongruent (inhibition) and mixed block (shifting) of trials were used for further analyses.

Visual-Spatial Working Memory.
Children's visual-spatial working memory was measured with the Position Span Task (Frick & Möhring, 2016).This task is based on the Corsi-Block Tapping Task (Corsi, 1972), and was adapted for children.In this task, a mole appeared in different locations in a 4 × 4 grid in a fixed pseudo-randomized order.Children were asked to memorize the locations where the groundhog had appeared and to touch those locations (i.e., fields) in reverse order after a delay of 1000 ms.Each mole was presented for 1200 ms with an inter-stimuli interval of 500 ms when the empty grid remained visible.The task started with a sequence of two items and was increased by one item when the child remembered at least three out of six sequences of each sequence length correctly.The task terminated at the end of a span length when the child recalled more than three sequences incorrectly.The total number of correctly remembered sequences across all span lengths was used as the measure of visual-spatial working memory.

Preliminary Analyses
We excluded values exceeding three SD of the interindividual mean.This led to the exclusion of n = 3 handwriting fluency (NIV) values.Furthermore, we excluded n = 3 accuracies below the chance level (i.e., 50%) in the Hearts and Flowers task.Analyses on the different educational backgrounds of the parents of the children revealed no meaningful performance differences on any of the included motor, cognitive, or early handwriting variables, F(40, 247) = .94,p = .58,for the child's mother (n = 95), and F (40, 195) = .78,p = .83,for the child's father (n = 85).Consequently, the parents' educational background was not further considered.

Results
In the first section of the results, an overview of all included measures and the corresponding descriptive statistics is presented, followed by comparisons between girls' and boys' early handwriting, cognitive, and motor skills.Finally, results are presented on the correlates of early handwriting on the overall sample, as well as for girls and boys separately.

Overview
Table 1 shows the descriptive statistics of all included variables, indicating large interindividual differences in the present sample of first-grade children.The skewness and kurtosis indicators suggest close to normally distributed data.The handwriting time measures, namely "time on-paper," "time off-paper," and "number of pauses" as indications of handwriting (dys)fluency all capture a certain time aspect of handwriting.The similarity of those three measures is also reflected in the substantial Pearson correlations among those measures, varying between r = .54,p < .001,and r = .81,p < .001.Therefore, and as we aimed to map handwriting time broadly, we z-standardized each variable and then aggregated the three measures.This combined variable, now called "handwriting time," will be included in the analyses that follow.

Early Handwriting Performance in Girls and Boys
Prior to testing for differences in girls' and boys' handwriting and their correlates, we ensured there is no meaningful age difference between girls and boys that could account for potential performance differences.In the next step, a multivariate analysis of variance (MANOVA) was run to test whether girls and boys performed significantly differently with regard to early handwriting skills, cognitive functions, and motor skills.The results of the MANOVA revealed significant differences between girls' and boys' fine motor skills, F = 10.70,p = .001,η p 2 = .078,visuomotor integration, F = 4.27, p = .041,η p 2 = .034,and handwriting legibility, F = 11.84,p < .001,η p 2 = .085,with girls outperforming boys.The full test statistics are presented in Table 2.

Correlates of Early Handwriting
We tested Pearson correlations between early handwriting (legibility, fluency, and time), and potential cognitive (executive functions) and motor (fine motor, visuomotor integration) correlates for the overall sample.The results are presented in Table 3.As expected, fine motor skills and visuomotor integration correlated substantially.Moreover, fine motor skills and visuomotor integration were identified as meaningful motor correlates of early handwriting.While fine motor skills were associated with handwriting legibility and handwriting time, visuomotor integration was associated with all handwriting variables (legibility, fluency, and time).
With regard to potential cognitive correlates of early handwriting, results revealed associations between handwriting legibility and shifting, and between handwriting fluency (NIV) and working memory, whereas handwriting time was associated with both shifting and working memory.In contrast, inhibition was not identified as a cognitive correlate of handwriting in the present sample.However, inhibition was associated with both fine motor skills and visuomotor integration.Interrelations among the handwriting measures indicate an association between handwriting legibility and handwriting time, but no meaningful associations between handwriting legibility and fluency (NIV).As expected, handwriting time, as an indication of handwriting fluency, correlated strongly with handwriting fluency (NIV).
Moreover, we explored potential differences in the pattern of correlates for girls and boys.Correlation coefficients among early handwriting and potential motor and cognitive correlates, separately for girls and boys, are depicted in Table 4.The results revealed a substantially different pattern of associations for girls than for boys.While compared to the results of the overall sample, the magnitudes of the correlation coefficients increased for girls, they decreased or even vanished completely for boys.Inhibition stands out as an exception, as significant associations between inhibition and fine motor skills and visuomotor integration emerged only for boys, but not for girls.To test whether the correlation coefficients of girls and boys differed statistically, we tested Fisher's z-tests for each pair of correlations.Significant differences in the magnitude of correlation coefficients for girls and boys were found for the association between handwriting legibility and fine motor skills, z = 2.03, p = .042,and handwriting legibility and shifting, z = 2.13, p = .034.

Discussion
This study investigated concurrent associations between early handwriting (legibility, fluency, and time), and potential motor (fine motor, visuomotor integration) and cognitive (executive functions) correlates in first-grade children.Moreover, we explored differences between girls' and boys' handwriting and their specific correlates that provide more nuanced insights into the differential correlates of early handwriting in first-grade girls and boys.

Correlates of Early Handwriting
In line with previous studies' results (e.g., Hamstra-Bletz & Blöte, 1993;Seo, 2018), fine motor skills and visuomotor integration -the two main predictors of graphomotor skills, were identified as moderate correlates of early handwriting in the present sample.The findings of the present study add to previous evidence by showing that fine motor skills and visuomotor integration are not only correlates of handwriting legibility but also handwriting time.Moreover, visuomotor integration was associated moderately with handwriting fluency.First-grade children with better fine motor skills and visuomotor integration wrote not only more legibly, but also more fluently (NIV), and needed less time to write.A child who writes more legibly and fluently and produces more text in a certain time can cope with the classroom demands more easily and has more cognitive resources to follow the lesson.When handwriting becomes more efficient and fluent (i.e., automatic), cognitive capacity (i.e., attention) is freed up and can be used elsewhere, for instance for generating and revising text (Berninger & Amtmann, 2003;Berninger & Winn, 2006;Caravolas et al., 2020).
Concerning cognitive correlates of early handwriting, the results suggest that children with better shifting skills could switch attention more flexibly between their handwriting and the template sentences.The handwriting process of children with better attention-shifting skills therefore was disrupted less often, which likely led to more legible handwriting and less time needed to write.In line with these results are meta-analytic findings revealing meaningfully less legible and less fluent handwriting in children with attentional difficulties (i.e., ADHD) compared to controls matched on age, gender, and socioeconomic status (Graham et al., 2016).Besides attention-shifting, working memory was also weakly-to-moderately associated with handwriting skills.It is reasonable to assume that children with better visual-spatial working memory skills could remember the sentences and letter shapes more accurately and therefore wrote more fluently and needed less time to write the sentences.These results extend previous evidence in more proficient writers (e.g., Salas & Silvente, 2020) by pointing to the important role of specific executive functions in legible and fluent handwriting in beginning handwriting.
The weak interrelation between handwriting legibility and handwriting time and the absence of an association between handwriting legibility and fluency (NIV) indicate that the two main characteristics of handwriting -legibility and fluency -are two separable constructs in this early stage of handwriting acquisition.Longitudinal studies investigating the developmental trajectories of handwriting legibility and fluency will teach us more about the evolvement and the interrelation of those characteristics across time and handwriting practice, as well as inform theoretical conceptualizations of handwriting development.

Gender Differences in Early Handwriting
Beyond investigating the sample as a homogenous group, we specifically looked at association patterns between early handwriting skills and motor and cognitive correlates for girls and boys separately.The results were surprising: It appears that the correlates of early handwriting found for the overall sample were mainly driven by the girls.While for girls the correlates of handwriting were numerous and substantial, with correlation coefficients ranging up to r = .56,most associations were small in magnitude or vanished completely for the boys in the sample.In contrast to these results, better inhibition skills, indicated for instance by not getting distracted and maintaining attention on the task, coincide with more accurately copying shapes (i.e., better visuomotor integration) in boys, but not in girls.While in boys, inhibition appears to be the executive function associated with copying shapes accurately, in girls, individual differences in shifting, rather than inhibition, were associated with copying shapes and letters accurately.Accordingly, it could be speculated that especially boys might benefit from promoting inhibition skills, or from environments that facilitate inhibition (e.g., quiet classroom) during handwriting activities.Furthermore, these exploratory findings indicate that poor fine motor skills and visuomotor integration in transition to school seem to be risk factors for acquiring fluent, legible, and efficient handwriting.If these findings can be replicated in future studies, theoretical models of (hand)writing should consider gender by specifying the potential different correlates for girls and boys.
By investigating girls and boys separately, we created groups based on a child's gender.Investigating potential gender differences often unnecessarily stresses (negligible) disparities, which are rarely insightful for our understanding of the underlying developmental processes as other variables than gender typically better explain individual differences.Nevertheless, in the domain of motor development, specific gender differences in certain developmental periods are widely acknowledged (Flatters et al., 2014;Gaul & Issartel, 2016;Morley et al., 2015).In the present sample, girls on average outperformed boys in their fine motor skills and visuomotor integration, representing a small to moderate effect.Environmental influences are being discussed as partly responsible for the gender differences found in motor skills (Haywood & Getchell, 2009).Research has shown that girls are typically more encouraged to engage in fine motor activities and receive more reinforcement to participate in fine motor activities than boys (Hume et al., 2008;Okely & Booth, 2004).Consequently, girls tend to be more exposed to fine motor learning opportunities and consequently develop their fine motor and handwriting skills more than boys.This circumstance might explain the higher performance of girls compared to boys in fine motor skills, visuomotor integration, and handwriting legibility in the present sample -a result that is in line with previous studies' findings (Blöte & Hamstra-Bletz, 1991;Flatters et al., 2014;Morley et al., 2015).
Given the result that girls outperformed boys regarding fine motor skills and visuomotor integration in the present sample, it is plausible to assume that the studied groups of girls and boys rather represent higher and lower fine motor and visuomotor integration performers, respectively.Consequently, it is a valid question whether groups based on motor performance rather than gender would explain the differential pattern found.I tested this hypothesis in an exploratory posthoc analysis by applying a median split on children's fine motor skills and visuomotor integration, comparing the lower and higher performers.However, the pattern of correlates of handwriting that emerged when comparing high and low performers was different from the pattern of correlates I found when comparing girls and boys.This finding suggests it is not fine motor or visuomotor performance (alone) which explains the diverse patterns of correlates for girls and boys.

Potential Explanations for Individual Differences in Handwriting
These findings raise the question of what other variables may explain differences between boys and girls in the absolute level of early handwriting and the pattern of correlates, namely the substantial and diverse motor and cognitive correlates of handwriting for girls, and the few and weak correlates for boys.A potential variable explaining differences between individuals (over and above gender) is the individually perceived value and importance of neat (i.e., legible) handwriting.Either consciously or subconsciously, some children are likely more willing to make their writing look neat, while others prioritize efficiency (i.e., speed) of handwriting over clarity (i.e., legibility).Besides this individual speed -legibility trade-off, also a child's teacher and the handwriting instruction likely affect children's handwriting development (Santangelo & Graham, 2016).Teachers vary in their emphasis on developing fluent and/or legible handwriting as well as the learning experiences they provide to their pupils to develop fluent and legible handwriting (Bonneton-Botte et al., 2021).In general, teachers' methods of instruction and practices tend to focus more on legibility than on the fluency and processes of handwriting acquisition (Bonneton-Botte et al., 2021).This might be problematic because when a child at the initial stage of letter learning tries hard to write neatly, handwriting fluency likely gets interrupted (Bara & Bonneton Botté, 2021).However, providing varying learning opportunities that foster the internalization of the letter shapes through fluent movements is essential and necessary in the early stages of handwriting acquisition to develop automated handwriting (Bara & Bonneton Botté, 2021).
The importance of the quality of handwriting instruction for developing legible and fluent handwriting was further shown in a comprehensive meta-analysis (Santangelo & Graham, 2016).The authors found a medium-sized effect (0.6 SD) of handwriting instruction on handwriting legibility and fluency in children with and without handwriting difficulties (Santangelo & Graham, 2016).Besides the importance of learning opportunities and handwriting instruction, there are indications that handwriting improves across the primary school years not only with handwriting practice, but also with spelling ability (Caravolas et al., 2020).In other words, when a child shows poor handwriting, this may be a sign of underlying spelling difficulties, rather than (only) graphomotor difficulties.Similarly, letter knowledge (i.e., phoneme-grapheme encoding) affects handwriting fluency of first-grade children when copying letters (Fitjar et al., 2021).

Limitations and Future Directions
Taken together, the findings of this exploratory study suggest differences in girls' and boys' handwriting as well as differential correlates of acquiring legible, fluent, and efficient handwriting.However, these findings should be interpreted cautiously and need to be confirmed in a more extensive sample before drawing firm conclusions.It is important to note that spelling, which impacts handwriting (Berninger et al., 2002;Caravolas et al., 2020;Odersky, 2018), was not considered in this study.It is likely to assume that spelling ability constrains handwriting even at this early stage of copylevel handwriting (Laishley et al., 2014).
Furthermore, previous findings from the literature reviewed in the current paper call for taking further factors into consideration.Specifically, individual factors such as motivation to write, as well as context factors such as handwriting instruction (Santangelo & Graham, 2016) might explain individual differences in handwriting across the primary school years.Large-scale longitudinal studies that consider broad measures of graphomotor, cognitive, and motivational factors are a crucial next step for deepening our theoretical and practical understanding of handwriting development.If we understand individual differences in handwriting acquisition in more depth, this will enable teachers and therapists to address children's individual needs adequately and to tailor effective interventions to acquire legible, fluent, and efficient handwriting.

Disclosure statement
No potential conflict of interest was reported by the author(s).

Table 1 .
Descriptive statistics of all measures.
NIV = Number of inversions in velocity.Time = Composite score of handwriting time (sum of z-variables of time on and off-paper, and pauses).η p 2 = Partial Eta squared.

Table 4 .
Pearson correlations separate for girls (n = 54) below the diagonal, and boys (n = 64) above the diagonal.