Effects of Spatial and Motor Demands in Handwriting

Four experiments were conducted to study response programming in handwriting tasks. Twelve right-handed subjects wrote acoustically presented words and phrases, and their handwriting was digitally recorded. Changes in latency, movement time, trajectory length, and pen pressure were studied as a function of response complexity (i.e., word length, complexity of initial letter, and spacing distance). The lengthening of the spatiotemporal parameters preceding the more complex structures is interpreted to be a reflection of the effects of mental load. The results further indicate that the choice of a programming strategy is dependent on the structural complexity of the task. Writing pressure decreased as a function of increased sequence length. The findings support a hierarchical model of handwriting.     

The dynamic programming matching analysis of handwriting movement in delayed vision

Abstract: Dynamic programming matching analysis of the velocity profile of handwriting was used to examine temporally invariant characteristics of handwriting. This was done by comparing the performance of 12 subjects in writing five words under various delayed visual feedback conditions. The rate of temporally invariant handwriting decreased when delay of visual feedback was introduced. That is, the mean number of fluctuations or hesitations increased as a function of the delay time. This indicates that subjects wrote words by segmenting their movements into submovements. The relative positions of the boundaries of submovements was shown using dynamic programming matching analysis by the distribution of fluctuations along a time axis of templates. The results suggest the development of a segmented "move-and-wait" strategy under conditions of delayed vision. It was shown that in the "move" phase, subjects performed appropriate submovements as smoothly as in the no delay condition and waited during the delay until visual feedback caught up. The increased errors were due to inadequate segmentation of movements.     

Comparing the handwriting behaviours of true and false writing with computerized handwriting measures

The goal of this study is to compare the handwriting behaviours of true and false writing. Based on the cognitive load and dis‐automaticity known to be experienced while communicating a deceptive message, we hypothesized a difference (in temporal and spatial, pressure measures and peak velocities) between the handwriting of true vs. false messages. Thirty‐four participants wrote true and false sentences on a digitizer, which is part of a new system called the Computerized Penmanship Evaluation Tool (ComPET). The ComPET evaluates brain‐hand performance, as manifested through handwriting behaviour, and was found to be a valid measure for detecting the dis‐automaticity that is indicative of certain diseases in the clinical field. Differences were found in mean pressure, spatial measures (mean stroke length and mean stroke height), but no differences were found in temporal measures and in the number of peak velocities. The use of ComPET in lie detection is discussed. Copyright © 2009 John Wiley & Sons, Ltd.     

Reaction Time Analysis of Two Types of Motor Preparation for Speech Articulation: Action as a Sequence of Chunks

Reaction time (RT) prior to speech articulation increased as a function of response complexity. The RT findings formed 2 patterns, each of which was a different Response Complexity × Paradigm (choice RT vs. simple RT) interaction. That result extends previous findings from manual button-pressing tasks (S. T. Klapp, 1995) to a different action modality. Two different types of response programming, INT and SEQ, are assumed in the interpretation. Whereas INT can be identified with response programming within a word, SEQ fits a different interpretation related to timing of onsets of speech units. A critical assumption is that a long response is represented as a sequence of chunks; that organization is subject to manipulation. New findings suggest some modifications of the previous theory.     

Reaction time analysis of two types of motor preparation for speech articulation: action as a sequence of chunks

Reaction time (RT) prior to speech articulation increased as a function of response complexity. The RT findings formed 2 patterns, each of which was a different Response Complexity x Paradigm (choice RT vs. simple RT) interaction. That result extends previous findings from manual button-pressing tasks (S. T. Klapp, 1995) to a different action modality. Two different types of response programming, INT and SEQ, are assumed in the interpretation. Whereas INT can be identified with response programming within a word, SEQ fits a different interpretation related to timing of onsets of speech units. A critical assumption is that a long response is represented as a sequence of chunks; that organization is subject to manipulation. New findings suggest some modifications of the previous theory.     

The temporal selectivity of additive factor effects on the reaction process revealed in ERP component latencies

An experiment was conducted to relate individual components of the event-related brain potential to specific stages of information processing in a two-choice reaction time (RT) task in a group of undergraduate students. Specifically, the latency of the P300 component and the lateralized readiness potential (LRP) were studied as a function of variations in stimulus degradation and response complexity. It was hypothesized that degrading the stimulus would delay the P300 and LRP to the same extent as RT, and that increasing response complexity would affect RT but not P300 latency. The extant literature did not permit any hypothesis regarding the effect of response complexity on LRP latency. The two task variables were found to have additive effects on RT. As predicted, variations in stimulus degradation influenced the latencies of both components, whereas alterations in response complexity had no effect on P300 latency. A significant new finding was that the onset latency of the LRP remained unchanged across levels of response complexity. The overall pattern of results supports the notion of temporal selectivity of stage manipulations that is derived from discrete stage models of human information processing. Furthermore, these results refine the functional interpretation of the LRP by indicating that within the conceptual framework of a stage model the processes this component indexes succeed the start of response choice but precede the start of motor programming.     

快速书写条件下硬笔笔迹变量与认知及个性特征的关系

以圆珠笔为书写工具．北京市某中学高一学生为被试,有效数据169人．探讨了在快速抄写条件下,笔迹书写特征与认知及个性的关系：18个笔迹变量可抽取笔压、结构、特征、字体和空间五个反映字的书写特征的因素;书写特征与认知因素间,横、竖笔压与概念形成速度。整篇压与视力追踪、字位与眼手协调相关显著;横笔压与16PF测验中的畏缩退怯——冒险敢为有正相关;竖笔压与艾森克个性因素的N有高相关。     

Motor Programming as a Function of Constraints on Movement Initiation

Three experiments are reported that test the hypothesis that under certain conditions programming time is a function of the directional accuracy demand of a response, directional accuracy being quantified by the minimal angle subtended at the point of movement initiation by the circular targets within the response. Subjects in three simple reaction time experiments were required to tap a single target or a series of circular targets as rapidly as possible with a hand-held stylus. Experiments 1 and 3 showed that the subtended angle (SA) of a response can have a more powerful effect on programming time, as indexed by reaction time and premotor time, than the number of movement parts in the response. The results of Experiment 2 revealed that the locus of the directional accuracy effect was SA and not target size or movement distance. In all three experiments, response SA was a better predictor of programming time than was number of movement parts, target size, movement distance, movement time, and average movement velocity. The findings support the notion that constraints placed upon movement initiation by the directional accuracy demand of the task can play an important role in determining the length of the programming process.     

Motor programming as a function of constraints on movement initiation

Three experiments are reported that test the hypothesis that under certain conditions programming time is a function of the directional accuracy demand of a response, directional accuracy being quantified by the minimal angle subtended at the point of movement initiation by the circular targets within the response. Subjects in three simple reaction time experiments were required to tap a single target or a series of circular targets as rapidly as possible with a hand-held stylus. Experiments 1 and 3 showed that the subtended angle (SA) of a response can have a more powerful effect on programming time, as indexed by reaction time and premotor time, than the number of movement parts in the response. The results of Experiment 2 revealed that the locus of the directional accuracy effect was SA and not target size or movement distance. In all three experiments, response SA was a better predictor of programming time than was number of movement parts, target size, movement distance, movement time, and average movement velocity. The findings support the notion that constraints placed upon movement initiation by the directional accuracy demand of the task can play an important role in determining the length of the programming process.     

A computerized multidimensional measurement of mental workload via handwriting analysis

The goal of this study was to test the effect of mental workload on handwriting behavior and to identify characteristics of low versus high mental workload in handwriting. We hypothesized differences between handwriting under three different load conditions and tried to establish a profile that integrated these indicators. Fifty-six participants wrote three numerical progressions of varying difficulty on a digitizer attached to a computer so that we could evaluate their handwriting behavior. Differences were found in temporal, spatial, and angular velocity handwriting measures, but no significant differences were found for pressure measures. Using data reduction, we identified three clusters of handwriting, two of which differentiated well according to the three mental workload conditions. We concluded that handwriting behavior is affected by mental workload and that each measure provides distinct information, so that they present a comprehensive indicator of mental workload.     

Peripheral constraint versus on-line programming in rapid aimed sequential movements.

The purpose of this investigation was to examine how the programming and control of a rapid aiming sequence shifts with increased complexity. One objective was to determine if a preprogramming/peripheral constraint explanation is adequate to characterize control of an increasingly complex rapid aiming sequence, and if not, at what point on-line programming better accounts for the data. A second objective was to examine when on-line programming occurs. Three experiments were conducted in which complexity was manipulated by increasing the number of targets from 1 to 11. Initiation- and execution-timing patterns, probe reaction time (RT), and movement kinematics were measured. Results supported the peripheral constraint/pre-programming explanation for sequences up to 7 targets if they were executed in a blocked fashion. For sequences executed in a random fashion (one length followed by a different length), preprogramming did not increase with complexity, and on-line programming occurred without time cost. Across all sequences there was evidence that the later targets created a peripheral constraint on movements to previous targets. We suggest that programming is influenced by two factors: the overall spatial trajectory, which is consistent with Sidaway's subtended angle (SA) hypothesis (1991), and average velocity, with the latter established based on the number of targets in the sequence. As the number of targets increases, average velocity decreases, which controls variability of error in the extent of each movement segment. Overall the data support a continuous model of processing, one in which programming and execution co-occur, and can do so without time cost.     

计算机时代的书写心理学

计算机的普及使人们阅读及书写的能力降低, 这引发了社会对书写的关注。书写涉及大量高级神经活动, 与认知、人格、疾病等均有关联, 对个体发展也具有重要作用。现代书写心理学通过使用书写板等设备, 实现了对书写过程及结果的量化研究, 发现了书写速度、压力、握笔等指标与智力、认知负荷等的一些关联。未来对书写过程的研究可以进一步深入; 测量方面的研究成果可以应用到日常人机交互及教学、司法等实践中; 还可以研究用书写促进个体认知及人格发展的具体途径。     

Programming time as a function of number of movement parts and changes in movement direction

The question of whether changes seen in simple reaction time (SRT) as a function of response complexity (i.e., number of movement parts) should be considered as differences in the time needed to centrally program a motor response was addressed. Using a large-scale tapping response, 14 subjects contacted from one to five targets positioned in a straight line, while a second group of 14 subjects executed 90 degrees changes in direction in striking the targets. Results revealed that mean SRT and mean premotor time increased linearly as the number of movement parts increased, regardless of whether changes in movement direction had to be programmed, with the greatest increase occurring between one-, and two-part responses. Increases in motor time were not sufficient to account for the sizeable SRT effect. These findings support the position of increased central programming time for more complex responses, and also help establish some of the boundaries of the complexity effect.     

Adapting to the surface: A comparison of handwriting measures when writing on a tablet computer and on paper

Our study addresses the following research questions: Are there differences between handwriting movements on paper and on a tablet computer? Can experienced writers, such as most adults, adapt their graphomotor execution during writing to a rather unfamiliar surface for instance a tablet computer?We examined the handwriting performance of adults in three tasks with different complexity: (a) graphomotor abilities, (b) visuomotor abilities and (c) handwriting. Each participant performed each task twice, once on paper and once on a tablet computer with a pen.We tested 25 participants by measuring their writing duration, in air time, number of pen lifts, writing velocity and number of inversions in velocity. The data were analyzed using linear mixed-effects modeling with repeated measures.Our results reveal differences between writing on paper and on a tablet computer which were partly task-dependent. Our findings also show that participants were able to adapt their graphomotor execution to the smoother surface of the tablet computer during the tasks.     

The interaction of response complexity and instructional set

This study investigated the interaction of experimental instructions and response complexity in an attempt to provide a possible explanation for some of the equivocalness in the programming time literature. Response complexity was manipulated by varying the accuracy required of subjects striking circular targets in a simple reaction time paradigm. Subjects were tested on two days, one week apart, during which experimental instructions emphasized either leaving the start position as soon as possible (initiation emphasis) or completing the response with a rapid but smooth movement (form emphasis). Subjects had shorter reaction times but longer movement times when they performed under initiation-emphasis instructions rather than under form-emphasis instructions. Furthermore, in contrast to form-emphasis conditions, there was no effect of response complexity on reaction time in conditions of initiation emphasis. It appears that subtle changes in experimental instructions can lead to very different patterns of reaction time and movement time data. These findings highlight the need for caution in preparing subject instructions in response programming experiments.     

Motor Programming Within a Sequence of Responses

Choice reaction time prior to a motor response has been shown to depend on the nature of the response to be made. This effect is assumed to represent variations in programming time. However, as the length of a response sequence increases this effect becomes smaller, suggesting that some response programming is postponed until after the response sequence is initiated. The present experiment studied this assumed programming within a sequence of responses. For sequences comprised of two Morse Code responses (e.g. dit-dah) the initial reaction time was independent of the terminal response. However, programming of this terminal response was apparent as a lengthening of the duration of intervals within the response when the terminal response was dah rather than dit. When programming of parts of the sequence is postponed beyond the reaction time interval, the programming occurs later and influences the timing of the sequence of responses.     

Eye movements during the handwriting of words: Individually and within sentences

Handwriting, a complex motor process involves the coordination of both the upper limb and visual system. The gaze behavior that occurs during the handwriting process is an area that has been little studied. This study investigated the eye-movements of adults during writing and reading tasks. Eye and handwriting movements were recorded for six different words over three different tasks. The results compared reading and handwriting the same words, a between condition comparison and a comparison between the two handwriting tasks. Compared to reading, participants produced more fixations during handwriting tasks and the average fixation durations were longer. When reading fixations were found to be mostly around the center of word, whereas fixations when writing appear to be made for each letter in a written word and were located around the base of letters and flowed in a left to right direction. Between the two writing tasks more fixations were made when words were written individually compared to within sentences, yet fixation durations were no different. Correlation of the number of fixations made to kinematic variables revealed that horizontal size and road length held a strong correlation with the number of fixations made by participants.     

Processing complex graphemes in handwriting production

Recent studies on handwriting production and neuropsychological data have suggested that orthographic representations are multilevel structures that encode information on letter identity and order, but also on intermediate-grained processing units such as syllables and morphemes. This study on handwriting production examined whether orthographic representations also include a graphemic-processing level. French adults wrote words containing an embedded one-, two-, or three-letter grapheme (e.g., a in clavier, ai in prairie, ain in plainte) on a digitizer. The results for letter duration revealed that the timing of movement processing depends on grapheme length (e.g., the duration of a for one-letter graphemes was shorter than that for two-letter graphemes, which, in turn, was shorter than that for three-letter graphemes). Two- and three-letter graphemes start to be processed before we start to write them. The results therefore revealed that orthographic representations also encode information on grapheme complexity.     

For a psycholinguistic model of handwriting production: testing the syllable-bigram controversy

This study examined the theoretical controversy on the impact of syllables and bigrams in handwriting production. French children and adults wrote words on a digitizer so that we could collect data on the local, online processing of handwriting production. The words differed in the position of the lowest frequency bigram. In one condition, it coincided with the word's syllable boundary. In the other condition, it was located before the syllable boundary. The results yielded higher movement durations at the position where the low-frequency bigram coincided with the syllable boundary compared to where the low-frequency bigram appeared before the syllable boundary. Syllable-oriented strategies failed with the presence of a very low-frequency bigram within the initial syllable. Further analysis showed that children in grades 3 and 4 privileged syllable-oriented programming strategies. The production times of children in grade 4 were also affected by syllable frequency and, to a lesser extent, bigram frequency. The adults writing durations were modulated by bigram frequency. Therefore, both bigrams and syllables regulate handwriting production although the influence of bigrams was stronger in adults than children. In the light of these results, we propose a psycholinguistic model of handwriting production.     

Handwriting process and product characteristics of children diagnosed with developmental coordination disorder

Deficits in handwriting performance limit the school participation of children with developmental coordination disorder (DCD). The aim of this study was to compare the handwriting process and product characteristics of children with DCD to those of typically developing (TD) children in order to determine the best means of differentiation between the groups. Participants were 40 children, from 7 to 10 years old. The experimental group consisted of 20 children who met the criteria of DCD, and the control group consisted of 20 age- and gender-matched controls. The children were asked to perform three graded writing tasks on an electronic tablet, which was part of a computerized handwriting evaluation system (ComPET), in order to obtain measures of their handwriting process. The children's handwriting product was then evaluated by the Hebrew Handwriting Evaluation (HHE). Results showed significant differences between the groups for the handwriting process measures (on-paper and in-air time, mean pressure) and for the handwriting product characteristics (global legibility, number of letters erased or overwritten, spatial arrangement, and number of letters written in the first minute). The discriminant analysis yielded a high significant discrimination (80-90%), with the 'number of letters erased or overwritten' variable as the most differentiating variable (-.67). We concluded that an evaluation of both handwriting process and product characteristics among children with DCD provides a more comprehensive picture of their deficits. Using this method may enable practitioners to focus on children's main deficits and to tailor intervention methods so as to prevent academic underachievement and its consequences on their emotional well-being.