工作難度對序列動作編序的影響及其年齡差異

Effects of task difficulty on serial movement programming and its age differences

目的：探討序列動作編序是否受後續工作難度的影響及其年齡差異。方法：參加者為兒童（6.8±0.1歲）與成人（25.5±1.9歲）各12名。實驗工作為連續按壓兩個目標的序列動作，第一目標大小維持恆常，而第二目標分為大或小目標情境，參加者須以快又準確方式完成。利用時間測量板及6自由度磁力追蹤儀收集反應時間、動作時間及手部運動學參數。結果：經2（年齡）X2（第二目標尺寸）混合設計二因子變異數分析，發現（一）當第二工作難度增加，反應時間顯著增長，延長訊息處理時間。動作一時間、減速時間百分比顯著增加，而平均速度與最大速度下降，顯示第一動作速度變慢，減速階段時間加長，（二）動作一結束速度年齡×第二目標尺寸的交互作用達顯著差異，相較於兒童，成人傾向將二段動作視為單一動作加以編序，與（三）動作一／動作二時間比率年齡×第二目標尺寸的交互作用達顯著差異，當第二工作難度由低變高時，兒童由「長－短」轉換為「短－長」序列動作時間型態，與成人不同。結論：（一）後續工作難度影響成人與兒童序列動作編序，與（二）兒童具備將後續工作要求納入動作編序的能力，然而兒童與成人的動作編序不同。Purpose: This study examined whether serial movement programming was affected by the subsequent movement difficulty, and whether there exhibited age-related differences. Method: Twelve children (6.8 ± 0.1 yrs.) and twelve adults (25.5 ± 1.9 yrs.) served as participants and were asked to press two targets sequentially. The first target size was constant, whereas there were small or large size conditions for the second targets. Participants had to perform as quickly and accurately as possible. The reaction time, movement time, and kinematic characteristics were recorded by movement timing equipment and six degrees of freedom Polhemus Liberty system. Results: The 2 (age) × 2 (second target size) mixed design 2-way ANOVA revealed that (1) when difficulty of the second movement increased, reaction time prolonged significantly, indicating the time for information processing was longer. The first movement time and percentage of deceleration time increased significantly, whereas the average velocity and peak velocity were significant lower, which indicated the first movement was slower and deceleration phase was longer; (2) the significant age × second target size interaction for the first movement terminal velocity suggested that, compared with children, adults tended to program the two movement segments as a whole; and (3) the age × second target size interaction for the first/second movement time ratio was significant. When difficulty of the second movement was changed from low to high, children transformed the long-short serial movement time pattern into a short-long one, which was different from that of adults. Conclusions: (1) programming of serial movement in children and adults was affected by the subsequent movement difficulty; and (2) children may possess the capability to take subsequent movement demand into account when programming the response, however, the motor programming characteristics of children still differed from that of adults.