抓取動作之手指數與身體尺度比率的年齡差異

Age differences in finger numbers and body-scaled ratios of prehension

目的：以環境賦使觀點為基礎，設計抓取不同尺寸球體，探討抓取動作之手指數與身體尺度比率的年齡差異。方法：兒童組（6.1±0.4歲）、成人組（29.6±4.7歲）與老人組（69.5±4.5歲）各18名實驗參與者，分別抓取5種尺寸球體（直徑為2、4、6、8與10公分）各3次，由兩位動作行為研究專家以系統觀察法進行影片分析，分析者間一致性為.80，分析者內一致性分別為.88與.91。結果：（1）卡方考驗發現兒童組抓取相對較大球體（直徑4、6、8與10公分）使用的手指數與成人和老人組有顯著差異（p＜.05）；（2）3（年齡組）×5（球體）混合設計二因子變異數分析，後者為重複量數，並以杜凱氏HSD法進行事後比較，兩因子主要效果達顯著水準（p＜.05），發現兒童組抓取之身體尺度換算值（RC＝1.44）顯著小於成人組（RA＝1.80）與老人組（RO＝1.69），且球體尺寸越大身體尺度換算值越大（R1＝0.79，R2＝1.35，R3＝1.73，R4＝2.03，R5＝2.32）。結論：（1）兒童抓取相對較大球體使用手指數較成人與老人多；（2）兒童抓取的身體尺度比率比成人與老人小，且抓取的身體尺度比率有年齡差異。Purpose: Based on the affordances concepts, grasping ball with various sizes was designed to examine age differences in finger numbers and body-scaled ratios of prehension. Methods: Eighteen participants were in each of child (6-yr-old), adult (30-yr-old), and older adult (70-yr-old) groups (N = 54). All participants were asked to grasp a stationary ball (diameter are 2, 4, 6, 8, and 10 cm.) in separate trial and each size for 3 trials. Two researchers of motor behavior were employed in video systematic observation method for analyzing filmed prehensile trials. The inter-rater reliability was .80 and the intra-rater reliability were .88 and .91, respectively. Results: (1) χ2 test showed that child group utilized the finger numbers more in relative bigger sizes ball than adult and older adult groups significantly (p < .05); and (2) Mixed-design two-way ANOVA, 3 (age) × 5 (ball sizes) with the ball sizes were repeated measure, and Tukey's HSD Post Hoc test showed significant main effects (p < .05) in age and ball sizes, that revealed the body-scaled conduced ratios of child group were significant (p < .05) different with adult (R0 = 1.80) and older adult (R0 = 1.69) groups, and the bigger sizes ball had bigger body-scaled conduced ratios (R1 = 0.79, R2 = 1.35, R3 = 1.73, R4 = 2.03, R5 = 2.32). Conclusions: (1) Children's prehension utilized more fingers for relative bigger ball than adults and older adults did; and (2) Children's body-scaled ratios of prehension smaller then adults and older adults, and there were age differences in body-scaled ratios of prehension.