| dc.description.abstract | The ability to perceive the properties and orientation of objects by means of active manipulation and contact with only a part of an object can be defined as dynamic touch. The few existing evidence in the literature on dynamic touch in children demonstrates worse performance of children compared to adults. One hypothesis is that childrens exploratory pattern might not yet be effective to reveal information that support perception of object properties. The purpose of the present study was to evaluate the performance, the dependence of perception on the informational parameter and the exploratory pattern adopted in a haptic length perception task without the aid of vision, in children of different age groups (4 , 6 , 8 and 10 years) and adults. Participants firmly grasped and manipulated occluded rods with different distributions of mass and judged their length. The exploratory pattern was recorded by means of a motion analysis system. Analyses of variance showed that 4-year-old children were less accurate than children of other age groups and adults (p < 0.05). But the consistency of the perceptual judgment continued to improve with age (p < 0.05), since the reliability of the judgment of 6-years-old-children was better than 4- years-old-children (p < 0.0001) as the adult when compared to 10-years-old children (p < 0.0001). Hierarchical regression models showed that the informational parameter - moment of inertia - was a predictor of perceived length (p < 0.0001) but there was significant variability among individuals (p = 0.001). The introduction of the factor group (ages), in a second model, explained part of this variance (p = 0.003). Individual regression analyses indicated that the dependence of the informational parameter for perception seems to improve with age. Regarding the exploratory pattern, assessed by the standard deviation of acceleration, there was an interaction group × axes (p = 0.020), in which adults demonstrated greater variability in the acceleration pattern in the X axis compared to other groups. The results of the study demonstrated that 6-years-old-children showed levels of accuracy similar to adults, although the consistency of the perceptual judgment continues to improve even after the age of 10-years-old, as well as the dependence of the perception of length on the informational parameter. However, the differences in performance and the improvement the use of informational parameter could not be explained by changes in exploratory pattern characterized in this study, by the variable of standard deviation of the acceleration. | |
