RESUMO
The mental fatigue elicited by working and studying consumed mental resources, thereby eliciting a declined performance and an increased mental stress. The long-term continuous work and study, which is typical for modern workers and students, can increase mental fatigue and health risks. Previous studies reported that the natural environment (i.e., forest and waterside) has a restorative of mental resources (i.e., attention) and reducing stress. However, it is difficult for urban workers and students to take sufficient breaks in real natural environment. We conducted an experiment to examine whether brief and indirect exposure to the natural environment elicits a restorative of attention and reducing stress. Twenty-five undergraduate and graduate students from the university of modern city participated in the experiment. The experiment involved measuring the changes in the task performance of the participants (i.e., sustained attention to response task) and the subjective mental workload (i.e., arousal, valence, and NASA-TLX), while the attention restoration was indexed from physiological response (i.e., skin conductance level, SCL) over time. The participants had two types of resting periods in the middle of the task, i.e., by looking at a blank display (simple break) or by watching a nature video having scenes of, e.g., a forest, small waterfall, and rustling leaves (nature break). The results indicate that the natural environment indirectly depicted through the nature videos does not affect the task performance and the subjective mental workload but decreases the SCL. The results of the physiological response suggest that having rest periods depicting the natural environment, even if indirectly and briefly, can restore the directed attention (i.e., mental resources) for the task. This experiment revealed a useful method of resting for urban workers and students to restore their attention to a task.
RESUMO
In brachiating gibbons, it is thought that there is little movement in the hindlimb joints and that lateral body movement is quite limited. These hypotheses are based on naked-eye observations, and no quantitative motion analyses of the hindlimbs have been reported. This study quantitatively describes the three-dimensional movements of the lower trunk and distal thigh during continuous-contact brachiation in a white-handed gibbon (Hylobates lar) to evaluate the roles of the trunk and hindlimb. The results revealed that the lower trunk moved both laterally and vertically. The lateral movement of the lower trunk resulted from the lateral inclination of the trunk by gravity. The vertical movement of the trunk was converted into forward velocity, indicating an exchange between potential and kinetic energy. We also observed flexion and extension of the hip, although the excursion was within a small range. In addition, the lateral movement of the hindlimb in thedirection opposite to that of trunk movement helped to reduce the lateral sway of the body. These results suggest that during continuous-contact brachiation a gibbon uses hip flexion and extension motions to increase the kinetic energy in the swing. In addition, fine motions of the hip may restrict the lateral sway of the center of body mass.
