This study was aimed at grasping the right-left difference of the body using the measured value of 28 items on the right-left parts of the body of adult females, and further grasping its relation with the right-left difference expressed on clothes due to the wearing conditions of upper and lower experimental clothes designed and prepared with a fixed standard. When measured values on the right-left parts of the body were compared, right-left difference was much more recognized in the items of body surface length rather than in those of body projected length. The number of persons who expressed right-left difference in wearing condition of experimental clothes was 243 (93.8%) among 259 examinees for upper suit and 192 (74.1%) for skirt. It was proven that by comparing measured values on the right-left pats of the body (anterior and posterior neck base length; lateral length from waist to hip; shoulder slope; shoulder point, bust point to waist anterior (A); shoulder point, waist posterior (B); and difference between (A) and (B)), prediction of right-left difference while wearing clothes is possible to a certain extent. In addition, it was possible to grasp relation between the right-left difference by body size measurement and the right-left difference expressed on each of upper and lower experimental clothes.

View full abstract

In this study, the chaotic features of postural steadiness were investigated using a reconstructed phase portrait, fractal dimension and first Lyapunov exponent, as well as the basic measures of postural steadiness. The experimental variables were presence of visual information (eyes-opened and eyes-closed) and postures (standing straight on both feet: SBF, standing straight on left foot only: SLF, standing straight on right foot only: SRF). The first Lyapunov exponent tended to be larger for SRF and SLF conditions as compared with SBF condition, which showed that the postural control system under SLF and SRF conditions was more chaotic. As for SLF and SRF conditions, the first Lyapunov exponent tended to be smaller for the eyes-closed condition than for the eyes-open condition. The fractal dimension of the eyes-closed condition tended to be lower than that of the eyes-open condition. We can conclude that the postural control system under SLF and SRF conditions behaves more chaotically than the SBF condition, and leads to the unstability of the center of pressure (COP) at the feet. Moreover, it was clarified that the presence of visual information influenced the chaotic features of postural sway.

View full abstract

The present study investigated how suitable duration of switching pauses (i.e. silent intervals between the utterances of two speakers: SP) is decided in dialogues. The study focused on the congruency of the durations of the two speakers' SP, and investigated the congruency process in two experiments. The results of Experiment 1, which confirmed the congruency of the SP durations of the two speakers in telephone conversations, indicated that the vocal behavior of one speaker represents a factor that influences the congruency of the SP durations of the two speakers. In Experiment 2, the speech rate and SP durations of one speaker were manipulated, and the consequent influence on the subjects' SP (the subjects representing the second speaker) was analyzed. The results indicated that the duration of the subjects' SP was influenced by the SP duration, but not by the speech rate of the conversational partner. This suggests that in ordinary dialogues, each speaker changes the duration of their own SP according to the SP duration of the conversational partner, and thus the SP durations of the speakers become congruent, and that the appropriate SP duration is decided by the mutual influence of the SP durations of the two speakers.

View full abstract

The driver's reaction time and his frequency of looking at various points, was experimentally examined on a public road. The subject drivers consisted of three age groups: those in their twenty's, those ranging from forty to fifty nine, and those in their sixty's. Two driving situations were set up. The first, driving with an open road and the second, driving following another vehicle. Additionally two types of sudden hazards were set up. Hazard (a) had a pedestrian suddenly appear from the side of a house, while hazard (b) had the preceding driver suddenly brake. As far as the brake reaction time to hazard (a) was concerned, the difference between the average reaction time of drivers in their sixty's and that of the other age groups was statistically significant. On the other hand, the brake reaction time to hazard (b) was not different among each group. However it should be noted that most drivers in their sixty's had exceptionally long delayed brake reaction times to both hazards (a) and (b). Also, the older the drivers were, the lower their frequency of looking at various points was. Therefore, the cause of the delayed brake reaction times of, driver's in their sixty's, is likely to be the result of a low frequency of awareness.

View full abstract

The purpose of this study was to examine differences in the visual search strategies between expert and novice batters during the sequential phases of the pitcher's motion under the field condition. In particular, we focused on how they utilize peripheral vision properties to pick up visual information. Members of college baseball team (expert group) and ordinary college students (novice group) participated in this experiment. The subjects stood in an actual batter's box, viewed 10 types of pitches thrown by real pitcher, and their eye movements were measured. Eye movements of subjects during the preparatory phase of batting, during which a batter should gather visual information from the motion of the pitcher, were analyzed. The distribution of experts' viewing points was smaller than that of novices. In particular, experts set their visual pivot on the pitching arm and utilized peripheral vision to pick up important movement information for batting such as movements of the pitcher's arm or his whole body. Therefore, experts used a systematic visual search strategy, utilizing peripheral vision properties to evaluate visually the pitcher's motion efficiently and anticipate the ball's trajectory.

View full abstract