Attentional processing of location and color cues during driving.

Studies have shown that prior information concerning the spatial location of a subsequent target facilitates the selection of that target for further visual processing in three-dimensional (3-D) space. Using Posner's cuing paradigm, our work examined the reaction time of drivers when cue duration and peripheral environment luminance was changed, and explored the effect color and location on reaction time. Experiment 1 showed that reaction time was not affected by cue duration, and that shifts of attention operated more efficiently for cue location validity. Experiment 2 showed that there was no main effect of background luminance on reaction time. Experiment 3 showed that location produces a greater effect than color.

Is the useful field of view a good predictor of at-fault crash risk in elderly Japanese drivers?

AIM: Although age-related decline in the useful field of view (UFOV) is well recognized as a risk factor for at-fault crash involvement in elderly drivers, there is still room to study its applicability to elderly Japanese drivers. In the current study, we thus examined the relationship between UFOV and at-fault crash history in an elderly Japanese population. We also explored whether potential factors that create awareness of reduced driving fitness could be a trigger for the self-regulation of driving in elderly drivers. METHODS: We measured UFOV and at-fault crash history from 151 community-dwelling Japanese aged 60 years or older, and compared UFOV of at-fault crash-free and crash-involved drivers. We also measured self-evaluated driving style using a questionnaire. RESULTS: UFOV in crash-involved drivers was significantly lower than that in crash-free drivers. No significant difference was found in self-evaluated driving style between crash-free and crash-involved drivers. In addition, there was no significant association between UFOV and self-evaluated driving style. CONCLUSIONS: The present study showed that UFOV is a good predictor of at-fault crash risk in elderly Japanese drivers. Furthermore, our data imply that it might be difficult for elderly drivers to adopt appropriate driving strategies commensurate with their current driving competence.

Can passengers' active head tilt decrease the severity of carsickness? Effect of head tilt on severity of motion sickness in a lateral acceleration environment.

OBJECTIVE: We investigated the effect of the passenger head-tilt strategy on the severity of carsickness in lateral acceleration situations in automobiles. BACKGROUND: It is well known that the driver is generally less susceptible to carsickness than are the passengers. However, it is also known that the driver tilts his or her head toward the curve center when negotiating a curve, whereas the passenger's head moves in the opposite direction. Therefore, we hypothesized that the head-tilt strategy has the effect of reducing the severity of carsickness. METHOD: A passenger car was driven on a quasi-oval track with a pylon slalom while the participant sat in the navigator seat. The experiment was terminated when either the participant felt the initial symptoms of motion sickness or the car finished 20 laps. In the natural head-tilt condition, the participants were instructed to sit naturally, to relax, and not to oppose the lateral acceleration intentionally. In the active head-tilt condition, the participants were asked to tilt their heads against the centrifugal acceleration, thus imitating the driver's head tilt. RESULTS: The number of laps achieved in the active condition was significantly greater than that in the natural condition. In addition, the subjective ratings of motion sickness and symptoms in the active condition were significantly lower than those in the natural condition. CONCLUSION: We suggest that an active head tilt against centrifugal acceleration reduces the severity of motion sickness. APPLICATION: Potential applications of this study include development of a methodology to reduce carsickness.

Regional frontal gray matter volume associated with executive function capacity as a risk factor for vehicle crashes in normal aging adults.

Although low executive functioning is a risk factor for vehicle crashes among elderly drivers, the neural basis of individual differences in this cognitive ability remains largely unknown. Here we aimed to examine regional frontal gray matter volume associated with executive functioning in normal aging individuals, using voxel-based morphometry (VBM). To this end, 39 community-dwelling elderly volunteers who drove a car on a daily basis participated in structural magnetic resonance imaging, and completed two questionnaires concerning executive functioning and risky driving tendencies in daily living. Consequently, we found that participants with low executive function capacity were prone to risky driving. Furthermore, VBM analysis revealed that lower executive function capacity was associated with smaller gray matter volume in the supplementary motor area (SMA). Thus, the current data suggest that SMA volume is a reliable predictor of individual differences in executive function capacity as a risk factor for vehicle crashes among elderly persons. The implication of our results is that regional frontal gray matter volume might underlie the variation in driving tendencies among elderly drivers. Therefore, detailed driving behavior assessments might be able to detect early neurodegenerative changes in the frontal lobe in normal aging adults.

Effects of self-motion on attention in real 3D space.

Human behavioral space is three-dimensional (3D), and when moving through 3D space individuals selectively allocate their attention to acquire necessary information. This study aimed to examine the characteristics of attention in real 3D space when observers were moving forward. In static and self-motion situations, relative and absolute cues were used. Results indicated that internal representation for allocation of attention in 3D space is in depth-aware mode whether in static or moving condition. Moreover, near superior asymmetrical switching of attention is more strongly manifested under moving than under static conditions. Our findings indicate that focusing of attention by relative and absolute cues is maintained in self-motion, and that allocation of attention during movement is more viewer-centered than when observers are static.