Deviating to the right: Using eyetracking to study the role of attention in navigation asymmetries

Lateral spatial biases in naturalistic and simulated driving: Does pseudoneglect influence performance?

Whereas a rightward bump is more likely than a leftward bump when walking through a doorway, investigations into potential similar asymmetries for drivers are limited. The research presented here aims to determine the influence of innate lateral spatial biases when driving. Data from the Strategic Highway Research Program Naturalistic Driving Study (SHRP 2 NDS) and a driving simulation were used to address our research questions. Data points from SHRP 2 were aggregated within relevant variables (e.g., left/right obstacles). In the simulation, participants drove in ways that were consistent with their everyday driving in urban and rural environments. Collision frequency, collision severity and average lateral lane position were analyzed with rightward biases throughout both analyzes. SHRP 2 data indicated greater likelihoods of collisions when vehicles crossed the right line/edge of the road and when making a right turn. There were more collisions with obstacles on the right side, which were also more severe, and greater rightward lane deviations in the driving simulation, contrasted with more severe collisions on the left side in SHRP 2 data, possibly because of the presence of traffic. These findings suggest that previously observed rightward biases in distant space when walking are also present when driving.

Smartphones and rightward collisions

People tend to deviate to the right when walking through a narrow aperture (e.g., a doorway), resulting in a rightward bias in collisions. This study examines the effects of smartphone use on rightward collisions while walking. When pedestrians walk through a narrow aperture, they usually head straight to the perceived centre of the aperture, which is shifted slightly to the right, without updating the estimates. The rightward shift of the perceived centre is attributable to the rightward attentional shift in the extrapersonal space. Pedestrians using smartphones tend to fixate on the phone most of the time and thus tend not to look at their surroundings (i.e., extrapersonal space). Therefore, we predict that smartphone use will reduce rightward collisions. To test this prediction, we used a narrow-doorway task in which participants walked through a narrow doorway either with or without a smartphone. The participants with smartphones used them to perform either verbal or spatial tasks. The number of rightward collisions decreased when the participants used smartphones. The type of task had no effect on the lateral collision biases. These results were interpreted in terms of lateral attentional bias in peripersonal and extrapersonal spaces.

Through Doorways and Down Corridors: Investigating Asymmetries During Computer Maze Navigation

Pseudoneglect causes neurologically intact individuals to bias their attention to the left in near space, and to the right in far space. These attentional asymmetries impact both ambulatory and non-ambulatory activities, causing individuals to deviate rightward. While most studies investigating real-world navigation have found a rightward deviation when passing through a door, some have found the opposite pattern for corridors. To explore this dissociation, the current experiment explicitly compared navigation through doorways and corridors. To allow for a direct comparison between these two environments, the navigation task was undertaken in a simulated environment. Dextral participants (n = 98) completed several trials in either the doorway or corridor condition and their mean lateral position and variance was analysed. A rightward deviation was observed for doorways, consistent with previous research. Rightward biases were also observed for corridors, irrespective of the position within the corridor. The results argue against an explanation based on near/far space for the leftward bias in corridors. An explanation based on elevation of view is proposed as an alternative. The study also demonstrates that simulated environments provide an efficient means of investigating asymmetries in navigation.

Right-lateralised lane keeping in young and older British drivers

Young adults demonstrate a small, but consistent, asymmetry of spatial attention favouring the left side of space (“pseudoneglect”) in laboratory-based tests of perception. Conversely, in more naturalistic environments, behavioural errors towards the right side of space are often observed. In the older population, spatial attention asymmetries are generally diminished, or even reversed to favour the right side of space, but much of this evidence has been gained from lab-based and/or psychophysical testing. In this study we assessed whether spatial biases can be elicited during a simulated driving task, and secondly whether these biases also shift with age, in line with standard lab-based measures. Data from 77 right-handed adults with full UK driving licences (i.e. prior experience of left-lane driving) were analysed: 38 young (mean age = 21.53) and 39 older adults (mean age = 70.38). Each participant undertook 3 tests of visuospatial attention: the landmark task, line bisection task, and a simulated lane-keeping task. We found leftward biases in young adults for the landmark and line bisection tasks, indicative of pseudoneglect, and a mean lane position towards the right of centre. In young adults the leftward landmark task biases were negatively correlated with rightward lane-keeping biases, hinting that a common property of the spatial attention networks may have influenced both tasks. As predicted, older adults showed no group-level spatial asymmetry on the landmark nor the line bisection task, but they maintained a mean rightward lane position, similar to young adults. The 3 tasks were not inter-correlated in the older group. These results suggest that spatial biases in older adults may be elicited more effectively in experiments involving complex behaviour rather than abstract, lab-based measures. More broadly, these results confirm that lateral biases of spatial attention are linked to driving behaviour, and this could prove informative in the development of future vehicle safety and driving technology.

The right-side perceptual bias in aging determined in a laboratory setting and during a virtual driving task

Spatial perceptual rightward bias which was originally described in Dichotic Listening studies seems to be a general phenomenon. This bias is age dependent, being evident in children with developing executive functions, and emerging again at older age as a function of aging and the declining executive functions. In the two studies presented here we compared the performance of young and elderly adults in spatial divided attention tasks with auditory and visual stimuli when the stimulus detection performance was measured in separate sessions in a laboratory setting (Study I), to performance when the same types of stimuli were mixed with a task in which the subject's primary objective was to drive a car in a virtual environment (virtual reality; Study II). The aim was to see if the perceptual bias could be detected and also to look at how it would differ in these two situations. 90 right-handed subjects (50 young and 40 elderly) participated in Study I and 84 subjects (64 young and 20 elderly) participated in Study II. Study I showed the rightward bias to be more evident in the elderly subjects in both modalities and in more demanding tasks. Study II revealed that in the triple task the spatial perceptual bias was evident in both modalities for the elderly participants when the conditions were more demanding. An interesting finding concerning the right-side perceptual bias was the simultaneous occurrence of left-side driving errors, i.e. crossing the lane border to the left especially by the elderly. Both of these biases may reflect the asymmetries of the attention-related neuronal networks.

Crashing Left vs. Right: Examining Navigation Asymmetries Using the SHRP2 Naturalistic Driving Study Data

The magnitude of leftward bias demonstrated in pseudoneglect has been found to differ between younger and older adults in laboratory settings. The objective of this study was to examine the association between age and asymmetries in navigation in a naturalistic setting by examining the frequency of the location of impact on participants' vehicles during crashes and near crashes. The location of impact following crashes and near crashes, and participant's age and gender were retrieved from the SHRP2 NDS database, a large scale naturalistic driving study. Over the course of the study, data were collected from 3,546 participants driving in the United States of America (right-side traffic directionality), which included 1,465 crashes and 2,722 near crashes. During crashes and near crashes, irrespective of age, the location impact was most often on the front side of the participant vehicle. In contrast with results from laboratory environments, age was not associated with the location of impact during crashes and near crashes, and overall, crashes were over-represented on the left side of the vehicle compared to the right. Specifically, crashes were 1.41 times as likely to occur on the left compared to the right side of participants' vehicles. Overall, these findings inform future research that attempts to apply laboratory research, regarding asymmetry in navigation, to naturalistic settings.

An investigation of left/right driving rules on deviations while walking

When traversing through an aperture, such as a doorway, people characteristically deviate towards the right. This rightward deviation can be explained by a rightward attentional bias which leads to rightward bisections in far space. It is also possible, however, that left or right driving practices affect the deviation. To explore this possibility, Australian (left-side drivers) and Swiss (right-side drivers) participants (n = 36 & 34) walked through the middle of an aperture. To control for the sway of the body, participants started with either their left or right foot. Sway had a significant effect on participants' position in the doorway and the amount of sway was greater for Australians-perhaps due to national differences in gait. There was a significant rightward deviation for the Swiss, but not for the Australians. It is suggested that driving practices have a small additive effect on rightward attentional biases whereby the bias is increased for people who drive on the right and reduced in people who drive on the left.

Analysis of gaze points for mouth images using an eye tracking system

PURPOSE

We aimed to clarify whether people stare at non-esthetic restorations by analyzing the gaze point of laypersons looking at mouth images with intraoral non-esthetic restoration.

METHODS

The gaze points of 47 laypersons who do not visit dentists were measured using an eye tracker. The stimuli were 18 photographs of mouths with or without a non-esthetic tooth restoration, each randomly shown for 5s. The analysis sites included a tooth with non-esthetic restoration and the same tooth on the opposite side of the mouth. We measured the proportion of participants who first fixated on each analysis site, and total fixation time for each site.

RESULTS

In images without non-esthetic restorations, a similar proportion of participants first fixated on each analysis site. However, more participants first fixated on non-esthetic restorations when the images contained them. Total fixation time for each site did not differ significantly between the left and right sides in the images without non-esthetic restoration (P>0.05). Participants fixated on the non-esthetic restoration significantly more in the images containing them (P<0.01).

CONCLUSIONS

Within the limitations of this study, the present findings suggest that in photographs of the mouth with non-esthetic restoration on either side, the non-esthetic restoration is first gazed before the opposite side. In addition, the non-esthetic restoration is gazed longer than the opposite side, and there was no major difference in the fixation time regarding the state of non-esthetic restoration.