Exploring the nature of visual fixations on other pedestrians

Abstract

How we look at other people may affect conclusions drawn about the effect of changes in lighting when this task needs to be done after dark. This paper reports further analysis of the distance and duration of fixation on other pedestrians, updating a previous review by considering a greater number of fixations and by examining the influence on these of other characteristics such as the relative direction of travel. This analysis provides further support for a tendency to fixate others at a distance of 15 m and for a duration of 500 ms.

Road lighting research for drivers and pedestrians: The basis of luminance and illuminance recommendations

“…Other studies, however, concluded that there is a significant effect of SPD 137,160 and these data contributed to an assumed benefit of better colour quality in revised guidance. 68 Subsequent research first examined methodology, proposing that different procedures may lead to different conclusions, 161,162 that facial emotion recognition from expression is a more suitable task than identify recognition, [163][164][165] that a brief duration of 500 ms better resembles typical behaviour than does continuous observation, 166,167 and that the stop-distance approach used in many studies may not lead to the same conclusions as evaluations made at the desirable observation distance of 15 m. 166,167 In studies carried out using facial emotion recognition, SPD is not suggested to be a critical parameter. [168][169][170][171] One question still to be resolved is whether a measure of vertical illuminance is needed to characterise this task or whether it is safe to assume that horizontal illuminance at the road surface is sufficient.…”

Appraising the intention of other people: Ecological validity and procedures for investigating effects of lighting for pedestrians

“…Given that observation duration affects the chance of correct facial identity recognition, 47 then further research should at least include a duration of 500 ms. Eye-tracking data suggest a mean tendency to look at other people 2.4 times, 101 although the nature of these repeated fixations was not established. Overall, this is 1.2 s observation, which indicates that the stop-distance procedure used in some past studies of lighting (Table 1) is not realistic as it instructs an observation of longer (likely continuous) duration.…”

“…99 Consider next evidence as to the typical time desired for looking at other people. Two studies 100,101 investigated this using the data recorded in a pedestrian eye-tracking study, 8 including the duration of visual fixations towards other people. These studies reported a median of 480 ms, 100 and a mean of 475 ms, 101 the latter using a larger data set comprising 5955 fixations towards 2496 pedestrians.…”

“…Two studies 100,101 investigated this using the data recorded in a pedestrian eye-tracking study, 8 including the duration of visual fixations towards other people. These studies reported a median of 480 ms, 100 and a mean of 475 ms, 101 the latter using a larger data set comprising 5955 fixations towards 2496 pedestrians. For convenience, this might be rounded to 500 ms. Further evidence that 500 ms is a typical duration of observation is found in an additional eye-tracking study in which test participants walked around an oval circuit in a laboratory in the opposite direction to target pedestrians.…”

“…An estimate of desirable fixation distances was made by further analysis of pedestrian eye tracking recorded in natural settings, 8 and this suggested that fixations took place at a mean distance of 14.0 m. 101 For the purposes of investigating the effects of lighting on interpersonal judgements, this was rounded to 15 m with consideration to other evidence. It is a practical distance, being shorter than that (23 m) at which the rate of correct facial identity recognition reduces to only 25%, 57 it falls within the 'action space' zone (2 m-30 m) of Cutting and Vishton 107 and agrees with Townshend's finding of the preferred comfort distance after dark (15 m).…”