Is the size of the useful field of view affected by postural demands associated with standing and stepping?

The useful field of view (UFOV) is the visual area from which information is obtained at a brief glance. While studies have examined the effects of increased cognitive load on the visual field, no one has specifically looked at the effects of postural control or locomotor activity on the UFOV. The current study aimed to examine the effects of postural demand and locomotor activity on UFOV performance in healthy young adults. Eleven participants were tested on three modified UFOV tasks (central processing, peripheral processing, and divided-attention) while seated, standing, and stepping in place. Across all postural conditions, participants showed no difference in their central or peripheral processing. However, in the divided-attention task (reporting the letter in central vision and target location in peripheral vision amongst distracter items) a main effect of posture condition on peripheral target accuracy was found for targets at 57° of eccentricity (p = .037). The mean accuracy reduced from 80.5% (standing) to 74% (seated) to 56.3% (stepping). These findings show that postural demands do affect UFOV divided-attention performance. In particular, the size of the useful field of view significantly decreases when stepping. This finding has important implications for how the results of a UFOV test are used to evaluate the general size of the UFOV during varying activities, as the traditional seated test procedure may overestimate the size of the UFOV during locomotor activities.