Using a smartphone on the move: do visual constraints explain why we slow walking speed?

Abstract

Viewing one’s smartphone whilst walking commonly leads to a slowing of walking. Slowing walking-speed may occur because of safety concerns or because of visual constraints. We determine how walking-induced phone motion affects the ability to read on-screen information. Phone-reading performance (PRP) was assessed whilst participants walked on a treadmill at various speeds. The fastest speed was repeated, wearing an elbow-brace (Braced) or with the phone mounted stationary (Fixed). An audible cue (‘text-alert’), indicated participants had 2 seconds to lift/view the phone and read aloud a series of digits. PRP was the number of digits read correctly. Each condition was repeated 5 times. 3D-motion analyses determined phone-motion relative to the head, from which the variability in acceleration in viewing distance, and in the gaze angles in the up-down and right-left directions were assessed. A main-effect of condition indicated PRP decreased with walking speed; particularly so for the Braced and Fixed conditions (p=0.022). Walking condition also affected the phone’s relative motion (p