Why walkers slip: Shine is not a reliable cue for slippery ground

Abstract

In a series of four studies, we investigated the visual cues that walkers use to predict slippery ground surfaces and tested whether visual information is reliable for specifying low-friction conditions. In Study 1, 91% of participants surveyed responded that they would use shine to identify upcoming slippery ground. Studies 2-4 confirmed participants' reliance on shine to predict slip. Participants viewed ground surfaces varying in gloss, paint color, and viewing distance under indoor and outdoor lighting conditions. Shine and slip ratings and functional walking judgments were related to surface gloss level and to surface coefficient of friction (COF). However, judgments were strongly affected by surface color, viewing distance, and lighting conditions-extraneous factors that do not change the surface COF. Results suggest that, although walkers rely on shine to predict slippery ground, shine is not a reliable visual cue for friction. Poor visual information for friction may underlie the high prevalence of friction-related slips and falls.

Gauging possibilities for action based on friction underfoot.

“…Previous work showed that observers erroneously base judgments about slip on visual cues such as surface color and shine (Joh, Adolph, Campbell, & Eppler, 2006). It is possible that the different feel-but similar appearance-of the low-and high-friction surfaces affected participants' perceptual judgments.…”

An ecological stance on risk and safe behaviors in children: The role of affordances and emergent behaviors

“…For instance, walkers rely on shine to predict slippery ground even though shine is not always a reliable visual cue for friction (Joh, Adolph, Campbell, & Eppler, 2006). Temperature is also a difficult variable to become attuned to.…”

State of science: occupational slips, trips and falls on the same level

“…Joh et al (2006) reported that people rely on ‘shine’ information in forming judgements of slipperiness under dry conditions despite variations as a function of surface colour, viewing distance and lighting conditions. Lesch, Chang, and Chang (2008) asked participants to rate 38 different floor surfaces under dry conditions in terms of slipperiness, reflectiveness, light/dark, traction, texture and likelihood of slipping just by looking at them.…”