Physical fatigue and its effect on road crossing decisions: an examination of the embodied perception perspective.

Road crossing is an everyday task that requires integration of information (e.g., speed and distance of an oncoming vehicle) to effectively guide behaviour. The embodied perception perspective suggests that individuals' perception of environmental stimuli is influenced by their psychophysiological state. Upon this premise, the current study examined whether acute physical fatigue influences visual perception and associated decision-making in road crossing. Using a between-subject design, 54 participants (healthy adults, aged 18-35) were divided into a fatigue and no-fatigue group. To manipulate fatigue, participants completed a vigorous cycling protocol (fatigue group) or a light cycling protocol (no-fatigue group) prior to completing a video-based examination of road crossing decisions (cross vs. not cross; action-based) and verbal judgments of speed and distance of an oncoming vehicle. Measures of heart rate, self-perceived recovery, and preferred walking speed indicated that fatigue was successfully induced (all p's < 0.03). Participants effectively distinguished between different speeds (30-50-70 km/h; p < 0.001), and distances (10-100 m in 10 m increments; p < 0.001). Moreover, both vehicle speed and distance (p's < 0.001) significantly influenced road crossing decisions. However, no significant effects of fatigue were observed for visual perception or road crossing decisions (all p's > 0.26). This study demonstrated that individuals are sensitive to changes in vehicle speed and distance and respond to these changes in making road crossing decisions. In contrast to the embodied perception perspective, however, physical fatigue did not alter perceptual judgments of vehicle speed and distance nor did it influence road crossing decisions in a video-simulated road crossing environment.