How distraction affects pedestrian response: Evidence from behavior patterns and cortex oxyhemoglobin changes.

• Behavior patterns and fNIRS were used to investigate neurocognitive mechanisms of distraction affecting pedestrian response. • Pedestrians responded more slowly when distracted by phone calls or texting compared to when undistracted or listening to music. • Higher cognitive load distraction impacted pedestrians' response and resulted in higher activation in cortices related to the mode of distraction. • Pedestrian's response to traffic lights were impaired by visual distraction, resulting in higher activation in occipital and prefrontal cortices. • Pedestrian's responses to car horns were impaired by auditory distraction, resulting in higher activation in temporal areas. Distracted walking is a major cause of pedestrian road traffic injuries, but little is known about how distraction affects pedestrian safety. The study was designed to explore how visual and auditory distraction might influence pedestrian safety. Three experiments were conducted to explore causal mechanisms from two theoretical perspectives, increased cognitive load from the distraction task and resource competition in the same sensory modality. Pedestrians' behavior patterns and cortex oxyhemoglobin changes were recorded while they performed a series of dual tasks. Four primary results emerged: (a) participants responded more slowly to both visual and auditory stimuli in traffic, as well as walked more slowly, while talking on the phone or text messaging compared to when undistracted or listening to music; (b) when participants completed pedestrian response tasks while distracted with a high cognitive load, their response was significantly slower and poorer than when they carried out a lower cognitive load distraction task, (c) participants had higher levels of oxy-Hb change in cortices related to visual processing and executive function while distracted with a higher cognitive load; and (d) participants' responses to traffic lights were slower and resulted in a higher activation in prefrontal cortex and occipital areas when distracted by a visual distraction task compared to when distracted with an auditory task; similarly, brain activation increased significantly in temporal areas when participants responded to an auditory car horn task compared to when they responded to visual traffic lights. Both distracting cognitive load demands and the type of distraction task significantly affect young adult pedestrian performance and threaten pedestrian safety. Pedestrian injury prevention efforts should consider the effects of the type of distracting task and its cognitive demands on pedestrian safety. [ABSTRACT FROM AUTHOR]