Information processing in the blink of an eye : safety and safety-related perceptions under varying presentation times

One important function of street lighting is providing people with a sense of safety at night. Yet, little is understood of how street lighting affects people’s perceptions of safety and, on an even more basic level, how these perceptions come into existence. We present two studies in which we explore how much time people need to make accurate judgments of personal safety and prospect (i.e., overview over the environment) from photographs of night-time urban environments. A pilot study revealed a marginal response time difference between making a safety (~1100ms) and a prospect judgment (~900ms). This difference disappeared when participants made their judgments of safety after making the prospect judgments, indicating that judgments of prospect are perhaps used as a proxy for safety when prospect is highly salient. In a follow-up study we again presented participants photographs of safe and unsafe environments, but manipulated stimulus presentation time (SPT). We found that participants could correctly categorize scenes as safe or unsafe at a SPT of 50ms and, in line with the literature on gist perception, that longer SPTs did not significantly improve performance. Contrary to our expectations, safe environments were easier to categorize than unsafe environment. The findings from these studies extend the literature on gist perception to include complex appraisals of safety, while simultaneously opening up a whole new paradigm for studying environmental safety perceptions.