Risk propensity, or individuals' attitude toward risk, can highly impact individuals' decision-making in high-risk environments since those who merely focus on positive consequences associated with high-risk acts are more likely to engage in risk-taking behaviors. Previous studies identified activation in the prefrontal cortex during decision-making under risk to be a sign of an individual's attitude toward risks. To investigate whether such past work - prevalent in behavioral research domains - translates into construction safety, this study conducted an experiment in a mixed-reality environment using functional near-infrared spectroscopy (fNIRS) technology to examine whether positive risk attitudes cause individuals to adopt risky construction behaviors and whether the activation of the prefrontal cortex of the brain can represent such risk attitudes. The results show that participants with a higher risk propensity had a higher brain activation during the risky electrical tasks; these individuals merely focused on gains, which motivated them to increase their risk-taking behavior and consequently experience more electrical accidents. Understanding workers' attitudes toward risk will thus influence future understandings of decision behavior under risk.