Our stress system evolved to help us detect threats by narrowing the focus of our attention, facilitating swift decision making in threatening situations.
To find out whether threat-related decision making might be enhanced by stress, we exposed police officers to a stressful situation intended to increase their cortisol and then examined their decisions about whether or not to fire their weapon. In a computer simulation, they had to quickly decide whether or not to shoot armed and unarmed black and white male targets. Officers with greater increases in cortisol made fewer errors in their shooting decisions, particularly with black armed targets — those considered the most threatening based on societal stereotypes. Although studies have found that increases in cortisol can impair risky and moral decision making, we found that cortisol can enhance decision making when the task requires vigilance and attention to threat. These findings underscore the importance of understanding the nature of decision-making tasks when predicting the influence of stress.