Anticipating the unknown: The stimulus-preceding negativity is enhanced by uncertain threat

Anticipating the future is an important psychological process that facilitates adaptive functioning. The stimulus preceding negativity (SPN) is an event-related potential index of anticipation that is elicited in the several hundred milliseconds before an outcome occurs. The SPN is elicited by emotional stimuli, such as electric shocks, and has been proposed to reflect emotional anticipation. To better characterize the functional significance of the SPN, the current study examined the effects of uncertain threat on SPN amplitude. Fifty-three participants from the community completed a task that compared the SPN when anticipating uncertain threat (a 50% chance of electric shock), certain threat (a 100% chance of electric shock), and safety (a 0% chance of electric shock). The SPN was enhanced by uncertain threat relative to certain threat and safety. Thus, the SPN appears to be specifically sensitive to uncertainty above and beyond threat. These results replicate and extend previous findings and inform theoretical accounts regarding the functional significance of the SPN. Furthermore, the findings highlight the utility of the SPN as a measure of anticipation and a tool for research on the effects of uncertainty, in line with recent calls for the development of additional laboratory-based measures of responding to uncertainty.