Indecision under time pressure arises from suboptimal switching behavior.

Indecisive behavior can be catastrophic, leading to car crashes or stock market losses. Despite fruitful efforts across several decades to understand decision making, there has been little research on what leads to indecision. Here, we examined how indecisions arise under high-pressure deadlines. In our first experiment, participants attempted to select a target by either reacting to a stimulus or guessing, when acting under a high-pressure time constraint. We found that participants were suboptimal, displaying a below chance win percentage due to an excessive number of indecisions. Computational modeling suggested that participants were excessively indecisive because they failed to account for a time delay and temporal uncertainty when switching from reacting to guessing, a phenomenon previously unreported in the literature. In a follow-up experiment, we provide direct evidence for a functionally relevant time delay and temporal uncertainty when switching from reacting to guessing. Collectively, our results indicate that participants failed to account for a time delay and temporal uncertainty associated with switching from reacting to guessing, leading to suboptimal and indecisive behavior.NEW & NOTEWORTHY Indecisive behavior is highly prevalent in many aspects of daily life. Despite its ubiquity, there has been very little focus and a lack of explanation for why indecisions occur. Here, we find under high time pressure scenarios that indecisions arise by misrepresenting additional time delays and temporal uncertainties associated when attempting to switch from reacting to guessing. Our novel paradigm presents a new way to elucidate and study indecisions.