A common behaviour in natural environments is foraging for rewards. However, this is often in the presence of predators. Therefore, one of the most fundamental decisions for humans, as for other animals, is how to apportion time between reward-motivated pursuit behaviour and threat-motivated checking behaviour. To understand how moment-to-moment emotions and both healthy-range and clinically-relevant traits promote or hinder the striking of this balance, we used a novel task in two large internet samples (n=374 and n=702). We found that people regulate task-evoked stress homeostatically by changing behaviour (increasing foraging). Individual differences, even in superficially related traits (apathy-anhedonia and anxiety-compulsive checking) reliably mapped onto unique behaviours. Worse task performance, due to maladaptive checking, was linked to gender (women: excessive checking) and specific anxiety-related traits: somatic anxiety (reduced checking due to worry) and compulsivity (disorganized checking). While anhedonia decreased self-reported task engagement, apathy improved task performance by reducing excessive checking.