When do facial emotions impact inhibitory control and response readiness? A gateway to understanding emotion processing

For the past 25 years, it has been widely believed that humans react automatically to emotional stimuli, as such responses are thought to be crucial for survival. However, recent empirical evidence from studies with healthy individuals suggests that the emotional valence of stimuli influences motor behavior only when it aligns with the individual's goals. In this review, we focused on research examining whether, when, and how emotional facial expressions influence reactive motor inhibition and response readiness in healthy young adults depending on their relevance to current goals. Following PRISMA guidelines, we identified 52 studies using the Stop-signal tasks and Go/No-go where participants responded with their hands or arms. After excluding 10 low-quality studies, 42 articles were retained for inclusion in our review. By selecting this subset of studies, we aimed to ensure consistency and comparability in the research. Despite the presence of several confounding factors that limit the interpretability of the findings, our results suggest that emotional stimuli do not influence motor behavior when they are irrelevant to the task. In contrast, when the emotional content is relevant to the task, the valence of emotional expressions tends to impact behavior. This effect is particularly evident in studies that employed within-subjects designs allowing to control for interindividual variability (n = 7). While further research is certainly needed, the current evidence suggests that emotional expressions do not automatically elicit behavioral responses. Instead, individual's current goals appear to play a pivotal role in determining how people respond to facial emotions.