Happy and threatening faces differentially influence facilitation and interference over time.

The influence of emotion on attention remains debated across competing theoretical models. Using a modified flanker task, this study examined how happy and threatening facial expressions modulate focused attention across early and late stages of task performance. In the neutral baseline, participants displayed classic flanker patterns—both facilitation and interference—in the early stage. While interference persisted into the late stage, facilitation dissipated, indicating a transient attentional benefit. Emotion conditions revealed distinct early-stage modulations. Happy faces selectively enhanced early-stage facilitation and reduced interference, whereas threat faces amplified early-stage interference and eliminated facilitation. In the late stage, facilitation disappeared across all conditions, while interference persisted. Comparatively, happy expressions enhanced early facilitation but showed no late-stage facilitation effects, while producing increased interference in the late stage; threat expressions consistently abolished facilitation across both stages and produced stronger early- than late-stage interference. Distributional analyses revealed that these temporal shifts were not simply mean-level changes but reflected stage-specific dynamics in selective attention and processing efficiency. Together, these findings challenge models predicting sustained emotional modulation and instead support transient attentional recalibration shaped by adaptation and habituation. This study underscores the value of integrating temporal and distributional approaches to capture how brief emotional signals reshape attention over time.