Bilinguals have been found to possess cognitive advantages. But the nature of this advantage is unclear. While some evidence suggests that bilinguals have developed enhanced inhibitory control abilities, other evidence suggests that they possess enhanced attentional control abilities. In the current study, English monolingual and English–Chinese bilingual young adults were tested in three non-verbal conflict tasks (Flanker task, Spatial Stroop task and Simon task). Ex-Gaussian analyses were utilized to inspect response time distributions. The two participant groups showed comparable effects of stimulus-response congruency on the Gaussian part of response distributions (μ), but different effects on the distribution tails (τ), with reduced tails for bilingual speakers particularly in the more demanding incongruent condition. These results suggest that bilingual advantage emerges from better sustained attention and attentional monitoring rather than inhibition. We also discuss the usefulness of ex-Gaussian analyses.