This cross-cultural investigation examined task engagement in matrix reasoning performance using the Matrix Reasoning Item Bank, an online measure that captures both accuracy and response time. In a sample of 458 participants from China and the United Kingdom, the study found strong psychometric properties across contexts but systematic between-group differences in performance. Chinese participants were generally slower and more accurate, while UK participants responded more quickly with lower overall accuracy. The findings suggest that cross-cultural differences in matrix reasoning may reflect not only performance levels, but also how participants allocate time, persist on difficult items, and sustain engagement during cognitively demanding reasoning tasks.